diff options
Diffstat (limited to 'arch/x86/mm/kaiser.c')
| -rw-r--r-- | arch/x86/mm/kaiser.c | 36 |
1 files changed, 32 insertions, 4 deletions
diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index b0b3a69f1c7f..8af98513d36c 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -20,6 +20,7 @@ #include <asm/pgalloc.h> #include <asm/desc.h> #include <asm/cmdline.h> +#include <asm/vsyscall.h> int kaiser_enabled __read_mostly = 1; EXPORT_SYMBOL(kaiser_enabled); /* for inlined TLB flush functions */ @@ -111,12 +112,13 @@ static inline unsigned long get_pa_from_mapping(unsigned long vaddr) * * Returns a pointer to a PTE on success, or NULL on failure. */ -static pte_t *kaiser_pagetable_walk(unsigned long address) +static pte_t *kaiser_pagetable_walk(unsigned long address, bool user) { pmd_t *pmd; pud_t *pud; pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(address)); gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO); + unsigned long prot = _KERNPG_TABLE; if (pgd_none(*pgd)) { WARN_ONCE(1, "All shadow pgds should have been populated"); @@ -124,6 +126,17 @@ static pte_t *kaiser_pagetable_walk(unsigned long address) } BUILD_BUG_ON(pgd_large(*pgd) != 0); + if (user) { + /* + * The vsyscall page is the only page that will have + * _PAGE_USER set. Catch everything else. + */ + BUG_ON(address != VSYSCALL_ADDR); + + set_pgd(pgd, __pgd(pgd_val(*pgd) | _PAGE_USER)); + prot = _PAGE_TABLE; + } + pud = pud_offset(pgd, address); /* The shadow page tables do not use large mappings: */ if (pud_large(*pud)) { @@ -136,7 +149,7 @@ static pte_t *kaiser_pagetable_walk(unsigned long address) return NULL; spin_lock(&shadow_table_allocation_lock); if (pud_none(*pud)) { - set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page))); + set_pud(pud, __pud(prot | __pa(new_pmd_page))); __inc_zone_page_state(virt_to_page((void *) new_pmd_page), NR_KAISERTABLE); } else @@ -156,7 +169,7 @@ static pte_t *kaiser_pagetable_walk(unsigned long address) return NULL; spin_lock(&shadow_table_allocation_lock); if (pmd_none(*pmd)) { - set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page))); + set_pmd(pmd, __pmd(prot | __pa(new_pte_page))); __inc_zone_page_state(virt_to_page((void *) new_pte_page), NR_KAISERTABLE); } else @@ -185,6 +198,8 @@ static int kaiser_add_user_map(const void *__start_addr, unsigned long size, * requires that not to be #defined to 0): so mask it off here. */ flags &= ~_PAGE_GLOBAL; + if (!(__supported_pte_mask & _PAGE_NX)) + flags &= ~_PAGE_NX; for (; address < end_addr; address += PAGE_SIZE) { target_address = get_pa_from_mapping(address); @@ -192,7 +207,7 @@ static int kaiser_add_user_map(const void *__start_addr, unsigned long size, ret = -EIO; break; } - pte = kaiser_pagetable_walk(address); + pte = kaiser_pagetable_walk(address, flags & _PAGE_USER); if (!pte) { ret = -ENOMEM; break; @@ -319,6 +334,19 @@ void __init kaiser_init(void) kaiser_init_all_pgds(); + /* + * Note that this sets _PAGE_USER and it needs to happen when the + * pagetable hierarchy gets created, i.e., early. Otherwise + * kaiser_pagetable_walk() will encounter initialized PTEs in the + * hierarchy and not set the proper permissions, leading to the + * pagefaults with page-protection violations when trying to read the + * vsyscall page. For example. + */ + if (vsyscall_enabled()) + kaiser_add_user_map_early((void *)VSYSCALL_ADDR, + PAGE_SIZE, + __PAGE_KERNEL_VSYSCALL); + for_each_possible_cpu(cpu) { void *percpu_vaddr = __per_cpu_user_mapped_start + per_cpu_offset(cpu); |