[PATCH 4/8] x86/MCE/AMD: Collect error info even if valid bits are not set

Borislav Petkov
2018-02-21T10:19:25Z

From: Borislav Petkov <bp@suse.de>

The MCA banks log error info into MCA_ADDR, MCA_MISC0, and MCA_SYND even
if the corresponding valid bits are not set:

"Error handlers should save the values in MCA_ADDR, MCA_MISC0,
and MCA_SYND even if MCA_STATUS[AddrV], MCA_STATUS[MiscV], and
MCA_STATUS[SyndV] are zero."

Do so by setting those bits so that code down the MCE processing path
doesn't need to be changed.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/cpu/mcheck/mce.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index b16b184d90c5..dd713335f5d9 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -437,6 +437,20 @@ static inline void mce_gather_info(struct mce *m, struct pt_regs *regs)
if (mca_cfg.rip_msr)
m->ip = mce_rdmsrl(mca_cfg.rip_msr);
}
+
+ /*
+ * Error handlers should save the values in MCA_ADDR, MCA_MISC0, and
+ * MCA_SYND even if MCA_STATUS[AddrV], MCA_STATUS[MiscV], and
+ * MCA_STATUS[SyndV] are zero.
+ */
+ if (m->cpuvendor == X86_VENDOR_AMD) {
+ u64 status = MCI_STATUS_ADDRV | MCI_STATUS_MISCV;
+
+ if (mce_flags.smca)
+ status |= MCI_STATUS_SYNDV;
+
+ m->status |= status;
+ }
}

int mce_available(struct cpuinfo_x86 *c)
--
2.13.0