diff options
Diffstat (limited to 'arch/arm64/mm/mmap.c')
| -rw-r--r-- | arch/arm64/mm/mmap.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 08ee177432c2..92b2f5097a96 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -34,6 +34,8 @@ static pgprot_t protection_map[16] __ro_after_init = { [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_EXEC }; +static ptdesc_t gcs_page_prot __ro_after_init = _PAGE_GCS_RO; + /* * You really shouldn't be using read() or write() on /dev/mem. This might go * away in the future. @@ -73,9 +75,11 @@ static int __init adjust_protection_map(void) protection_map[VM_EXEC | VM_SHARED] = PAGE_EXECONLY; } - if (lpa2_is_enabled()) + if (lpa2_is_enabled()) { for (int i = 0; i < ARRAY_SIZE(protection_map); i++) pgprot_val(protection_map[i]) &= ~PTE_SHARED; + gcs_page_prot &= ~PTE_SHARED; + } return 0; } @@ -87,7 +91,11 @@ pgprot_t vm_get_page_prot(vm_flags_t vm_flags) /* Short circuit GCS to avoid bloating the table. */ if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { - prot = _PAGE_GCS_RO; + /* Honour mprotect(PROT_NONE) on shadow stack mappings */ + if (vm_flags & VM_ACCESS_FLAGS) + prot = gcs_page_prot; + else + prot = pgprot_val(protection_map[VM_NONE]); } else { prot = pgprot_val(protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); |