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authorMichael Clark <mjc@sifive.com>2019-06-24 16:42:33 -0700
committerPalmer Dabbelt <palmer@sifive.com>2019-06-27 02:44:35 -0700
commitf88222dae552c202685f5bee43e6c2e12d3c088c (patch)
treecff6f231606d5ef22065e242e000c59211ae4392 /disas
parent28a4df979a2ef92d9129886cd9dcb00c497ac4cb (diff)
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disas/riscv: Disassemble reserved compressed encodings as illegal
Due to the design of the disassembler, the immediate is not known during decoding of the opcode; so to handle compressed encodings with reserved immediate values (non-zero), we need to add an additional check during decompression to match reserved encodings with zero immediates and translate them into the illegal instruction. The following compressed opcodes have reserved encodings with zero immediates: c.addi4spn, c.addi, c.lui, c.addi16sp, c.srli, c.srai, c.andi and c.slli Signed-off-by: Michael Clark <mjc@sifive.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com> [Palmer: Broke long lines] Reviewed-by: Palmer Dabbelt <palmer@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'disas')
-rw-r--r--disas/riscv.c62
1 files changed, 45 insertions, 17 deletions
diff --git a/disas/riscv.c b/disas/riscv.c
index 59a9b04..d373127 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -504,14 +504,19 @@ typedef struct {
const rvc_constraint *constraints;
} rv_comp_data;
+enum {
+ rvcd_imm_nz = 0x1
+};
+
typedef struct {
const char * const name;
const rv_codec codec;
const char * const format;
const rv_comp_data *pseudo;
- const int decomp_rv32;
- const int decomp_rv64;
- const int decomp_rv128;
+ const short decomp_rv32;
+ const short decomp_rv64;
+ const short decomp_rv128;
+ const short decomp_data;
} rv_opcode_data;
/* register names */
@@ -1011,7 +1016,8 @@ const rv_opcode_data opcode_data[] = {
{ "fcvt.q.lu", rv_codec_r_m, rv_fmt_rm_frd_rs1, NULL, 0, 0, 0 },
{ "fmv.x.q", rv_codec_r, rv_fmt_rd_frs1, NULL, 0, 0, 0 },
{ "fmv.q.x", rv_codec_r, rv_fmt_frd_rs1, NULL, 0, 0, 0 },
- { "c.addi4spn", rv_codec_ciw_4spn, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
+ { "c.addi4spn", rv_codec_ciw_4spn, rv_fmt_rd_rs1_imm, NULL, rv_op_addi,
+ rv_op_addi, rv_op_addi, rvcd_imm_nz },
{ "c.fld", rv_codec_cl_ld, rv_fmt_frd_offset_rs1, NULL, rv_op_fld, rv_op_fld, 0 },
{ "c.lw", rv_codec_cl_lw, rv_fmt_rd_offset_rs1, NULL, rv_op_lw, rv_op_lw, rv_op_lw },
{ "c.flw", rv_codec_cl_lw, rv_fmt_frd_offset_rs1, NULL, rv_op_flw, 0, 0 },
@@ -1019,14 +1025,20 @@ const rv_opcode_data opcode_data[] = {
{ "c.sw", rv_codec_cs_sw, rv_fmt_rs2_offset_rs1, NULL, rv_op_sw, rv_op_sw, rv_op_sw },
{ "c.fsw", rv_codec_cs_sw, rv_fmt_frs2_offset_rs1, NULL, rv_op_fsw, 0, 0 },
{ "c.nop", rv_codec_ci_none, rv_fmt_none, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
- { "c.addi", rv_codec_ci, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
+ { "c.addi", rv_codec_ci, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi,
+ rv_op_addi, rvcd_imm_nz },
{ "c.jal", rv_codec_cj_jal, rv_fmt_rd_offset, NULL, rv_op_jal, 0, 0 },
{ "c.li", rv_codec_ci_li, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
- { "c.addi16sp", rv_codec_ci_16sp, rv_fmt_rd_rs1_imm, NULL, rv_op_addi, rv_op_addi, rv_op_addi },
- { "c.lui", rv_codec_ci_lui, rv_fmt_rd_imm, NULL, rv_op_lui, rv_op_lui, rv_op_lui },
- { "c.srli", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srli, rv_op_srli, rv_op_srli },
- { "c.srai", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srai, rv_op_srai, rv_op_srai },
- { "c.andi", rv_codec_cb_imm, rv_fmt_rd_rs1_imm, NULL, rv_op_andi, rv_op_andi, rv_op_andi },
+ { "c.addi16sp", rv_codec_ci_16sp, rv_fmt_rd_rs1_imm, NULL, rv_op_addi,
+ rv_op_addi, rv_op_addi, rvcd_imm_nz },
+ { "c.lui", rv_codec_ci_lui, rv_fmt_rd_imm, NULL, rv_op_lui, rv_op_lui,
+ rv_op_lui, rvcd_imm_nz },
+ { "c.srli", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srli,
+ rv_op_srli, rv_op_srli, rvcd_imm_nz },
+ { "c.srai", rv_codec_cb_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_srai,
+ rv_op_srai, rv_op_srai, rvcd_imm_nz },
+ { "c.andi", rv_codec_cb_imm, rv_fmt_rd_rs1_imm, NULL, rv_op_andi,
+ rv_op_andi, rv_op_andi, rvcd_imm_nz },
{ "c.sub", rv_codec_cs, rv_fmt_rd_rs1_rs2, NULL, rv_op_sub, rv_op_sub, rv_op_sub },
{ "c.xor", rv_codec_cs, rv_fmt_rd_rs1_rs2, NULL, rv_op_xor, rv_op_xor, rv_op_xor },
{ "c.or", rv_codec_cs, rv_fmt_rd_rs1_rs2, NULL, rv_op_or, rv_op_or, rv_op_or },
@@ -1036,7 +1048,8 @@ const rv_opcode_data opcode_data[] = {
{ "c.j", rv_codec_cj, rv_fmt_rd_offset, NULL, rv_op_jal, rv_op_jal, rv_op_jal },
{ "c.beqz", rv_codec_cb, rv_fmt_rs1_rs2_offset, NULL, rv_op_beq, rv_op_beq, rv_op_beq },
{ "c.bnez", rv_codec_cb, rv_fmt_rs1_rs2_offset, NULL, rv_op_bne, rv_op_bne, rv_op_bne },
- { "c.slli", rv_codec_ci_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_slli, rv_op_slli, rv_op_slli },
+ { "c.slli", rv_codec_ci_sh6, rv_fmt_rd_rs1_imm, NULL, rv_op_slli,
+ rv_op_slli, rv_op_slli, rvcd_imm_nz },
{ "c.fldsp", rv_codec_ci_ldsp, rv_fmt_frd_offset_rs1, NULL, rv_op_fld, rv_op_fld, rv_op_fld },
{ "c.lwsp", rv_codec_ci_lwsp, rv_fmt_rd_offset_rs1, NULL, rv_op_lw, rv_op_lw, rv_op_lw },
{ "c.flwsp", rv_codec_ci_lwsp, rv_fmt_frd_offset_rs1, NULL, rv_op_flw, 0, 0 },
@@ -2795,8 +2808,13 @@ static void decode_inst_decompress_rv32(rv_decode *dec)
{
int decomp_op = opcode_data[dec->op].decomp_rv32;
if (decomp_op != rv_op_illegal) {
- dec->op = decomp_op;
- dec->codec = opcode_data[decomp_op].codec;
+ if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
+ && dec->imm == 0) {
+ dec->op = rv_op_illegal;
+ } else {
+ dec->op = decomp_op;
+ dec->codec = opcode_data[decomp_op].codec;
+ }
}
}
@@ -2804,8 +2822,13 @@ static void decode_inst_decompress_rv64(rv_decode *dec)
{
int decomp_op = opcode_data[dec->op].decomp_rv64;
if (decomp_op != rv_op_illegal) {
- dec->op = decomp_op;
- dec->codec = opcode_data[decomp_op].codec;
+ if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
+ && dec->imm == 0) {
+ dec->op = rv_op_illegal;
+ } else {
+ dec->op = decomp_op;
+ dec->codec = opcode_data[decomp_op].codec;
+ }
}
}
@@ -2813,8 +2836,13 @@ static void decode_inst_decompress_rv128(rv_decode *dec)
{
int decomp_op = opcode_data[dec->op].decomp_rv128;
if (decomp_op != rv_op_illegal) {
- dec->op = decomp_op;
- dec->codec = opcode_data[decomp_op].codec;
+ if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
+ && dec->imm == 0) {
+ dec->op = rv_op_illegal;
+ } else {
+ dec->op = decomp_op;
+ dec->codec = opcode_data[decomp_op].codec;
+ }
}
}