From dc9b3c0f381f1747eb8020e069649033606342b9 Mon Sep 17 00:00:00 2001
From: Andre Richter <andre.o.richter@gmail.com>
Date: Fri, 29 Jan 2021 22:26:45 +0100
Subject: [PATCH] Add isb before timer read

---
 08_timestamps/README.md                       |  19 +++++++++++++++---
 08_timestamps/src/_arch/aarch64/time.rs       |  17 ++++++++++++++--
 09_hw_debug_JTAG/src/_arch/aarch64/time.rs    |  17 ++++++++++++++--
 10_privilege_level/src/_arch/aarch64/time.rs  |  17 ++++++++++++++--
 .../src/_arch/aarch64/time.rs                 |  17 ++++++++++++++--
 .../src/_arch/aarch64/time.rs                 |  17 ++++++++++++++--
 .../src/_arch/aarch64/time.rs                 |  17 ++++++++++++++--
 .../src/_arch/aarch64/time.rs                 |  17 ++++++++++++++--
 .../src/_arch/aarch64/time.rs                 |  17 ++++++++++++++--
 X1_JTAG_boot/jtag_boot_rpi3.img               | Bin 8144 -> 8144 bytes
 X1_JTAG_boot/jtag_boot_rpi4.img               | Bin 6848 -> 6864 bytes
 X1_JTAG_boot/src/_arch/aarch64/time.rs        |  17 ++++++++++++++--
 12 files changed, 151 insertions(+), 21 deletions(-)

diff --git a/08_timestamps/README.md b/08_timestamps/README.md
index 83e38ca5..0f8ec5d2 100644
--- a/08_timestamps/README.md
+++ b/08_timestamps/README.md
@@ -175,7 +175,7 @@ diff -uNr 07_uart_chainloader/src/_arch/aarch64/cpu.rs 08_timestamps/src/_arch/a
 diff -uNr 07_uart_chainloader/src/_arch/aarch64/time.rs 08_timestamps/src/_arch/aarch64/time.rs
 --- 07_uart_chainloader/src/_arch/aarch64/time.rs
 +++ 08_timestamps/src/_arch/aarch64/time.rs
-@@ -0,0 +1,105 @@
+@@ -0,0 +1,118 @@
 +// SPDX-License-Identifier: MIT OR Apache-2.0
 +//
 +// Copyright (c) 2018-2021 Andre Richter <andre.o.richter@gmail.com>
@@ -191,7 +191,7 @@ diff -uNr 07_uart_chainloader/src/_arch/aarch64/time.rs 08_timestamps/src/_arch/
 +
 +use crate::{time, warn};
 +use core::time::Duration;
-+use cortex_a::regs::*;
++use cortex_a::{barrier, regs::*};
 +
 +//--------------------------------------------------------------------------------------------------
 +// Private Definitions
@@ -209,6 +209,19 @@ diff -uNr 07_uart_chainloader/src/_arch/aarch64/time.rs 08_timestamps/src/_arch/
 +static TIME_MANAGER: GenericTimer = GenericTimer;
 +
 +//--------------------------------------------------------------------------------------------------
++// Private Code
++//--------------------------------------------------------------------------------------------------
++
++impl GenericTimer {
++    #[inline(always)]
++    fn read_cntpct(&self) -> u64 {
++        // Prevent that the counter is read ahead of time due to out-of-order execution.
++        unsafe { barrier::isb(barrier::SY) };
++        CNTPCT_EL0.get()
++    }
++}
++
++//--------------------------------------------------------------------------------------------------
 +// Public Code
 +//--------------------------------------------------------------------------------------------------
 +
@@ -227,8 +240,8 @@ diff -uNr 07_uart_chainloader/src/_arch/aarch64/time.rs 08_timestamps/src/_arch/
 +    }
 +
 +    fn uptime(&self) -> Duration {
++        let current_count: u64 = self.read_cntpct() * NS_PER_S;
 +        let frq: u64 = CNTFRQ_EL0.get() as u64;
-+        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 +
 +        Duration::from_nanos(current_count / frq)
 +    }
diff --git a/08_timestamps/src/_arch/aarch64/time.rs b/08_timestamps/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/08_timestamps/src/_arch/aarch64/time.rs
+++ b/08_timestamps/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/09_hw_debug_JTAG/src/_arch/aarch64/time.rs b/09_hw_debug_JTAG/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/09_hw_debug_JTAG/src/_arch/aarch64/time.rs
+++ b/09_hw_debug_JTAG/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/10_privilege_level/src/_arch/aarch64/time.rs b/10_privilege_level/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/10_privilege_level/src/_arch/aarch64/time.rs
+++ b/10_privilege_level/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/time.rs b/11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/time.rs
+++ b/11_virtual_mem_part1_identity_mapping/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/12_exceptions_part1_groundwork/src/_arch/aarch64/time.rs b/12_exceptions_part1_groundwork/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/12_exceptions_part1_groundwork/src/_arch/aarch64/time.rs
+++ b/12_exceptions_part1_groundwork/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/13_integrated_testing/src/_arch/aarch64/time.rs b/13_integrated_testing/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/13_integrated_testing/src/_arch/aarch64/time.rs
+++ b/13_integrated_testing/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/time.rs b/14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/time.rs
+++ b/14_exceptions_part2_peripheral_IRQs/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/15_virtual_mem_part2_mmio_remap/src/_arch/aarch64/time.rs b/15_virtual_mem_part2_mmio_remap/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/15_virtual_mem_part2_mmio_remap/src/_arch/aarch64/time.rs
+++ b/15_virtual_mem_part2_mmio_remap/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }
diff --git a/X1_JTAG_boot/jtag_boot_rpi3.img b/X1_JTAG_boot/jtag_boot_rpi3.img
index 9f8ada21812d7d7772028c6bfed45c182479b457..4cd4401535b2b3cb1f5cbf807c72b1f69637cedd 100755
GIT binary patch
delta 236
zcmca$f5Co&3?utQ+0%@dH@=K#WUSuo$@G{{NP&YP<i0)gRjmisS2=;WQ)IH0;61ig
z|Nc)uz&Tk?NX}^y149Tm1H*(@3=KiqJGCZqFffR4A2>G2yZHI1ct-BmoSYE(Qy}?;
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aQE5()J(@r}I5s<q{%2uy+3YCQ&k6uTj#{h$

delta 265
zcmca$f5Co&3?s)x+0%?yHolB!WUSfj$@G|ykAZ_Bg!6&*RV^US6q;-&c+Y9|zyH%0
za4?wu3wHSV|1i_U1I+Q)v}!qKb2`in@+@9n6wk={`VmkYHv_|jR}2k7**mo+zFy6+
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tBZzY*!%o}DvLfz`w<f2GY-bdnEGsI_$^mqb=4MCH|16B=n;oV4SphXEZ3h4V

diff --git a/X1_JTAG_boot/jtag_boot_rpi4.img b/X1_JTAG_boot/jtag_boot_rpi4.img
index e9d7e7ddde04a9b940c72fac1745384b4231845f..c753511524cbbc8a737fb914a5a7469ed49ea7e4 100755
GIT binary patch
delta 960
zcmZ8g-%C?b9RHr(ZQbcmr<?nswhhgB)gDU4!HQi=3!{e|QUuYk9}oQiY5%~kXhik0
z!!dkSqF_E5d(nqtAwj*AgX|%~wxU?{U_J!RYNzkL_ax;P4&U?roX_{?IVV4`Hjrs0
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Uii(7Ofey29;5f;!D}ghA0D_wcQUCw|

delta 961
zcmZ8fO-vI(6n@if>lO^S*s^T_+ooW<EgldE8WLGFL?s@yfyl{%hKnH~>A}Q{T?odg
zmre%5wT&^Mc!AV|Jt!q=j2D$eJeWv|MuU1FUW`TU`gV6T%1d_Nyf@$Xe&=O(sXNn5
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zoKis4LX>Dgr`ZANl(gZ-(DwW$hOGg}3{J5dQXmS=w0sQc)=zyd2*Fpw0JApyjI%D-
zR;#^G5zD=63R{yVT)7ynL+W$F1{<&scB!E!tv1r~dqUp{gw9m;Ih8<nGAOL+x-J7^
zp%kGQFmqIm(vYAfj_^e0UAC19cy~b!Q#<OJQrL_$=Fk$~FqTn7Nl3mH@y>N-pb~Sa
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z7kd@H8~A6sJ~Xad1?Z2+YPAz8pRpiOm`;d~ms3F}+%q`w6*s%P_X_D}F?V3MF^Sta
ziAO+N*syyhJ%$SfEwLF9@<t0HE?7_F2GWi^K8H-mAcVmreEp@*Ww-UN|Hd-fW{suX
zW@3!7Oz^P)sFk->UB<C5h;|hpi@5L!ZIiD>C?Q&cjd<E61@=P^bb%9a(kNmf=ZTP$
zQ6E<Hj~tdQ8&_q@Kq@tv!c&<08@Ycc&dVgZuOsTU*j5UFIJdD&Q+8%+XH)W4DC@Ua
z8b{A_d!E}O%Xwt!gvUaSa4oW;H$p_V;SJ!Q_#$MLDL&kq;ZaJwFNtS1w2I#%_t$g(
YGF$RZN>QHC$GttQ!+)G;?6UvtZ#~ur2LJ#7

diff --git a/X1_JTAG_boot/src/_arch/aarch64/time.rs b/X1_JTAG_boot/src/_arch/aarch64/time.rs
index 3a766009..63017305 100644
--- a/X1_JTAG_boot/src/_arch/aarch64/time.rs
+++ b/X1_JTAG_boot/src/_arch/aarch64/time.rs
@@ -13,7 +13,7 @@
 
 use crate::{time, warn};
 use core::time::Duration;
-use cortex_a::regs::*;
+use cortex_a::{barrier, regs::*};
 
 //--------------------------------------------------------------------------------------------------
 // Private Definitions
@@ -30,6 +30,19 @@ struct GenericTimer;
 
 static TIME_MANAGER: GenericTimer = GenericTimer;
 
+//--------------------------------------------------------------------------------------------------
+// Private Code
+//--------------------------------------------------------------------------------------------------
+
+impl GenericTimer {
+    #[inline(always)]
+    fn read_cntpct(&self) -> u64 {
+        // Prevent that the counter is read ahead of time due to out-of-order execution.
+        unsafe { barrier::isb(barrier::SY) };
+        CNTPCT_EL0.get()
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 // Public Code
 //--------------------------------------------------------------------------------------------------
@@ -49,8 +62,8 @@ impl time::interface::TimeManager for GenericTimer {
     }
 
     fn uptime(&self) -> Duration {
+        let current_count: u64 = self.read_cntpct() * NS_PER_S;
         let frq: u64 = CNTFRQ_EL0.get() as u64;
-        let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
 
         Duration::from_nanos(current_count / frq)
     }