[PATCH 3.10 246/268] x86/mce/AMD: Give a name to MCA bank 3 when accessed with legacy MSRs

From: Willy Tarreau
Date: Mon Jun 19 2017 - 15:26:18 EST

From: Yazen Ghannam <yazen.ghannam@xxxxxxx>

commit 29f72ce3e4d18066ec75c79c857bee0618a3504b upstream.

MCA bank 3 is reserved on systems pre-Fam17h, so it didn't have a name.
However, MCA bank 3 is defined on Fam17h systems and can be accessed
using legacy MSRs. Without a name we get a stack trace on Fam17h systems
when trying to register sysfs files for bank 3 on kernels that don't
recognize Scalable MCA.

Call MCA bank 3 "decode_unit" since this is what it represents on
Fam17h. This will allow kernels without SMCA support to see this bank on
Fam17h+ and prevent the stack trace. This will not affect older systems
since this bank is reserved on them, i.e. it'll be ignored.

Tested on AMD Fam15h and Fam17h systems.

WARNING: CPU: 26 PID: 1 at lib/kobject.c:210 kobject_add_internal
kobject: (ffff88085bb256c0): attempted to be registered with empty name!
Call Trace:

Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: http://lkml.kernel.org/r/1490102285-3659-1-git-send-email-Yazen.Ghannam@xxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
arch/x86/kernel/cpu/mcheck/mce_amd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index 9cb5276..338a4ae 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -51,7 +51,7 @@ static const char * const th_names[] = {
- "",
+ "decode_unit",