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Diffstat (limited to '')
| -rw-r--r-- | arch/loongarch/kernel/unwind_prologue.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c new file mode 100644 index 000000000000..b206d9159205 --- /dev/null +++ b/arch/loongarch/kernel/unwind_prologue.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022 Loongson Technology Corporation Limited + */ +#include <linux/kallsyms.h> + +#include <asm/inst.h> +#include <asm/ptrace.h> +#include <asm/unwind.h> + +unsigned long unwind_get_return_address(struct unwind_state *state) +{ + + if (unwind_done(state)) + return 0; + else if (state->type) + return state->pc; + else if (state->first) + return state->pc; + + return *(unsigned long *)(state->sp); + +} +EXPORT_SYMBOL_GPL(unwind_get_return_address); + +static bool unwind_by_guess(struct unwind_state *state) +{ + struct stack_info *info = &state->stack_info; + unsigned long addr; + + for (state->sp += sizeof(unsigned long); + state->sp < info->end; + state->sp += sizeof(unsigned long)) { + addr = *(unsigned long *)(state->sp); + if (__kernel_text_address(addr)) + return true; + } + + return false; +} + +static bool unwind_by_prologue(struct unwind_state *state) +{ + struct stack_info *info = &state->stack_info; + union loongarch_instruction *ip, *ip_end; + unsigned long frame_size = 0, frame_ra = -1; + unsigned long size, offset, pc = state->pc; + + if (state->sp >= info->end || state->sp < info->begin) + return false; + + if (!kallsyms_lookup_size_offset(pc, &size, &offset)) + return false; + + ip = (union loongarch_instruction *)(pc - offset); + ip_end = (union loongarch_instruction *)pc; + + while (ip < ip_end) { + if (is_stack_alloc_ins(ip)) { + frame_size = (1 << 12) - ip->reg2i12_format.immediate; + ip++; + break; + } + ip++; + } + + if (!frame_size) { + if (state->first) + goto first; + + return false; + } + + while (ip < ip_end) { + if (is_ra_save_ins(ip)) { + frame_ra = ip->reg2i12_format.immediate; + break; + } + if (is_branch_ins(ip)) + break; + ip++; + } + + if (frame_ra < 0) { + if (state->first) { + state->sp = state->sp + frame_size; + goto first; + } + return false; + } + + if (state->first) + state->first = false; + + state->pc = *(unsigned long *)(state->sp + frame_ra); + state->sp = state->sp + frame_size; + return !!__kernel_text_address(state->pc); + +first: + state->first = false; + if (state->pc == state->ra) + return false; + + state->pc = state->ra; + + return !!__kernel_text_address(state->ra); +} + +void unwind_start(struct unwind_state *state, struct task_struct *task, + struct pt_regs *regs) +{ + memset(state, 0, sizeof(*state)); + + if (regs && __kernel_text_address(regs->csr_era)) { + state->pc = regs->csr_era; + state->sp = regs->regs[3]; + state->ra = regs->regs[1]; + state->type = UNWINDER_PROLOGUE; + } + + state->task = task; + state->first = true; + + get_stack_info(state->sp, state->task, &state->stack_info); + + if (!unwind_done(state) && !__kernel_text_address(state->pc)) + unwind_next_frame(state); +} +EXPORT_SYMBOL_GPL(unwind_start); + +bool unwind_next_frame(struct unwind_state *state) +{ + struct stack_info *info = &state->stack_info; + struct pt_regs *regs; + unsigned long pc; + + if (unwind_done(state)) + return false; + + do { + switch (state->type) { + case UNWINDER_GUESS: + state->first = false; + if (unwind_by_guess(state)) + return true; + break; + + case UNWINDER_PROLOGUE: + if (unwind_by_prologue(state)) + return true; + + if (info->type == STACK_TYPE_IRQ && + info->end == state->sp) { + regs = (struct pt_regs *)info->next_sp; + pc = regs->csr_era; + + if (user_mode(regs) || !__kernel_text_address(pc)) + return false; + + state->pc = pc; + state->sp = regs->regs[3]; + state->ra = regs->regs[1]; + state->first = true; + get_stack_info(state->sp, state->task, info); + + return true; + } + } + + state->sp = info->next_sp; + + } while (!get_stack_info(state->sp, state->task, info)); + + return false; +} +EXPORT_SYMBOL_GPL(unwind_next_frame); |