diff options
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/init.c | 23 | ||||
| -rw-r--r-- | arch/x86/mm/kmmio.c | 25 | ||||
| -rw-r--r-- | arch/x86/mm/mmap.c | 21 | ||||
| -rw-r--r-- | arch/x86/mm/pageattr.c | 8 | ||||
| -rw-r--r-- | arch/x86/mm/pti.c | 1 |
5 files changed, 64 insertions, 14 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 74b157ac078d..156ed8154af8 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -4,6 +4,8 @@ #include <linux/swap.h> #include <linux/memblock.h> #include <linux/bootmem.h> /* for max_low_pfn */ +#include <linux/swapfile.h> +#include <linux/swapops.h> #include <asm/set_memory.h> #include <asm/e820/api.h> @@ -911,3 +913,24 @@ void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache) __cachemode2pte_tbl[cache] = __cm_idx2pte(entry); __pte2cachemode_tbl[entry] = cache; } + +unsigned long max_swapfile_size(void) +{ + unsigned long pages; + + pages = generic_max_swapfile_size(); + + if (boot_cpu_has_bug(X86_BUG_L1TF)) { + /* Limit the swap file size to MAX_PA/2 for L1TF workaround */ + unsigned long l1tf_limit = l1tf_pfn_limit() + 1; + /* + * We encode swap offsets also with 3 bits below those for pfn + * which makes the usable limit higher. + */ +#if CONFIG_PGTABLE_LEVELS > 2 + l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT; +#endif + pages = min_t(unsigned long, l1tf_limit, pages); + } + return pages; +} diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c index 7c8686709636..79eb55ce69a9 100644 --- a/arch/x86/mm/kmmio.c +++ b/arch/x86/mm/kmmio.c @@ -126,24 +126,29 @@ static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long addr) static void clear_pmd_presence(pmd_t *pmd, bool clear, pmdval_t *old) { + pmd_t new_pmd; pmdval_t v = pmd_val(*pmd); if (clear) { - *old = v & _PAGE_PRESENT; - v &= ~_PAGE_PRESENT; - } else /* presume this has been called with clear==true previously */ - v |= *old; - set_pmd(pmd, __pmd(v)); + *old = v; + new_pmd = pmd_mknotpresent(*pmd); + } else { + /* Presume this has been called with clear==true previously */ + new_pmd = __pmd(*old); + } + set_pmd(pmd, new_pmd); } static void clear_pte_presence(pte_t *pte, bool clear, pteval_t *old) { pteval_t v = pte_val(*pte); if (clear) { - *old = v & _PAGE_PRESENT; - v &= ~_PAGE_PRESENT; - } else /* presume this has been called with clear==true previously */ - v |= *old; - set_pte_atomic(pte, __pte(v)); + *old = v; + /* Nothing should care about address */ + pte_clear(&init_mm, 0, pte); + } else { + /* Presume this has been called with clear==true previously */ + set_pte_atomic(pte, __pte(*old)); + } } static int clear_page_presence(struct kmmio_fault_page *f, bool clear) diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 48c591251600..f40ab8185d94 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -240,3 +240,24 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t count) return phys_addr_valid(addr + count - 1); } + +/* + * Only allow root to set high MMIO mappings to PROT_NONE. + * This prevents an unpriv. user to set them to PROT_NONE and invert + * them, then pointing to valid memory for L1TF speculation. + * + * Note: for locked down kernels may want to disable the root override. + */ +bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot) +{ + if (!boot_cpu_has_bug(X86_BUG_L1TF)) + return true; + if (!__pte_needs_invert(pgprot_val(prot))) + return true; + /* If it's real memory always allow */ + if (pfn_valid(pfn)) + return true; + if (pfn > l1tf_pfn_limit() && !capable(CAP_SYS_ADMIN)) + return false; + return true; +} diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 0a74996a1149..8d6c34fe49be 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1015,8 +1015,8 @@ static long populate_pmd(struct cpa_data *cpa, pmd = pmd_offset(pud, start); - set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | - massage_pgprot(pmd_pgprot))); + set_pmd(pmd, pmd_mkhuge(pfn_pmd(cpa->pfn, + canon_pgprot(pmd_pgprot)))); start += PMD_SIZE; cpa->pfn += PMD_SIZE >> PAGE_SHIFT; @@ -1088,8 +1088,8 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, p4d_t *p4d, * Map everything starting from the Gb boundary, possibly with 1G pages */ while (boot_cpu_has(X86_FEATURE_GBPAGES) && end - start >= PUD_SIZE) { - set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | - massage_pgprot(pud_pgprot))); + set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn, + canon_pgprot(pud_pgprot)))); start += PUD_SIZE; cpa->pfn += PUD_SIZE >> PAGE_SHIFT; diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index d58b4aba9510..31341ae7309f 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -45,6 +45,7 @@ #include <asm/pgalloc.h> #include <asm/tlbflush.h> #include <asm/desc.h> +#include <asm/sections.h> #undef pr_fmt #define pr_fmt(fmt) "Kernel/User page tables isolation: " fmt |