diff options
| -rw-r--r-- | arch/x86/include/asm/special_insns.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index c8c8143ab27b..b2e84d113f2a 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -31,7 +31,20 @@ static inline unsigned long native_read_cr0(void) static inline void native_write_cr0(unsigned long val) { - asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order)); + unsigned long bits_missing = 0; + +set_register: + asm volatile("mov %0,%%cr0": "+r" (val), "+m" (__force_order)); + + if (static_branch_likely(&cr_pinning)) { + if (unlikely((val & X86_CR0_WP) != X86_CR0_WP)) { + bits_missing = X86_CR0_WP; + val |= bits_missing; + goto set_register; + } + /* Warn after we've set the missing bits. */ + WARN_ONCE(bits_missing, "CR0 WP bit went missing!?\n"); + } } static inline unsigned long native_read_cr2(void) |