Re: [PATCH v7 13/39] arm64/mm: Map pages for guarded control stack

Hello,

Mark Brown broonie@kernel.org writes:

diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 645fe60d000f..605d4e6edc1d 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -79,9 +79,20 @@ 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. */
• 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)]);
  

• }

• /* VM_ARM64_BTI on a GCS is rejected in arch_valdiate_flags() */

s/valdiate/validate/

if (vm_flags & VM_ARM64_BTI) prot |= PTE_GP;