diff options
Diffstat (limited to 'arch/x86/mm/pageattr.c')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 61 |
1 files changed, 52 insertions, 9 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 61ff27848452..1f2519055b30 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -42,6 +42,13 @@ struct cpa_data { struct page **pages; }; +enum cpa_warn { + CPA_PROTECT, + CPA_DETECT, +}; + +static const int cpa_warn_level = CPA_PROTECT; + /* * Serialize cpa() (for !DEBUG_PAGEALLOC which uses large identity mappings) * using cpa_lock. So that we don't allow any other cpu, with stale large tlb @@ -395,6 +402,28 @@ static pgprotval_t protect_kernel_text_ro(unsigned long start, } #endif +static inline bool conflicts(pgprot_t prot, pgprotval_t val) +{ + return (pgprot_val(prot) & ~val) != pgprot_val(prot); +} + +static inline void check_conflict(int warnlvl, pgprot_t prot, pgprotval_t val, + unsigned long start, unsigned long end, + unsigned long pfn, const char *txt) +{ + static const char *lvltxt[] = { + [CPA_PROTECT] = "protect", + [CPA_DETECT] = "detect", + }; + + if (warnlvl > cpa_warn_level || !conflicts(prot, val)) + return; + + pr_warn("CPA %8s %10s: 0x%016lx - 0x%016lx PFN %lx req %016llx prevent %016llx\n", + lvltxt[warnlvl], txt, start, end, pfn, (unsigned long long)pgprot_val(prot), + (unsigned long long)val); +} + /* * Certain areas of memory on x86 require very specific protection flags, * for example the BIOS area or kernel text. Callers don't always get this @@ -402,19 +431,31 @@ static pgprotval_t protect_kernel_text_ro(unsigned long start, * checks and fixes these known static required protection bits. */ static inline pgprot_t static_protections(pgprot_t prot, unsigned long start, - unsigned long pfn, unsigned long npg) + unsigned long pfn, unsigned long npg, + int warnlvl) { - pgprotval_t forbidden; + pgprotval_t forbidden, res; unsigned long end; /* Operate on the virtual address */ end = start + npg * PAGE_SIZE - 1; - forbidden = protect_kernel_text(start, end); - forbidden |= protect_kernel_text_ro(start, end); + + res = protect_kernel_text(start, end); + check_conflict(warnlvl, prot, res, start, end, pfn, "Text NX"); + forbidden = res; + + res = protect_kernel_text_ro(start, end); + check_conflict(warnlvl, prot, res, start, end, pfn, "Text RO"); + forbidden |= res; /* Check the PFN directly */ - forbidden |= protect_pci_bios(pfn, pfn + npg - 1); - forbidden |= protect_rodata(pfn, pfn + npg - 1); + res = protect_pci_bios(pfn, pfn + npg - 1); + check_conflict(warnlvl, prot, res, start, end, pfn, "PCIBIOS NX"); + forbidden |= res; + + res = protect_rodata(pfn, pfn + npg - 1); + check_conflict(warnlvl, prot, res, start, end, pfn, "Rodata RO"); + forbidden |= res; return __pgprot(pgprot_val(prot) & ~forbidden); } @@ -686,10 +727,11 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address, * in it results in a different pgprot than the first one of the * requested range. If yes, then the page needs to be split. */ - new_prot = static_protections(req_prot, address, pfn, 1); + new_prot = static_protections(req_prot, address, pfn, 1, CPA_DETECT); pfn = old_pfn; for (i = 0, addr = lpaddr; i < numpages; i++, addr += PAGE_SIZE, pfn++) { - pgprot_t chk_prot = static_protections(req_prot, addr, pfn, 1); + pgprot_t chk_prot = static_protections(req_prot, addr, pfn, 1, + CPA_DETECT); if (pgprot_val(chk_prot) != pgprot_val(new_prot)) return 1; @@ -1299,7 +1341,8 @@ repeat: pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr); pgprot_val(new_prot) |= pgprot_val(cpa->mask_set); - new_prot = static_protections(new_prot, address, pfn, 1); + new_prot = static_protections(new_prot, address, pfn, 1, + CPA_PROTECT); new_prot = pgprot_clear_protnone_bits(new_prot); |