1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_X86_UNWIND_H
  3#define _ASM_X86_UNWIND_H
  4
  5#include <linux/sched.h>
  6#include <linux/ftrace.h>
  7#include <linux/rethook.h>
  8#include <asm/ptrace.h>
  9#include <asm/stacktrace.h>
 10
 11#define IRET_FRAME_OFFSET (offsetof(struct pt_regs, ip))
 12#define IRET_FRAME_SIZE   (sizeof(struct pt_regs) - IRET_FRAME_OFFSET)
 13
 14struct unwind_state {
 15	struct stack_info stack_info;
 16	unsigned long stack_mask;
 17	struct task_struct *task;
 18	int graph_idx;
 19#if defined(CONFIG_RETHOOK)
 20	struct llist_node *kr_cur;
 21#endif
 22	bool error;
 23#if defined(CONFIG_UNWINDER_ORC)
 24	bool signal, full_regs;
 25	unsigned long sp, bp, ip;
 26	struct pt_regs *regs, *prev_regs;
 27#elif defined(CONFIG_UNWINDER_FRAME_POINTER)
 28	bool got_irq;
 29	unsigned long *bp, *orig_sp, ip;
 30	/*
 31	 * If non-NULL: The current frame is incomplete and doesn't contain a
 32	 * valid BP. When looking for the next frame, use this instead of the
 33	 * non-existent saved BP.
 34	 */
 35	unsigned long *next_bp;
 36	struct pt_regs *regs;
 37#else
 38	unsigned long *sp;
 39#endif
 40};
 41
 42void __unwind_start(struct unwind_state *state, struct task_struct *task,
 43		    struct pt_regs *regs, unsigned long *first_frame);
 44bool unwind_next_frame(struct unwind_state *state);
 45unsigned long unwind_get_return_address(struct unwind_state *state);
 46unsigned long *unwind_get_return_address_ptr(struct unwind_state *state);
 47
 48static inline bool unwind_done(struct unwind_state *state)
 49{
 50	return state->stack_info.type == STACK_TYPE_UNKNOWN;
 51}
 52
 53static inline bool unwind_error(struct unwind_state *state)
 54{
 55	return state->error;
 56}
 57
 58static inline
 59void unwind_start(struct unwind_state *state, struct task_struct *task,
 60		  struct pt_regs *regs, unsigned long *first_frame)
 61{
 62	first_frame = first_frame ? : get_stack_pointer(task, regs);
 63
 64	__unwind_start(state, task, regs, first_frame);
 65}
 66
 67#if defined(CONFIG_UNWINDER_ORC) || defined(CONFIG_UNWINDER_FRAME_POINTER)
 68/*
 69 * If 'partial' returns true, only the iret frame registers are valid.
 70 */
 71static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state,
 72						    bool *partial)
 73{
 74	if (unwind_done(state))
 75		return NULL;
 76
 77	if (partial) {
 78#ifdef CONFIG_UNWINDER_ORC
 79		*partial = !state->full_regs;
 80#else
 81		*partial = false;
 82#endif
 83	}
 84
 85	return state->regs;
 86}
 87#else
 88static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state,
 89						    bool *partial)
 90{
 91	return NULL;
 92}
 93#endif
 94
 95#ifdef CONFIG_UNWINDER_ORC
 96void unwind_init(void);
 97void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
 98			void *orc, size_t orc_size);
 99#else
100static inline void unwind_init(void) {}
101static inline
102void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
103			void *orc, size_t orc_size) {}
104#endif
105
106static inline
107unsigned long unwind_recover_rethook(struct unwind_state *state,
108				     unsigned long addr, unsigned long *addr_p)
109{
110#ifdef CONFIG_RETHOOK
111	if (is_rethook_trampoline(addr))
112		return rethook_find_ret_addr(state->task, (unsigned long)addr_p,
113					     &state->kr_cur);
114#endif
115	return addr;
116}
117
118/* Recover the return address modified by rethook and ftrace_graph. */
119static inline
120unsigned long unwind_recover_ret_addr(struct unwind_state *state,
121				     unsigned long addr, unsigned long *addr_p)
122{
123	unsigned long ret;
124
125	ret = ftrace_graph_ret_addr(state->task, &state->graph_idx,
126				    addr, addr_p);
127	return unwind_recover_rethook(state, ret, addr_p);
128}
129
130/*
131 * This disables KASAN checking when reading a value from another task's stack,
132 * since the other task could be running on another CPU and could have poisoned
133 * the stack in the meantime.
134 */
135#define READ_ONCE_TASK_STACK(task, x)			\
136({							\
137	unsigned long val;				\
138	if (task == current)				\
139		val = READ_ONCE(x);			\
140	else						\
141		val = READ_ONCE_NOCHECK(x);		\
142	val;						\
143})
144
145static inline bool task_on_another_cpu(struct task_struct *task)
146{
147#ifdef CONFIG_SMP
148	return task != current && task->on_cpu;
149#else
150	return false;
151#endif
152}
153
154#endif /* _ASM_X86_UNWIND_H */