| // SPDX-License-Identifier: GPL-2.0 | |
| /* | |
| * Copyright (C) 2022 Loongson Technology Corporation Limited | |
| */ | |
| #include <linux/init.h> | |
| #include <linux/ftrace.h> | |
| #include <linux/syscalls.h> | |
| #include <linux/uaccess.h> | |
| #include <asm/asm.h> | |
| #include <asm/asm-offsets.h> | |
| #include <asm/cacheflush.h> | |
| #include <asm/inst.h> | |
| #include <asm/loongarch.h> | |
| #include <asm/syscall.h> | |
| #include <asm-generic/sections.h> | |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER | |
| /* | |
| * As `call _mcount` follows LoongArch psABI, ra-saved operation and | |
| * stack operation can be found before this insn. | |
| */ | |
| static int ftrace_get_parent_ra_addr(unsigned long insn_addr, int *ra_off) | |
| { | |
| int limit = 32; | |
| union loongarch_instruction *insn; | |
| insn = (union loongarch_instruction *)insn_addr; | |
| do { | |
| insn--; | |
| limit--; | |
| if (is_ra_save_ins(insn)) | |
| *ra_off = -((1 << 12) - insn->reg2i12_format.immediate); | |
| } while (!is_stack_alloc_ins(insn) && limit); | |
| if (!limit) | |
| return -EINVAL; | |
| return 0; | |
| } | |
| void prepare_ftrace_return(unsigned long self_addr, | |
| unsigned long callsite_sp, unsigned long old) | |
| { | |
| int ra_off; | |
| unsigned long return_hooker = (unsigned long)&return_to_handler; | |
| if (unlikely(ftrace_graph_is_dead())) | |
| return; | |
| if (unlikely(atomic_read(¤t->tracing_graph_pause))) | |
| return; | |
| if (ftrace_get_parent_ra_addr(self_addr, &ra_off)) | |
| goto out; | |
| if (!function_graph_enter(old, self_addr, 0, NULL)) | |
| *(unsigned long *)(callsite_sp + ra_off) = return_hooker; | |
| return; | |
| out: | |
| ftrace_graph_stop(); | |
| WARN_ON(1); | |
| } | |
| #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |