From 9662d43f523dfc0dc242ec29c2921c43898d6ae5 Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Mon, 24 Jul 2017 12:12:28 +0200 Subject: [PATCH] x86/mce/AMD: Allow any CPU to initialize the smca_banks array Current SMCA implementations have the same banks on each CPU with the non-core banks only visible to a "master thread" on each die. Practically, this means the smca_banks array, which describes the banks, only needs to be populated once by a single master thread. CPU 0 seemed like a good candidate to do the populating. However, it's possible that CPU 0 is not enabled in which case the smca_banks array won't be populated. Rather than try to figure out another master thread to do the populating, we should just allow any CPU to populate the array. Drop the CPU 0 check and return early if the bank was already initialized. Also, drop the WARNing about an already initialized bank, since this will be a common, expected occurrence. The smca_banks array is only populated at boot time and CPUs are brought online sequentially. So there's no need for locking around the array. If the first CPU up is a master thread, then it will populate the array with all banks, core and non-core. Every CPU afterwards will return early. If the first CPU up is not a master thread, then it will populate the array with all core banks. The first CPU afterwards that is a master thread will skip populating the core banks and continue populating the non-core banks. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Acked-by: Jack Miller Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20170724101228.17326-4-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/mcheck/mce_amd.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c index 9e314bc..5ce1a56 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -201,8 +201,8 @@ static void smca_configure(unsigned int bank, unsigned int cpu) wrmsr(smca_config, low, high); } - /* Collect bank_info using CPU 0 for now. */ - if (cpu) + /* Return early if this bank was already initialized. */ + if (smca_banks[bank].hwid) return; if (rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) { @@ -216,11 +216,6 @@ static void smca_configure(unsigned int bank, unsigned int cpu) for (i = 0; i < ARRAY_SIZE(smca_hwid_mcatypes); i++) { s_hwid = &smca_hwid_mcatypes[i]; if (hwid_mcatype == s_hwid->hwid_mcatype) { - - WARN(smca_banks[bank].hwid, - "Bank %s already initialized!\n", - smca_get_name(s_hwid->bank_type)); - smca_banks[bank].hwid = s_hwid; smca_banks[bank].id = low; smca_banks[bank].sysfs_id = s_hwid->count++; -- 2.7.4