From ee1dd1e3dc774cf257012215d996e8e7e370c162 Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Wed, 10 Jul 2013 18:32:56 +0530 Subject: [PATCH] powerpc: Fix the corrupt r3 error during MCE handling. During Machine Check interrupt on pseries platform, R3 generally points to memory region inside RTAS (FWNMI) area. We see r3 corruption because when RTAS delivers the machine check exception it passes the address inside FWNMI area with the top most bit set. This patch fixes this issue by masking top two bit in machine check exception handler. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/ras.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index 7b3cbde8c783..721c0586b284 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -287,6 +287,9 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs) unsigned long *savep; struct rtas_error_log *h, *errhdr = NULL; + /* Mask top two bits */ + regs->gpr[3] &= ~(0x3UL << 62); + if (!VALID_FWNMI_BUFFER(regs->gpr[3])) { printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]); return NULL; -- 2.20.1