From 13c877f4b48b943105ad9e13ba2c7a093fb694e8 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Tue, 8 Sep 2020 10:55:12 -0700 Subject: [PATCH] x86/mce: Stop mce_reign() from re-computing severity for every CPU Back in commit: 20d51a426fe9 ("x86/mce: Reuse one of the u16 padding fields in 'struct mce'") a field was added to "struct mce" to save the computed error severity. Make use of this in mce_reign() to avoid re-computing the severity for every CPU. In the case where the machine panics, one call to mce_severity() is still needed in order to provide the correct message giving the reason for the panic. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200908175519.14223-2-tony.luck@intel.com --- arch/x86/kernel/cpu/mce/core.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index a697baee9aa0..5b1d5f33d60b 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -920,7 +920,6 @@ static void mce_reign(void) struct mce *m = NULL; int global_worst = 0; char *msg = NULL; - char *nmsg = NULL; /* * This CPU is the Monarch and the other CPUs have run @@ -928,12 +927,10 @@ static void mce_reign(void) * Grade the severity of the errors of all the CPUs. */ for_each_possible_cpu(cpu) { - int severity = mce_severity(&per_cpu(mces_seen, cpu), - mca_cfg.tolerant, - &nmsg, true); - if (severity > global_worst) { - msg = nmsg; - global_worst = severity; + struct mce *mtmp = &per_cpu(mces_seen, cpu); + + if (mtmp->severity > global_worst) { + global_worst = mtmp->severity; m = &per_cpu(mces_seen, cpu); } } @@ -943,8 +940,11 @@ static void mce_reign(void) * This dumps all the mces in the log buffer and stops the * other CPUs. */ - if (m && global_worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) + if (m && global_worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) { + /* call mce_severity() to get "msg" for panic */ + mce_severity(m, mca_cfg.tolerant, &msg, true); mce_panic("Fatal machine check", m, msg); + } /* * For UC somewhere we let the CPU who detects it handle it.