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[PATCH 07/22] target/i386: reimplement check for validity of LOCK prefix
From: |
Paolo Bonzini |
Subject: |
[PATCH 07/22] target/i386: reimplement check for validity of LOCK prefix |
Date: |
Fri, 22 Dec 2023 19:15:48 +0100 |
The previous check erroneously allowed CMP to be modified with LOCK.
Instead, tag explicitly the instructions that do support LOCK.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target/i386/tcg/decode-new.c.inc | 17 ++++++++++-------
target/i386/tcg/decode-new.h | 3 +++
target/i386/tcg/emit.c.inc | 5 -----
3 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc
index 232c6a45c96..5eb2e9d0224 100644
--- a/target/i386/tcg/decode-new.c.inc
+++ b/target/i386/tcg/decode-new.c.inc
@@ -151,6 +151,7 @@
#define cpuid(feat) .cpuid = X86_FEAT_##feat,
#define xchg .special = X86_SPECIAL_Locked,
+#define lock .special = X86_SPECIAL_HasLock,
#define mmx .special = X86_SPECIAL_MMX,
#define zext0 .special = X86_SPECIAL_ZExtOp0,
#define zext2 .special = X86_SPECIAL_ZExtOp2,
@@ -1103,10 +1104,6 @@ static int decode_modrm(DisasContext *s, CPUX86State
*env, X86DecodedInsn *decod
{
int modrm = get_modrm(s, env);
if ((modrm >> 6) == 3) {
- if (s->prefix & PREFIX_LOCK) {
- decode->e.gen = gen_illegal;
- return 0xff;
- }
op->n = (modrm & 7);
if (type != X86_TYPE_Q && type != X86_TYPE_N) {
op->n |= REX_B(s);
@@ -1881,6 +1878,9 @@ static void disas_insn_new(DisasContext *s, CPUState
*cpu, int b)
if (decode.op[0].has_ea) {
s->prefix |= PREFIX_LOCK;
}
+ decode.e.special = X86_SPECIAL_HasLock;
+ /* fallthrough */
+ case X86_SPECIAL_HasLock:
break;
case X86_SPECIAL_ZExtOp0:
@@ -1909,6 +1909,12 @@ static void disas_insn_new(DisasContext *s, CPUState
*cpu, int b)
break;
}
+ if (s->prefix & PREFIX_LOCK) {
+ if (decode.e.special != X86_SPECIAL_HasLock || !decode.op[0].has_ea) {
+ goto illegal_op;
+ }
+ }
+
if (!validate_vex(s, &decode)) {
return;
}
@@ -1952,9 +1958,6 @@ static void disas_insn_new(DisasContext *s, CPUState
*cpu, int b)
gen_load_ea(s, &decode.mem, decode.e.vex_class == 12);
}
if (s->prefix & PREFIX_LOCK) {
- if (decode.op[0].unit != X86_OP_INT || !decode.op[0].has_ea) {
- goto illegal_op;
- }
gen_load(s, &decode, 2, s->T1);
decode.e.gen(s, env, &decode);
} else {
diff --git a/target/i386/tcg/decode-new.h b/target/i386/tcg/decode-new.h
index e6c904a3192..611bfddd957 100644
--- a/target/i386/tcg/decode-new.h
+++ b/target/i386/tcg/decode-new.h
@@ -158,6 +158,9 @@ typedef enum X86InsnCheck {
typedef enum X86InsnSpecial {
X86_SPECIAL_None,
+ /* Accepts LOCK prefix; LOCKed operations do not load or writeback operand
0 */
+ X86_SPECIAL_HasLock,
+
/* Always locked if it has a memory operand (XCHG) */
X86_SPECIAL_Locked,
diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
index d444d83e534..98c4c9569ef 100644
--- a/target/i386/tcg/emit.c.inc
+++ b/target/i386/tcg/emit.c.inc
@@ -55,11 +55,6 @@ static void gen_NM_exception(DisasContext *s)
gen_exception(s, EXCP07_PREX);
}
-static void gen_illegal(DisasContext *s, CPUX86State *env, X86DecodedInsn
*decode)
-{
- gen_illegal_opcode(s);
-}
-
static void gen_load_ea(DisasContext *s, AddressParts *mem, bool is_vsib)
{
TCGv ea = gen_lea_modrm_1(s, *mem, is_vsib);
--
2.43.0
- Re: [PATCH 13/22] target/i386: do not clobber T0 on string operations, (continued)
- [PATCH 16/22] target/i386: do not use s->tmp0 for jumps on ECX ==/!= 0, Paolo Bonzini, 2023/12/22
- [PATCH 15/22] target/i386: do not use s->tmp4 for push, Paolo Bonzini, 2023/12/22
- [PATCH 19/22] target/i386: move operand load and writeback out of gen_cmovcc1, Paolo Bonzini, 2023/12/22
- [PATCH 20/22] target/i386: adjust decoding of J operand, Paolo Bonzini, 2023/12/22
- [PATCH 05/22] target/i386: clean up cpu_cc_compute_all, Paolo Bonzini, 2023/12/22
- [PATCH 07/22] target/i386: reimplement check for validity of LOCK prefix,
Paolo Bonzini <=
- [PATCH 09/22] target/i386: rename zext0/zext2 and make them closer to the manual, Paolo Bonzini, 2023/12/22
- [PATCH 21/22] target/i386: introduce flags writeback mechanism, Paolo Bonzini, 2023/12/22
- [PATCH 22/22] target/i386: implement CMPccXADD, Paolo Bonzini, 2023/12/22
- [PATCH 17/22] target/i386: extract gen_far_call/jmp, reordering temporaries, Paolo Bonzini, 2023/12/22