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powerpc: introduce die_mce 

As explained by commit daf00ae71d ("powerpc/traps: restore
recoverability of machine_check interrupts"), die() can't be called from
within nmi_enter to nicely kill a process context that was interrupted.
nmi_exit must be called first.

This adds a function die_mce which takes care of this for machine check
handlers.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-24-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-01-30 23:08:33 +10:00 committed by Michael Ellerman
parent dcdb4f1296
commit 209e9d500e
4 changed files with 18 additions and 8 deletions
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1
arch/powerpc/include/asm/bug.h
View File

@ -118,6 +118,7 @@ void do_bad_page_fault_segv(struct pt_regs *regs);
extern void _exception(int, struct pt_regs *, int, unsigned long);
extern void _exception_pkey(struct pt_regs *, unsigned long, int);
extern void die(const char *, struct pt_regs *, long);
void die_mce(const char *str, struct pt_regs *regs, long err);
extern bool die_will_crash(void);
extern void panic_flush_kmsg_start(void);
extern void panic_flush_kmsg_end(void);

21
arch/powerpc/kernel/traps.c
View File

@ -789,6 +789,19 @@ int machine_check_generic(struct pt_regs *regs)
}
#endif /* everything else */
void die_mce(const char *str, struct pt_regs *regs, long err)
{
/*
* The machine check wants to kill the interrupted context, but
* do_exit() checks for in_interrupt() and panics in that case, so
* exit the irq/nmi before calling die.
*/
if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
nmi_exit();
die(str, regs, err);
}
NOKPROBE_SYMBOL(die_mce);
void machine_check_exception(struct pt_regs *regs)
{
int recover = 0;
@ -831,15 +844,11 @@ void machine_check_exception(struct pt_regs *regs)
if (check_io_access(regs))
goto bail;
if (nmi) nmi_exit();
die("Machine check", regs, SIGBUS);
die_mce("Machine check", regs, SIGBUS);
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
die("Unrecoverable Machine check", regs, SIGBUS);
return;
die_mce("Unrecoverable Machine check", regs, SIGBUS);
bail:
if (nmi) nmi_exit();

2
arch/powerpc/platforms/powernv/opal.c
View File

@ -624,7 +624,7 @@ static int opal_recover_mce(struct pt_regs *regs,
*/
recovered = 0;
} else {
die("Machine check", regs, SIGBUS);
die_mce("Machine check", regs, SIGBUS);
recovered = 1;
}
}

2
arch/powerpc/platforms/pseries/ras.c
View File

@ -808,7 +808,7 @@ static int recover_mce(struct pt_regs *regs, struct machine_check_event *evt)
*/
recovered = 0;
} else {
die("Machine check", regs, SIGBUS);
die_mce("Machine check", regs, SIGBUS);
recovered = 1;
}
}