diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 16:30:38 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 10:32:40 +0100 |
| commit | fe379fa4d199abc52d5b4a256e52cf94eff685cf (patch) | |
| tree | 4466b0d16bc23c3b36f574ef17113bb3cbcfd497 /arch/x86/kernel/cpu/common.c | |
| parent | 99c95c5d4f1027130d555fdb27b576520894827d (diff) | |
x86/ibt: Disable IBT around firmware
Assume firmware isn't IBT clean and disable it across calls.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.759989383@infradead.org
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 709acab25f3c..03bd73f16d74 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -517,6 +517,34 @@ static __init int setup_disable_pku(char *arg) __setup("nopku", setup_disable_pku); #endif /* CONFIG_X86_64 */ +#ifdef CONFIG_X86_KERNEL_IBT + +__noendbr u64 ibt_save(void) +{ + u64 msr = 0; + + if (cpu_feature_enabled(X86_FEATURE_IBT)) { + rdmsrl(MSR_IA32_S_CET, msr); + wrmsrl(MSR_IA32_S_CET, msr & ~CET_ENDBR_EN); + } + + return msr; +} + +__noendbr void ibt_restore(u64 save) +{ + u64 msr; + + if (cpu_feature_enabled(X86_FEATURE_IBT)) { + rdmsrl(MSR_IA32_S_CET, msr); + msr &= ~CET_ENDBR_EN; + msr |= (save & CET_ENDBR_EN); + wrmsrl(MSR_IA32_S_CET, msr); + } +} + +#endif + static __always_inline void setup_cet(struct cpuinfo_x86 *c) { u64 msr = CET_ENDBR_EN; |