From cfee4f6f0b2026380c6bc6913dbd27943df17371 Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Mon, 12 Sep 2016 09:59:31 +0200 Subject: [PATCH] x86/mce/AMD: Read MSRs on the CPU allocating the threshold blocks Scalable MCA systems allow non-core MCA banks to only be accessible by certain CPUs. The MSRs for these banks are Read-as-Zero on other CPUs. During allocate_threshold_blocks(), get_block_address() can be scheduled on CPUs other than the one allocating the block. This causes the MSRs to be read on the wrong CPU and results in incorrect behavior. Add a @cpu parameter to get_block_address() and pass this in to ensure that the MSRs are only read on the CPU that is allocating the block. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1472673994-12235-2-git-send-email-Yazen.Ghannam@amd.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/mcheck/mce_amd.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c index 419e0ee..9da92fb 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -293,7 +293,7 @@ static void deferred_error_interrupt_enable(struct cpuinfo_x86 *c) wrmsr(MSR_CU_DEF_ERR, low, high); } -static u32 get_block_address(u32 current_addr, u32 low, u32 high, +static u32 get_block_address(unsigned int cpu, u32 current_addr, u32 low, u32 high, unsigned int bank, unsigned int block) { u32 addr = 0, offset = 0; @@ -309,13 +309,13 @@ static u32 get_block_address(u32 current_addr, u32 low, u32 high, */ u32 low, high; - if (rdmsr_safe(MSR_AMD64_SMCA_MCx_CONFIG(bank), &low, &high)) + if (rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_CONFIG(bank), &low, &high)) return addr; if (!(low & MCI_CONFIG_MCAX)) return addr; - if (!rdmsr_safe(MSR_AMD64_SMCA_MCx_MISC(bank), &low, &high) && + if (!rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_MISC(bank), &low, &high) && (low & MASK_BLKPTR_LO)) addr = MSR_AMD64_SMCA_MCx_MISCy(bank, block - 1); } @@ -421,12 +421,12 @@ out: void mce_amd_feature_init(struct cpuinfo_x86 *c) { u32 low = 0, high = 0, address = 0; - unsigned int bank, block; + unsigned int bank, block, cpu = smp_processor_id(); int offset = -1; for (bank = 0; bank < mca_cfg.banks; ++bank) { for (block = 0; block < NR_BLOCKS; ++block) { - address = get_block_address(address, low, high, bank, block); + address = get_block_address(cpu, address, low, high, bank, block); if (!address) break; @@ -544,15 +544,14 @@ static void amd_deferred_error_interrupt(void) static void amd_threshold_interrupt(void) { u32 low = 0, high = 0, address = 0; - int cpu = smp_processor_id(); - unsigned int bank, block; + unsigned int bank, block, cpu = smp_processor_id(); /* assume first bank caused it */ for (bank = 0; bank < mca_cfg.banks; ++bank) { if (!(per_cpu(bank_map, cpu) & (1 << bank))) continue; for (block = 0; block < NR_BLOCKS; ++block) { - address = get_block_address(address, low, high, bank, block); + address = get_block_address(cpu, address, low, high, bank, block); if (!address) break; @@ -774,7 +773,7 @@ static int allocate_threshold_blocks(unsigned int cpu, unsigned int bank, if (err) goto out_free; recurse: - address = get_block_address(address, low, high, bank, ++block); + address = get_block_address(cpu, address, low, high, bank, ++block); if (!address) return 0; -- 2.7.4