Fix zero-sized bss handling

02_runtime_init/README.md

@@ -48,7 +48,7 @@ diff -uNr 01_wait_forever/src/_arch/aarch64/cpu.S 02_runtime_init/src/_arch/aarc
 diff -uNr 01_wait_forever/src/bsp/raspberrypi/link.ld 02_runtime_init/src/bsp/raspberrypi/link.ld
 --- 01_wait_forever/src/bsp/raspberrypi/link.ld
 +++ 02_runtime_init/src/bsp/raspberrypi/link.ld
-@@ -13,5 +13,24 @@
+@@ -13,5 +13,27 @@
          *(.text._start) *(.text*)
      }
 
@@ -68,6 +68,9 @@ diff -uNr 01_wait_forever/src/bsp/raspberrypi/link.ld 02_runtime_init/src/bsp/ra
 +        __bss_start = .;
 +        *(.bss*);
 +        . = ALIGN(8);
++
++        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
++        . += 8;
 +        __bss_end_inclusive = . - 8;
 +    }
 +
@@ -77,7 +80,7 @@ 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 +1,31 @@
+@@ -0,0 +1,37 @@
 +// SPDX-License-Identifier: MIT OR Apache-2.0
 +//
 +// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
@@ -107,7 +110,13 @@ diff -uNr 01_wait_forever/src/bsp/raspberrypi/memory.rs 02_runtime_init/src/bsp/
 +/// - 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_inclusive() -> RangeInclusive<*mut u64> {
-+    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
++    let range;
++    unsafe {
++        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
++    }
++    assert!(!range.is_empty());
++
++    range
 +}
 
 diff -uNr 01_wait_forever/src/bsp/raspberrypi.rs 02_runtime_init/src/bsp/raspberrypi.rs
@@ -150,7 +159,7 @@ 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 +1,34 @@
+@@ -0,0 +1,30 @@
 +// SPDX-License-Identifier: MIT OR Apache-2.0
 +//
 +// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
@@ -176,13 +185,9 @@ diff -uNr 01_wait_forever/src/memory.rs 02_runtime_init/src/memory.rs
 +    let mut ptr = *range.start();
 +    let end_inclusive = *range.end();
 +
-+    loop {
++    while ptr <= end_inclusive {
 +        core::ptr::write_volatile(ptr, T::from(0));
 +        ptr = ptr.offset(1);
-+
-+        if ptr > end_inclusive {
-+            break;
-+        }
 +    }
 +}
 

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -27,5 +27,11 @@ extern "Rust" {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

02_runtime_init/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -27,5 +27,11 @@ extern "Rust" {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

03_hacky_hello_world/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -43,5 +43,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

04_zero_overhead_abstraction/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -43,5 +43,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

05_safe_globals/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -66,5 +66,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

06_drivers_gpio_uart/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

07_uart_chainloader/README.md

@@ -310,7 +310,7 @@ diff -uNr 06_drivers_gpio_uart/src/bsp/raspberrypi/link.ld 07_uart_chainloader/s
      }
 
      .rodata :
-@@ -32,5 +35,16 @@
+@@ -35,5 +38,16 @@
          __bss_end_inclusive = . - 8;
      }
 
@@ -357,7 +357,7 @@ diff -uNr 06_drivers_gpio_uart/src/bsp/raspberrypi/memory.rs 07_uart_chainloader
 
      /// Physical devices.
      #[cfg(feature = "bsp_rpi3")]
-@@ -59,12 +64,34 @@
+@@ -59,13 +64,35 @@
      map::BOOT_CORE_STACK_END
  }
 
@@ -392,8 +392,9 @@ diff -uNr 06_drivers_gpio_uart/src/bsp/raspberrypi/memory.rs 07_uart_chainloader
  /// - The linker-provided addresses must be u64 aligned.
 -pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
 +pub fn relocated_bss_range_inclusive() -> RangeInclusive<*mut u64> {
-     unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
- }
+     let range;
+     unsafe {
+         range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
 
 diff -uNr 06_drivers_gpio_uart/src/console.rs 07_uart_chainloader/src/console.rs
 --- 06_drivers_gpio_uart/src/console.rs
@@ -531,7 +532,7 @@ diff -uNr 06_drivers_gpio_uart/src/main.rs 07_uart_chainloader/src/main.rs
 diff -uNr 06_drivers_gpio_uart/src/relocate.rs 07_uart_chainloader/src/relocate.rs
 --- 06_drivers_gpio_uart/src/relocate.rs
 +++ 07_uart_chainloader/src/relocate.rs
-@@ -0,0 +1,55 @@
+@@ -0,0 +1,51 @@
 +// SPDX-License-Identifier: MIT OR Apache-2.0
 +//
 +// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
@@ -561,17 +562,13 @@ diff -uNr 06_drivers_gpio_uart/src/relocate.rs 07_uart_chainloader/src/relocate.
 +    let mut current_binary_start_addr = bsp::memory::board_default_load_addr();
 +
 +    // Copy the whole binary.
-+    loop {
++    while relocated_binary_start_addr <= relocated_binary_end_addr_inclusive {
 +        core::ptr::write_volatile(
 +            relocated_binary_start_addr,
 +            core::ptr::read_volatile(current_binary_start_addr),
 +        );
 +        relocated_binary_start_addr = relocated_binary_start_addr.offset(1);
 +        current_binary_start_addr = current_binary_start_addr.offset(1);
-+
-+        if relocated_binary_start_addr > relocated_binary_end_addr_inclusive {
-+            break;
-+        }
 +    }
 +
 +    // The following function calls form a hack to achieve an "absolute jump" to

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

@@ -32,6 +32,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -93,5 +93,11 @@ pub fn relocated_runtime_init_addr() -> *const u64 {
 /// - Values are provided by the linker script and must be trusted as-is.
 /// - The linker-provided addresses must be u64 aligned.
 pub fn relocated_bss_range_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

07_uart_chainloader/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

07_uart_chainloader/src/relocate.rs

@@ -27,17 +27,13 @@ pub unsafe fn relocate_self() -> ! {
     let mut current_binary_start_addr = bsp::memory::board_default_load_addr();
 
     // Copy the whole binary.
-    loop {
+    while relocated_binary_start_addr <= relocated_binary_end_addr_inclusive {
         core::ptr::write_volatile(
             relocated_binary_start_addr,
             core::ptr::read_volatile(current_binary_start_addr),
         );
         relocated_binary_start_addr = relocated_binary_start_addr.offset(1);
         current_binary_start_addr = current_binary_start_addr.offset(1);
-
-        if relocated_binary_start_addr > relocated_binary_end_addr_inclusive {
-            break;
-        }
     }
 
     // The following function calls form a hack to achieve an "absolute jump" to

08_timestamps/README.md

@@ -301,7 +301,7 @@ diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/link.ld 08_timestamps/src/bsp/
      }
 
      .rodata :
-@@ -35,16 +32,5 @@
+@@ -38,16 +35,5 @@
          __bss_end_inclusive = . - 8;
      }
 
@@ -348,7 +348,7 @@ diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/memory.rs 08_timestamps/src/bs
 
      /// Physical devices.
      #[cfg(feature = "bsp_rpi3")]
-@@ -64,34 +59,12 @@
+@@ -64,35 +59,13 @@
      map::BOOT_CORE_STACK_END
  }
 
@@ -383,8 +383,9 @@ diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/memory.rs 08_timestamps/src/bs
  /// - The linker-provided addresses must be u64 aligned.
 -pub fn relocated_bss_range_inclusive() -> RangeInclusive<*mut u64> {
 +pub fn bss_range_inclusive() -> RangeInclusive<*mut u64> {
-     unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
- }
+     let range;
+     unsafe {
+         range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
 
 diff -uNr 07_uart_chainloader/src/main.rs 08_timestamps/src/main.rs
 --- 07_uart_chainloader/src/main.rs
@@ -586,7 +587,7 @@ diff -uNr 07_uart_chainloader/src/print.rs 08_timestamps/src/print.rs
 diff -uNr 07_uart_chainloader/src/relocate.rs 08_timestamps/src/relocate.rs
 --- 07_uart_chainloader/src/relocate.rs
 +++ 08_timestamps/src/relocate.rs
-@@ -1,55 +0,0 @@
+@@ -1,51 +0,0 @@
 -// SPDX-License-Identifier: MIT OR Apache-2.0
 -//
 -// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
@@ -616,17 +617,13 @@ diff -uNr 07_uart_chainloader/src/relocate.rs 08_timestamps/src/relocate.rs
 -    let mut current_binary_start_addr = bsp::memory::board_default_load_addr();
 -
 -    // Copy the whole binary.
--    loop {
+-    while relocated_binary_start_addr <= relocated_binary_end_addr_inclusive {
 -        core::ptr::write_volatile(
 -            relocated_binary_start_addr,
 -            core::ptr::read_volatile(current_binary_start_addr),
 -        );
 -        relocated_binary_start_addr = relocated_binary_start_addr.offset(1);
 -        current_binary_start_addr = current_binary_start_addr.offset(1);
--
--        if relocated_binary_start_addr > relocated_binary_end_addr_inclusive {
--            break;
--        }
 -    }
 -
 -    // The following function calls form a hack to achieve an "absolute jump" to

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -66,5 +66,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

08_timestamps/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -66,5 +66,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

09_hw_debug_JTAG/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -66,5 +66,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

10_privilege_level/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -32,6 +32,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -98,5 +98,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

11_virtual_mem_part1_identity_mapping/src/memory.rs

@@ -25,12 +25,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

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

@@ -37,6 +37,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -98,5 +98,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

12_exceptions_part1_groundwork/src/memory.rs

@@ -25,12 +25,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }

13_integrated_testing/README.md

@@ -1512,8 +1512,8 @@ 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
-@@ -34,3 +34,40 @@
-         }
+@@ -30,3 +30,40 @@
+         ptr = ptr.offset(1);
      }
  }
 +

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

@@ -37,6 +37,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -98,5 +98,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

13_integrated_testing/src/memory.rs

@@ -25,13 +25,9 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }
 

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

@@ -37,6 +37,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

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

@@ -102,5 +102,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

14_exceptions_part2_peripheral_IRQs/src/memory.rs

@@ -25,13 +25,9 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }
 

15_virtual_mem_part2_mmio_remap/README.md

@@ -1453,8 +1453,8 @@ diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/driver.rs 15_v
 diff -uNr 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/link.ld 15_virtual_mem_part2_mmio_remap/src/bsp/raspberrypi/link.ld
 --- 14_exceptions_part2_peripheral_IRQs/src/bsp/raspberrypi/link.ld
 +++ 15_virtual_mem_part2_mmio_remap/src/bsp/raspberrypi/link.ld
-@@ -39,6 +39,11 @@
-         . = ALIGN(8);
+@@ -42,6 +42,11 @@
+         . += 8;
          __bss_end_inclusive = . - 8;
      }
 +    . = ALIGN(65536);

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

@@ -37,6 +37,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
     . = ALIGN(65536);

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

@@ -184,5 +184,11 @@ pub fn phys_boot_core_stack_end() -> Address<Physical> {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

15_virtual_mem_part2_mmio_remap/src/memory.rs

@@ -25,13 +25,9 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }
 

X1_JTAG_boot/src/bsp/raspberrypi/link.ld

@@ -29,6 +29,9 @@ SECTIONS
         __bss_start = .;
         *(.bss*);
         . = ALIGN(8);
+
+        /* Fill for the bss == 0 case, so that __bss_start <= __bss_end_inclusive holds */
+        . += 8;
         __bss_end_inclusive = . - 8;
     }
 

X1_JTAG_boot/src/bsp/raspberrypi/memory.rs

@@ -66,5 +66,11 @@ pub fn boot_core_stack_end() -> usize {
 /// - 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_inclusive() -> RangeInclusive<*mut u64> {
-    unsafe { RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get()) }
+    let range;
+    unsafe {
+        range = RangeInclusive::new(__bss_start.get(), __bss_end_inclusive.get());
+    }
+    assert!(!range.is_empty());
+
+    range
 }

X1_JTAG_boot/src/memory.rs

@@ -23,12 +23,8 @@ where
     let mut ptr = *range.start();
     let end_inclusive = *range.end();
 
-    loop {
+    while ptr <= end_inclusive {
         core::ptr::write_volatile(ptr, T::from(0));
         ptr = ptr.offset(1);
-
-        if ptr > end_inclusive {
-            break;
-        }
     }
 }