From 6497b66ba6945f142902c7e8fce86e47016ead1c Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 1 Oct 2024 23:58:54 +0100 Subject: arm64/mm: Map pages for guarded control stack 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. Reviewed-by: Thiago Jung Bauermann Reviewed-by: Catalin Marinas Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-15-222b78d87eee@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/mm/mmap.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/arm64/mm/mmap.c') diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 7e3ad97e27d8..07aeab8a7606 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -83,8 +83,15 @@ 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; + + /* Short circuit GCS to avoid bloating the table. */ + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { + 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; -- cgit v1.2.3