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arm64: arch_timer: Add workaround for ARM erratum 1188873

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When running on Cortex-A76, a timer access from an AArch32 EL0
task may end up with a corrupted value or register. The workaround for
this is to trap these accesses at EL1/EL2 and execute them there.

This only affects versions r0p0, r1p0 and r2p0 of the CPU.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Marc Zyngier 2018-09-27 17:15:34 +01:00 committed by Catalin Marinas
parent 32a3e635fb
commit 95b861a4a6
5 changed files with 39 additions and 1 deletions
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12
arch/arm64/Kconfig
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@ -481,6 +481,18 @@ config ARM64_ERRATUM_1024718
If unsure, say Y.
config ARM64_ERRATUM_1188873
bool "Cortex-A76: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
default y
help
This option adds work arounds for ARM Cortex-A76 erratum 1188873
Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could cause
register corruption when accessing the timer registers from
AArch32 userspace.
If unsure, say Y.
config CAVIUM_ERRATUM_22375
bool "Cavium erratum 22375, 24313"
default y

3
arch/arm64/include/asm/cpucaps.h
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@ -53,7 +53,8 @@
#define ARM64_HAS_STAGE2_FWB 32
#define ARM64_HAS_CRC32 33
#define ARM64_SSBS 34
#define ARM64_WORKAROUND_1188873 35
#define ARM64_NCAPS 35
#define ARM64_NCAPS 36
#endif /* __ASM_CPUCAPS_H */

2
arch/arm64/include/asm/cputype.h
View File

@ -86,6 +86,7 @@
#define ARM_CPU_PART_CORTEX_A75 0xD0A
#define ARM_CPU_PART_CORTEX_A35 0xD04
#define ARM_CPU_PART_CORTEX_A55 0xD05
#define ARM_CPU_PART_CORTEX_A76 0xD0B
#define APM_CPU_PART_POTENZA 0x000
@ -110,6 +111,7 @@
#define MIDR_CORTEX_A75 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A75)
#define MIDR_CORTEX_A35 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A35)
#define MIDR_CORTEX_A55 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A55)
#define MIDR_CORTEX_A76 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A76)
#define MIDR_THUNDERX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX)
#define MIDR_THUNDERX_81XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_81XX)
#define MIDR_THUNDERX_83XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_83XX)

8
arch/arm64/kernel/cpu_errata.c
View File

@ -696,6 +696,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
.matches = has_ssbd_mitigation,
},
#endif
#ifdef CONFIG_ARM64_ERRATUM_1188873
{
/* Cortex-A76 r0p0 to r2p0 */
.desc = "ARM erratum 1188873",
.capability = ARM64_WORKAROUND_1188873,
ERRATA_MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0),
},
#endif
{
}

15
drivers/clocksource/arm_arch_timer.c
View File

@ -319,6 +319,13 @@ static u64 notrace arm64_858921_read_cntvct_el0(void)
}
#endif
#ifdef CONFIG_ARM64_ERRATUM_1188873
static u64 notrace arm64_1188873_read_cntvct_el0(void)
{
return read_sysreg(cntvct_el0);
}
#endif
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround);
EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
@ -408,6 +415,14 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
.read_cntvct_el0 = arm64_858921_read_cntvct_el0,
},
#endif
#ifdef CONFIG_ARM64_ERRATUM_1188873
{
.match_type = ate_match_local_cap_id,
.id = (void *)ARM64_WORKAROUND_1188873,
.desc = "ARM erratum 1188873",
.read_cntvct_el0 = arm64_1188873_read_cntvct_el0,
},
#endif
};
typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *,