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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-14-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2020-05-08 14:34:05 +10:00 committed by Michael Ellerman
parent f2d7f62e4a
commit abd106fb43

View file

@ -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;
}