blob: c5572fd770b0cf147ff7d3cc8494f54196c218bf [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
* Shadow Call Stack support.
* Copyright (C) 2019 Google LLC
#ifndef _LINUX_SCS_H
#define _LINUX_SCS_H
#include <linux/gfp.h>
#include <linux/sched.h>
#include <asm/page.h>
* In testing, 1 KiB shadow stack size (i.e. 128 stack frames on a 64-bit
* architecture) provided ~40% safety margin on stack usage while keeping
* memory allocation overhead reasonable.
#define SCS_SIZE 1024UL
* A random number outside the kernel's virtual address space to mark the
* end of the shadow stack.
#define SCS_END_MAGIC 0xaf0194819b1635f6UL
#define task_scs(tsk) (task_thread_info(tsk)->shadow_call_stack)
static inline void task_set_scs(struct task_struct *tsk, void *s)
task_scs(tsk) = s;
extern void scs_init(void);
extern void scs_task_reset(struct task_struct *tsk);
extern int scs_prepare(struct task_struct *tsk, int node);
extern bool scs_corrupted(struct task_struct *tsk);
extern void scs_release(struct task_struct *tsk);
#define task_scs(tsk) NULL
static inline void task_set_scs(struct task_struct *tsk, void *s) {}
static inline void scs_init(void) {}
static inline void scs_task_reset(struct task_struct *tsk) {}
static inline int scs_prepare(struct task_struct *tsk, int node) { return 0; }
static inline bool scs_corrupted(struct task_struct *tsk) { return false; }
static inline void scs_release(struct task_struct *tsk) {}
#endif /* _LINUX_SCS_H */