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x86/cpu: Add a helper function x86_read_arch_cap_msr() 

Add a helper function to read the IA32_ARCH_CAPABILITIES MSR.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Pawan Gupta 2019-10-23 10:52:35 +02:00 committed by Thomas Gleixner
parent c2955f270a
commit 286836a704
2 changed files with 13 additions and 4 deletions
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15
arch/x86/kernel/cpu/common.c
View File

@ -1092,19 +1092,26 @@ static bool __init cpu_matches(unsigned long which)
return m && !!(m->driver_data & which);
}
static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
u64 x86_read_arch_cap_msr(void)
{
u64 ia32_cap = 0;
if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
return ia32_cap;
}
static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
{
u64 ia32_cap = x86_read_arch_cap_msr();
if (cpu_matches(NO_SPECULATION))
return;
setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES))
rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
if (!cpu_matches(NO_SSB) && !(ia32_cap & ARCH_CAP_SSB_NO) &&
!cpu_has(c, X86_FEATURE_AMD_SSB_NO))
setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS);

2
arch/x86/kernel/cpu/cpu.h
View File

@ -62,4 +62,6 @@ unsigned int aperfmperf_get_khz(int cpu);
extern void x86_spec_ctrl_setup_ap(void);
extern u64 x86_read_arch_cap_msr(void);
#endif /* ARCH_X86_CPU_H */