Commit abd106fb authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/64s: machine check do not trace real-mode handler 



Rather than notrace annotations throughout a significant part of the
machine check code across kernel/ pseries/ and powernv/ which can
easily be broken and is infrequently tested, use paca->ftrace_enabled
to blanket-disable tracing of the real-mode non-maskable handler.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-14-npiggin@gmail.com
parent f2d7f62e

arch/powerpc/kernel/mce.c

+8 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/export.h>

#include <linux/irq_work.h>

#include <linux/extable.h>

#include <linux/ftrace.h>



#include <asm/machdep.h>

#include <asm/mce.h>
@@ -571,10 +572,14 @@ EXPORT_SYMBOL_GPL(machine_check_print_event_info); 
 *

 * regs->nip and regs->msr contains srr0 and ssr1.

 */

long machine_check_early(struct pt_regs *regs)

long notrace machine_check_early(struct pt_regs *regs)

{

	long handled = 0;

	bool nested = in_nmi();

	u8 ftrace_enabled = this_cpu_get_ftrace_enabled();



	this_cpu_set_ftrace_enabled(0);



	if (!nested)

		nmi_enter();
@@ -589,6 +594,8 @@ long machine_check_early(struct pt_regs *regs) 
	if (!nested)

		nmi_exit();



	this_cpu_set_ftrace_enabled(ftrace_enabled);



	return handled;

}