@@ -79,8 +79,23 @@ arch_initcall(adjust_protection_map);
pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
- pteval_t prot = pgprot_val(protection_map[vm_flags &
+ pteval_t prot;
+
+ /*
+ * If this is a GCS then only interpret VM_WRITE.
+ *
+ * TODO: Just make protection_map[] bigger? Nothing seems
+ * ideal here.
+ */
+ if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) {
+ if (vm_flags & VM_WRITE)
+ prot = _PAGE_GCS;
+ else
+ prot = _PAGE_GCS_RO;
+ } else {
+ prot = pgprot_val(protection_map[vm_flags &
(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);
+ }
if (vm_flags & VM_ARM64_BTI)
prot |= PTE_GP;
Map pages flagged as being part of a GCS as such rather than using the full set of generic VM flags. This is done using a conditional rather than extending the size of protection_map since that would make for a very sparse array. Signed-off-by: Mark Brown <broonie@kernel.org> --- arch/arm64/mm/mmap.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)