Remove UB in linker script symbol <-> Rust handover

02_runtime_init/README.md

@@ -68,7 +68,7 @@ diff -uNr 01_wait_forever/src/bsp/raspberrypi/link.ld 02_runtime_init/src/bsp/ra
 +        __bss_start = .;
 +        *(.bss*);
 +        . = ALIGN(8);
-+        __bss_end = .;
++        __bss_end_inclusive = . - 8;
 +    }
 +
      /DISCARD/ : { *(.comment*) }
@@ -77,42 +77,37 @@ diff -uNr 01_wait_forever/src/bsp/raspberrypi/link.ld 02_runtime_init/src/bsp/ra
 diff -uNr 01_wait_forever/src/bsp/raspberrypi/memory.rs 02_runtime_init/src/bsp/raspberrypi/memory.rs
 --- 01_wait_forever/src/bsp/raspberrypi/memory.rs
 +++ 02_runtime_init/src/bsp/raspberrypi/memory.rs
-@@ -0,0 +1,36 @@
+@@ -0,0 +1,31 @@
 +// SPDX-License-Identifier: MIT OR Apache-2.0
 +//
 +// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
 +
 +//! BSP Memory Management.
 +
-+use core::ops::Range;
++use core::{cell::UnsafeCell, ops::RangeInclusive};
 +
 +//--------------------------------------------------------------------------------------------------
 +// Private Definitions
 +//--------------------------------------------------------------------------------------------------
 +
 +// Symbols from the linker script.
-+extern "C" {
-+    static __bss_start: usize;
-+    static __bss_end: usize;
++extern "Rust" {
++    static __bss_start: UnsafeCell<u64>;
++    static __bss_end_inclusive: UnsafeCell<u64>;
 +}
 +
 +//--------------------------------------------------------------------------------------------------
 +// Public Code
 +//--------------------------------------------------------------------------------------------------
 +
-+/// Return the range spanning the .bss section.
++/// Return the inclusive range spanning the .bss section.
 +///
 +/// # Safety
 +///
 +/// - Values are provided by the linker script and must be trusted as-is.
 +/// - The linker-provided addresses must be u64 aligned.
-+pub fn bss_range() -> Range<*mut u64> {
-+    unsafe {
-+        Range {
-+            start: &__bss_start as *const _ as *mut u64,
-+            end: &__bss_end as *const _ as *mut u64,
-+        }
-+    }
++pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
++    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 +}
 
 diff -uNr 01_wait_forever/src/bsp/raspberrypi.rs 02_runtime_init/src/bsp/raspberrypi.rs
@@ -155,34 +150,39 @@ diff -uNr 01_wait_forever/src/main.rs 02_runtime_init/src/main.rs
 diff -uNr 01_wait_forever/src/memory.rs 02_runtime_init/src/memory.rs
 --- 01_wait_forever/src/memory.rs
 +++ 02_runtime_init/src/memory.rs
-@@ -0,0 +1,29 @@
+@@ -0,0 +1,34 @@
 +// SPDX-License-Identifier: MIT OR Apache-2.0
 +//
 +// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
 +
 +//! Memory Management.
 +
-+use core::ops::Range;
++use core::ops::RangeInclusive;
 +
 +//--------------------------------------------------------------------------------------------------
 +// Public Code
 +//--------------------------------------------------------------------------------------------------
 +
-+/// Zero out a memory range.
++/// Zero out an inclusive memory range.
 +///
 +/// # Safety
 +///
 +/// - `range.start` and `range.end` must be valid.
 +/// - `range.start` and `range.end` must be `T` aligned.
-+pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
++pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 +where
 +    T: From<u8>,
 +{
-+    let mut ptr = range.start;
++    let mut ptr = *range.start();
++    let end_inclusive = *range.end();
 +
-+    while ptr < range.end {
++    loop {
 +        core::ptr::write_volatile(ptr, T::from(0));
 +        ptr = ptr.offset(1);
++
++        if ptr > end_inclusive {
++            break;
++        }
 +    }
 +}
 
@@ -209,7 +209,7 @@ diff -uNr 01_wait_forever/src/runtime_init.rs 02_runtime_init/src/runtime_init.r
 +/// - Must only be called pre `kernel_init()`.
 +#[inline(always)]
 +unsafe fn zero_bss() {
-+    memory::zero_volatile(bsp::memory::bss_range());
++    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 +}
 +
 +//--------------------------------------------------------------------------------------------------

02_runtime_init/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

02_runtime_init/src/bsp/raspberrypi/memory.rs

@@ -4,33 +4,28 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

02_runtime_init/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

02_runtime_init/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

03_hacky_hello_world/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

03_hacky_hello_world/src/bsp/raspberrypi/memory.rs

@@ -4,33 +4,28 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

03_hacky_hello_world/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

03_hacky_hello_world/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

04_zero_overhead_abstraction/README.md

@@ -180,7 +180,7 @@ diff -uNr 03_hacky_hello_world/src/bsp/raspberrypi/memory.rs 04_zero_overhead_ab
 +    map::BOOT_CORE_STACK_END
 +}
 +
- /// Return the range spanning the .bss section.
+ /// Return the inclusive range spanning the .bss section.
  ///
  /// # Safety
 

04_zero_overhead_abstraction/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

04_zero_overhead_abstraction/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -36,17 +36,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

04_zero_overhead_abstraction/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

04_zero_overhead_abstraction/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

05_safe_globals/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

05_safe_globals/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -36,17 +36,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

05_safe_globals/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

05_safe_globals/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

06_drivers_gpio_uart/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

06_drivers_gpio_uart/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -59,17 +59,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

06_drivers_gpio_uart/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

06_drivers_gpio_uart/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

07_uart_chainloader/README.md

@@ -263,7 +263,7 @@ diff -uNr 06_drivers_gpio_uart/src/bsp/raspberrypi/link.ld 07_uart_chainloader/s
      {
          *(.text._start) *(.text*)
 @@ -32,5 +33,14 @@
-         __bss_end = .;
+         __bss_end_inclusive = . - 8;
      }
 
 +    .got :
@@ -307,7 +307,7 @@ diff -uNr 06_drivers_gpio_uart/src/bsp/raspberrypi/memory.rs 07_uart_chainloader
 +    map::BOARD_DEFAULT_LOAD_ADDRESS
 +}
 +
- /// Return the range spanning the .bss section.
+ /// Return the inclusive range spanning the .bss section.
  ///
  /// # Safety
 

07_uart_chainloader/src/bsp/raspberrypi/link.ld

@@ -30,7 +30,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     .got :

07_uart_chainloader/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -67,17 +67,12 @@ pub fn board_default_load_addr() -> usize {
     map::BOARD_DEFAULT_LOAD_ADDRESS
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

07_uart_chainloader/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

07_uart_chainloader/src/runtime_init.rs

@@ -51,7 +51,7 @@ impl RunTimeInit for Traitor {}
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

08_timestamps/README.md

@@ -263,7 +263,7 @@ diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/link.ld 08_timestamps/src/bsp/
      {
          *(.text._start) *(.text*)
 @@ -33,14 +32,5 @@
-         __bss_end = .;
+         __bss_end_inclusive = . - 8;
      }
 
 -    .got :
@@ -307,7 +307,7 @@ diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/memory.rs 08_timestamps/src/bs
 -    map::BOARD_DEFAULT_LOAD_ADDRESS
 -}
 -
- /// Return the range spanning the .bss section.
+ /// Return the inclusive range spanning the .bss section.
  ///
  /// # Safety
 

08_timestamps/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

08_timestamps/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -59,17 +59,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

08_timestamps/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

08_timestamps/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

09_hw_debug_JTAG/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

09_hw_debug_JTAG/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -59,17 +59,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

09_hw_debug_JTAG/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

09_hw_debug_JTAG/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

10_privilege_level/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

10_privilege_level/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -59,17 +59,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

10_privilege_level/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

10_privilege_level/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

11_virtual_mem_part1_identity_mapping/README.md

@@ -152,8 +152,8 @@ type ArchTranslationTable = FixedSizeTranslationTable<NUM_LVL2_TABLES>;
 ///
 /// # Safety
 ///
-/// - Supposed to land in `.bss`. Therefore, ensure that they boil down to all "0" entries.
-static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
+/// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
+static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 ```
 
 They are populated using `bsp::memory::mmu::virt_mem_layout().virt_addr_properties()` and a bunch of
@@ -443,7 +443,7 @@ diff -uNr 10_privilege_level/src/_arch/aarch64/memory/mmu.rs 11_virtual_mem_part
 +/// # Safety
 +///
 +/// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
-+static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
++static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 +
 +static MMU: MemoryManagementUnit = MemoryManagementUnit;
 +
@@ -559,10 +559,10 @@ diff -uNr 10_privilege_level/src/_arch/aarch64/memory/mmu.rs 11_virtual_mem_part
 +///
 +/// - Modifies a `static mut`. Ensure it only happens from here.
 +unsafe fn populate_tt_entries() -> Result<(), &'static str> {
-+    for (l2_nr, l2_entry) in TABLES.lvl2.iter_mut().enumerate() {
-+        *l2_entry = TABLES.lvl3[l2_nr].base_addr_usize().into();
++    for (l2_nr, l2_entry) in KERNEL_TABLES.lvl2.iter_mut().enumerate() {
++        *l2_entry = KERNEL_TABLES.lvl3[l2_nr].base_addr_usize().into();
 +
-+        for (l3_nr, l3_entry) in TABLES.lvl3[l2_nr].iter_mut().enumerate() {
++        for (l3_nr, l3_entry) in KERNEL_TABLES.lvl3[l2_nr].iter_mut().enumerate() {
 +            let virt_addr = (l2_nr << FIVETWELVE_MIB_SHIFT) + (l3_nr << SIXTYFOUR_KIB_SHIFT);
 +
 +            let (output_addr, attribute_fields) =
@@ -618,7 +618,7 @@ diff -uNr 10_privilege_level/src/_arch/aarch64/memory/mmu.rs 11_virtual_mem_part
 +        populate_tt_entries()?;
 +
 +        // Set the "Translation Table Base Register".
-+        TTBR0_EL1.set_baddr(TABLES.lvl2.base_addr_u64());
++        TTBR0_EL1.set_baddr(KERNEL_TABLES.lvl2.base_addr_u64());
 +
 +        configure_translation_control();
 +
@@ -760,18 +760,18 @@ diff -uNr 10_privilege_level/src/bsp/raspberrypi/memory.rs 11_virtual_mem_part1_
 
 +pub mod mmu;
 +
- use core::ops::Range;
+ use core::{cell::UnsafeCell, ops::RangeInclusive};
 
  //--------------------------------------------------------------------------------------------------
-@@ -12,6 +14,8 @@
-
- // Symbols from the linker script.
- extern "C" {
-+    static __ro_start: usize;
-+    static __ro_end: usize;
-     static __bss_start: usize;
-     static __bss_end: usize;
+@@ -14,6 +16,8 @@
+ extern "Rust" {
+     static __bss_start: UnsafeCell<u64>;
+     static __bss_end_inclusive: UnsafeCell<u64>;
++    static __ro_start: UnsafeCell<()>;
++    static __ro_end: UnsafeCell<()>;
  }
+
+ //--------------------------------------------------------------------------------------------------
 @@ -23,6 +27,8 @@
  /// The board's memory map.
  #[rustfmt::skip]
@@ -808,7 +808,7 @@ diff -uNr 10_privilege_level/src/bsp/raspberrypi/memory.rs 11_virtual_mem_part1_
 +/// - Value is provided by the linker script and must be trusted as-is.
 +#[inline(always)]
 +fn ro_start() -> usize {
-+    unsafe { &__ro_start as *const _ as usize }
++    unsafe { __ro_start.get() as usize }
 +}
 +
 +/// Size of the Read-Only (RO) range of the kernel binary.
@@ -818,7 +818,7 @@ diff -uNr 10_privilege_level/src/bsp/raspberrypi/memory.rs 11_virtual_mem_part1_
 +/// - Value is provided by the linker script and must be trusted as-is.
 +#[inline(always)]
 +fn ro_end() -> usize {
-+    unsafe { &__ro_end as *const _ as usize }
++    unsafe { __ro_end.get() as usize }
 +}
 +
 +//--------------------------------------------------------------------------------------------------
@@ -1123,7 +1123,7 @@ diff -uNr 10_privilege_level/src/memory.rs 11_virtual_mem_part1_identity_mapping
 
 +pub mod mmu;
 +
- use core::ops::Range;
+ use core::ops::RangeInclusive;
 
  //--------------------------------------------------------------------------------------------------
 

11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/memory/mmu.rs

@@ -138,7 +138,7 @@ struct MemoryManagementUnit;
 /// # Safety
 ///
 /// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
-static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
+static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 
 static MMU: MemoryManagementUnit = MemoryManagementUnit;
 
@@ -254,10 +254,10 @@ fn set_up_mair() {
 ///
 /// - Modifies a `static mut`. Ensure it only happens from here.
 unsafe fn populate_tt_entries() -> Result<(), &'static str> {
-    for (l2_nr, l2_entry) in TABLES.lvl2.iter_mut().enumerate() {
-        *l2_entry = TABLES.lvl3[l2_nr].base_addr_usize().into();
+    for (l2_nr, l2_entry) in KERNEL_TABLES.lvl2.iter_mut().enumerate() {
+        *l2_entry = KERNEL_TABLES.lvl3[l2_nr].base_addr_usize().into();
 
-        for (l3_nr, l3_entry) in TABLES.lvl3[l2_nr].iter_mut().enumerate() {
+        for (l3_nr, l3_entry) in KERNEL_TABLES.lvl3[l2_nr].iter_mut().enumerate() {
             let virt_addr = (l2_nr << FIVETWELVE_MIB_SHIFT) + (l3_nr << SIXTYFOUR_KIB_SHIFT);
 
             let (output_addr, attribute_fields) =
@@ -313,7 +313,7 @@ impl memory::mmu::interface::MMU for MemoryManagementUnit {
         populate_tt_entries()?;
 
         // Set the "Translation Table Base Register".
-        TTBR0_EL1.set_baddr(TABLES.lvl2.base_addr_u64());
+        TTBR0_EL1.set_baddr(KERNEL_TABLES.lvl2.base_addr_u64());
 
         configure_translation_control();
 

11_virtual_mem_part1_identity_mapping/src/bsp/raspberrypi/link.ld

@@ -32,7 +32,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

11_virtual_mem_part1_identity_mapping/src/bsp/raspberrypi/memory.rs

@@ -6,18 +6,18 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __ro_start: usize;
-    static __ro_end: usize;
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
+    static __ro_start: UnsafeCell<()>;
+    static __ro_end: UnsafeCell<()>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -68,7 +68,7 @@ pub(super) mod map {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_start() -> usize {
-    unsafe { &__ro_start as *const _ as usize }
+    unsafe { __ro_start.get() as usize }
 }
 
 /// Size of the Read-Only (RO) range of the kernel binary.
@@ -78,7 +78,7 @@ fn ro_start() -> usize {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_end() -> usize {
-    unsafe { &__ro_end as *const _ as usize }
+    unsafe { __ro_end.get() as usize }
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -91,17 +91,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

11_virtual_mem_part1_identity_mapping/src/memory.rs

@@ -6,26 +6,31 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

11_virtual_mem_part1_identity_mapping/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

12_exceptions_part1_groundwork/README.md

@@ -486,7 +486,7 @@ diff -uNr 11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/exception.rs 1
  //! Architectural synchronous and asynchronous exception handling.
 
 -use cortex_a::regs::*;
-+use core::fmt;
++use core::{cell::UnsafeCell, fmt};
 +use cortex_a::{asm, barrier, regs::*};
 +use register::InMemoryRegister;
 +
@@ -713,7 +713,7 @@ diff -uNr 11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/exception.rs 1
 
  //--------------------------------------------------------------------------------------------------
  // Public Code
-@@ -21,3 +244,24 @@
+@@ -21,3 +244,23 @@
          _ => (PrivilegeLevel::Unknown, "Unknown"),
      }
  }
@@ -728,12 +728,11 @@ diff -uNr 11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/exception.rs 1
 +///   Manual.
 +pub unsafe fn handling_init() {
 +    // Provided by exception.S.
-+    extern "C" {
-+        static mut __exception_vector_start: u64;
++    extern "Rust" {
++        static __exception_vector_start: UnsafeCell<()>;
 +    }
-+    let addr: u64 = &__exception_vector_start as *const _ as u64;
 +
-+    VBAR_EL1.set(addr);
++    VBAR_EL1.set(__exception_vector_start.get() as u64);
 +
 +    // Force VBAR update to complete before next instruction.
 +    barrier::isb(barrier::SY);

12_exceptions_part1_groundwork/src/_arch/aarch64/exception.rs

@@ -4,7 +4,7 @@
 
 //! Architectural synchronous and asynchronous exception handling.
 
-use core::fmt;
+use core::{cell::UnsafeCell, fmt};
 use cortex_a::{asm, barrier, regs::*};
 use register::InMemoryRegister;
 
@@ -255,12 +255,11 @@ pub fn current_privilege_level() -> (PrivilegeLevel, &'static str) {
 ///   Manual.
 pub unsafe fn handling_init() {
     // Provided by exception.S.
-    extern "C" {
-        static mut __exception_vector_start: u64;
+    extern "Rust" {
+        static __exception_vector_start: UnsafeCell<()>;
     }
-    let addr: u64 = &__exception_vector_start as *const _ as u64;
 
-    VBAR_EL1.set(addr);
+    VBAR_EL1.set(__exception_vector_start.get() as u64);
 
     // Force VBAR update to complete before next instruction.
     barrier::isb(barrier::SY);

12_exceptions_part1_groundwork/src/_arch/aarch64/memory/mmu.rs

@@ -138,7 +138,7 @@ struct MemoryManagementUnit;
 /// # Safety
 ///
 /// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
-static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
+static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 
 static MMU: MemoryManagementUnit = MemoryManagementUnit;
 
@@ -254,10 +254,10 @@ fn set_up_mair() {
 ///
 /// - Modifies a `static mut`. Ensure it only happens from here.
 unsafe fn populate_tt_entries() -> Result<(), &'static str> {
-    for (l2_nr, l2_entry) in TABLES.lvl2.iter_mut().enumerate() {
-        *l2_entry = TABLES.lvl3[l2_nr].base_addr_usize().into();
+    for (l2_nr, l2_entry) in KERNEL_TABLES.lvl2.iter_mut().enumerate() {
+        *l2_entry = KERNEL_TABLES.lvl3[l2_nr].base_addr_usize().into();
 
-        for (l3_nr, l3_entry) in TABLES.lvl3[l2_nr].iter_mut().enumerate() {
+        for (l3_nr, l3_entry) in KERNEL_TABLES.lvl3[l2_nr].iter_mut().enumerate() {
             let virt_addr = (l2_nr << FIVETWELVE_MIB_SHIFT) + (l3_nr << SIXTYFOUR_KIB_SHIFT);
 
             let (output_addr, attribute_fields) =
@@ -313,7 +313,7 @@ impl memory::mmu::interface::MMU for MemoryManagementUnit {
         populate_tt_entries()?;
 
         // Set the "Translation Table Base Register".
-        TTBR0_EL1.set_baddr(TABLES.lvl2.base_addr_u64());
+        TTBR0_EL1.set_baddr(KERNEL_TABLES.lvl2.base_addr_u64());
 
         configure_translation_control();
 

12_exceptions_part1_groundwork/src/bsp/raspberrypi/link.ld

@@ -37,7 +37,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

12_exceptions_part1_groundwork/src/bsp/raspberrypi/memory.rs

@@ -6,18 +6,18 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __ro_start: usize;
-    static __ro_end: usize;
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
+    static __ro_start: UnsafeCell<()>;
+    static __ro_end: UnsafeCell<()>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -68,7 +68,7 @@ pub(super) mod map {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_start() -> usize {
-    unsafe { &__ro_start as *const _ as usize }
+    unsafe { __ro_start.get() as usize }
 }
 
 /// Size of the Read-Only (RO) range of the kernel binary.
@@ -78,7 +78,7 @@ fn ro_start() -> usize {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_end() -> usize {
-    unsafe { &__ro_end as *const _ as usize }
+    unsafe { __ro_end.get() as usize }
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -91,17 +91,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

12_exceptions_part1_groundwork/src/memory.rs

@@ -6,26 +6,31 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

12_exceptions_part1_groundwork/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------

13_integrated_testing/README.md

@@ -720,14 +720,17 @@ RUSTFLAGS="-C link-arg=-Tsrc/bsp/raspberrypi/link.ld -C target-cpu=cortex-a53 -D
     Finished release [optimized] target(s) in 0.01s
      Running target/aarch64-unknown-none-softfloat/release/deps/libkernel-4cc6412ddf631982
          -------------------------------------------------------------------
-         🦀 Running 5 tests
+         🦀 Running 8 tests
          -------------------------------------------------------------------
 
-           1. bss_section_is_sane.......................................[ok]
-           2. virt_mem_layout_sections_are_64KiB_aligned................[ok]
-           3. virt_mem_layout_has_no_overlaps...........................[ok]
-           4. test_runner_executes_in_kernel_mode.......................[ok]
-           5. zero_volatile_works.......................................[ok]
+           1. virt_mem_layout_sections_are_64KiB_aligned................[ok]
+           2. virt_mem_layout_has_no_overlaps...........................[ok]
+           3. test_runner_executes_in_kernel_mode.......................[ok]
+           4. size_of_tabledescriptor_equals_64_bit.....................[ok]
+           5. size_of_pagedescriptor_equals_64_bit......................[ok]
+           6. kernel_tables_in_bss......................................[ok]
+           7. zero_volatile_works.......................................[ok]
+           8. bss_section_is_sane.......................................[ok]
 
          -------------------------------------------------------------------
          ✅ Success: libkernel
@@ -974,7 +977,7 @@ diff -uNr 12_exceptions_part1_groundwork/src/_arch/aarch64/exception.rs 13_integ
 @@ -5,7 +5,7 @@
  //! Architectural synchronous and asynchronous exception handling.
 
- use core::fmt;
+ use core::{cell::UnsafeCell, fmt};
 -use cortex_a::{asm, barrier, regs::*};
 +use cortex_a::{barrier, regs::*};
  use register::InMemoryRegister;
@@ -998,6 +1001,51 @@ diff -uNr 12_exceptions_part1_groundwork/src/_arch/aarch64/exception.rs 13_integ
  }
 
 
+diff -uNr 12_exceptions_part1_groundwork/src/_arch/aarch64/memory/mmu.rs 13_integrated_testing/src/_arch/aarch64/memory/mmu.rs
+--- 12_exceptions_part1_groundwork/src/_arch/aarch64/memory/mmu.rs
++++ 13_integrated_testing/src/_arch/aarch64/memory/mmu.rs
+@@ -331,3 +331,40 @@
+         Ok(())
+     }
+ }
++
++//--------------------------------------------------------------------------------------------------
++// Testing
++//--------------------------------------------------------------------------------------------------
++
++#[cfg(test)]
++mod tests {
++    use super::*;
++    use test_macros::kernel_test;
++
++    /// Check if the size of `struct TableDescriptor` is as expected.
++    #[kernel_test]
++    fn size_of_tabledescriptor_equals_64_bit() {
++        assert_eq!(
++            core::mem::size_of::<TableDescriptor>(),
++            core::mem::size_of::<u64>()
++        );
++    }
++
++    /// Check if the size of `struct PageDescriptor` is as expected.
++    #[kernel_test]
++    fn size_of_pagedescriptor_equals_64_bit() {
++        assert_eq!(
++            core::mem::size_of::<PageDescriptor>(),
++            core::mem::size_of::<u64>()
++        );
++    }
++
++    /// Check if KERNEL_TABLES is in .bss.
++    #[kernel_test]
++    fn kernel_tables_in_bss() {
++        let bss_range = bsp::memory::bss_range_inclusive();
++        let kernel_tables_addr = unsafe { &KERNEL_TABLES as *const _ as usize as *mut u64 };
++
++        assert!(bss_range.contains(&kernel_tables_addr));
++    }
++}
+
 diff -uNr 12_exceptions_part1_groundwork/src/bsp/raspberrypi/console.rs 13_integrated_testing/src/bsp/raspberrypi/console.rs
 --- 12_exceptions_part1_groundwork/src/bsp/raspberrypi/console.rs
 +++ 13_integrated_testing/src/bsp/raspberrypi/console.rs
@@ -1478,8 +1526,8 @@ diff -uNr 12_exceptions_part1_groundwork/src/memory/mmu.rs 13_integrated_testing
 diff -uNr 12_exceptions_part1_groundwork/src/memory.rs 13_integrated_testing/src/memory.rs
 --- 12_exceptions_part1_groundwork/src/memory.rs
 +++ 13_integrated_testing/src/memory.rs
-@@ -29,3 +29,24 @@
-         ptr = ptr.offset(1);
+@@ -34,3 +34,40 @@
+         }
      }
  }
 +
@@ -1497,11 +1545,27 @@ diff -uNr 12_exceptions_part1_groundwork/src/memory.rs 13_integrated_testing/src
 +    fn zero_volatile_works() {
 +        let mut x: [usize; 3] = [10, 11, 12];
 +        let x_range = x.as_mut_ptr_range();
++        let x_range_inclusive =
++            RangeInclusive::new(x_range.start, unsafe { x_range.end.offset(-1) });
 +
-+        unsafe { zero_volatile(x_range) };
++        unsafe { zero_volatile(x_range_inclusive) };
 +
 +        assert_eq!(x, [0, 0, 0]);
 +    }
++
++    /// Check `bss` section layout.
++    #[kernel_test]
++    fn bss_section_is_sane() {
++        use crate::bsp::memory::bss_range_inclusive;
++        use core::mem;
++
++        let start = *bss_range_inclusive().start() as usize;
++        let end = *bss_range_inclusive().end() as usize;
++
++        assert_eq!(start modulo mem::size_of::<usize>(), 0);
++        assert_eq!(end modulo mem::size_of::<usize>(), 0);
++        assert!(end >= start);
++    }
 +}
 
 diff -uNr 12_exceptions_part1_groundwork/src/panic_wait.rs 13_integrated_testing/src/panic_wait.rs
@@ -1553,40 +1617,18 @@ diff -uNr 12_exceptions_part1_groundwork/src/panic_wait.rs 13_integrated_testing
 diff -uNr 12_exceptions_part1_groundwork/src/runtime_init.rs 13_integrated_testing/src/runtime_init.rs
 --- 12_exceptions_part1_groundwork/src/runtime_init.rs
 +++ 13_integrated_testing/src/runtime_init.rs
-@@ -31,7 +31,33 @@
+@@ -31,7 +31,10 @@
  ///
  /// - Only a single core must be active and running this function.
  pub unsafe fn runtime_init() -> ! {
+-    zero_bss();
 +    extern "Rust" {
 +        fn kernel_init() -> !;
 +    }
-+
-     zero_bss();
-+    kernel_init()
-+}
-+
-+//--------------------------------------------------------------------------------------------------
-+// Testing
-+//--------------------------------------------------------------------------------------------------
-+
-+#[cfg(test)]
-+mod tests {
-+    use super::*;
-+    use test_macros::kernel_test;
-+
-+    /// Check `bss` section layout.
-+    #[kernel_test]
-+    fn bss_section_is_sane() {
-+        use core::mem;
-+
-+        let start = bsp::memory::bss_range().start as *const _ as usize;
-+        let end = bsp::memory::bss_range().end as *const _ as usize;
 
 -    crate::kernel_init()
-+        assert_eq!(start modulo mem::size_of::<usize>(), 0);
-+        assert_eq!(end modulo mem::size_of::<usize>(), 0);
-+        assert!(end >= start);
-+    }
++    zero_bss();
++    kernel_init()
  }
 
 diff -uNr 12_exceptions_part1_groundwork/test-macros/Cargo.toml 13_integrated_testing/test-macros/Cargo.toml

13_integrated_testing/src/_arch/aarch64/exception.rs

@@ -4,7 +4,7 @@
 
 //! Architectural synchronous and asynchronous exception handling.
 
-use core::fmt;
+use core::{cell::UnsafeCell, fmt};
 use cortex_a::{barrier, regs::*};
 use register::InMemoryRegister;
 
@@ -245,12 +245,11 @@ pub fn current_privilege_level() -> (PrivilegeLevel, &'static str) {
 ///   Manual.
 pub unsafe fn handling_init() {
     // Provided by exception.S.
-    extern "C" {
-        static mut __exception_vector_start: u64;
+    extern "Rust" {
+        static __exception_vector_start: UnsafeCell<()>;
     }
-    let addr: u64 = &__exception_vector_start as *const _ as u64;
 
-    VBAR_EL1.set(addr);
+    VBAR_EL1.set(__exception_vector_start.get() as u64);
 
     // Force VBAR update to complete before next instruction.
     barrier::isb(barrier::SY);

13_integrated_testing/src/_arch/aarch64/memory/mmu.rs

@@ -138,7 +138,7 @@ struct MemoryManagementUnit;
 /// # Safety
 ///
 /// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
-static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
+static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 
 static MMU: MemoryManagementUnit = MemoryManagementUnit;
 
@@ -254,10 +254,10 @@ fn set_up_mair() {
 ///
 /// - Modifies a `static mut`. Ensure it only happens from here.
 unsafe fn populate_tt_entries() -> Result<(), &'static str> {
-    for (l2_nr, l2_entry) in TABLES.lvl2.iter_mut().enumerate() {
-        *l2_entry = TABLES.lvl3[l2_nr].base_addr_usize().into();
+    for (l2_nr, l2_entry) in KERNEL_TABLES.lvl2.iter_mut().enumerate() {
+        *l2_entry = KERNEL_TABLES.lvl3[l2_nr].base_addr_usize().into();
 
-        for (l3_nr, l3_entry) in TABLES.lvl3[l2_nr].iter_mut().enumerate() {
+        for (l3_nr, l3_entry) in KERNEL_TABLES.lvl3[l2_nr].iter_mut().enumerate() {
             let virt_addr = (l2_nr << FIVETWELVE_MIB_SHIFT) + (l3_nr << SIXTYFOUR_KIB_SHIFT);
 
             let (output_addr, attribute_fields) =
@@ -313,7 +313,7 @@ impl memory::mmu::interface::MMU for MemoryManagementUnit {
         populate_tt_entries()?;
 
         // Set the "Translation Table Base Register".
-        TTBR0_EL1.set_baddr(TABLES.lvl2.base_addr_u64());
+        TTBR0_EL1.set_baddr(KERNEL_TABLES.lvl2.base_addr_u64());
 
         configure_translation_control();
 
@@ -331,3 +331,40 @@ impl memory::mmu::interface::MMU for MemoryManagementUnit {
         Ok(())
     }
 }
+
+//--------------------------------------------------------------------------------------------------
+// Testing
+//--------------------------------------------------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use test_macros::kernel_test;
+
+    /// Check if the size of `struct TableDescriptor` is as expected.
+    #[kernel_test]
+    fn size_of_tabledescriptor_equals_64_bit() {
+        assert_eq!(
+            core::mem::size_of::<TableDescriptor>(),
+            core::mem::size_of::<u64>()
+        );
+    }
+
+    /// Check if the size of `struct PageDescriptor` is as expected.
+    #[kernel_test]
+    fn size_of_pagedescriptor_equals_64_bit() {
+        assert_eq!(
+            core::mem::size_of::<PageDescriptor>(),
+            core::mem::size_of::<u64>()
+        );
+    }
+
+    /// Check if KERNEL_TABLES is in .bss.
+    #[kernel_test]
+    fn kernel_tables_in_bss() {
+        let bss_range = bsp::memory::bss_range_inclusive();
+        let kernel_tables_addr = unsafe { &KERNEL_TABLES as *const _ as usize as *mut u64 };
+
+        assert!(bss_range.contains(&kernel_tables_addr));
+    }
+}

13_integrated_testing/src/bsp/raspberrypi/link.ld

@@ -37,7 +37,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

13_integrated_testing/src/bsp/raspberrypi/memory.rs

@@ -6,18 +6,18 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __ro_start: usize;
-    static __ro_end: usize;
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
+    static __ro_start: UnsafeCell<()>;
+    static __ro_end: UnsafeCell<()>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -68,7 +68,7 @@ pub(super) mod map {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_start() -> usize {
-    unsafe { &__ro_start as *const _ as usize }
+    unsafe { __ro_start.get() as usize }
 }
 
 /// Size of the Read-Only (RO) range of the kernel binary.
@@ -78,7 +78,7 @@ fn ro_start() -> usize {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_end() -> usize {
-    unsafe { &__ro_end as *const _ as usize }
+    unsafe { __ro_end.get() as usize }
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -91,17 +91,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

13_integrated_testing/src/memory.rs

@@ -6,27 +6,32 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }
 
@@ -44,9 +49,25 @@ mod tests {
     fn zero_volatile_works() {
         let mut x: [usize; 3] = [10, 11, 12];
         let x_range = x.as_mut_ptr_range();
+        let x_range_inclusive =
+            RangeInclusive::new(x_range.start, unsafe { x_range.end.offset(-1) });
 
-        unsafe { zero_volatile(x_range) };
+        unsafe { zero_volatile(x_range_inclusive) };
 
         assert_eq!(x, [0, 0, 0]);
     }
+
+    /// Check `bss` section layout.
+    #[kernel_test]
+    fn bss_section_is_sane() {
+        use crate::bsp::memory::bss_range_inclusive;
+        use core::mem;
+
+        let start = *bss_range_inclusive().start() as usize;
+        let end = *bss_range_inclusive().end() as usize;
+
+        assert_eq!(start % mem::size_of::<usize>(), 0);
+        assert_eq!(end % mem::size_of::<usize>(), 0);
+        assert!(end >= start);
+    }
 }

13_integrated_testing/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -38,26 +38,3 @@ pub unsafe fn runtime_init() -> ! {
     zero_bss();
     kernel_init()
 }
-
-//--------------------------------------------------------------------------------------------------
-// Testing
-//--------------------------------------------------------------------------------------------------
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use test_macros::kernel_test;
-
-    /// Check `bss` section layout.
-    #[kernel_test]
-    fn bss_section_is_sane() {
-        use core::mem;
-
-        let start = bsp::memory::bss_range().start as *const _ as usize;
-        let end = bsp::memory::bss_range().end as *const _ as usize;
-
-        assert_eq!(start % mem::size_of::<usize>(), 0);
-        assert_eq!(end % mem::size_of::<usize>(), 0);
-        assert!(end >= start);
-    }
-}

14_exceptions_part2_peripheral_IRQs/README.md

@@ -853,7 +853,7 @@ diff -uNr 13_integrated_testing/src/_arch/aarch64/exception.rs 14_exceptions_par
  //! Architectural synchronous and asynchronous exception handling.
 
 +use crate::{bsp, exception};
- use core::fmt;
+ use core::{cell::UnsafeCell, fmt};
  use cortex_a::{barrier, regs::*};
  use register::InMemoryRegister;
 @@ -84,8 +85,11 @@

14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/exception.rs

@@ -5,7 +5,7 @@
 //! Architectural synchronous and asynchronous exception handling.
 
 use crate::{bsp, exception};
-use core::fmt;
+use core::{cell::UnsafeCell, fmt};
 use cortex_a::{barrier, regs::*};
 use register::InMemoryRegister;
 
@@ -249,12 +249,11 @@ pub fn current_privilege_level() -> (PrivilegeLevel, &'static str) {
 ///   Manual.
 pub unsafe fn handling_init() {
     // Provided by exception.S.
-    extern "C" {
-        static mut __exception_vector_start: u64;
+    extern "Rust" {
+        static __exception_vector_start: UnsafeCell<()>;
     }
-    let addr: u64 = &__exception_vector_start as *const _ as u64;
 
-    VBAR_EL1.set(addr);
+    VBAR_EL1.set(__exception_vector_start.get() as u64);
 
     // Force VBAR update to complete before next instruction.
     barrier::isb(barrier::SY);

14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/memory/mmu.rs

@@ -138,7 +138,7 @@ struct MemoryManagementUnit;
 /// # Safety
 ///
 /// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
-static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
+static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 
 static MMU: MemoryManagementUnit = MemoryManagementUnit;
 
@@ -254,10 +254,10 @@ fn set_up_mair() {
 ///
 /// - Modifies a `static mut`. Ensure it only happens from here.
 unsafe fn populate_tt_entries() -> Result<(), &'static str> {
-    for (l2_nr, l2_entry) in TABLES.lvl2.iter_mut().enumerate() {
-        *l2_entry = TABLES.lvl3[l2_nr].base_addr_usize().into();
+    for (l2_nr, l2_entry) in KERNEL_TABLES.lvl2.iter_mut().enumerate() {
+        *l2_entry = KERNEL_TABLES.lvl3[l2_nr].base_addr_usize().into();
 
-        for (l3_nr, l3_entry) in TABLES.lvl3[l2_nr].iter_mut().enumerate() {
+        for (l3_nr, l3_entry) in KERNEL_TABLES.lvl3[l2_nr].iter_mut().enumerate() {
             let virt_addr = (l2_nr << FIVETWELVE_MIB_SHIFT) + (l3_nr << SIXTYFOUR_KIB_SHIFT);
 
             let (output_addr, attribute_fields) =
@@ -313,7 +313,7 @@ impl memory::mmu::interface::MMU for MemoryManagementUnit {
         populate_tt_entries()?;
 
         // Set the "Translation Table Base Register".
-        TTBR0_EL1.set_baddr(TABLES.lvl2.base_addr_u64());
+        TTBR0_EL1.set_baddr(KERNEL_TABLES.lvl2.base_addr_u64());
 
         configure_translation_control();
 
@@ -331,3 +331,40 @@ impl memory::mmu::interface::MMU for MemoryManagementUnit {
         Ok(())
     }
 }
+
+//--------------------------------------------------------------------------------------------------
+// Testing
+//--------------------------------------------------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use test_macros::kernel_test;
+
+    /// Check if the size of `struct TableDescriptor` is as expected.
+    #[kernel_test]
+    fn size_of_tabledescriptor_equals_64_bit() {
+        assert_eq!(
+            core::mem::size_of::<TableDescriptor>(),
+            core::mem::size_of::<u64>()
+        );
+    }
+
+    /// Check if the size of `struct PageDescriptor` is as expected.
+    #[kernel_test]
+    fn size_of_pagedescriptor_equals_64_bit() {
+        assert_eq!(
+            core::mem::size_of::<PageDescriptor>(),
+            core::mem::size_of::<u64>()
+        );
+    }
+
+    /// Check if KERNEL_TABLES is in .bss.
+    #[kernel_test]
+    fn kernel_tables_in_bss() {
+        let bss_range = bsp::memory::bss_range_inclusive();
+        let kernel_tables_addr = unsafe { &KERNEL_TABLES as *const _ as usize as *mut u64 };
+
+        assert!(bss_range.contains(&kernel_tables_addr));
+    }
+}

14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/link.ld

@@ -37,7 +37,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/memory.rs

@@ -6,18 +6,18 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __ro_start: usize;
-    static __ro_end: usize;
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
+    static __ro_start: UnsafeCell<()>;
+    static __ro_end: UnsafeCell<()>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -72,7 +72,7 @@ pub(super) mod map {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_start() -> usize {
-    unsafe { &__ro_start as *const _ as usize }
+    unsafe { __ro_start.get() as usize }
 }
 
 /// Size of the Read-Only (RO) range of the kernel binary.
@@ -82,7 +82,7 @@ fn ro_start() -> usize {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_end() -> usize {
-    unsafe { &__ro_end as *const _ as usize }
+    unsafe { __ro_end.get() as usize }
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -95,17 +95,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

14_exceptions_part2_peripheral_IRQs/src/memory.rs

@@ -6,27 +6,32 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }
 
@@ -44,9 +49,25 @@ mod tests {
     fn zero_volatile_works() {
         let mut x: [usize; 3] = [10, 11, 12];
         let x_range = x.as_mut_ptr_range();
+        let x_range_inclusive =
+            RangeInclusive::new(x_range.start, unsafe { x_range.end.offset(-1) });
 
-        unsafe { zero_volatile(x_range) };
+        unsafe { zero_volatile(x_range_inclusive) };
 
         assert_eq!(x, [0, 0, 0]);
     }
+
+    /// Check `bss` section layout.
+    #[kernel_test]
+    fn bss_section_is_sane() {
+        use crate::bsp::memory::bss_range_inclusive;
+        use core::mem;
+
+        let start = *bss_range_inclusive().start() as usize;
+        let end = *bss_range_inclusive().end() as usize;
+
+        assert_eq!(start % mem::size_of::<usize>(), 0);
+        assert_eq!(end % mem::size_of::<usize>(), 0);
+        assert!(end >= start);
+    }
 }

14_exceptions_part2_peripheral_IRQs/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -38,26 +38,3 @@ pub unsafe fn runtime_init() -> ! {
     zero_bss();
     kernel_init()
 }
-
-//--------------------------------------------------------------------------------------------------
-// Testing
-//--------------------------------------------------------------------------------------------------
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use test_macros::kernel_test;
-
-    /// Check `bss` section layout.
-    #[kernel_test]
-    fn bss_section_is_sane() {
-        use core::mem;
-
-        let start = bsp::memory::bss_range().start as *const _ as usize;
-        let end = bsp::memory::bss_range().end as *const _ as usize;
-
-        assert_eq!(start % mem::size_of::<usize>(), 0);
-        assert_eq!(end % mem::size_of::<usize>(), 0);
-        assert!(end >= start);
-    }
-}

15_virtual_mem_part2_mmio_remap/README.md

@@ -452,7 +452,7 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/memory/mmu.rs 15
  /// # Safety
  ///
  /// - Supposed to land in `.bss`. Therefore, ensure that all initial member values boil down to "0".
--static mut TABLES: ArchTranslationTable = ArchTranslationTable::new();
+-static mut KERNEL_TABLES: ArchTranslationTable = ArchTranslationTable::new();
 +static KERNEL_TABLES: InitStateLock<ArchTranslationTable> =
 +    InitStateLock::new(ArchTranslationTable::new());
 
@@ -591,10 +591,10 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/memory/mmu.rs 15
 -///
 -/// - Modifies a `static mut`. Ensure it only happens from here.
 -unsafe fn populate_tt_entries() -> Result<(), &'static str> {
--    for (l2_nr, l2_entry) in TABLES.lvl2.iter_mut().enumerate() {
--        *l2_entry = TABLES.lvl3[l2_nr].base_addr_usize().into();
+-    for (l2_nr, l2_entry) in KERNEL_TABLES.lvl2.iter_mut().enumerate() {
+-        *l2_entry = KERNEL_TABLES.lvl3[l2_nr].base_addr_usize().into();
 -
--        for (l3_nr, l3_entry) in TABLES.lvl3[l2_nr].iter_mut().enumerate() {
+-        for (l3_nr, l3_entry) in KERNEL_TABLES.lvl3[l2_nr].iter_mut().enumerate() {
 -            let virt_addr = (l2_nr << FIVETWELVE_MIB_SHIFT) + (l3_nr << SIXTYFOUR_KIB_SHIFT);
 -
 -            let (output_addr, attribute_fields) =
@@ -678,14 +678,14 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/memory/mmu.rs 15
 +        if p.len() != v.len() {
 +            return Err("Tried to map page slices with unequal sizes");
 +        }
-+
+
+-impl memory::mmu::interface::MMU for MemoryManagementUnit {
+-    unsafe fn init(&self) -> Result<(), &'static str> {
 +        // No work to do for empty slices.
 +        if p.is_empty() {
 +            return Ok(());
 +        }
-
--impl memory::mmu::interface::MMU for MemoryManagementUnit {
--    unsafe fn init(&self) -> Result<(), &'static str> {
++
 +        if p.last().unwrap().as_ptr() >= bsp::memory::mmu::phys_addr_space_end_page() {
 +            return Err("Tried to map outside of physical address space");
 +        }
@@ -757,55 +757,30 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/memory/mmu.rs 15
 -        populate_tt_entries()?;
 -
          // Set the "Translation Table Base Register".
--        TTBR0_EL1.set_baddr(TABLES.lvl2.base_addr_u64());
+-        TTBR0_EL1.set_baddr(KERNEL_TABLES.lvl2.base_addr_u64());
 +        TTBR0_EL1.set_baddr(phys_kernel_table_base_addr.into_usize() as u64);
 
          configure_translation_control();
 
-@@ -331,3 +511,43 @@
-         Ok(())
-     }
- }
-+
-+//--------------------------------------------------------------------------------------------------
-+// Testing
-+//--------------------------------------------------------------------------------------------------
-+
-+#[cfg(test)]
+@@ -337,6 +517,9 @@
+ //--------------------------------------------------------------------------------------------------
+
+ #[cfg(test)]
 +pub(in crate::memory::mmu) type MinSizeArchTranslationTable = FixedSizeTranslationTable<1>;
 +
 +#[cfg(test)]
-+mod tests {
-+    use super::*;
-+    use test_macros::kernel_test;
-+
-+    /// Check if the size of `struct TableDescriptor` is as expected.
-+    #[kernel_test]
-+    fn size_of_tabledescriptor_equals_64_bit() {
-+        assert_eq!(
-+            core::mem::size_of::<TableDescriptor>(),
-+            core::mem::size_of::<u64>()
-+        );
-+    }
-+
-+    /// Check if the size of `struct PageDescriptor` is as expected.
-+    #[kernel_test]
-+    fn size_of_pagedescriptor_equals_64_bit() {
-+        assert_eq!(
-+            core::mem::size_of::<PageDescriptor>(),
-+            core::mem::size_of::<u64>()
-+        );
-+    }
-+
-+    /// Check if KERNEL_TABLES is in .bss.
-+    #[kernel_test]
-+    fn kernel_tables_in_bss() {
-+        let bss_range = bsp::memory::bss_range();
+ mod tests {
+     use super::*;
+     use test_macros::kernel_test;
+@@ -363,7 +546,7 @@
+     #[kernel_test]
+     fn kernel_tables_in_bss() {
+         let bss_range = bsp::memory::bss_range_inclusive();
+-        let kernel_tables_addr = unsafe { &KERNEL_TABLES as *const _ as usize as *mut u64 };
 +        let kernel_tables_addr = &KERNEL_TABLES as *const _ as usize as *mut u64;
-+
-+        assert!(bss_range.contains(&kernel_tables_addr));
-+    }
-+}
+
+         assert!(bss_range.contains(&kernel_tables_addr));
+     }
 
 diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/device_driver/arm/gicv2/gicc.rs 15_virtual_mem_part2_mmio_remap/src/bsp/device_driver/arm/gicv2/gicc.rs
 --- 14_exceptions_part2_peripheral_IRQs/src/bsp/device_driver/arm/gicv2/gicc.rs
@@ -1467,7 +1442,7 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/link.ld 15_vir
 +++ 15_virtual_mem_part2_mmio_remap/src/bsp/raspberrypi/link.ld
 @@ -39,6 +39,11 @@
          . = ALIGN(8);
-         __bss_end = .;
+         __bss_end_inclusive = . - 8;
      }
 +    . = ALIGN(65536);
 +    __data_end = .;
@@ -1749,18 +1724,16 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/memory.rs 15_v
  pub mod mmu;
 
 +use crate::memory::mmu::{Address, Physical, Virtual};
- use core::ops::Range;
+ use core::{cell::UnsafeCell, ops::RangeInclusive};
 
  //--------------------------------------------------------------------------------------------------
-@@ -15,36 +47,41 @@
- // Symbols from the linker script.
- extern "C" {
-     static __ro_start: usize;
--    static __ro_end: usize;
-+    static __ro_size: usize;
-     static __bss_start: usize;
-     static __bss_end: usize;
-+    static __data_size: usize;
+@@ -17,34 +49,39 @@
+     static __bss_start: UnsafeCell<u64>;
+     static __bss_end_inclusive: UnsafeCell<u64>;
+     static __ro_start: UnsafeCell<()>;
+-    static __ro_end: UnsafeCell<()>;
++    static __ro_size: UnsafeCell<()>;
++    static __data_size: UnsafeCell<()>;
  }
 
  //--------------------------------------------------------------------------------------------------
@@ -1841,9 +1814,9 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/memory.rs 15_v
  /// - Value is provided by the linker script and must be trusted as-is.
  #[inline(always)]
 -fn ro_start() -> usize {
--    unsafe { &__ro_start as *const _ as usize }
+-    unsafe { __ro_start.get() as usize }
 +fn virt_ro_start() -> Address<Virtual> {
-+    Address::new(unsafe { &__ro_start as *const _ as usize })
++    Address::new(unsafe { __ro_start.get() as usize })
  }
 
  /// Size of the Read-Only (RO) range of the kernel binary.
@@ -1852,9 +1825,9 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/memory.rs 15_v
  /// - Value is provided by the linker script and must be trusted as-is.
  #[inline(always)]
 -fn ro_end() -> usize {
--    unsafe { &__ro_end as *const _ as usize }
+-    unsafe { __ro_end.get() as usize }
 +fn ro_size() -> usize {
-+    unsafe { &__ro_size as *const _ as usize }
++    unsafe { __ro_size.get() as usize }
 +}
 +
 +/// Start address of the data range.
@@ -1870,7 +1843,7 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/memory.rs 15_v
 +/// - Value is provided by the linker script and must be trusted as-is.
 +#[inline(always)]
 +fn data_size() -> usize {
-+    unsafe { &__data_size as *const _ as usize }
++    unsafe { __data_size.get() as usize }
 +}
 +
 +/// Start address of the boot core's stack.
@@ -1904,7 +1877,7 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/memory.rs 15_v
 +    Address::new(end)
  }
 
- /// Return the range spanning the .bss section.
+ /// Return the inclusive range spanning the .bss section.
 
 diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi.rs 15_virtual_mem_part2_mmio_remap/src/bsp/raspberrypi.rs
 --- 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi.rs

15_virtual_mem_part2_mmio_remap/src/_arch/aarch64/exception.rs

@@ -5,7 +5,7 @@
 //! Architectural synchronous and asynchronous exception handling.
 
 use crate::{bsp, exception};
-use core::fmt;
+use core::{cell::UnsafeCell, fmt};
 use cortex_a::{barrier, regs::*};
 use register::InMemoryRegister;
 
@@ -249,12 +249,11 @@ pub fn current_privilege_level() -> (PrivilegeLevel, &'static str) {
 ///   Manual.
 pub unsafe fn handling_init() {
     // Provided by exception.S.
-    extern "C" {
-        static mut __exception_vector_start: u64;
+    extern "Rust" {
+        static __exception_vector_start: UnsafeCell<()>;
     }
-    let addr: u64 = &__exception_vector_start as *const _ as u64;
 
-    VBAR_EL1.set(addr);
+    VBAR_EL1.set(__exception_vector_start.get() as u64);
 
     // Force VBAR update to complete before next instruction.
     barrier::isb(barrier::SY);

15_virtual_mem_part2_mmio_remap/src/_arch/aarch64/memory/mmu.rs

@@ -545,7 +545,7 @@ mod tests {
     /// Check if KERNEL_TABLES is in .bss.
     #[kernel_test]
     fn kernel_tables_in_bss() {
-        let bss_range = bsp::memory::bss_range();
+        let bss_range = bsp::memory::bss_range_inclusive();
         let kernel_tables_addr = &KERNEL_TABLES as *const _ as usize as *mut u64;
 
         assert!(bss_range.contains(&kernel_tables_addr));

15_virtual_mem_part2_mmio_remap/src/bsp/raspberrypi/link.ld

@@ -37,7 +37,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
     . = ALIGN(65536);
     __data_end = .;

15_virtual_mem_part2_mmio_remap/src/bsp/raspberrypi/memory.rs

@@ -38,19 +38,19 @@
 pub mod mmu;
 
 use crate::memory::mmu::{Address, Physical, Virtual};
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __ro_start: usize;
-    static __ro_size: usize;
-    static __bss_start: usize;
-    static __bss_end: usize;
-    static __data_size: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
+    static __ro_start: UnsafeCell<()>;
+    static __ro_size: UnsafeCell<()>;
+    static __data_size: UnsafeCell<()>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -118,7 +118,7 @@ pub(super) mod map {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn virt_ro_start() -> Address<Virtual> {
-    Address::new(unsafe { &__ro_start as *const _ as usize })
+    Address::new(unsafe { __ro_start.get() as usize })
 }
 
 /// Size of the Read-Only (RO) range of the kernel binary.
@@ -128,7 +128,7 @@ fn virt_ro_start() -> Address<Virtual> {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn ro_size() -> usize {
-    unsafe { &__ro_size as *const _ as usize }
+    unsafe { __ro_size.get() as usize }
 }
 
 /// Start address of the data range.
@@ -144,7 +144,7 @@ fn virt_data_start() -> Address<Virtual> {
 /// - Value is provided by the linker script and must be trusted as-is.
 #[inline(always)]
 fn data_size() -> usize {
-    unsafe { &__data_size as *const _ as usize }
+    unsafe { __data_size.get() as usize }
 }
 
 /// Start address of the boot core's stack.
@@ -177,17 +177,12 @@ pub fn phys_boot_core_stack_end() -> Address<Physical> {
     Address::new(end)
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

15_virtual_mem_part2_mmio_remap/src/memory.rs

@@ -6,27 +6,32 @@
 
 pub mod mmu;
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }
 
@@ -44,9 +49,25 @@ mod tests {
     fn zero_volatile_works() {
         let mut x: [usize; 3] = [10, 11, 12];
         let x_range = x.as_mut_ptr_range();
+        let x_range_inclusive =
+            RangeInclusive::new(x_range.start, unsafe { x_range.end.offset(-1) });
 
-        unsafe { zero_volatile(x_range) };
+        unsafe { zero_volatile(x_range_inclusive) };
 
         assert_eq!(x, [0, 0, 0]);
     }
+
+    /// Check `bss` section layout.
+    #[kernel_test]
+    fn bss_section_is_sane() {
+        use crate::bsp::memory::bss_range_inclusive;
+        use core::mem;
+
+        let start = *bss_range_inclusive().start() as usize;
+        let end = *bss_range_inclusive().end() as usize;
+
+        assert_eq!(start % mem::size_of::<usize>(), 0);
+        assert_eq!(end % mem::size_of::<usize>(), 0);
+        assert!(end >= start);
+    }
 }

15_virtual_mem_part2_mmio_remap/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -38,26 +38,3 @@ pub unsafe fn runtime_init() -> ! {
     zero_bss();
     kernel_init()
 }
-
-//--------------------------------------------------------------------------------------------------
-// Testing
-//--------------------------------------------------------------------------------------------------
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use test_macros::kernel_test;
-
-    /// Check `bss` section layout.
-    #[kernel_test]
-    fn bss_section_is_sane() {
-        use core::mem;
-
-        let start = bsp::memory::bss_range().start as *const _ as usize;
-        let end = bsp::memory::bss_range().end as *const _ as usize;
-
-        assert_eq!(start % mem::size_of::<usize>(), 0);
-        assert_eq!(end % mem::size_of::<usize>(), 0);
-        assert!(end >= start);
-    }
-}

X1_JTAG_boot/src/bsp/raspberrypi/link.ld

@@ -29,7 +29,7 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
-        __bss_end = .;
+        __bss_end_inclusive = . - 8;
     }
 
     /DISCARD/ : { *(.comment*) }

X1_JTAG_boot/src/bsp/raspberrypi/memory.rs

@@ -4,16 +4,16 @@
 
 //! BSP Memory Management.
 
-use core::ops::Range;
+use core::{cell::UnsafeCell, ops::RangeInclusive};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
 //--------------------------------------------------------------------------------------------------
 
 // Symbols from the linker script.
-extern "C" {
-    static __bss_start: usize;
-    static __bss_end: usize;
+extern "Rust" {
+    static __bss_start: UnsafeCell<u64>;
+    static __bss_end_inclusive: UnsafeCell<u64>;
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -59,17 +59,12 @@ pub fn boot_core_stack_end() -> usize {
     map::BOOT_CORE_STACK_END
 }
 
-/// Return the range spanning the .bss section.
+/// Return the inclusive range spanning the .bss section.
 ///
 /// # Safety
 ///
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
-pub fn bss_range() -> Range<*mut u64> {
-    unsafe {
-        Range {
-            start: &__bss_start as *const _ as *mut u64,
-            end: &__bss_end as *const _ as *mut u64,
-        }
-    }
+pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
 }

X1_JTAG_boot/src/memory.rs

@@ -4,26 +4,31 @@
 
 //! Memory Management.
 
-use core::ops::Range;
+use core::ops::RangeInclusive;
 
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
 
-/// Zero out a memory range.
+/// Zero out an inclusive memory range.
 ///
 /// # Safety
 ///
 /// - `range.start` and `range.end` must be valid.
 /// - `range.start` and `range.end` must be `T` aligned.
-pub unsafe fn zero_volatile<T>(range: Range<*mut T>)
+pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
 where
     T: From<u8>,
 {
-    let mut ptr = range.start;
+    let mut ptr = *range.start();
+    let end_inclusive = *range.end();
 
-    while ptr < range.end {
+    loop {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
+
+        if ptr > end_inclusive {
+            break;
+        }
     }
 }

X1_JTAG_boot/src/runtime_init.rs

@@ -17,7 +17,7 @@ use crate::{bsp, memory};
 /// - Must only be called pre `kernel_init()`.
 #[inline(always)]
 unsafe fn zero_bss() {
-    memory::zero_volatile(bsp::memory::bss_range());
+    memory::zero_volatile(bsp::memory::bss_range_inclusive());
 }
 
 //--------------------------------------------------------------------------------------------------