[U-Boot] [PATCH v2] armv8: errata: Implement workaround for Cortex-A53 Erratum 855873
855873: An eviction might overtake a cache clean operation Workaround: The erratum can be avoided by upgrading cache clean by address operations to cache clean and invalidate operations. For Cortex-A53 r0p3 and later release, this can be achieved by setting CPUACTLR.ENDCCASCI to 1.
This patch is to implement the workaround for this erratum.
Signed-off-by: Alison Wang alison.wang@nxp.com --- Changes in v2: - Check the revision of Cortex-A53 and apply the erratum to r0p3 and later release. - Fix the mistake in the commit description.
arch/arm/Kconfig | 3 +++ arch/arm/cpu/armv8/fsl-layerscape/Kconfig | 2 ++ arch/arm/cpu/armv8/start.S | 20 +++++++++++++++++++- 3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index d43aaac..4a885a3 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -103,6 +103,9 @@ config ARM_ERRATA_852421 config ARM_ERRATA_852423 bool
+config ARM_ERRATA_855873 + bool + config CPU_ARM720T bool select SYS_CACHE_SHIFT_5 diff --git a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig index 5825f9b..63658b5 100644 --- a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig +++ b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig @@ -1,6 +1,7 @@ config ARCH_LS1012A bool select ARMV8_SET_SMPEN + select ARM_ERRATA_855873 select FSL_LSCH2 select SYS_FSL_DDR_BE select SYS_FSL_MMDC @@ -11,6 +12,7 @@ config ARCH_LS1012A config ARCH_LS1043A bool select ARMV8_SET_SMPEN + select ARM_ERRATA_855873 select FSL_LSCH2 select SYS_FSL_DDR select SYS_FSL_DDR_BE diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 5c500be..6ca054b 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -170,7 +170,10 @@ reset_sctrl: WEAK(apply_core_errata)
mov x29, lr /* Save LR */ - /* For now, we support Cortex-A57 specific errata only */ + /* For now, we support Cortex-A53, Cortex-A57 specific errata */ + + /* Check if we are running on a Cortex-A53 core */ + branch_if_a53_core x0, apply_a53_core_errata
/* Check if we are running on a Cortex-A57 core */ branch_if_a57_core x0, apply_a57_core_errata @@ -178,6 +181,21 @@ WEAK(apply_core_errata) mov lr, x29 /* Restore LR */ ret
+apply_a53_core_errata: + +#ifdef CONFIG_ARM_ERRATA_855873 + mrs x0, midr_el1 + and x0, x0, #0xf + cmp x0, #3 + b.lt 0b + + mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */ + /* Enable data cache clean as data cache clean/invalidate */ + orr x0, x0, #1 << 44 + msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */ +#endif + b 0b + apply_a57_core_errata:
#ifdef CONFIG_ARM_ERRATA_828024
On 21/07/17 09:00, Alison Wang wrote:
Hi,
855873: An eviction might overtake a cache clean operation Workaround: The erratum can be avoided by upgrading cache clean by address operations to cache clean and invalidate operations. For Cortex-A53 r0p3 and later release, this can be achieved by setting CPUACTLR.ENDCCASCI to 1.
This patch is to implement the workaround for this erratum.
Signed-off-by: Alison Wang alison.wang@nxp.com
Changes in v2:
- Check the revision of Cortex-A53 and apply the erratum to r0p3 and later release.
- Fix the mistake in the commit description.
Thanks for those fixes, this looks much better now. One thing below ....
arch/arm/Kconfig | 3 +++ arch/arm/cpu/armv8/fsl-layerscape/Kconfig | 2 ++ arch/arm/cpu/armv8/start.S | 20 +++++++++++++++++++- 3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index d43aaac..4a885a3 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -103,6 +103,9 @@ config ARM_ERRATA_852421 config ARM_ERRATA_852423 bool
+config ARM_ERRATA_855873
- bool
config CPU_ARM720T bool select SYS_CACHE_SHIFT_5 diff --git a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig index 5825f9b..63658b5 100644 --- a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig +++ b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig @@ -1,6 +1,7 @@ config ARCH_LS1012A bool select ARMV8_SET_SMPEN
- select ARM_ERRATA_855873 select FSL_LSCH2 select SYS_FSL_DDR_BE select SYS_FSL_MMDC
@@ -11,6 +12,7 @@ config ARCH_LS1012A config ARCH_LS1043A bool select ARMV8_SET_SMPEN
- select ARM_ERRATA_855873 select FSL_LSCH2 select SYS_FSL_DDR select SYS_FSL_DDR_BE
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 5c500be..6ca054b 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -170,7 +170,10 @@ reset_sctrl: WEAK(apply_core_errata)
mov x29, lr /* Save LR */
- /* For now, we support Cortex-A57 specific errata only */
/* For now, we support Cortex-A53, Cortex-A57 specific errata */
/* Check if we are running on a Cortex-A53 core */
branch_if_a53_core x0, apply_a53_core_errata
/* Check if we are running on a Cortex-A57 core */ branch_if_a57_core x0, apply_a57_core_errata
@@ -178,6 +181,21 @@ WEAK(apply_core_errata) mov lr, x29 /* Restore LR */ ret
+apply_a53_core_errata:
+#ifdef CONFIG_ARM_ERRATA_855873
- mrs x0, midr_el1
- and x0, x0, #0xf
- cmp x0, #3
This only checks for the revision field being 3 (which is correct), but the condition is really >= r0p3, so you have to check bits 23:20 ("variant") as well, by concatenating the two fields to end up comparing against 0x03. It's a few more instructions only.
The rest of the patch is fine.
Thanks, Andre.
- b.lt 0b
- mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
- /* Enable data cache clean as data cache clean/invalidate */
- orr x0, x0, #1 << 44
- msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
+#endif
- b 0b
apply_a57_core_errata:
#ifdef CONFIG_ARM_ERRATA_828024
On 21/07/17 09:00, Alison Wang wrote:
Hi,
855873: An eviction might overtake a cache clean operation Workaround: The erratum can be avoided by upgrading cache clean by address operations to cache clean and invalidate operations. For Cortex-A53 r0p3 and later release, this can be achieved by setting CPUACTLR.ENDCCASCI to 1.
This patch is to implement the workaround for this erratum.
Signed-off-by: Alison Wang alison.wang@nxp.com
Changes in v2:
- Check the revision of Cortex-A53 and apply the erratum to r0p3 and
later release.
- Fix the mistake in the commit description.
Thanks for those fixes, this looks much better now. One thing below ....
arch/arm/Kconfig | 3 +++ arch/arm/cpu/armv8/fsl-layerscape/Kconfig | 2 ++ arch/arm/cpu/armv8/start.S | 20 +++++++++++++++++++- 3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index d43aaac..4a885a3 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -103,6 +103,9 @@ config ARM_ERRATA_852421 config
ARM_ERRATA_852423
bool
+config ARM_ERRATA_855873
- bool
config CPU_ARM720T bool select SYS_CACHE_SHIFT_5 diff --git a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig index 5825f9b..63658b5 100644 --- a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig +++ b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig @@ -1,6 +1,7 @@ config ARCH_LS1012A bool select ARMV8_SET_SMPEN
- select ARM_ERRATA_855873 select FSL_LSCH2 select SYS_FSL_DDR_BE select SYS_FSL_MMDC
@@ -11,6 +12,7 @@ config ARCH_LS1012A config ARCH_LS1043A bool select ARMV8_SET_SMPEN
- select ARM_ERRATA_855873 select FSL_LSCH2 select SYS_FSL_DDR select SYS_FSL_DDR_BE
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 5c500be..6ca054b 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -170,7 +170,10 @@ reset_sctrl: WEAK(apply_core_errata)
mov x29, lr /* Save LR */
- /* For now, we support Cortex-A57 specific errata only */
/* For now, we support Cortex-A53, Cortex-A57 specific errata */
/* Check if we are running on a Cortex-A53 core */
branch_if_a53_core x0, apply_a53_core_errata
/* Check if we are running on a Cortex-A57 core */ branch_if_a57_core x0, apply_a57_core_errata @@ -178,6 +181,21 @@
WEAK(apply_core_errata) mov lr, x29 /* Restore LR */ ret
+apply_a53_core_errata:
+#ifdef CONFIG_ARM_ERRATA_855873
- mrs x0, midr_el1
- and x0, x0, #0xf
- cmp x0, #3
This only checks for the revision field being 3 (which is correct), but the condition is really >= r0p3, so you have to check bits 23:20 ("variant") as well, by concatenating the two fields to end up comparing against 0x03. It's a few more instructions only.
The rest of the patch is fine.
Thanks, Andre.
[Alison Wang] I have checked Revision >=3. Do you mean to check variant bit[23:20] >= 0 too?
Best Regards, Alison Wang
- b.lt 0b
- mrs x0, S3_1_c15_c2_0 /* cpuactlr_el1 */
- /* Enable data cache clean as data cache clean/invalidate */
- orr x0, x0, #1 << 44
- msr S3_1_c15_c2_0, x0 /* cpuactlr_el1 */
+#endif
- b 0b
apply_a57_core_errata:
#ifdef CONFIG_ARM_ERRATA_828024
participants (3)
-
Alison Wang -
Alison Wang -
André Przywara