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target/i386/tcg: fix POP to memory in long mode

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In long mode, POP to memory will write a full 64-bit value.  However,
the call to gen_writeback() in gen_POP will use MO_32 because the
decoding table is incorrect.

The bug was latent until commit aea49fbb01a ("target/i386: use gen_writeback()
within gen_POP()", 2024-06-08), and then became visible because gen_op_st_v
now receives op->ot instead of the "ot" returned by gen_pop_T0.

Analyzed-by: Clément Chigot <chigot@adacore.com>
Fixes: 5e9e21bcc4d ("target/i386: move 60-BF opcodes to new decoder", 2024-05-07)
Tested-by: Clément Chigot <chigot@adacore.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2024-07-10 12:40:24 +02:00
parent 340627ec14
commit 3afc6539a8
2 changed files with 2 additions and 1 deletions
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2
target/i386/tcg/decode-new.c.inc
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@ -1717,7 +1717,7 @@ static const X86OpEntry opcodes_root[256] = {
[0x8C] = X86_OP_ENTRYwr(MOV, E,v, S,w, op0_Mw), [0x8C] = X86_OP_ENTRYwr(MOV, E,v, S,w, op0_Mw),
[0x8D] = X86_OP_ENTRYwr(LEA, G,v, M,v, nolea), [0x8D] = X86_OP_ENTRYwr(LEA, G,v, M,v, nolea),
[0x8E] = X86_OP_ENTRYwr(MOV, S,w, E,w), [0x8E] = X86_OP_ENTRYwr(MOV, S,w, E,w),
[0x8F] = X86_OP_GROUPw(group1A, E,v), [0x8F] = X86_OP_GROUPw(group1A, E,d64),
[0x98] = X86_OP_ENTRY1(CBW, 0,v), /* rAX */ [0x98] = X86_OP_ENTRY1(CBW, 0,v), /* rAX */
[0x99] = X86_OP_ENTRYwr(CWD, 2,v, 0,v), /* rDX, rAX */ [0x99] = X86_OP_ENTRYwr(CWD, 2,v, 0,v), /* rDX, rAX */

1
target/i386/tcg/emit.c.inc
View File

@ -2788,6 +2788,7 @@ static void gen_POP(DisasContext *s, X86DecodedInsn *decode)
X86DecodedOp *op = &decode->op[0]; X86DecodedOp *op = &decode->op[0];
MemOp ot = gen_pop_T0(s); MemOp ot = gen_pop_T0(s);
assert(ot >= op->ot);
if (op->has_ea || op->unit == X86_OP_SEG) { if (op->has_ea || op->unit == X86_OP_SEG) {
/* NOTE: order is important for MMU exceptions */ /* NOTE: order is important for MMU exceptions */
gen_writeback(s, decode, 0, s->T0); gen_writeback(s, decode, 0, s->T0);