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aarch64: Use __alloc_gcs in makecontext

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Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Szabolcs Nagy
2024-08-28 11:00:19 +01:00
committed by Yury Khrustalev
parent 3d8da0d91b
commit a335acb8b8
1 changed files with 8 additions and 30 deletions
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38
sysdeps/unix/sysv/linux/aarch64/makecontext.c
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@@ -23,6 +23,8 @@
#include <ucontext.h> #include <ucontext.h>
#include <sys/mman.h> #include <sys/mman.h>
#include "aarch64-gcs.h"
#define GCS_MAGIC 0x47435300 #define GCS_MAGIC 0x47435300
static struct _aarch64_ctx *extension (void *p) static struct _aarch64_ctx *extension (void *p)
@@ -30,41 +32,17 @@ static struct _aarch64_ctx *extension (void *p)
return p; return p;
} }
#ifndef SHADOW_STACK_SET_TOKEN /* Allocate GCS stack for new context. */
# 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 * static void *
alloc_makecontext_gcs (size_t stack_size) alloc_makecontext_gcs (size_t stack_size)
{ {
size_t size = (stack_size / 2 + GCS_ALTSTACK_RESERVE) & -8UL; void *base;
if (size > GCS_MAX_SIZE) size_t size;
size = GCS_MAX_SIZE; void *gcsp = __alloc_gcs (stack_size, &base, &size);
if (gcsp == NULL)
unsigned long flags = SHADOW_STACK_SET_MARKER | SHADOW_STACK_SET_TOKEN;
void *base = map_shadow_stack (NULL, size, flags);
if (base == MAP_FAILED)
/* ENOSYS, bad size or OOM. */ /* ENOSYS, bad size or OOM. */
abort (); abort ();
uint64_t *gcsp = (uint64_t *) ((char *) base + size); return gcsp;
/* 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;
} }
/* makecontext sets up a stack and the registers for the /* makecontext sets up a stack and the registers for the