From: Richard Henderson <richard.henderson@linaro.org>
To: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>, qemu-devel@nongnu.org
Cc: qemu-riscv@nongnu.org, palmer@dabbelt.com,
alistair.francis@wdc.com, dbarboza@ventanamicro.com,
liwei1518@gmail.com, bmeng.cn@gmail.com
Subject: Re: [PATCH 1/1] disas/riscv: Guard dec->cfg dereference for host disassemble
Date: Thu, 5 Dec 2024 21:36:42 -0600 [thread overview]
Message-ID: <79a76786-9ba7-4c04-8c11-52c92376e6df@linaro.org> (raw)
In-Reply-To: <20241206032411.52528-1-zhiwei_liu@linux.alibaba.com>
On 12/5/24 21:24, LIU Zhiwei wrote:
> For riscv host, it will set dec->cfg to zero. Thus we shuld guard
> the dec->cfg deference for riscv host disassemble.
>
> And in general, we should only use dec->cfg for target in three cases:
>
> 1) For not incompatible encodings, such as zcmp/zcmt/zfinx.
> 2) For maybe-ops encodings, they are better to be disassembled to
> the "real" extensions, such as zicfiss. The guard of dec->zimop
> and dec->zcmop is for comment and avoid check for every extension
> that encoded in maybe-ops area.
> 3) For custom encodings, we have to use dec->cfg to disassemble
> custom encodings using the same encoding area.
>
> Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
...
> @@ -5112,28 +5112,28 @@ static GString *format_inst(size_t tab, rv_decode *dec)
> g_string_append(buf, rv_ireg_name_sym[dec->rs2]);
> break;
> case '3':
> - if (dec->cfg->ext_zfinx) {
> + if (dec->cfg && dec->cfg->ext_zfinx) {
> g_string_append(buf, rv_ireg_name_sym[dec->rd]);
> } else {
> g_string_append(buf, rv_freg_name_sym[dec->rd]);
> }
> break;
> case '4':
> - if (dec->cfg->ext_zfinx) {
> + if (dec->cfg && dec->cfg->ext_zfinx) {
> g_string_append(buf, rv_ireg_name_sym[dec->rs1]);
> } else {
> g_string_append(buf, rv_freg_name_sym[dec->rs1]);
> }
> break;
> case '5':
> - if (dec->cfg->ext_zfinx) {
> + if (dec->cfg && dec->cfg->ext_zfinx) {
> g_string_append(buf, rv_ireg_name_sym[dec->rs2]);
> } else {
> g_string_append(buf, rv_freg_name_sym[dec->rs2]);
> }
> break;
> case '6':
> - if (dec->cfg->ext_zfinx) {
> + if (dec->cfg && dec->cfg->ext_zfinx) {
> g_string_append(buf, rv_ireg_name_sym[dec->rs3]);
> } else {
> g_string_append(buf, rv_freg_name_sym[dec->rs3]);
These are the only tests of cfg that are required.
None of the other standard isa extensions overlap.
> @@ -5439,7 +5439,8 @@ static GString *disasm_inst(rv_isa isa, uint64_t pc, rv_inst inst,
> const rv_opcode_data *opcode_data = decoders[i].opcode_data;
> void (*decode_func)(rv_decode *, rv_isa) = decoders[i].decode_func;
>
> - if (guard_func(cfg)) {
> + /* always_true_p don't dereference cfg */
> + if (((i == 0) || cfg) && guard_func(cfg)) {
This should be i == 0 || (cfg && guard_func(cfg)).
r~
next prev parent reply other threads:[~2024-12-06 3:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-06 3:24 [PATCH 1/1] disas/riscv: Guard dec->cfg dereference for host disassemble LIU Zhiwei
2024-12-06 3:36 ` Richard Henderson [this message]
2024-12-06 4:39 ` LIU Zhiwei
2024-12-06 13:36 ` Richard Henderson
2024-12-07 1:27 ` LIU Zhiwei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=79a76786-9ba7-4c04-8c11-52c92376e6df@linaro.org \
--to=richard.henderson@linaro.org \
--cc=alistair.francis@wdc.com \
--cc=bmeng.cn@gmail.com \
--cc=dbarboza@ventanamicro.com \
--cc=liwei1518@gmail.com \
--cc=palmer@dabbelt.com \
--cc=qemu-devel@nongnu.org \
--cc=qemu-riscv@nongnu.org \
--cc=zhiwei_liu@linux.alibaba.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).