Messages in this thread Patch in this message | | | From | Emil Renner Berthing <> | Subject | [PATCH v3 8/8] riscv: Use asm/insn.h for dynamic ftrace | Date | Thu, 24 Feb 2022 16:24:56 +0100 |
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This converts kernel/ftrace.c to use asm/insn.h to generate the instructions for dynamic ftrace. This also converts the make_call macro into a regular static function.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk> --- arch/riscv/kernel/ftrace.c | 69 ++++++++++++-------------------------- 1 file changed, 22 insertions(+), 47 deletions(-)
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 2cc15dc45ce0..7dd3aafa17aa 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -9,6 +9,7 @@ #include <linux/uaccess.h> #include <linux/memory.h> #include <asm/cacheflush.h> +#include <asm/insn.h> #include <asm/patch.h> #ifdef CONFIG_DYNAMIC_FTRACE @@ -21,31 +22,13 @@ * Dynamic ftrace generates probes to call sites, so we must deal with * both auipc and jalr at the same time. */ +static void make_call(unsigned long caller, unsigned long callee, unsigned int call[2]) +{ + u32 offset = callee - caller; -#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_BASIC (0x000080e7) -#define AUIPC_BASIC (0x00000097) -#define NOP4 (0x00000013) - -#define make_call(caller, callee, call) \ -do { \ - call[0] = to_auipc_insn((unsigned int)((unsigned long)callee - \ - (unsigned long)caller)); \ - call[1] = to_jalr_insn((unsigned int)((unsigned long)callee - \ - (unsigned long)caller)); \ -} while (0) - -#define to_jalr_insn(offset) \ - (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC) - -#define to_auipc_insn(offset) \ - ((offset & JALR_SIGN_MASK) ? \ - (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) : \ - ((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC)) + call[0] = RISCV_INSN_AUIPC | RISCV_INSN_RD_RA | riscv_insn_u_imm(offset + 0x800); + call[1] = RISCV_INSN_JALR | RISCV_INSN_RD_RA | RISCV_INSN_RS1_RA | riscv_insn_i_imm(offset); +} int ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex) { @@ -63,7 +46,7 @@ static int ftrace_check_current_call(unsigned long hook_pos, unsigned int *expected) { unsigned int replaced[2]; - unsigned int nops[2] = {NOP4, NOP4}; + unsigned int nops[2] = { RISCV_INSN_NOP, RISCV_INSN_NOP }; /* we expect nops at the hook position */ if (!expected) @@ -95,7 +78,7 @@ static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target, bool enable) { unsigned int call[2]; - unsigned int nops[2] = {NOP4, NOP4}; + unsigned int nops[2] = { RISCV_INSN_NOP, RISCV_INSN_NOP }; make_call(hook_pos, target, call); @@ -108,39 +91,31 @@ static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target, } /* - * Put 5 instructions with 16 bytes at the front of function within + * Put 4 instructions with 16 bytes at the front of function within * patchable function entry nops' area. * * 0: REG_S ra, -SZREG(sp) - * 1: auipc ra, 0x? - * 2: jalr -?(ra) + * 1: auipc ra, ? + * 2: jalr ra, ra, ? * 3: REG_L ra, -SZREG(sp) - * - * So the opcodes is: - * 0: 0xfe113c23 (sd)/0xfe112e23 (sw) - * 1: 0x???????? -> auipc - * 2: 0x???????? -> jalr - * 3: 0xff813083 (ld)/0xffc12083 (lw) */ -#if __riscv_xlen == 64 -#define INSN0 0xfe113c23 -#define INSN3 0xff813083 -#elif __riscv_xlen == 32 -#define INSN0 0xfe112e23 -#define INSN3 0xffc12083 -#endif - #define FUNC_ENTRY_SIZE 16 #define FUNC_ENTRY_JMP 4 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { - unsigned int call[4] = {INSN0, 0, 0, INSN3}; + unsigned int call[4] = { + RISCV_INSN_REG_S | RISCV_INSN_RS2_RA | RISCV_INSN_RS1_SP | + riscv_insn_s_imm(-RISCV_INSN_SZREG), + 0, + 0, + RISCV_INSN_REG_L | RISCV_INSN_RD_RA | RISCV_INSN_RS1_SP | + riscv_insn_i_imm(-RISCV_INSN_SZREG), + }; unsigned long target = addr; unsigned long caller = rec->ip + FUNC_ENTRY_JMP; - call[1] = to_auipc_insn((unsigned int)(target - caller)); - call[2] = to_jalr_insn((unsigned int)(target - caller)); + make_call(caller, target, &call[1]); if (patch_text_nosync((void *)rec->ip, call, FUNC_ENTRY_SIZE)) return -EPERM; @@ -151,7 +126,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - unsigned int nops[4] = {NOP4, NOP4, NOP4, NOP4}; + unsigned int nops[4] = { RISCV_INSN_NOP, RISCV_INSN_NOP, RISCV_INSN_NOP, RISCV_INSN_NOP }; if (patch_text_nosync((void *)rec->ip, nops, FUNC_ENTRY_SIZE)) return -EPERM; -- 2.35.1
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