Commit 209e9d50 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: introduce die_mce 



As explained by commit daf00ae7 ("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: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-24-npiggin@gmail.com
parent dcdb4f12

arch/powerpc/include/asm/bug.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/kernel/traps.c

+15 −6
Original line number Diff line number Diff line
@@ -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();

arch/powerpc/platforms/powernv/opal.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

		}

	}

arch/powerpc/platforms/pseries/ras.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

		}

	}