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Diffstat (limited to 'arch/riscv/include/asm/ftrace.h')
| -rw-r--r-- | arch/riscv/include/asm/ftrace.h | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h new file mode 100644 index 000000000000..e5026cd8f022 --- /dev/null +++ b/arch/riscv/include/asm/ftrace.h @@ -0,0 +1,242 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2017 Andes Technology Corporation */ + +#ifndef _ASM_RISCV_FTRACE_H +#define _ASM_RISCV_FTRACE_H + +/* + * The graph frame test is not possible if CONFIG_FRAME_POINTER is not enabled. + * Check arch/riscv/kernel/mcount.S for detail. + */ +#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && defined(CONFIG_FRAME_POINTER) +#define HAVE_FUNCTION_GRAPH_FP_TEST +#endif + +#define ARCH_SUPPORTS_FTRACE_OPS 1 +#ifndef __ASSEMBLER__ + +extern void *return_address(unsigned int level); + +#define ftrace_return_address(n) return_address(n) + +void _mcount(void); +unsigned long ftrace_call_adjust(unsigned long addr); +unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip); +#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) + +/* + * Let's do like x86/arm64 and ignore the compat syscalls. + */ +#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS +static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) +{ + return is_compat_task(); +} + +#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME +static inline bool arch_syscall_match_sym_name(const char *sym, + const char *name) +{ + /* + * Since all syscall functions have __riscv_ prefix, we must skip it. + * However, as we described above, we decided to ignore compat + * syscalls, so we don't care about __riscv_compat_ prefix here. + */ + return !strcmp(sym + 8, name); +} + +struct dyn_arch_ftrace { +}; +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +/* + * A general call in RISC-V is a pair of insts: + * 1) auipc: setting high-20 pc-related bits to ra register + * 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to + * return address (original pc + 4) + * + * The first 2 instructions for each tracable function is compiled to 2 nop + * instructions. Then, the kernel initializes the first instruction to auipc at + * boot time (<ftrace disable>). The second instruction is patched to jalr to + * start the trace. + * + *<Image>: + * 0: nop + * 4: nop + * + *<ftrace enable>: + * 0: auipc t0, 0x? + * 4: jalr t0, ?(t0) + * + *<ftrace disable>: + * 0: auipc t0, 0x? + * 4: nop + * + * Dynamic ftrace generates probes to call sites, so we must deal with + * both auipc and jalr at the same time. + */ + +#define MCOUNT_ADDR ((unsigned long)_mcount) +#define JALR_SIGN_MASK (0x00000800) +#define JALR_OFFSET_MASK (0x00000fff) +#define AUIPC_OFFSET_MASK (0xfffff000) +#define AUIPC_PAD (0x00001000) +#define JALR_SHIFT 20 +#define JALR_T0 (0x000282e7) +#define AUIPC_T0 (0x00000297) +#define JALR_RANGE (JALR_SIGN_MASK - 1) + +#define to_jalr_t0(offset) \ + (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0) + +#define to_auipc_t0(offset) \ + ((offset & JALR_SIGN_MASK) ? \ + (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) : \ + ((offset & AUIPC_OFFSET_MASK) | AUIPC_T0)) + +#define make_call_t0(caller, callee, call) \ +do { \ + unsigned int offset = \ + (unsigned long) (callee) - (unsigned long) (caller); \ + call[0] = to_auipc_t0(offset); \ + call[1] = to_jalr_t0(offset); \ +} while (0) + +/* + * Only the jalr insn in the auipc+jalr is patched, so we make it 4 + * bytes here. + */ +#define MCOUNT_INSN_SIZE 4 +#define MCOUNT_AUIPC_SIZE 4 +#define MCOUNT_JALR_SIZE 4 +#define MCOUNT_NOP4_SIZE 4 + +#ifndef __ASSEMBLER__ +struct dyn_ftrace; +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); +#define ftrace_init_nop ftrace_init_nop + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS +#define arch_ftrace_get_regs(regs) NULL +#define HAVE_ARCH_FTRACE_REGS +struct ftrace_ops; +struct ftrace_regs; +#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs)) + +struct __arch_ftrace_regs { + unsigned long epc; + unsigned long ra; + unsigned long sp; + unsigned long s0; + unsigned long t1; +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + unsigned long direct_tramp; +#endif + union { + unsigned long args[8]; + struct { + unsigned long a0; + unsigned long a1; + unsigned long a2; + unsigned long a3; + unsigned long a4; + unsigned long a5; + unsigned long a6; + unsigned long a7; +#ifdef CONFIG_CC_IS_CLANG + unsigned long t2; + unsigned long t3; + unsigned long t4; + unsigned long t5; + unsigned long t6; +#endif + }; + }; +}; + +static __always_inline unsigned long ftrace_regs_get_instruction_pointer(const struct ftrace_regs + *fregs) +{ + return arch_ftrace_regs(fregs)->epc; +} + +static __always_inline void ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, + unsigned long pc) +{ + arch_ftrace_regs(fregs)->epc = pc; +} + +static __always_inline unsigned long ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs) +{ + return arch_ftrace_regs(fregs)->sp; +} + +static __always_inline unsigned long ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs) +{ + return arch_ftrace_regs(fregs)->s0; +} + +static __always_inline unsigned long ftrace_regs_get_argument(struct ftrace_regs *fregs, + unsigned int n) +{ + if (n < 8) + return arch_ftrace_regs(fregs)->args[n]; + return 0; +} + +static __always_inline unsigned long ftrace_regs_get_return_value(const struct ftrace_regs *fregs) +{ + return arch_ftrace_regs(fregs)->a0; +} + +static __always_inline unsigned long ftrace_regs_get_return_address(const struct ftrace_regs *fregs) +{ + return arch_ftrace_regs(fregs)->ra; +} + +static __always_inline void ftrace_regs_set_return_value(struct ftrace_regs *fregs, + unsigned long ret) +{ + arch_ftrace_regs(fregs)->a0 = ret; +} + +static __always_inline void ftrace_override_function_with_return(struct ftrace_regs *fregs) +{ + arch_ftrace_regs(fregs)->epc = arch_ftrace_regs(fregs)->ra; +} + +static __always_inline struct pt_regs * +ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) +{ + struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs); + + memcpy(®s->a_regs, afregs->args, sizeof(afregs->args)); + regs->epc = afregs->epc; + regs->ra = afregs->ra; + regs->sp = afregs->sp; + regs->s0 = afregs->s0; + regs->t1 = afregs->t1; + return regs; +} + +int ftrace_regs_query_register_offset(const char *name); + +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs); +#define ftrace_graph_func ftrace_graph_func + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr) +{ + arch_ftrace_regs(fregs)->t1 = addr; +} +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */ + +#endif /* __ASSEMBLER__ */ + +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#endif /* _ASM_RISCV_FTRACE_H */ |