[PATCH AUTOSEL 5.4 078/130] x86/mce: Move the mce_panic() call and 'kill_it' assignments to the right places

Sasha Levin
2020-12-23T02:57:56Z

From: Gabriele Paoloni <gabriele.paoloni@intel.com>

[ Upstream commit e273e6e12ab1db3eb57712bd60655744d0091fa3 ]

Right now, for local MCEs the machine calls panic(), if needed, right
after lmce is set. For MCE broadcasting, mce_reign() takes care of
calling mce_panic().

Hence:
- improve readability by moving the conditional evaluation of
tolerant up to when kill_it is set first;
- move the mce_panic() call up into the statement where mce_end()
fails.

[ bp: Massage, remove comment in the mce_end() failure case because it
is superfluous; use local ptr 'cfg' in both tests. ]

Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20201127161819.3106432-3-gabriele.paoloni@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kernel/cpu/mce/core.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index c2a9762d278dd..10f69e045d3ea 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1328,8 +1328,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
* severity is MCE_AR_SEVERITY we have other options.
*/
if (!(m.mcgstatus & MCG_STATUS_RIPV))
- kill_it = 1;
-
+ kill_it = (cfg->tolerant == 3) ? 0 : 1;
/*
* Check if this MCE is signaled to only this logical processor,
* on Intel only.
@@ -1364,6 +1363,9 @@ void do_machine_check(struct pt_regs *regs, long error_code)
if (mce_end(order) < 0) {
if (!no_way_out)
no_way_out = worst >= MCE_PANIC_SEVERITY;
+
+ if (no_way_out && cfg->tolerant < 3)
+ mce_panic("Fatal machine check on current CPU", &m, msg);
}
} else {
/*
@@ -1380,15 +1382,6 @@ void do_machine_check(struct pt_regs *regs, long error_code)
}
}

- /*
- * If tolerant is at an insane level we drop requests to kill
- * processes and continue even when there is no way out.
- */
- if (cfg->tolerant == 3)
- kill_it = 0;
- else if (no_way_out)
- mce_panic("Fatal machine check on current CPU", &m, msg);
-
if (worst > 0)
irq_work_queue(&mce_irq_work);

--
2.27.0