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 <linux/kprobes.h> 8 #include <linux/llist.h> 9 #include <asm/ptrace.h> 10 #include <asm/stacktrace.h> 11 12 /* 13 * To use the stack unwinder it has to be initialized with unwind_start. 14 * There four combinations for task and regs: 15 * 1) task==NULL, regs==NULL: the unwind starts for the task that is currently 16 * running, sp/ip picked up from the CPU registers 17 * 2) task==NULL, regs!=NULL: the unwind starts from the sp/ip found in 18 * the struct pt_regs of an interrupt frame for the current task 19 * 3) task!=NULL, regs==NULL: the unwind starts for an inactive task with 20 * the sp picked up from task->thread.ksp and the ip picked up from the 21 * return address stored by __switch_to 22 * 4) task!=NULL, regs!=NULL: the sp/ip are picked up from the interrupt 23 * frame 'regs' of a inactive task 24 * If 'first_frame' is not zero unwind_start skips unwind frames until it 25 * reaches the specified stack pointer. 26 * The end of the unwinding is indicated with unwind_done, this can be true 27 * right after unwind_start, e.g. with first_frame!=0 that can not be found. 28 * unwind_next_frame skips to the next frame. 29 * Once the unwind is completed unwind_error() can be used to check if there 30 * has been a situation where the unwinder could not correctly understand 31 * the tasks call chain. 32 */ 33 34 struct unwind_state { 35 struct stack_info stack_info; 36 unsigned long stack_mask; 37 struct task_struct *task; 38 struct pt_regs *regs; 39 unsigned long sp, ip; 40 int graph_idx; 41 struct llist_node *kr_cur; 42 bool reliable; 43 bool error; 44 }; 45 46 /* Recover the return address modified by kretprobe and ftrace_graph. */ 47 static inline unsigned long unwind_recover_ret_addr(struct unwind_state *state, 48 unsigned long ip) 49 { 50 ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, NULL); 51 if (is_kretprobe_trampoline(ip)) 52 ip = kretprobe_find_ret_addr(state->task, (void *)state->sp, &state->kr_cur); 53 return ip; 54 } 55 56 void __unwind_start(struct unwind_state *state, struct task_struct *task, 57 struct pt_regs *regs, unsigned long first_frame); 58 bool unwind_next_frame(struct unwind_state *state); 59 unsigned long unwind_get_return_address(struct unwind_state *state); 60 61 static inline bool unwind_done(struct unwind_state *state) 62 { 63 return state->stack_info.type == STACK_TYPE_UNKNOWN; 64 } 65 66 static inline bool unwind_error(struct unwind_state *state) 67 { 68 return state->error; 69 } 70 71 static __always_inline void unwind_start(struct unwind_state *state, 72 struct task_struct *task, 73 struct pt_regs *regs, 74 unsigned long first_frame) 75 { 76 task = task ?: current; 77 first_frame = first_frame ?: get_stack_pointer(task, regs); 78 __unwind_start(state, task, regs, first_frame); 79 } 80 81 static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state) 82 { 83 return unwind_done(state) ? NULL : state->regs; 84 } 85 86 #define unwind_for_each_frame(state, task, regs, first_frame) \ 87 for (unwind_start(state, task, regs, first_frame); \ 88 !unwind_done(state); \ 89 unwind_next_frame(state)) 90 91 static inline void unwind_init(void) {} 92 static inline void unwind_module_init(struct module *mod, void *orc_ip, 93 size_t orc_ip_size, void *orc, 94 size_t orc_size) {} 95 96 #endif /* _ASM_S390_UNWIND_H */ 97