1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Stack trace management functions 4 * 5 * Copyright (C) 2022 Loongson Technology Corporation Limited 6 */ 7 #include <linux/sched.h> 8 #include <linux/stacktrace.h> 9 #include <linux/uaccess.h> 10 11 #include <asm/stacktrace.h> 12 #include <asm/unwind.h> 13 14 void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, 15 struct task_struct *task, struct pt_regs *regs) 16 { 17 unsigned long addr; 18 struct pt_regs dummyregs; 19 struct unwind_state state; 20 21 regs = &dummyregs; 22 23 if (task == current) { 24 regs->regs[3] = (unsigned long)__builtin_frame_address(0); 25 regs->csr_era = (unsigned long)__builtin_return_address(0); 26 } else { 27 regs->regs[3] = thread_saved_fp(task); 28 regs->csr_era = thread_saved_ra(task); 29 } 30 31 regs->regs[1] = 0; 32 for (unwind_start(&state, task, regs); 33 !unwind_done(&state); unwind_next_frame(&state)) { 34 addr = unwind_get_return_address(&state); 35 if (!addr || !consume_entry(cookie, addr)) 36 break; 37 } 38 } 39 40 static int 41 copy_stack_frame(unsigned long fp, struct stack_frame *frame) 42 { 43 int ret = 1; 44 unsigned long err; 45 unsigned long __user *user_frame_tail; 46 47 user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame)); 48 if (!access_ok(user_frame_tail, sizeof(*frame))) 49 return 0; 50 51 pagefault_disable(); 52 err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame))); 53 if (err || (unsigned long)user_frame_tail >= frame->fp) 54 ret = 0; 55 pagefault_enable(); 56 57 return ret; 58 } 59 60 void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, 61 const struct pt_regs *regs) 62 { 63 unsigned long fp = regs->regs[22]; 64 65 while (fp && !((unsigned long)fp & 0xf)) { 66 struct stack_frame frame; 67 68 frame.fp = 0; 69 frame.ra = 0; 70 if (!copy_stack_frame(fp, &frame)) 71 break; 72 if (!frame.ra) 73 break; 74 if (!consume_entry(cookie, frame.ra)) 75 break; 76 fp = frame.fp; 77 } 78 } 79