[PATCH 3/4] x86, AMD: Correct {rd,wr}msr_amd_safe warnings

Borislav Petkov
2013-04-08T15:58:19Z

From: Borislav Petkov <bp@suse.de>

The idea with those routines is to slowly phase them out and not call
them on anything else besides K8. They even have a check for that which,
when called too early, fails. Let me explain:

It gets the cpuinfo_x86 pointer from the per_cpu array and when this
happens for cpu0, before its boot_cpu_data has been copied back to the
per_cpu array in smp_store_boot_cpu_info(), we get an empty struct and
thus the check fails.

Use boot_cpu_data directly instead.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/cpu/amd.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 9a2a71669c5d..cea02d703bca 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -20,11 +20,11 @@

static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
{
- struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
u32 gprs[8] = { 0 };
int err;

- WARN_ONCE((c->x86 != 0xf), "%s should only be used on K8!\n", __func__);
+ WARN_ONCE((boot_cpu_data.x86 != 0xf),
+ "%s should only be used on K8!\n", __func__);

gprs[1] = msr;
gprs[7] = 0x9c5a203a;
@@ -38,10 +38,10 @@ static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)

static inline int wrmsrl_amd_safe(unsigned msr, unsigned long long val)
{
- struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
u32 gprs[8] = { 0 };

- WARN_ONCE((c->x86 != 0xf), "%s should only be used on K8!\n", __func__);
+ WARN_ONCE((boot_cpu_data.x86 != 0xf),
+ "%s should only be used on K8!\n", __func__);

gprs[0] = (u32)val;
gprs[1] = msr;
--
1.8.2.135.g7b592fa