arch/s390/include/asm/unwind.h

   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
  48 static inline bool unwind_done(struct unwind_state *state)
  49 {
  50         return state->stack_info.type == STACK_TYPE_UNKNOWN;
  51 }
  52
  53 static inline bool unwind_error(struct unwind_state *state)
  54 {
  55         return state->error;
  56 }
  57
  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
  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
  78 static inline void unwind_init(void) {}
  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 */