63 lines
1.9 KiB
Diff
63 lines
1.9 KiB
Diff
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
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Date: Wed, 23 Oct 2019 10:52:35 +0200
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Subject: x86/cpu: Add a helper function x86_read_arch_cap_msr()
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commit 286836a70433fb64131d2590f4bf512097c255e1 upstream
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Add a helper function to read the IA32_ARCH_CAPABILITIES MSR.
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Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
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Signed-off-by: Borislav Petkov <bp@suse.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
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Reviewed-by: Mark Gross <mgross@linux.intel.com>
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Reviewed-by: Tony Luck <tony.luck@intel.com>
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Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
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---
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arch/x86/kernel/cpu/common.c | 15 +++++++++++----
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arch/x86/kernel/cpu/cpu.h | 2 ++
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2 files changed, 13 insertions(+), 4 deletions(-)
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--- a/arch/x86/kernel/cpu/common.c
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+++ b/arch/x86/kernel/cpu/common.c
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@@ -1017,19 +1017,26 @@ static bool __init cpu_matches(unsigned
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return m && !!(m->driver_data & which);
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}
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-static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
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+u64 x86_read_arch_cap_msr(void)
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{
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u64 ia32_cap = 0;
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+ if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
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+ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
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+
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+ return ia32_cap;
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+}
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+
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+static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
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+{
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+ u64 ia32_cap = x86_read_arch_cap_msr();
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+
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if (cpu_matches(NO_SPECULATION))
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return;
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setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
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setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
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- if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES))
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- rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
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-
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if (!cpu_matches(NO_SSB) && !(ia32_cap & ARCH_CAP_SSB_NO) &&
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!cpu_has(c, X86_FEATURE_AMD_SSB_NO))
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setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS);
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--- a/arch/x86/kernel/cpu/cpu.h
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+++ b/arch/x86/kernel/cpu/cpu.h
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@@ -65,4 +65,6 @@ unsigned int aperfmperf_get_khz(int cpu)
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extern void x86_spec_ctrl_setup_ap(void);
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+extern u64 x86_read_arch_cap_msr(void);
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+
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#endif /* ARCH_X86_CPU_H */
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