arch/x86/include/asm/unwind.h

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