# \[PATCH v4 07/16\] powerpc/pseries/ras: fwnmi avoid modifying r3 in error case - From: Nicholas Piggin \ - Date: 2020-05-08 04:51:14 - List: linuxppc-dev - Page: https://ratatoskr.run/linuxppc-dev/2020/05/9516036 - Thread: https://ratatoskr.run/linuxppc-dev/2020/05/9516029/t.md ```text If there is some error with the fwnmi save area, r3 has already been modified which doesn't help with debugging. Only update r3 when to restore the saved value. Signed-off-by: Nicholas Piggin --- arch/powerpc/platforms/pseries/ras.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index a5bd0f747bb1..fe14186a8cef 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -423,18 +423,19 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void) */ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs) { + unsigned long savep_ra; unsigned long *savep; struct rtas_error_log *h; /* Mask top two bits */ - regs->gpr[3] &= ~(0x3UL << 62); + savep_ra = regs->gpr[3] & ~(0x3UL << 62); - if (!VALID_FWNMI_BUFFER(regs->gpr[3])) { + if (!VALID_FWNMI_BUFFER(savep_ra)) { printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]); return NULL; } - savep = __va(regs->gpr[3]); + savep = __va(savep_ra); regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */ h = (struct rtas_error_log *)&savep[1]; -- 2.23.0 ```