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[Stable-8.2.6,01/18] target/i386: fix size of EBP writeback in gen_enter()

Message ID 20240704155251.1481617-1-mjt@tls.msk.ru
State New
Headers show
Series [Stable-8.2.6,01/18] target/i386: fix size of EBP writeback in gen_enter() | expand

Commit Message

Michael Tokarev July 4, 2024, 3:52 p.m. UTC 
From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

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>
(cherry picked from commit 3973615e7fbaeef1deeaa067577e373781ced70a)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
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Patch

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 063727c912..716a747df7 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -2662,7 +2662,7 @@  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);