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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>
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Most of this ideas comes from x86.
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*
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* Copyright (C) 2022 Loongson Technology Corporation Limited
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*/
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#ifndef _ASM_UNWIND_H
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#define _ASM_UNWIND_H
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#include <linux/sched.h>
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#include <linux/ftrace.h>
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#include <asm/ptrace.h>
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#include <asm/stacktrace.h>
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enum unwinder_type {
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UNWINDER_GUESS,
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UNWINDER_PROLOGUE,
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UNWINDER_ORC,
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};
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struct unwind_state {
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char type; /* UNWINDER_XXX */
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struct stack_info stack_info;
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struct task_struct *task;
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bool first, error, reset;
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int graph_idx;
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unsigned long sp, fp, pc, ra;
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};
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bool default_next_frame(struct unwind_state *state);
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void unwind_start(struct unwind_state *state,
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struct task_struct *task, struct pt_regs *regs);
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bool unwind_next_frame(struct unwind_state *state);
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unsigned long unwind_get_return_address(struct unwind_state *state);
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static inline bool unwind_done(struct unwind_state *state)
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{
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return state->stack_info.type == STACK_TYPE_UNKNOWN;
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}
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static inline bool unwind_error(struct unwind_state *state)
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{
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return state->error;
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}
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#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
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static inline unsigned long unwind_graph_addr(struct unwind_state *state,
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unsigned long pc, unsigned long cfa)
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{
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return ftrace_graph_ret_addr(state->task, &state->graph_idx,
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pc, (unsigned long *)(cfa - GRAPH_FAKE_OFFSET));
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}
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static __always_inline void __unwind_start(struct unwind_state *state,
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struct task_struct *task, struct pt_regs *regs)
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{
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memset(state, 0, sizeof(*state));
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if (regs) {
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state->sp = regs->regs[3];
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state->pc = regs->csr_era;
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state->ra = regs->regs[1];
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state->fp = regs->regs[22];
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} else if (task && task != current) {
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state->sp = thread_saved_fp(task);
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state->pc = thread_saved_ra(task);
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state->ra = 0;
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state->fp = 0;
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} else {
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state->sp = (unsigned long)__builtin_frame_address(0);
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state->pc = (unsigned long)__builtin_return_address(0);
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state->ra = 0;
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state->fp = 0;
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}
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state->task = task;
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get_stack_info(state->sp, state->task, &state->stack_info);
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state->pc = unwind_graph_addr(state, state->pc, state->sp);
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}
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static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
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{
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if (unwind_done(state))
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return 0;
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return __kernel_text_address(state->pc) ? state->pc : 0;
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}
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#ifdef CONFIG_UNWINDER_ORC
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void unwind_init(void);
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void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size);
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#else
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static inline void unwind_init(void) {}
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static inline void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size) {}
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#endif
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#endif /* _ASM_UNWIND_H */
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