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f3856cd343
No functional change. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Uros Bizjak <ubizjak@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250303165246.2175811-11-brgerst@gmail.com
57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* GCC stack protector support.
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*
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* Stack protector works by putting a predefined pattern at the start of
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* the stack frame and verifying that it hasn't been overwritten when
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* returning from the function. The pattern is called the stack canary
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* and is a unique value for each task.
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*/
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#ifndef _ASM_STACKPROTECTOR_H
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#define _ASM_STACKPROTECTOR_H 1
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#ifdef CONFIG_STACKPROTECTOR
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#include <asm/tsc.h>
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#include <asm/processor.h>
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#include <asm/percpu.h>
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#include <asm/desc.h>
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#include <linux/sched.h>
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DECLARE_PER_CPU_CACHE_HOT(unsigned long, __stack_chk_guard);
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/*
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* Initialize the stackprotector canary value.
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*
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* NOTE: this must only be called from functions that never return
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* and it must always be inlined.
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*
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* In addition, it should be called from a compilation unit for which
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* stack protector is disabled. Alternatively, the caller should not end
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* with a function call which gets tail-call optimized as that would
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* lead to checking a modified canary value.
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*/
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static __always_inline void boot_init_stack_canary(void)
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{
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unsigned long canary = get_random_canary();
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current->stack_canary = canary;
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this_cpu_write(__stack_chk_guard, canary);
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}
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static inline void cpu_init_stack_canary(int cpu, struct task_struct *idle)
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{
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per_cpu(__stack_chk_guard, cpu) = idle->stack_canary;
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}
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#else /* STACKPROTECTOR */
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/* dummy boot_init_stack_canary() is defined in linux/stackprotector.h */
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static inline void cpu_init_stack_canary(int cpu, struct task_struct *idle)
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{ }
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#endif /* STACKPROTECTOR */
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#endif /* _ASM_STACKPROTECTOR_H */
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