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/*
* Copyright 2019 The Hafnium Authors.
*
* Use of this source code is governed by a BSD-style
* license that can be found in the LICENSE file or at
* https://opensource.org/licenses/BSD-3-Clause.
*/
#include <stdint.h>
#include <stdnoreturn.h>
#include "hf/panic.h"
#include "plat/prng/prng.h"
/**
* This is the value that is used as the stack canary. It is written to the top
* of the stack when entering a function and compared against the stack when
* exiting a function. If there is a mismatch, a failure is triggered.
*
* As the value must be the same at the beginning and end of the function, this
* is a global variable and there are multiple CPUs executing concurrently, this
* value cannot change after being initialized.
*/
uint64_t __attribute__((used)) __stack_chk_guard = 0x72afaf72bad0feed;
/**
* Called when the stack canary is invalid. The stack can no longer be trusted
* so this function must not return.
*/
noreturn void __stack_chk_fail(void)
{
panic("stack corruption");
}
void __attribute__((no_stack_protector)) stack_protector_init(void)
{
/* The prng function is executed with the hardcoded stack guard. */
__stack_chk_guard = (uint64_t)plat_prng_get_number();
}
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