diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h index 07a25753e85c..bc97b8c0fdf7 100644 --- a/arch/x86/include/asm/set_memory.h +++ b/arch/x86/include/asm/set_memory.h @@ -90,28 +90,35 @@ 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) +/* + * Prevent speculative access to the page by either unmapping + * it (if we do not require access to any part of the page) or + * marking it uncacheable (if we want to try to retrieve data + * from non-poisoned lines in the page). + */ +static inline int set_mce_nospec(unsigned long pfn, bool unmap) { 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); + * set_memory_XX((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() + * This relies on set_memory_XX() 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 (unmap) + rc = set_memory_np(decoy_addr, 1); + else + 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; diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 1f69b12d5bb8..2a13468f8773 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -535,6 +535,13 @@ bool mce_is_memory_error(struct mce *m) } EXPORT_SYMBOL_GPL(mce_is_memory_error); +static bool whole_page(struct mce *m) +{ + if (!mca_cfg.ser || !(m->status & MCI_STATUS_MISCV)) + return true; + return MCI_MISC_ADDR_LSB(m->misc) >= PAGE_SHIFT; +} + bool mce_is_correctable(struct mce *m) { if (m->cpuvendor == X86_VENDOR_AMD && m->status & MCI_STATUS_DEFERRED) @@ -600,7 +607,7 @@ static int srao_decode_notifier(struct notifier_block *nb, unsigned long val, if (mce_usable_address(mce) && (mce->severity == MCE_AO_SEVERITY)) { pfn = mce->addr >> PAGE_SHIFT; if (!memory_failure(pfn, 0)) - set_mce_nospec(pfn); + set_mce_nospec(pfn, whole_page(mce)); } return NOTIFY_OK; @@ -1101,7 +1108,7 @@ static int do_memory_failure(struct mce *m) if (ret) pr_err("Memory error not recovered"); else - set_mce_nospec(m->addr >> PAGE_SHIFT); + set_mce_nospec(m->addr >> PAGE_SHIFT, whole_page(m)); return ret; } diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h index 2a986d282a97..a0e15e7b0b99 100644 --- a/include/linux/set_memory.h +++ b/include/linux/set_memory.h @@ -18,7 +18,7 @@ static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; } #endif #ifndef set_mce_nospec -static inline int set_mce_nospec(unsigned long pfn) +static inline int set_mce_nospec(unsigned long pfn, bool unmap) { return 0; }