[tip:x86/cpu] x86, AMD: Correct {rd,wr}msr_amd_safe warnings

tip-bot for Borislav Petkov
2013-04-08T16:29:32Z

Commit-ID: 982f33db626e7b42f44e0d404ebb110bf139c18b
Gitweb: http://git.kernel.org/tip/982f33db626e7b42f44e0d404ebb110bf139c18b
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Mon, 8 Apr 2013 17:57:45 +0200
Committer: H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 8 Apr 2013 09:07:17 -0700

x86, AMD: Correct {rd,wr}msr_amd_safe warnings

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>
Link: http://lkml.kernel.org/r/1365436666-9837-4-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
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 9a2a716..cea02d7 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;