From: "tip-bot2 for Nikolay Borisov" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Nikolay Borisov <nik.borisov@suse.com>,
Ingo Molnar <mingo@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/asm] x86/insn: Remove superfluous checks from instruction decoding routines
Date: Thu, 22 Feb 2024 11:31:07 -0000 [thread overview]
Message-ID: <170860146746.398.2924400958195588835.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20240222111636.2214523-2-nik.borisov@suse.com>
The following commit has been merged into the x86/asm branch of tip:
Commit-ID: 427e1646f1ef6c714a5bade30ca0302edc5d46a0
Gitweb: https://git.kernel.org/tip/427e1646f1ef6c714a5bade30ca0302edc5d46a0
Author: Nikolay Borisov <nik.borisov@suse.com>
AuthorDate: Thu, 22 Feb 2024 13:16:35 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 22 Feb 2024 12:23:04 +01:00
x86/insn: Remove superfluous checks from instruction decoding routines
It's pointless checking if a particular part of an instruction is
decoded before calling the routine responsible for decoding it as this
check is duplicated in the routines itself. Streamline the code by
removing the superfluous checks. No functional difference.
Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240222111636.2214523-2-nik.borisov@suse.com
---
arch/x86/lib/insn.c | 56 ++++++++++++++------------------------
tools/arch/x86/lib/insn.c | 56 ++++++++++++++------------------------
2 files changed, 42 insertions(+), 70 deletions(-)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 55e371c..3946bdc 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -268,11 +268,9 @@ int insn_get_opcode(struct insn *insn)
if (opcode->got)
return 0;
- if (!insn->prefixes.got) {
- ret = insn_get_prefixes(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_prefixes(insn);
+ if (ret)
+ return ret;
/* Get first opcode */
op = get_next(insn_byte_t, insn);
@@ -339,11 +337,9 @@ int insn_get_modrm(struct insn *insn)
if (modrm->got)
return 0;
- if (!insn->opcode.got) {
- ret = insn_get_opcode(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_opcode(insn);
+ if (ret)
+ return ret;
if (inat_has_modrm(insn->attr)) {
mod = get_next(insn_byte_t, insn);
@@ -386,11 +382,9 @@ int insn_rip_relative(struct insn *insn)
if (!insn->x86_64)
return 0;
- if (!modrm->got) {
- ret = insn_get_modrm(insn);
- if (ret)
- return 0;
- }
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return 0;
/*
* For rip-relative instructions, the mod field (top 2 bits)
* is zero and the r/m field (bottom 3 bits) is 0x5.
@@ -417,11 +411,9 @@ int insn_get_sib(struct insn *insn)
if (insn->sib.got)
return 0;
- if (!insn->modrm.got) {
- ret = insn_get_modrm(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return ret;
if (insn->modrm.nbytes) {
modrm = insn->modrm.bytes[0];
@@ -460,11 +452,9 @@ int insn_get_displacement(struct insn *insn)
if (insn->displacement.got)
return 0;
- if (!insn->sib.got) {
- ret = insn_get_sib(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_sib(insn);
+ if (ret)
+ return ret;
if (insn->modrm.nbytes) {
/*
@@ -628,11 +618,9 @@ int insn_get_immediate(struct insn *insn)
if (insn->immediate.got)
return 0;
- if (!insn->displacement.got) {
- ret = insn_get_displacement(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_displacement(insn);
+ if (ret)
+ return ret;
if (inat_has_moffset(insn->attr)) {
if (!__get_moffset(insn))
@@ -703,11 +691,9 @@ int insn_get_length(struct insn *insn)
if (insn->length)
return 0;
- if (!insn->immediate.got) {
- ret = insn_get_immediate(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_immediate(insn);
+ if (ret)
+ return ret;
insn->length = (unsigned char)((unsigned long)insn->next_byte
- (unsigned long)insn->kaddr);
diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c
index 8fd63a0..5d81924 100644
--- a/tools/arch/x86/lib/insn.c
+++ b/tools/arch/x86/lib/insn.c
@@ -268,11 +268,9 @@ int insn_get_opcode(struct insn *insn)
if (opcode->got)
return 0;
- if (!insn->prefixes.got) {
- ret = insn_get_prefixes(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_prefixes(insn);
+ if (ret)
+ return ret;
/* Get first opcode */
op = get_next(insn_byte_t, insn);
@@ -339,11 +337,9 @@ int insn_get_modrm(struct insn *insn)
if (modrm->got)
return 0;
- if (!insn->opcode.got) {
- ret = insn_get_opcode(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_opcode(insn);
+ if (ret)
+ return ret;
if (inat_has_modrm(insn->attr)) {
mod = get_next(insn_byte_t, insn);
@@ -386,11 +382,9 @@ int insn_rip_relative(struct insn *insn)
if (!insn->x86_64)
return 0;
- if (!modrm->got) {
- ret = insn_get_modrm(insn);
- if (ret)
- return 0;
- }
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return 0;
/*
* For rip-relative instructions, the mod field (top 2 bits)
* is zero and the r/m field (bottom 3 bits) is 0x5.
@@ -417,11 +411,9 @@ int insn_get_sib(struct insn *insn)
if (insn->sib.got)
return 0;
- if (!insn->modrm.got) {
- ret = insn_get_modrm(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return ret;
if (insn->modrm.nbytes) {
modrm = insn->modrm.bytes[0];
@@ -460,11 +452,9 @@ int insn_get_displacement(struct insn *insn)
if (insn->displacement.got)
return 0;
- if (!insn->sib.got) {
- ret = insn_get_sib(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_sib(insn);
+ if (ret)
+ return ret;
if (insn->modrm.nbytes) {
/*
@@ -628,11 +618,9 @@ int insn_get_immediate(struct insn *insn)
if (insn->immediate.got)
return 0;
- if (!insn->displacement.got) {
- ret = insn_get_displacement(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_displacement(insn);
+ if (ret)
+ return ret;
if (inat_has_moffset(insn->attr)) {
if (!__get_moffset(insn))
@@ -703,11 +691,9 @@ int insn_get_length(struct insn *insn)
if (insn->length)
return 0;
- if (!insn->immediate.got) {
- ret = insn_get_immediate(insn);
- if (ret)
- return ret;
- }
+ ret = insn_get_immediate(insn);
+ if (ret)
+ return ret;
insn->length = (unsigned char)((unsigned long)insn->next_byte
- (unsigned long)insn->kaddr);
next prev parent reply other threads:[~2024-02-22 11:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 11:16 [PATCH 0/2] Cleanup x86 instruction decoder Nikolay Borisov
2024-02-22 11:16 ` [PATCH 1/2] x86/insn: Remove superfluous checks from instruction decoding routines Nikolay Borisov
2024-02-22 11:31 ` tip-bot2 for Nikolay Borisov [this message]
2024-02-22 11:16 ` [PATCH 2/2] x86/insn: Directly assign x86_64 state in init_ins Nikolay Borisov
2024-02-22 11:31 ` [tip: x86/asm] x86/insn: Directly assign x86_64 state in insn_init() tip-bot2 for Nikolay Borisov
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