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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-08 16:59:34 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-08 16:59:34 -0700 |
| commit | a1aab6f3d295f078c008893ee7fa2c011626c46f (patch) | |
| tree | 1ae344c8ed1b1dc531be1ae99188c180ad0c6c7c /arch/x86/kernel/cpu | |
| parent | dad1c12ed831a7a89cc01e5582cd0b81a4be7f19 (diff) | |
| parent | 7457c0da024b181a9143988d740001f9bc98698d (diff) | |
| download | linux-a1aab6f3d295f078c008893ee7fa2c011626c46f.tar.bz2 | |
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
"Most of the changes relate to Peter Zijlstra's cleanup of ptregs
handling, in particular the i386 part is now much simplified and
standardized - no more partial ptregs stack frames via the esp/ss
oddity. This simplifies ftrace, kprobes, the unwinder, ptrace, kdump
and kgdb.
There's also a CR4 hardening enhancements by Kees Cook, to make the
generic platform functions such as native_write_cr4() less useful as
ROP gadgets that disable SMEP/SMAP. Also protect the WP bit of CR0
against similar attacks.
The rest is smaller cleanups/fixes"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/alternatives: Add int3_emulate_call() selftest
x86/stackframe/32: Allow int3_emulate_push()
x86/stackframe/32: Provide consistent pt_regs
x86/stackframe, x86/ftrace: Add pt_regs frame annotations
x86/stackframe, x86/kprobes: Fix frame pointer annotations
x86/stackframe: Move ENCODE_FRAME_POINTER to asm/frame.h
x86/entry/32: Clean up return from interrupt preemption path
x86/asm: Pin sensitive CR0 bits
x86/asm: Pin sensitive CR4 bits
Documentation/x86: Fix path to entry_32.S
x86/asm: Remove unused TASK_TI_flags from asm-offsets.c
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index dad20bc891d5..8febe90470f4 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -366,6 +366,25 @@ out: cr4_clear_bits(X86_CR4_UMIP); } +DEFINE_STATIC_KEY_FALSE_RO(cr_pinning); +EXPORT_SYMBOL(cr_pinning); +unsigned long cr4_pinned_bits __ro_after_init; +EXPORT_SYMBOL(cr4_pinned_bits); + +/* + * Once CPU feature detection is finished (and boot params have been + * parsed), record any of the sensitive CR bits that are set, and + * enable CR pinning. + */ +static void __init setup_cr_pinning(void) +{ + unsigned long mask; + + mask = (X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP); + cr4_pinned_bits = this_cpu_read(cpu_tlbstate.cr4) & mask; + static_key_enable(&cr_pinning.key); +} + /* * Protection Keys are not available in 32-bit mode. */ @@ -1468,6 +1487,7 @@ void __init identify_boot_cpu(void) enable_sep_cpu(); #endif cpu_detect_tlb(&boot_cpu_data); + setup_cr_pinning(); } void identify_secondary_cpu(struct cpuinfo_x86 *c) |