Re: [PATCH] powerpc/mce: save ignore_event flag unconditionally for UE

[Ganesh]

On 4/20/21 12:54 PM, Santosh Sivaraj wrote:

Hi Ganesh,

Ganesh Goudar <ganes...@linux.ibm.com> writes:

When we hit an UE while using machine check safe copy routines,
ignore_event flag is set and the event is ignored by mce handler,
And the flag is also saved for defered handling and printing of
mce event information, But as of now saving of this flag is done
on checking if the effective address is provided or physical address
is calculated, which is not right.

Save ignore_event flag regardless of whether the effective address is
provided or physical address is calculated.

Without this change following log is seen, when the event is to be
ignored.

[  512.971365] MCE: CPU1: machine check (Severe)  UE Load/Store [Recovered]
[  512.971509] MCE: CPU1: NIP: [c0000000000b67c0] memcpy+0x40/0x90
[  512.971655] MCE: CPU1: Initiator CPU
[  512.971739] MCE: CPU1: Unknown
[  512.972209] MCE: CPU1: machine check (Severe)  UE Load/Store [Recovered]
[  512.972334] MCE: CPU1: NIP: [c0000000000b6808] memcpy+0x88/0x90
[  512.972456] MCE: CPU1: Initiator CPU
[  512.972534] MCE: CPU1: Unknown

Signed-off-by: Ganesh Goudar <ganes...@linux.ibm.com>
---
  arch/powerpc/kernel/mce.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index 11f0cae086ed..db9363e131ce 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -131,6 +131,8 @@ void save_mce_event(struct pt_regs *regs, long handled,
         * Populate the mce error_type and type-specific error_type.
         */
        mce_set_error_info(mce, mce_err);
+       if (mce->error_type == MCE_ERROR_TYPE_UE)
+               mce->u.ue_error.ignore_event = mce_err->ignore_event;

if (!addr)

                return;
@@ -159,7 +161,6 @@ void save_mce_event(struct pt_regs *regs, long handled,
                if (phys_addr != ULONG_MAX) {
                        mce->u.ue_error.physical_address_provided = true;
                        mce->u.ue_error.physical_address = phys_addr;
-                       mce->u.ue_error.ignore_event = mce_err->ignore_event;
                        machine_check_ue_event(mce);
                }
        }

Small nit:
Setting ignore event can happen before the phys_addr check, under the existing
check for MCE_ERROR_TYPE_UE, instead of repeating the same condition again.

In some cases we may not get effective address also, so it is placed before 
effective
address check.

Except for the above nit

Reviewed-by: Santosh Sivaraj <sant...@fossix.org>

Thanks,
Santosh

--
2.26.2