[PATCH v3 51/51] x86/mm: convert arch_within_stack_frames() to use the new unwinder

[Josh Poimboeuf]

Convert arch_within_stack_frames() to use the new unwinder.

Boot tested with CONFIG_HARDENED_USERCOPY.

Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
---
 arch/x86/lib/usercopy.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
index 96ce151..9d0913c 100644
--- a/arch/x86/lib/usercopy.c
+++ b/arch/x86/lib/usercopy.c
@@ -50,12 +50,21 @@ int arch_within_stack_frames(const void * const stack,
                             const void * const stackend,
                             const void *obj, unsigned long len)
 {
-       const void *frame = NULL;
-       const void *oldframe;
+       struct unwind_state state;
+       const void *frame, *oldframe;
+
+       unwind_start(&state, current, NULL, NULL);
+
+       if (!unwind_next_frame(&state))
+               return 0;
+
+       oldframe = unwind_get_stack_ptr(&state);
+
+       if (!unwind_next_frame(&state))
+               return 0;
+
+       frame = unwind_get_stack_ptr(&state);
 
-       oldframe = __builtin_frame_address(2);
-       if (oldframe)
-               frame = __builtin_frame_address(3);
        /*
         * low ----------------------------------------------> high
         * [saved bp][saved ip][args][local vars][saved bp][saved ip]
@@ -71,8 +80,12 @@ int arch_within_stack_frames(const void * const stack,
                 */
                if (obj + len <= frame)
                        return obj >= oldframe + 2 * sizeof(void *) ? 1 : -1;
+
+               if (!unwind_next_frame(&state))
+                       return 0;
+
                oldframe = frame;
-               frame = *(const void * const *)frame;
+               frame = unwind_get_stack_ptr(&state);
        }
        return -1;
 }
-- 
2.7.4