On 5/19/26 13:47, Daniel Henrique Barboza wrote:
We forgot to add 'cbo' insns to disas/riscv.c. The result is that the
disassembler recognizes all of them as 'lq', an insn that happens to
share the same opcode space.
While we're at it reorder cbo_* entries in insn32.decode using opcode
order instead of insn name.
Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3480
Signed-off-by: Daniel Henrique Barboza <[email protected]>
---
disas/riscv.c | 29 ++++++++++++++++++++++++++++-
target/riscv/insn32.decode | 2 +-
2 files changed, 29 insertions(+), 2 deletions(-)
As far as it goes,
Reviewed-by: Richard Henderson <[email protected]>
However, I have long-standing nits:
diff --git a/disas/riscv.c b/disas/riscv.c
index d416a4d6b3..36609efdf5 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -985,6 +985,10 @@ typedef enum {
rv_op_ssamoswap_d = 953,
rv_op_c_sspush = 954,
rv_op_c_sspopchk = 955,
+ rv_op_cbo_inval = 956,
+ rv_op_cbo_clean = 957,
+ rv_op_cbo_flush = 958,
+ rv_op_cbo_zero = 959,
} rv_op;
/* register names */
@@ -2255,6 +2259,10 @@ const rv_opcode_data rvi_opcode_data[] = {
rv_op_sspush, 0 },
{ "c.sspopchk", rv_codec_cmop_ss, rv_fmt_rs1, NULL, rv_op_sspopchk,
rv_op_sspopchk, 0 },
+ { "cbo.inval", rv_codec_r, rv_fmt_rs1, NULL, 0, 0, 0 },
+ { "cbo.clean", rv_codec_r, rv_fmt_rs1, NULL, 0, 0, 0 },
+ { "cbo.flush", rv_codec_r, rv_fmt_rs1, NULL, 0, 0, 0 },
+ { "cbo.zero", rv_codec_r, rv_fmt_rs1, NULL, 0, 0, 0 },
};
There's got to be a better way to structure this code so that you don't have a magic
correspondence between enumerators and array indexes.
/* CSR names */
@@ -2876,7 +2884,26 @@ static void decode_inst_opcode(rv_decode *dec, rv_isa
isa)
switch ((inst >> 12) & 0b111) {
case 0: op = rv_op_fence; break;
case 1: op = rv_op_fence_i; break;
- case 2: op = rv_op_lq; break;
+ case 2:
+ /*
+ * 'lq' shares the "(...) 010 ..... 0001111" opcode space
+ * with 'cbo' insns. Check the next 5 bits to select
+ * what we want:
+ *
+ * cbo_inval 0000000 00000 ..... 010 00000 0001111
+ * cbo_clean 0000000 00001 ..... 010 00000 0001111
+ * cbo_flush 0000000 00010 ..... 010 00000 0001111
+ * cbo_zero 0000000 00100 ..... 010 00000 0001111
+ *
+ * Anything that doesn't match these will default to 'lq'.
+ */
+ switch ((inst >> 17) & 0b11111) {
+ case 0: op = rv_op_cbo_inval; break;
Surely "return foo" would be easier than arranging to fall through all the way to the
bottom of the function, just to do
dec->op = op;
with no return value.
To my mind,
void (*decode_func)(rv_decode *, rv_isa);
should return "const rv_opcode_data *", with NULL for unrecognized/illegal, so that each
opcode_data array need not be exported along with the decode function.
Indeed, that means you need not have opcode_data arrays at all, and could write
static const rv_op_cbo_inval = {
"cbo.inval", rv_codec_r, rv_fmt_rs1, NULL, 0, 0, 0
};
...
case 0: return &rv_op_cbo_inval;
r~
