mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 00:48:50 +00:00
6304672b7f
Pull x86/pti updates from Thomas Gleixner:
"Another set of melted spectrum related changes:
- Code simplifications and cleanups for RSB and retpolines.
- Make the indirect calls in KVM speculation safe.
- Whitelist CPUs which are known not to speculate from Meltdown and
prepare for the new CPUID flag which tells the kernel that a CPU is
not affected.
- A less rigorous variant of the module retpoline check which merily
warns when a non-retpoline protected module is loaded and reflects
that fact in the sysfs file.
- Prepare for Indirect Branch Prediction Barrier support.
- Prepare for exposure of the Speculation Control MSRs to guests, so
guest OSes which depend on those "features" can use them. Includes
a blacklist of the broken microcodes. The actual exposure of the
MSRs through KVM is still being worked on"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Simplify indirect_branch_prediction_barrier()
x86/retpoline: Simplify vmexit_fill_RSB()
x86/cpufeatures: Clean up Spectre v2 related CPUID flags
x86/cpu/bugs: Make retpoline module warning conditional
x86/bugs: Drop one "mitigation" from dmesg
x86/nospec: Fix header guards names
x86/alternative: Print unadorned pointers
x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
x86/msr: Add definitions for new speculation control MSRs
x86/cpufeatures: Add AMD feature bits for Speculation Control
x86/cpufeatures: Add Intel feature bits for Speculation Control
x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
module/retpoline: Warn about missing retpoline in module
KVM: VMX: Make indirect call speculation safe
KVM: x86: Make indirect calls in emulator speculation safe
81 lines
2 KiB
C
81 lines
2 KiB
C
/*
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* Routines to identify additional cpu features that are scattered in
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* cpuid space.
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*/
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#include <linux/cpu.h>
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#include <asm/pat.h>
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#include <asm/processor.h>
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#include <asm/apic.h>
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struct cpuid_bit {
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u16 feature;
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u8 reg;
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u8 bit;
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u32 level;
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u32 sub_leaf;
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};
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/* Please keep the leaf sorted by cpuid_bit.level for faster search. */
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static const struct cpuid_bit cpuid_bits[] = {
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{ X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 },
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{ X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 },
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{ X86_FEATURE_CAT_L3, CPUID_EBX, 1, 0x00000010, 0 },
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{ X86_FEATURE_CAT_L2, CPUID_EBX, 2, 0x00000010, 0 },
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{ X86_FEATURE_CDP_L3, CPUID_ECX, 2, 0x00000010, 1 },
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{ X86_FEATURE_CDP_L2, CPUID_ECX, 2, 0x00000010, 2 },
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{ X86_FEATURE_MBA, CPUID_EBX, 3, 0x00000010, 0 },
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{ X86_FEATURE_HW_PSTATE, CPUID_EDX, 7, 0x80000007, 0 },
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{ X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
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{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
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{ X86_FEATURE_SME, CPUID_EAX, 0, 0x8000001f, 0 },
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{ 0, 0, 0, 0, 0 }
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};
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void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
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{
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u32 max_level;
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u32 regs[4];
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const struct cpuid_bit *cb;
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for (cb = cpuid_bits; cb->feature; cb++) {
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/* Verify that the level is valid */
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max_level = cpuid_eax(cb->level & 0xffff0000);
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if (max_level < cb->level ||
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max_level > (cb->level | 0xffff))
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continue;
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cpuid_count(cb->level, cb->sub_leaf, ®s[CPUID_EAX],
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®s[CPUID_EBX], ®s[CPUID_ECX],
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®s[CPUID_EDX]);
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if (regs[cb->reg] & (1 << cb->bit))
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set_cpu_cap(c, cb->feature);
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}
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}
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u32 get_scattered_cpuid_leaf(unsigned int level, unsigned int sub_leaf,
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enum cpuid_regs_idx reg)
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{
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const struct cpuid_bit *cb;
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u32 cpuid_val = 0;
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for (cb = cpuid_bits; cb->feature; cb++) {
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if (level > cb->level)
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continue;
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if (level < cb->level)
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break;
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if (reg == cb->reg && sub_leaf == cb->sub_leaf) {
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if (cpu_has(&boot_cpu_data, cb->feature))
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cpuid_val |= BIT(cb->bit);
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}
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}
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return cpuid_val;
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}
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EXPORT_SYMBOL_GPL(get_scattered_cpuid_leaf);
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