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Commit 682469a5 authored by Borislav Petkov's avatar Borislav Petkov
Browse files

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: default avatarBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1365436666-9837-4-git-send-email-bp@alien8.de


Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 55a36b65

arch/x86/kernel/cpu/amd.c

+4 −4
Original line number Diff line number Diff line
@@ -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;