Messages in this thread Patch in this message | | | From | ira.weiny@intel ... | Subject | [RFC PATCH 5/5] x86/entry: Store CPU info on exception entry | Date | Fri, 5 Aug 2022 10:30:09 -0700 |
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From: Ira Weiny <ira.weiny@intel.com>
The CPU information of an exception is useful in determining where bad CPUs are in a large data center.
Define arch_{save|restore}_auxiliary_pt_regs() and set ARCH_HAS_PTREGS_AUXILIARY default to yes.
Store the CPU on exception entry and use it later.
Cc: Rik van Riel <riel@surriel.com> Suggested-by: Borislav Petkov <bp@alien8.de> Suggested-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> --- arch/x86/Kconfig | 2 +- arch/x86/include/asm/entry-common.h | 12 ++++++++++++ arch/x86/include/asm/ptrace.h | 1 + arch/x86/mm/fault.c | 4 ++-- 4 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index b35f6a472e09..707650a6ecb2 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1876,7 +1876,7 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS config ARCH_HAS_PTREGS_AUXILIARY depends on X86_64 - bool + def_bool y choice prompt "TSX enable mode" diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h index 674ed46d3ced..eb145106929a 100644 --- a/arch/x86/include/asm/entry-common.h +++ b/arch/x86/include/asm/entry-common.h @@ -95,4 +95,16 @@ static __always_inline void arch_exit_to_user_mode(void) } #define arch_exit_to_user_mode arch_exit_to_user_mode +#ifdef CONFIG_ARCH_HAS_PTREGS_AUXILIARY + +static inline void arch_save_aux_pt_regs(struct pt_regs *regs) +{ + struct pt_regs_auxiliary *aux_pt_regs = &to_extended_pt_regs(regs)->aux; + + aux_pt_regs->cpu = raw_smp_processor_id(); +} +#define arch_save_aux_pt_regs arch_save_aux_pt_regs + +#endif + #endif diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 5a9c85893459..b403b469996f 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -97,6 +97,7 @@ struct pt_regs { * ARCH_HAS_PTREGS_AUXILIARY. Failure to do so will result in a build failure. */ struct pt_regs_auxiliary { + int cpu; }; struct pt_regs_extended { diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 82cf23975aa1..5df99fe49494 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -768,9 +768,9 @@ static inline void show_signal_msg(struct pt_regs *regs, unsigned long error_code, unsigned long address, struct task_struct *tsk) { + struct pt_regs_auxiliary *aux_pt_regs = &to_extended_pt_regs(regs)->aux; const char *loglvl = task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG; - /* This is a racy snapshot, but it's better than nothing. */ - int cpu = raw_smp_processor_id(); + int cpu = aux_pt_regs->cpu; if (!unhandled_signal(tsk, SIGSEGV)) return; -- 2.35.3
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