58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Shadow Call Stack support.
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*
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* Copyright (C) 2019 Google LLC
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*/
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#ifndef _LINUX_SCS_H
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#define _LINUX_SCS_H
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#include <linux/gfp.h>
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#include <linux/sched.h>
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#include <asm/page.h>
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#ifdef CONFIG_SHADOW_CALL_STACK
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/*
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* In testing, 1 KiB shadow stack size (i.e. 128 stack frames on a 64-bit
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* architecture) provided ~40% safety margin on stack usage while keeping
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* memory allocation overhead reasonable.
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*/
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#define SCS_SIZE 1024UL
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#define GFP_SCS (GFP_KERNEL | __GFP_ZERO)
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/*
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* A random number outside the kernel's virtual address space to mark the
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* end of the shadow stack.
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*/
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#define SCS_END_MAGIC 0xaf0194819b1635f6UL
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#define task_scs(tsk) (task_thread_info(tsk)->shadow_call_stack)
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static inline void task_set_scs(struct task_struct *tsk, void *s)
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{
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task_scs(tsk) = s;
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}
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extern void scs_init(void);
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extern void scs_task_reset(struct task_struct *tsk);
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extern int scs_prepare(struct task_struct *tsk, int node);
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extern bool scs_corrupted(struct task_struct *tsk);
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extern void scs_release(struct task_struct *tsk);
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#else /* CONFIG_SHADOW_CALL_STACK */
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#define task_scs(tsk) NULL
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static inline void task_set_scs(struct task_struct *tsk, void *s) {}
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static inline void scs_init(void) {}
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static inline void scs_task_reset(struct task_struct *tsk) {}
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static inline int scs_prepare(struct task_struct *tsk, int node) { return 0; }
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static inline bool scs_corrupted(struct task_struct *tsk) { return false; }
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static inline void scs_release(struct task_struct *tsk) {}
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#endif /* CONFIG_SHADOW_CALL_STACK */
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#endif /* _LINUX_SCS_H */
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