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x86/ras: Flip the TSC-adding logic 

Add the TSC value to the MCE record only when the MCE being logged is
precise, i.e., it is logged as an exception or an MCE-related interrupt.

So it doesn't look particularly easy to do without touching/changing a
bunch of places. That's why I'm trying tricks first.

For example, the mce-apei.c case I'm addressing by setting ->tsc only
for errors of panic severity. The idea there is, that, panic errors will
have raised an #MC and not polled.

And then instead of propagating a flag to mce_setup(), it seems
easier/less code to set ->tsc depending on the call sites, i.e.,
are we polling or are we preparing an MCE record in an exception
handler/thresholding interrupt.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170123183514.13356-5-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov 2017-01-23 19:35:09 +01:00 committed by Ingo Molnar
parent 0b737a9c2a
commit 669c00f099
3 changed files with 9 additions and 11 deletions
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5
arch/x86/kernel/cpu/mcheck/mce-apei.c
View File

@ -52,8 +52,11 @@ void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
if (severity >= GHES_SEV_RECOVERABLE)
m.status |= MCI_STATUS_UC;
if (severity >= GHES_SEV_PANIC)
if (severity >= GHES_SEV_PANIC) {
m.status |= MCI_STATUS_PCC;
m.tsc = rdtsc();
}
m.addr = mem_err->physical_addr;
mce_log(&m);

12
arch/x86/kernel/cpu/mcheck/mce.c
View File

@ -128,7 +128,6 @@ void mce_setup(struct mce *m)
{
memset(m, 0, sizeof(struct mce));
m->cpu = m->extcpu = smp_processor_id();
m->tsc = rdtsc();
/* We hope get_seconds stays lockless */
m->time = get_seconds();
m->cpuvendor = boot_cpu_data.x86_vendor;
@ -710,14 +709,8 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
mce_gather_info(&m, NULL);
/*
* m.tsc was set in mce_setup(). Clear it if not requested.
*
* FIXME: Propagate @flags to mce_gather_info/mce_setup() to avoid
* that dance.
*/
if (!(flags & MCP_TIMESTAMP))
m.tsc = 0;
if (flags & MCP_TIMESTAMP)
m.tsc = rdtsc();
for (i = 0; i < mca_cfg.banks; i++) {
if (!mce_banks[i].ctl || !test_bit(i, *b))
@ -1156,6 +1149,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
goto out;
mce_gather_info(&m, regs);
m.tsc = rdtsc();
final = this_cpu_ptr(&mces_seen);
*final = m;

1
arch/x86/kernel/cpu/mcheck/mce_amd.c
View File

@ -779,6 +779,7 @@ __log_error(unsigned int bank, bool deferred_err, bool threshold_err, u64 misc)
m.status = status;
m.bank = bank;
m.tsc = rdtsc();
if (threshold_err)
m.misc = misc;