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 if (!regs) { 22 regs = &dummyregs; 23 24 if (task == current) { 25 regs->regs[3] = (unsigned long)__builtin_frame_address(0); 26 regs->csr_era = (unsigned long)__builtin_return_address(0); 27 } else { 28 regs->regs[3] = thread_saved_fp(task); 29 regs->csr_era = thread_saved_ra(task); 30 } 31 regs->regs[1] = 0; 32 regs->regs[22] = 0; 33 } 34 35 for (unwind_start(&state, task, regs); 36 !unwind_done(&state); unwind_next_frame(&state)) { 37 addr = unwind_get_return_address(&state); 38 if (!addr || !consume_entry(cookie, addr)) 39 break; 40 } 41 } 42 43 static int 44 copy_stack_frame(unsigned long fp, struct stack_frame *frame) 45 { 46 int ret = 1; 47 unsigned long err; 48 unsigned long __user *user_frame_tail; 49 50 user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame)); 51 if (!access_ok(user_frame_tail, sizeof(*frame))) 52 return 0; 53 54 pagefault_disable(); 55 err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame))); 56 if (err || (unsigned long)user_frame_tail >= frame->fp) 57 ret = 0; 58 pagefault_enable(); 59 60 return ret; 61 } 62 63 void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, 64 const struct pt_regs *regs) 65 { 66 unsigned long fp = regs->regs[22]; 67 68 while (fp && !((unsigned long)fp & 0xf)) { 69 struct stack_frame frame; 70 71 frame.fp = 0; 72 frame.ra = 0; 73 if (!copy_stack_frame(fp, &frame)) 74 break; 75 if (!frame.ra) 76 break; 77 if (!consume_entry(cookie, frame.ra)) 78 break; 79 fp = frame.fp; 80 } 81 } 82