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target/i386: fix size of EBP writeback in gen_enter()

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The calculation of FrameTemp is done using the size indicated by mo_pushpop()
before being written back to EBP, but the final writeback to EBP is done using
the size indicated by mo_stacksize().

In the case where mo_pushpop() is MO_32 and mo_stacksize() is MO_16 then the
final writeback to EBP is done using MO_16 which can leave junk in the top
16-bits of EBP after executing ENTER.

Change the writeback of EBP to use the same size indicated by mo_pushpop() to
ensure that the full value is written back.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2198
Message-ID: <20240606095319.229650-5-mark.cave-ayland@ilande.co.uk>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Mark Cave-Ayland 2024-06-06 10:53:19 +01:00 committed by Paolo Bonzini
parent f1b8613da3
commit 3973615e7f
1 changed files with 1 additions and 1 deletions
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2
target/i386/tcg/translate.c
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@ -2138,7 +2138,7 @@ static void gen_enter(DisasContext *s, int esp_addend, int level)
}
/* Copy the FrameTemp value to EBP. */
gen_op_mov_reg_v(s, a_ot, R_EBP, s->T1);
gen_op_mov_reg_v(s, d_ot, R_EBP, s->T1);
/* Compute the final value of ESP. */
tcg_gen_subi_tl(s->T1, s->T1, esp_addend + size * level);