diff options
| -rw-r--r-- | arch/x86/mm/fault_32.c | 59 | ||||
| -rw-r--r-- | arch/x86/mm/fault_64.c | 30 |
2 files changed, 83 insertions, 6 deletions
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c index 31113deeb7c0..eba90198b15a 100644 --- a/arch/x86/mm/fault_32.c +++ b/arch/x86/mm/fault_32.c @@ -217,6 +217,7 @@ KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n" KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n" KERN_ERR "******* Please consider a BIOS update.\n" KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n"; +#endif /* Workaround for K8 erratum #93 & buggy BIOS. BIOS SMM functions are required to use a specific workaround @@ -224,10 +225,12 @@ KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n"; A lot of BIOS that didn't get tested properly miss this. The OS sees this as a page fault with the upper 32bits of RIP cleared. Try to work around it here. - Note we only handle faults in kernel here. */ - + Note we only handle faults in kernel here. + Does nothing for X86_32 + */ static int is_errata93(struct pt_regs *regs, unsigned long address) { +#ifdef CONFIG_X86_64 static int warned; if (address != regs->ip) return 0; @@ -243,9 +246,10 @@ static int is_errata93(struct pt_regs *regs, unsigned long address) regs->ip = address; return 1; } +#endif return 0; } -#endif + /* * Handle a fault on the vmalloc or module mapping area @@ -254,6 +258,7 @@ static int is_errata93(struct pt_regs *regs, unsigned long address) */ static inline int vmalloc_fault(unsigned long address) { +#ifdef CONFIG_X86_32 unsigned long pgd_paddr; pmd_t *pmd_k; pte_t *pte_k; @@ -272,6 +277,51 @@ static inline int vmalloc_fault(unsigned long address) if (!pte_present(*pte_k)) return -1; return 0; +#else + pgd_t *pgd, *pgd_ref; + pud_t *pud, *pud_ref; + pmd_t *pmd, *pmd_ref; + pte_t *pte, *pte_ref; + + /* Copy kernel mappings over when needed. This can also + happen within a race in page table update. In the later + case just flush. */ + + pgd = pgd_offset(current->mm ?: &init_mm, address); + pgd_ref = pgd_offset_k(address); + if (pgd_none(*pgd_ref)) + return -1; + if (pgd_none(*pgd)) + set_pgd(pgd, *pgd_ref); + else + BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); + + /* Below here mismatches are bugs because these lower tables + are shared */ + + pud = pud_offset(pgd, address); + pud_ref = pud_offset(pgd_ref, address); + if (pud_none(*pud_ref)) + return -1; + if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref)) + BUG(); + pmd = pmd_offset(pud, address); + pmd_ref = pmd_offset(pud_ref, address); + if (pmd_none(*pmd_ref)) + return -1; + if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref)) + BUG(); + pte_ref = pte_offset_kernel(pmd_ref, address); + if (!pte_present(*pte_ref)) + return -1; + pte = pte_offset_kernel(pmd, address); + /* Don't use pte_page here, because the mappings can point + outside mem_map, and the NUMA hash lookup cannot handle + that. */ + if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref)) + BUG(); + return 0; +#endif } int show_unhandled_signals = 1; @@ -507,6 +557,9 @@ no_context: if (is_prefetch(regs, address, error_code)) return; + if (is_errata93(regs, address)) + return; + /* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice. diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c index c48d95c306df..75b7b165bdf3 100644 --- a/arch/x86/mm/fault_64.c +++ b/arch/x86/mm/fault_64.c @@ -223,6 +223,7 @@ KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n" KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n" KERN_ERR "******* Please consider a BIOS update.\n" KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n"; +#endif /* Workaround for K8 erratum #93 & buggy BIOS. BIOS SMM functions are required to use a specific workaround @@ -230,10 +231,12 @@ KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n"; A lot of BIOS that didn't get tested properly miss this. The OS sees this as a page fault with the upper 32bits of RIP cleared. Try to work around it here. - Note we only handle faults in kernel here. */ - + Note we only handle faults in kernel here. + Does nothing for X86_32 + */ static int is_errata93(struct pt_regs *regs, unsigned long address) { +#ifdef CONFIG_X86_64 static int warned; if (address != regs->ip) return 0; @@ -249,9 +252,9 @@ static int is_errata93(struct pt_regs *regs, unsigned long address) regs->ip = address; return 1; } +#endif return 0; } -#endif static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs, unsigned long error_code) @@ -278,6 +281,26 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs, */ static int vmalloc_fault(unsigned long address) { +#ifdef CONFIG_X86_32 + unsigned long pgd_paddr; + pmd_t *pmd_k; + pte_t *pte_k; + /* + * Synchronize this task's top level page-table + * with the 'reference' page table. + * + * Do _not_ use "current" here. We might be inside + * an interrupt in the middle of a task switch.. + */ + pgd_paddr = read_cr3(); + pmd_k = vmalloc_sync_one(__va(pgd_paddr), address); + if (!pmd_k) + return -1; + pte_k = pte_offset_kernel(pmd_k, address); + if (!pte_present(*pte_k)) + return -1; + return 0; +#else pgd_t *pgd, *pgd_ref; pud_t *pud, *pud_ref; pmd_t *pmd, *pmd_ref; @@ -321,6 +344,7 @@ static int vmalloc_fault(unsigned long address) if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref)) BUG(); return 0; +#endif } int show_unhandled_signals = 1; |