From: Pawan Gupta pawan.kumar.gupta@linux.intel.com
commit 286836a70433fb64131d2590f4bf512097c255e1 upstream.
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 Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/common.c | 15 +++++++++++---- arch/x86/kernel/cpu/cpu.h | 2 ++ 2 files changed, 13 insertions(+), 4 deletions(-)
--- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -918,19 +918,26 @@ static bool __init cpu_matches(unsigned 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); --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -49,4 +49,6 @@ extern void cpu_detect_cache_sizes(struc
extern void x86_spec_ctrl_setup_ap(void);
+extern u64 x86_read_arch_cap_msr(void); + #endif /* ARCH_X86_CPU_H */