diff options
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/fault.c | 10 | ||||
| -rw-r--r-- | arch/x86/mm/init_64.c | 19 | ||||
| -rw-r--r-- | arch/x86/mm/pat/set_memory.c | 49 |
3 files changed, 67 insertions, 11 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index d728791be8ac..7b0d4ab894c8 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -790,6 +790,8 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code, unsigned long address, struct task_struct *tsk) { const char *loglvl = task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG; + /* This is a racy snapshot, but it's better than nothing. */ + int cpu = raw_smp_processor_id(); if (!unhandled_signal(tsk, SIGSEGV)) return; @@ -803,6 +805,14 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code, print_vma_addr(KERN_CONT " in ", regs->ip); + /* + * Dump the likely CPU where the fatal segfault happened. + * This can help identify faulty hardware. + */ + printk(KERN_CONT " likely on CPU %d (core %d, socket %d)", cpu, + topology_core_id(cpu), topology_physical_package_id(cpu)); + + printk(KERN_CONT "\n"); show_opcodes(regs, loglvl); diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 39b6bfcaa0ed..3f040c6e5d13 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -90,6 +90,12 @@ DEFINE_ENTRY(pud, pud, init) DEFINE_ENTRY(pmd, pmd, init) DEFINE_ENTRY(pte, pte, init) +static inline pgprot_t prot_sethuge(pgprot_t prot) +{ + WARN_ON_ONCE(pgprot_val(prot) & _PAGE_PAT); + + return __pgprot(pgprot_val(prot) | _PAGE_PSE); +} /* * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the @@ -557,9 +563,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, if (page_size_mask & (1<<PG_LEVEL_2M)) { pages++; spin_lock(&init_mm.page_table_lock); - set_pte_init((pte_t *)pmd, - pfn_pte((paddr & PMD_MASK) >> PAGE_SHIFT, - __pgprot(pgprot_val(prot) | _PAGE_PSE)), + set_pmd_init(pmd, + pfn_pmd(paddr >> PAGE_SHIFT, prot_sethuge(prot)), init); spin_unlock(&init_mm.page_table_lock); paddr_last = paddr_next; @@ -644,12 +649,8 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, if (page_size_mask & (1<<PG_LEVEL_1G)) { pages++; spin_lock(&init_mm.page_table_lock); - - prot = __pgprot(pgprot_val(prot) | _PAGE_PSE); - - set_pte_init((pte_t *)pud, - pfn_pte((paddr & PUD_MASK) >> PAGE_SHIFT, - prot), + set_pud_init(pud, + pfn_pud(paddr >> PAGE_SHIFT, prot_sethuge(prot)), init); spin_unlock(&init_mm.page_table_lock); paddr_last = paddr_next; diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index 1abd5438f126..97342c42dda8 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -580,6 +580,46 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long start, } /* + * Validate strict W^X semantics. + */ +static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start, + unsigned long pfn, unsigned long npg) +{ + unsigned long end; + + /* + * 32-bit has some unfixable W+X issues, like EFI code + * and writeable data being in the same page. Disable + * detection and enforcement there. + */ + if (IS_ENABLED(CONFIG_X86_32)) + return new; + + /* Only verify when NX is supported: */ + if (!(__supported_pte_mask & _PAGE_NX)) + return new; + + if (!((pgprot_val(old) ^ pgprot_val(new)) & (_PAGE_RW | _PAGE_NX))) + return new; + + if ((pgprot_val(new) & (_PAGE_RW | _PAGE_NX)) != _PAGE_RW) + return new; + + end = start + npg * PAGE_SIZE - 1; + WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", + (unsigned long long)pgprot_val(old), + (unsigned long long)pgprot_val(new), + start, end, pfn); + + /* + * For now, allow all permission change attempts by returning the + * attempted permissions. This can 'return old' to actively + * refuse the permission change at a later time. + */ + return new; +} + +/* * Lookup the page table entry for a virtual address in a specific pgd. * Return a pointer to the entry and the level of the mapping. */ @@ -885,6 +925,8 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address, new_prot = static_protections(req_prot, lpaddr, old_pfn, numpages, psize, CPA_DETECT); + new_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages); + /* * If there is a conflict, split the large page. * @@ -1525,6 +1567,7 @@ repeat: if (level == PG_LEVEL_4K) { pte_t new_pte; + pgprot_t old_prot = pte_pgprot(old_pte); pgprot_t new_prot = pte_pgprot(old_pte); unsigned long pfn = pte_pfn(old_pte); @@ -1536,6 +1579,8 @@ repeat: new_prot = static_protections(new_prot, address, pfn, 1, 0, CPA_PROTECT); + new_prot = verify_rwx(old_prot, new_prot, address, pfn, 1); + new_prot = pgprot_clear_protnone_bits(new_prot); /* @@ -1944,7 +1989,7 @@ int set_mce_nospec(unsigned long pfn) return rc; } -static int set_memory_present(unsigned long *addr, int numpages) +static int set_memory_p(unsigned long *addr, int numpages) { return change_page_attr_set(addr, numpages, __pgprot(_PAGE_PRESENT), 0); } @@ -1954,7 +1999,7 @@ int clear_mce_nospec(unsigned long pfn) { unsigned long addr = (unsigned long) pfn_to_kaddr(pfn); - return set_memory_present(&addr, 1); + return set_memory_p(&addr, 1); } EXPORT_SYMBOL_GPL(clear_mce_nospec); #endif /* CONFIG_X86_64 */ |