arch/mips/include/asm/stackprotector.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * GCC stack protector support.
   4  *
   5  * (This is directly adopted from the ARM implementation)
   6  *
   7  * Stack protector works by putting predefined pattern at the start of
   8  * the stack frame and verifying that it hasn't been overwritten when
   9  * returning from the function.  The pattern is called stack canary
  10  * and gcc expects it to be defined by a global variable called
  11  * "__stack_chk_guard" on MIPS.  This unfortunately means that on SMP
  12  * we cannot have a different canary value per task.
  13  */
  14
  15 #ifndef _ASM_STACKPROTECTOR_H
  16 #define _ASM_STACKPROTECTOR_H 1
  17
  18 extern unsigned long __stack_chk_guard;
  19
  20 /*
  21  * Initialize the stackprotector canary value.
  22  *
  23  * NOTE: this must only be called from functions that never return,
  24  * and it must always be inlined.
  25  */
  26 static __always_inline void boot_init_stack_canary(void)
  27 {
  28         unsigned long canary = get_random_canary();
  29
  30         current->stack_canary = canary;
  31         __stack_chk_guard = current->stack_canary;
  32 }
  33
  34 #endif  /* _ASM_STACKPROTECTOR_H */