On Tue, Aug 01, 2023 at 12:37:35PM +0300, ovidiu.panait@windriver.com wrote:
From: D Scott Phillips scott@os.amperecomputing.com
commit 0e5d5ae837c8ce04d2ddb874ec5f920118bd9d31 upstream.
Per AmpereOne erratum AC03_CPU_12, "Branch history may allow control of speculative execution across software contexts," the AMPERE1 core needs the bhb clearing loop to mitigate Spectre-BHB, with a loop iteration count of 11.
Signed-off-by: D Scott Phillips scott@os.amperecomputing.com Link: https://lore.kernel.org/r/20221011022140.432370-1-scott@os.amperecomputing.c... Reviewed-by: James Morse james.morse@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Ovidiu Panait ovidiu.panait@windriver.com
arch/arm64/include/asm/cputype.h | 4 ++++ arch/arm64/kernel/cpu_errata.c | 6 ++++++ 2 files changed, 10 insertions(+)
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index f0165df489a3..08241810cfea 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -59,6 +59,7 @@ #define ARM_CPU_IMP_NVIDIA 0x4E #define ARM_CPU_IMP_FUJITSU 0x46 #define ARM_CPU_IMP_HISI 0x48 +#define ARM_CPU_IMP_AMPERE 0xC0 #define ARM_CPU_PART_AEM_V8 0xD0F #define ARM_CPU_PART_FOUNDATION 0xD00 @@ -101,6 +102,8 @@ #define HISI_CPU_PART_TSV110 0xD01 +#define AMPERE_CPU_PART_AMPERE1 0xAC3
#define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53) #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57) #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A72) @@ -131,6 +134,7 @@ #define MIDR_NVIDIA_CARMEL MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, NVIDIA_CPU_PART_CARMEL) #define MIDR_FUJITSU_A64FX MIDR_CPU_MODEL(ARM_CPU_IMP_FUJITSU, FUJITSU_CPU_PART_A64FX) #define MIDR_HISI_TSV110 MIDR_CPU_MODEL(ARM_CPU_IMP_HISI, HISI_CPU_PART_TSV110) +#define MIDR_AMPERE1 MIDR_CPU_MODEL(ARM_CPU_IMP_AMPERE, AMPERE_CPU_PART_AMPERE1) /* Fujitsu Erratum 010001 affects A64FX 1.0 and 1.1, (v0r0 and v1r0) */ #define MIDR_FUJITSU_ERRATUM_010001 MIDR_FUJITSU_A64FX diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index b18f307a3c59..342cba2ae982 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -1145,6 +1145,10 @@ u8 spectre_bhb_loop_affected(int scope) MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N1), {}, };
static const struct midr_range spectre_bhb_k11_list[] = {MIDR_ALL_VERSIONS(MIDR_AMPERE1),{},};@@ -1155,6 +1159,8 @@ u8 spectre_bhb_loop_affected(int scope) k = 32; else if (is_midr_in_range_list(read_cpuid_id(), spectre_bhb_k24_list)) k = 24;
else if (is_midr_in_range_list(read_cpuid_id(), spectre_bhb_k11_list))k = 11;2.39.1
Both now queued up, thanks.
greg k-h