Tiezhu Yang
cb8a2ef084
The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is similar in concept to a DWARF unwinder. The difference is that the format of the ORC data is much simpler than DWARF, which in turn allows the ORC unwinder to be much simpler and faster. The ORC data consists of unwind tables which are generated by objtool. After analyzing all the code paths of a .o file, it determines information about the stack state at each instruction address in the file and outputs that information to the .orc_unwind and .orc_unwind_ip sections. The per-object ORC sections are combined at link time and are sorted and post-processed at boot time. The unwinder uses the resulting data to correlate instruction addresses with their stack states at run time. Most of the logic are similar with x86, in order to get ra info before ra is saved into stack, add ra_reg and ra_offset into orc_entry. At the same time, modify some arch-specific code to silence the objtool warnings. Co-developed-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Co-developed-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
82 lines
1.9 KiB
C
82 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Stack trace management functions
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*
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* Copyright (C) 2022 Loongson Technology Corporation Limited
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*/
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#include <linux/sched.h>
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#include <linux/stacktrace.h>
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#include <linux/uaccess.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
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struct task_struct *task, struct pt_regs *regs)
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{
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unsigned long addr;
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struct pt_regs dummyregs;
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struct unwind_state state;
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if (!regs) {
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regs = &dummyregs;
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if (task == current) {
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regs->regs[3] = (unsigned long)__builtin_frame_address(0);
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regs->csr_era = (unsigned long)__builtin_return_address(0);
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} else {
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regs->regs[3] = thread_saved_fp(task);
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regs->csr_era = thread_saved_ra(task);
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}
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regs->regs[1] = 0;
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regs->regs[22] = 0;
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}
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for (unwind_start(&state, task, regs);
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!unwind_done(&state); unwind_next_frame(&state)) {
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addr = unwind_get_return_address(&state);
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if (!addr || !consume_entry(cookie, addr))
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break;
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}
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}
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static int
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copy_stack_frame(unsigned long fp, struct stack_frame *frame)
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{
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int ret = 1;
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unsigned long err;
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unsigned long __user *user_frame_tail;
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user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
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if (!access_ok(user_frame_tail, sizeof(*frame)))
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return 0;
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pagefault_disable();
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err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));
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if (err || (unsigned long)user_frame_tail >= frame->fp)
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ret = 0;
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pagefault_enable();
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return ret;
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}
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void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
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const struct pt_regs *regs)
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{
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unsigned long fp = regs->regs[22];
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while (fp && !((unsigned long)fp & 0xf)) {
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struct stack_frame frame;
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frame.fp = 0;
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frame.ra = 0;
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if (!copy_stack_frame(fp, &frame))
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break;
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if (!frame.ra)
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break;
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if (!consume_entry(cookie, frame.ra))
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break;
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fp = frame.fp;
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}
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}
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