path: root/mm/mmap.c
diff options
authorVladimir Murzin <vladimir.murzin@arm.com>2021-03-12 17:38:10 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2021-03-26 09:37:23 +0000
commit18107f8a2df6bf1c6cac8d0713f757f866d5af51 (patch)
tree0411230b8d6c259233a6aadcd0c0aaf261b86c2a /mm/mmap.c
parentLinux 5.12-rc3 (diff)
arm64: Support execute-only permissions with Enhanced PAN
Enhanced Privileged Access Never (EPAN) allows Privileged Access Never to be used with Execute-only mappings. Absence of such support was a reason for 24cecc377463 ("arm64: Revert support for execute-only user mappings"). Thus now it can be revisited and re-enabled. Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210312173811.58284-2-vladimir.murzin@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'mm/mmap.c')
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 3f287599a7a3..1d96a21acb2f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -93,6 +93,12 @@ static void unmap_region(struct mm_struct *mm,
* MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
* w: (no) no w: (no) no w: (copy) copy w: (no) no
* x: (no) no x: (no) yes x: (no) yes x: (yes) yes
+ *
+ * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
+ * MAP_PRIVATE (with Enhanced PAN supported):
+ * r: (no) no
+ * w: (no) no
+ * x: (yes) yes
pgprot_t protection_map[16] __ro_after_init = {
__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,