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RISC-V: Move riscv_insn_is_* macros into a common header
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Right now the riscv kernel has (at least) two independent sets
of functions to check if an encoded instruction is of a specific
type. One in kgdb and one kprobes simulate-insn code.

More parts of the kernel will probably need this in the future,
so instead of allowing this duplication to go on further,
move macros that do the function declaration in a common header,
similar to at least aarch64.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20221223221332.4127602-7-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Heiko Stuebner authored and palmer-dabbelt committed Dec 29, 2022
1 parent cde4a69 commit ec5f908
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Showing 3 changed files with 55 additions and 62 deletions.
42 changes: 35 additions & 7 deletions arch/riscv/include/asm/parse_asm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -193,13 +193,41 @@
#define __INSN_OPCODE_MASK _UL(0x7F)
#define __INSN_BRANCH_OPCODE _UL(RVG_OPCODE_BRANCH)

/* Define a series of is_XXX_insn functions to check if the value INSN
* is an instance of instruction XXX.
*/
#define DECLARE_INSN(INSN_NAME, INSN_MATCH, INSN_MASK) \
static inline bool is_ ## INSN_NAME ## _insn(long insn) \
{ \
return (insn & (INSN_MASK)) == (INSN_MATCH); \
#define __RISCV_INSN_FUNCS(name, mask, val) \
static __always_inline bool riscv_insn_is_##name(u32 code) \
{ \
BUILD_BUG_ON(~(mask) & (val)); \
return (code & (mask)) == (val); \
} \

#if __riscv_xlen == 32
/* C.JAL is an RV32C-only instruction */
__RISCV_INSN_FUNCS(c_jal, RVC_MASK_C_JAL, RVC_MATCH_C_JAL)
#else
#define riscv_insn_is_c_jal(opcode) 0
#endif
__RISCV_INSN_FUNCS(auipc, RVG_MASK_AUIPC, RVG_MATCH_AUIPC)
__RISCV_INSN_FUNCS(jalr, RVG_MASK_JALR, RVG_MATCH_JALR)
__RISCV_INSN_FUNCS(jal, RVG_MASK_JAL, RVG_MATCH_JAL)
__RISCV_INSN_FUNCS(c_jr, RVC_MASK_C_JR, RVC_MATCH_C_JR)
__RISCV_INSN_FUNCS(c_jalr, RVC_MASK_C_JALR, RVC_MATCH_C_JALR)
__RISCV_INSN_FUNCS(c_j, RVC_MASK_C_J, RVC_MATCH_C_J)
__RISCV_INSN_FUNCS(beq, RVG_MASK_BEQ, RVG_MATCH_BEQ)
__RISCV_INSN_FUNCS(bne, RVG_MASK_BNE, RVG_MATCH_BNE)
__RISCV_INSN_FUNCS(blt, RVG_MASK_BLT, RVG_MATCH_BLT)
__RISCV_INSN_FUNCS(bge, RVG_MASK_BGE, RVG_MATCH_BGE)
__RISCV_INSN_FUNCS(bltu, RVG_MASK_BLTU, RVG_MATCH_BLTU)
__RISCV_INSN_FUNCS(bgeu, RVG_MASK_BGEU, RVG_MATCH_BGEU)
__RISCV_INSN_FUNCS(c_beqz, RVC_MASK_C_BEQZ, RVC_MATCH_C_BEQZ)
__RISCV_INSN_FUNCS(c_bnez, RVC_MASK_C_BNEZ, RVC_MATCH_C_BNEZ)
__RISCV_INSN_FUNCS(c_ebreak, RVC_MASK_C_EBREAK, RVC_MATCH_C_EBREAK)
__RISCV_INSN_FUNCS(ebreak, RVG_MASK_EBREAK, RVG_MATCH_EBREAK)
__RISCV_INSN_FUNCS(sret, RVG_MASK_SRET, RVG_MATCH_SRET)

/* special case to catch _any_ branch instruction */
static __always_inline bool riscv_insn_is_branch(u32 code)
{
return (code & RV_INSN_OPCODE_MASK) == RVG_OPCODE_BRANCH;
}

#define RV_IMM_SIGN(x) (-(((x) >> 31) & 1))
Expand Down
49 changes: 15 additions & 34 deletions arch/riscv/kernel/kgdb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,27 +23,6 @@ enum {
static unsigned long stepped_address;
static unsigned int stepped_opcode;

#if __riscv_xlen == 32
/* C.JAL is an RV32C-only instruction */
DECLARE_INSN(c_jal, MATCH_C_JAL, MASK_C_JAL)
#else
#define is_c_jal_insn(opcode) 0
#endif
DECLARE_INSN(jalr, RVG_MATCH_JALR, RVG_MASK_JALR)
DECLARE_INSN(jal, RVG_MATCH_JAL, RVG_MASK_JAL)
DECLARE_INSN(c_jr, RVC_MATCH_C_JR, RVC_MASK_C_JR)
DECLARE_INSN(c_jalr, RVC_MATCH_C_JALR, RVC_MASK_C_JALR)
DECLARE_INSN(c_j, RVC_MATCH_C_J, RVC_MASK_C_J)
DECLARE_INSN(beq, RVG_MATCH_BEQ, RVG_MASK_BEQ)
DECLARE_INSN(bne, RVG_MATCH_BNE, RVG_MASK_BNE)
DECLARE_INSN(blt, RVG_MATCH_BLT, RVG_MASK_BLT)
DECLARE_INSN(bge, RVG_MATCH_BGE, RVG_MASK_BGE)
DECLARE_INSN(bltu, RVG_MATCH_BLTU, RVG_MASK_BLTU)
DECLARE_INSN(bgeu, RVG_MATCH_BGEU, RVG_MASK_BGEU)
DECLARE_INSN(c_beqz, RVC_MATCH_C_BEQZ, RVC_MASK_C_BEQZ)
DECLARE_INSN(c_bnez, RVC_MATCH_C_BNEZ, RVC_MASK_C_BNEZ)
DECLARE_INSN(sret, RVG_MATCH_SRET, RVG_MASK_SRET)

static int decode_register_index(unsigned long opcode, int offset)
{
return (opcode >> offset) & 0x1F;
Expand All @@ -65,19 +44,21 @@ static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
if (get_kernel_nofault(op_code, (void *)pc))
return -EINVAL;
if ((op_code & __INSN_LENGTH_MASK) != __INSN_LENGTH_GE_32) {
if (is_c_jalr_insn(op_code) || is_c_jr_insn(op_code)) {
if (riscv_insn_is_c_jalr(op_code) ||
riscv_insn_is_c_jr(op_code)) {
rs1_num = decode_register_index(op_code, RVC_C2_RS1_OPOFF);
*next_addr = regs_ptr[rs1_num];
} else if (is_c_j_insn(op_code) || is_c_jal_insn(op_code)) {
} else if (riscv_insn_is_c_j(op_code) ||
riscv_insn_is_c_jal(op_code)) {
*next_addr = RVC_EXTRACT_JTYPE_IMM(op_code) + pc;
} else if (is_c_beqz_insn(op_code)) {
} else if (riscv_insn_is_c_beqz(op_code)) {
rs1_num = decode_register_index_short(op_code,
RVC_C1_RS1_OPOFF);
if (!rs1_num || regs_ptr[rs1_num] == 0)
*next_addr = RVC_EXTRACT_BTYPE_IMM(op_code) + pc;
else
*next_addr = pc + 2;
} else if (is_c_bnez_insn(op_code)) {
} else if (riscv_insn_is_c_bnez(op_code)) {
rs1_num =
decode_register_index_short(op_code, RVC_C1_RS1_OPOFF);
if (rs1_num && regs_ptr[rs1_num] != 0)
Expand All @@ -100,34 +81,34 @@ static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
if (rs2_num)
rs2_val = regs_ptr[rs2_num];

if (is_beq_insn(op_code))
if (riscv_insn_is_beq(op_code))
result = (rs1_val == rs2_val) ? true : false;
else if (is_bne_insn(op_code))
else if (riscv_insn_is_bne(op_code))
result = (rs1_val != rs2_val) ? true : false;
else if (is_blt_insn(op_code))
else if (riscv_insn_is_blt(op_code))
result =
((long)rs1_val <
(long)rs2_val) ? true : false;
else if (is_bge_insn(op_code))
else if (riscv_insn_is_bge(op_code))
result =
((long)rs1_val >=
(long)rs2_val) ? true : false;
else if (is_bltu_insn(op_code))
else if (riscv_insn_is_bltu(op_code))
result = (rs1_val < rs2_val) ? true : false;
else if (is_bgeu_insn(op_code))
else if (riscv_insn_is_bgeu(op_code))
result = (rs1_val >= rs2_val) ? true : false;
if (result)
*next_addr = imm + pc;
else
*next_addr = pc + 4;
} else if (is_jal_insn(op_code)) {
} else if (riscv_insn_is_jal(op_code)) {
*next_addr = RV_EXTRACT_JTYPE_IMM(op_code) + pc;
} else if (is_jalr_insn(op_code)) {
} else if (riscv_insn_is_jalr(op_code)) {
rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
if (rs1_num)
*next_addr = ((unsigned long *)regs)[rs1_num];
*next_addr += RV_EXTRACT_ITYPE_IMM(op_code);
} else if (is_sret_insn(op_code)) {
} else if (riscv_insn_is_sret(op_code)) {
*next_addr = pc;
} else {
*next_addr = pc + 4;
Expand Down
26 changes: 5 additions & 21 deletions arch/riscv/kernel/probes/simulate-insn.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,14 +3,7 @@
#ifndef _RISCV_KERNEL_PROBES_SIMULATE_INSN_H
#define _RISCV_KERNEL_PROBES_SIMULATE_INSN_H

#define __RISCV_INSN_FUNCS(name, mask, val) \
static __always_inline bool riscv_insn_is_##name(probe_opcode_t code) \
{ \
BUILD_BUG_ON(~(mask) & (val)); \
return (code & (mask)) == (val); \
} \
bool simulate_##name(u32 opcode, unsigned long addr, \
struct pt_regs *regs)
#include <asm/parse_asm.h>

#define RISCV_INSN_REJECTED(name, code) \
do { \
Expand All @@ -30,18 +23,9 @@ __RISCV_INSN_FUNCS(fence, 0x7f, 0x0f);
} \
} while (0)

__RISCV_INSN_FUNCS(c_j, 0xe003, 0xa001);
__RISCV_INSN_FUNCS(c_jr, 0xf007, 0x8002);
__RISCV_INSN_FUNCS(c_jal, 0xe003, 0x2001);
__RISCV_INSN_FUNCS(c_jalr, 0xf007, 0x9002);
__RISCV_INSN_FUNCS(c_beqz, 0xe003, 0xc001);
__RISCV_INSN_FUNCS(c_bnez, 0xe003, 0xe001);
__RISCV_INSN_FUNCS(c_ebreak, 0xffff, 0x9002);

__RISCV_INSN_FUNCS(auipc, 0x7f, 0x17);
__RISCV_INSN_FUNCS(branch, 0x7f, 0x63);

__RISCV_INSN_FUNCS(jal, 0x7f, 0x6f);
__RISCV_INSN_FUNCS(jalr, 0x707f, 0x67);
bool simulate_auipc(u32 opcode, unsigned long addr, struct pt_regs *regs);
bool simulate_branch(u32 opcode, unsigned long addr, struct pt_regs *regs);
bool simulate_jal(u32 opcode, unsigned long addr, struct pt_regs *regs);
bool simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *regs);

#endif /* _RISCV_KERNEL_PROBES_SIMULATE_INSN_H */

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