diff options
Diffstat (limited to 'arch/x86/include/asm/set_memory.h')
| -rw-r--r-- | arch/x86/include/asm/set_memory.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h index 34cffcef7375..07a25753e85c 100644 --- a/arch/x86/include/asm/set_memory.h +++ b/arch/x86/include/asm/set_memory.h @@ -89,4 +89,46 @@ extern int kernel_set_to_readonly; void set_kernel_text_rw(void); void set_kernel_text_ro(void); +#ifdef CONFIG_X86_64 +static inline int set_mce_nospec(unsigned long pfn) +{ + unsigned long decoy_addr; + int rc; + + /* + * Mark the linear address as UC to make sure we don't log more + * errors because of speculative access to the page. + * We would like to just call: + * set_memory_uc((unsigned long)pfn_to_kaddr(pfn), 1); + * but doing that would radically increase the odds of a + * speculative access to the poison page because we'd have + * the virtual address of the kernel 1:1 mapping sitting + * around in registers. + * Instead we get tricky. We create a non-canonical address + * that looks just like the one we want, but has bit 63 flipped. + * This relies on set_memory_uc() properly sanitizing any __pa() + * results with __PHYSICAL_MASK or PTE_PFN_MASK. + */ + decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63)); + + rc = set_memory_uc(decoy_addr, 1); + if (rc) + pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn); + return rc; +} +#define set_mce_nospec set_mce_nospec + +/* Restore full speculative operation to the pfn. */ +static inline int clear_mce_nospec(unsigned long pfn) +{ + return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1); +} +#define clear_mce_nospec clear_mce_nospec +#else +/* + * Few people would run a 32-bit kernel on a machine that supports + * recoverable errors because they have too much memory to boot 32-bit. + */ +#endif + #endif /* _ASM_X86_SET_MEMORY_H */ |