VM_SHADOW_STACK (alias to VM_HIGH_ARCH_5) is used to encode shadow stack VMA on three architectures (x86 shadow stack, arm GCS and RISC-V shadow stack). In case architecture doesn't implement shadow stack, it's VM_NONE Introducing a helper `is_shadow_stack_vma` to determine shadow stack vma or not.
Signed-off-by: Deepak Gupta debug@rivosinc.com Reviewed-by: Mark Brown broonie@kernel.org --- mm/gup.c | 2 +- mm/mmap.c | 2 +- mm/vma.h | 10 +++++++--- 3 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c index 3883b307780e..8c64f3ff34ab 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1291,7 +1291,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) !writable_file_mapping_allowed(vma, gup_flags)) return -EFAULT;
- if (!(vm_flags & VM_WRITE) || (vm_flags & VM_SHADOW_STACK)) { + if (!(vm_flags & VM_WRITE) || is_shadow_stack_vma(vm_flags)) { if (!(gup_flags & FOLL_FORCE)) return -EFAULT; /* diff --git a/mm/mmap.c b/mm/mmap.c index cda01071c7b1..7b6be4eec35d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -648,7 +648,7 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) */ static inline unsigned long stack_guard_placement(vm_flags_t vm_flags) { - if (vm_flags & VM_SHADOW_STACK) + if (is_shadow_stack_vma(vm_flags)) return PAGE_SIZE;
return 0; diff --git a/mm/vma.h b/mm/vma.h index a2e8710b8c47..47482a25f5c3 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -278,7 +278,7 @@ static inline struct vm_area_struct *vma_prev_limit(struct vma_iterator *vmi, }
/* - * These three helpers classifies VMAs for virtual memory accounting. + * These four helpers classifies VMAs for virtual memory accounting. */
/* @@ -289,6 +289,11 @@ static inline bool is_exec_mapping(vm_flags_t flags) return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC; }
+static inline bool is_shadow_stack_vma(vm_flags_t vm_flags) +{ + return !!(vm_flags & VM_SHADOW_STACK); +} + /* * Stack area (including shadow stacks) * @@ -297,7 +302,7 @@ static inline bool is_exec_mapping(vm_flags_t flags) */ static inline bool is_stack_mapping(vm_flags_t flags) { - return ((flags & VM_STACK) == VM_STACK) || (flags & VM_SHADOW_STACK); + return ((flags & VM_STACK) == VM_STACK) || is_shadow_stack_vma(flags); }
/* @@ -308,7 +313,6 @@ static inline bool is_data_mapping(vm_flags_t flags) return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE; }
- static inline void vma_iter_config(struct vma_iterator *vmi, unsigned long index, unsigned long last) {