diff options
Diffstat (limited to 'arch/x86/mm/pageattr.c')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 97 |
1 files changed, 43 insertions, 54 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 85cf12219dea..0f3d50f4c48c 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -298,9 +298,11 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, /* * The .rodata section needs to be read-only. Using the pfn - * catches all aliases. + * catches all aliases. This also includes __ro_after_init, + * so do not enforce until kernel_set_to_readonly is true. */ - if (within(pfn, __pa_symbol(__start_rodata) >> PAGE_SHIFT, + if (kernel_set_to_readonly && + within(pfn, __pa_symbol(__start_rodata) >> PAGE_SHIFT, __pa_symbol(__end_rodata) >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_RW; @@ -512,6 +514,23 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) #endif } +static pgprot_t pgprot_clear_protnone_bits(pgprot_t prot) +{ + /* + * _PAGE_GLOBAL means "global page" for present PTEs. + * But, it is also used to indicate _PAGE_PROTNONE + * for non-present PTEs. + * + * This ensures that a _PAGE_GLOBAL PTE going from + * present to non-present is not confused as + * _PAGE_PROTNONE. + */ + if (!(pgprot_val(prot) & _PAGE_PRESENT)) + pgprot_val(prot) &= ~_PAGE_GLOBAL; + + return prot; +} + static int try_preserve_large_page(pte_t *kpte, unsigned long address, struct cpa_data *cpa) @@ -566,6 +585,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * up accordingly. */ old_pte = *kpte; + /* Clear PSE (aka _PAGE_PAT) and move PAT bit to correct position */ req_prot = pgprot_large_2_4k(old_prot); pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr); @@ -577,19 +597,9 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * different bit positions in the two formats. */ req_prot = pgprot_4k_2_large(req_prot); - - /* - * Set the PSE and GLOBAL flags only if the PRESENT flag is - * set otherwise pmd_present/pmd_huge will return true even on - * a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL - * for the ancient hardware that doesn't support it. - */ + req_prot = pgprot_clear_protnone_bits(req_prot); if (pgprot_val(req_prot) & _PAGE_PRESENT) - pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL; - else - pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL); - - req_prot = canon_pgprot(req_prot); + pgprot_val(req_prot) |= _PAGE_PSE; /* * old_pfn points to the large page base pfn. So we need @@ -674,8 +684,12 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, switch (level) { case PG_LEVEL_2M: ref_prot = pmd_pgprot(*(pmd_t *)kpte); - /* clear PSE and promote PAT bit to correct position */ + /* + * Clear PSE (aka _PAGE_PAT) and move + * PAT bit to correct position. + */ ref_prot = pgprot_large_2_4k(ref_prot); + ref_pfn = pmd_pfn(*(pmd_t *)kpte); break; @@ -698,23 +712,14 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, return 1; } - /* - * Set the GLOBAL flags only if the PRESENT flag is set - * otherwise pmd/pte_present will return true even on a non - * present pmd/pte. The canon_pgprot will clear _PAGE_GLOBAL - * for the ancient hardware that doesn't support it. - */ - if (pgprot_val(ref_prot) & _PAGE_PRESENT) - pgprot_val(ref_prot) |= _PAGE_GLOBAL; - else - pgprot_val(ref_prot) &= ~_PAGE_GLOBAL; + ref_prot = pgprot_clear_protnone_bits(ref_prot); /* * Get the target pfn from the original entry: */ pfn = ref_pfn; for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc) - set_pte(&pbase[i], pfn_pte(pfn, canon_pgprot(ref_prot))); + set_pte(&pbase[i], pfn_pte(pfn, ref_prot)); if (virt_addr_valid(address)) { unsigned long pfn = PFN_DOWN(__pa(address)); @@ -930,19 +935,7 @@ static void populate_pte(struct cpa_data *cpa, pte = pte_offset_kernel(pmd, start); - /* - * Set the GLOBAL flags only if the PRESENT flag is - * set otherwise pte_present will return true even on - * a non present pte. The canon_pgprot will clear - * _PAGE_GLOBAL for the ancient hardware that doesn't - * support it. - */ - if (pgprot_val(pgprot) & _PAGE_PRESENT) - pgprot_val(pgprot) |= _PAGE_GLOBAL; - else - pgprot_val(pgprot) &= ~_PAGE_GLOBAL; - - pgprot = canon_pgprot(pgprot); + pgprot = pgprot_clear_protnone_bits(pgprot); while (num_pages-- && start < end) { set_pte(pte, pfn_pte(cpa->pfn, pgprot)); @@ -1234,24 +1227,14 @@ repeat: new_prot = static_protections(new_prot, address, pfn); - /* - * Set the GLOBAL flags only if the PRESENT flag is - * set otherwise pte_present will return true even on - * a non present pte. The canon_pgprot will clear - * _PAGE_GLOBAL for the ancient hardware that doesn't - * support it. - */ - if (pgprot_val(new_prot) & _PAGE_PRESENT) - pgprot_val(new_prot) |= _PAGE_GLOBAL; - else - pgprot_val(new_prot) &= ~_PAGE_GLOBAL; + new_prot = pgprot_clear_protnone_bits(new_prot); /* * We need to keep the pfn from the existing PTE, * after all we're only going to change it's attributes * not the memory it points to */ - new_pte = pfn_pte(pfn, canon_pgprot(new_prot)); + new_pte = pfn_pte(pfn, new_prot); cpa->pfn = pfn; /* * Do we really change anything ? @@ -1428,11 +1411,11 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages, memset(&cpa, 0, sizeof(cpa)); /* - * Check, if we are requested to change a not supported - * feature: + * Check, if we are requested to set a not supported + * feature. Clearing non-supported features is OK. */ mask_set = canon_pgprot(mask_set); - mask_clr = canon_pgprot(mask_clr); + if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split) return 0; @@ -1775,6 +1758,12 @@ int set_memory_4k(unsigned long addr, int numpages) __pgprot(0), 1, 0, NULL); } +int set_memory_nonglobal(unsigned long addr, int numpages) +{ + return change_page_attr_clear(&addr, numpages, + __pgprot(_PAGE_GLOBAL), 0); +} + static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) { struct cpa_data cpa; |