1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_S390_UNWIND_H
3 #define _ASM_S390_UNWIND_H
4
5 #include <linux/sched.h>
6 #include <linux/ftrace.h>
7 #include <asm/ptrace.h>
8 #include <asm/stacktrace.h>
9
10 /*
11 * To use the stack unwinder it has to be initialized with unwind_start.
12 * There four combinations for task and regs:
13 * 1) task==NULL, regs==NULL: the unwind starts for the task that is currently
14 * running, sp/ip picked up from the CPU registers
15 * 2) task==NULL, regs!=NULL: the unwind starts from the sp/ip found in
16 * the struct pt_regs of an interrupt frame for the current task
17 * 3) task!=NULL, regs==NULL: the unwind starts for an inactive task with
18 * the sp picked up from task->thread.ksp and the ip picked up from the
19 * return address stored by __switch_to
20 * 4) task!=NULL, regs!=NULL: the sp/ip are picked up from the interrupt
21 * frame 'regs' of a inactive task
22 * If 'first_frame' is not zero unwind_start skips unwind frames until it
23 * reaches the specified stack pointer.
24 * The end of the unwinding is indicated with unwind_done, this can be true
25 * right after unwind_start, e.g. with first_frame!=0 that can not be found.
26 * unwind_next_frame skips to the next frame.
27 * Once the unwind is completed unwind_error() can be used to check if there
28 * has been a situation where the unwinder could not correctly understand
29 * the tasks call chain.
30 */
31
32 struct unwind_state {
33 struct stack_info stack_info;
34 unsigned long stack_mask;
35 struct task_struct *task;
36 struct pt_regs *regs;
37 unsigned long sp, ip;
38 int graph_idx;
39 bool reliable;
40 bool error;
41 };
42
43 void __unwind_start(struct unwind_state *state, struct task_struct *task,
44 struct pt_regs *regs, unsigned long first_frame);
45 bool unwind_next_frame(struct unwind_state *state);
46 unsigned long unwind_get_return_address(struct unwind_state *state);
47
unwind_done(struct unwind_state * state)48 static inline bool unwind_done(struct unwind_state *state)
49 {
50 return state->stack_info.type == STACK_TYPE_UNKNOWN;
51 }
52
unwind_error(struct unwind_state * state)53 static inline bool unwind_error(struct unwind_state *state)
54 {
55 return state->error;
56 }
57
unwind_start(struct unwind_state * state,struct task_struct * task,struct pt_regs * regs,unsigned long first_frame)58 static inline void unwind_start(struct unwind_state *state,
59 struct task_struct *task,
60 struct pt_regs *regs,
61 unsigned long first_frame)
62 {
63 task = task ?: current;
64 first_frame = first_frame ?: get_stack_pointer(task, regs);
65 __unwind_start(state, task, regs, first_frame);
66 }
67
unwind_get_entry_regs(struct unwind_state * state)68 static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
69 {
70 return unwind_done(state) ? NULL : state->regs;
71 }
72
73 #define unwind_for_each_frame(state, task, regs, first_frame) \
74 for (unwind_start(state, task, regs, first_frame); \
75 !unwind_done(state); \
76 unwind_next_frame(state))
77
unwind_init(void)78 static inline void unwind_init(void) {}
unwind_module_init(struct module * mod,void * orc_ip,size_t orc_ip_size,void * orc,size_t orc_size)79 static inline void unwind_module_init(struct module *mod, void *orc_ip,
80 size_t orc_ip_size, void *orc,
81 size_t orc_size) {}
82
83 #endif /* _ASM_S390_UNWIND_H */
84