diff mbox series

[v4,21/22] aarch64: Use __alloc_gcs in makecontext

Message ID 20241129163721.2385847-22-yury.khrustalev@arm.com
State Superseded
Delegated to: Carlos O'Donell
Headers
Series aarch64: Add support for Guarded Control Stack extension |

Checks

Context Check Description
redhat-pt-bot/TryBot-apply_patch success Patch applied to master at the time it was sent
linaro-tcwg-bot/tcwg_glibc_build--master-aarch64 success Build passed
linaro-tcwg-bot/tcwg_glibc_check--master-aarch64 success Test passed
linaro-tcwg-bot/tcwg_glibc_build--master-arm success Build passed
linaro-tcwg-bot/tcwg_glibc_check--master-arm success Test passed

Commit Message

Yury Khrustalev Nov. 29, 2024, 4:37 p.m. UTC 
  From: Szabolcs Nagy <szabolcs.nagy@arm.com>

---
 sysdeps/unix/sysv/linux/aarch64/makecontext.c | 41 +++----------------
 1 file changed, 6 insertions(+), 35 deletions(-)
diff mbox series

Patch

diff --git a/sysdeps/unix/sysv/linux/aarch64/makecontext.c b/sysdeps/unix/sysv/linux/aarch64/makecontext.c
index 779f7e55aa..33824ae614 100644
--- a/sysdeps/unix/sysv/linux/aarch64/makecontext.c
+++ b/sysdeps/unix/sysv/linux/aarch64/makecontext.c
@@ -23,6 +23,7 @@ 
 #include <stdlib.h>
 #include <ucontext.h>
 #include <sys/mman.h>
+#include "aarch64-gcs.h"
 
 #define GCS_MAGIC 0x47435300
 
@@ -72,47 +73,17 @@  __libc_aarch64_thread_freeres (void)
   free_gcs_list ();
 }
 
-#ifndef __NR_map_shadow_stack
-# define __NR_map_shadow_stack 453
-#endif
-#ifndef SHADOW_STACK_SET_TOKEN
-# define SHADOW_STACK_SET_TOKEN (1UL << 0)
-# define SHADOW_STACK_SET_MARKER (1UL << 1)
-#endif
-
-static void *
-map_shadow_stack (void *addr, size_t size, unsigned long flags)
-{
-  return (void *) INLINE_SYSCALL_CALL (map_shadow_stack, addr, size, flags);
-}
-
-#define GCS_MAX_SIZE (1UL << 31)
-#define GCS_ALTSTACK_RESERVE 160
-
 static void *
 alloc_makecontext_gcs (size_t stack_size)
 {
-  size_t size = (stack_size / 2 + GCS_ALTSTACK_RESERVE) & -8UL;
-  if (size > GCS_MAX_SIZE)
-    size = GCS_MAX_SIZE;
-
-  unsigned long flags = SHADOW_STACK_SET_MARKER | SHADOW_STACK_SET_TOKEN;
-  void *base = map_shadow_stack (NULL, size, flags);
-  if (base == (void *) -1)
+  void *base;
+  size_t size;
+  void *gcsp = __alloc_gcs (stack_size, &base, &size);
+  if (gcsp == NULL)
     /* ENOSYS, bad size or OOM.  */
     abort ();
-
   record_gcs (base, size);
-
-  uint64_t *gcsp = (uint64_t *) ((char *) base + size);
-  /* Skip end of GCS token.  */
-  gcsp--;
-  /* Verify GCS cap token.  */
-  gcsp--;
-  if (((uint64_t)gcsp & 0xfffffffffffff000) + 1 != *gcsp)
-    abort ();
-  /* Return the target GCS pointer for context switch.  */
-  return gcsp + 1;
+  return gcsp;
 }
 
 void