From: Andrzej Zaborowski <balrogg@gmail.com>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [5845] Don't rely on ARM tcg_out_goto() generating just a single insn.
Date: Mon, 01 Dec 2008 02:17:13 +0000 [thread overview]
Message-ID: <E1L6yLZ-0008Ie-QS@cvs.savannah.gnu.org> (raw)
Revision: 5845
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5845
Author: balrog
Date: 2008-12-01 02:17:12 +0000 (Mon, 01 Dec 2008)
Log Message:
-----------
Don't rely on ARM tcg_out_goto() generating just a single insn.
Otherwise when tb_exit generates a jump beyond the pc-relative range,
tcg_out_goto() spans two/three instructions and we load the tb return
value from a wrong address. This is #ifdefed out currently because
we take care for the jumps to be local.
Problem spotted by Steffen Liebergeld.
Modified Paths:
--------------
trunk/tcg/arm/tcg-target.c
Modified: trunk/tcg/arm/tcg-target.c
===================================================================
--- trunk/tcg/arm/tcg-target.c 2008-12-01 02:10:17 UTC (rev 5844)
+++ trunk/tcg/arm/tcg-target.c 2008-12-01 02:17:12 UTC (rev 5845)
@@ -1232,19 +1232,24 @@
if (args[0] >> 8)
tcg_out32(s, args[0]);
#else
- if (args[0] >> 8)
- tcg_out_ld32_12(s, COND_AL, 0, 15, 0);
- else
- tcg_out_dat_imm(s, COND_AL, ARITH_MOV, 0, 0, args[0]);
- tcg_out_goto(s, COND_AL, (tcg_target_ulong) tb_ret_addr);
- if (args[0] >> 8)
- tcg_out32(s, args[0]);
+ {
+ uint8_t *ld_ptr = s->code_ptr;
+ if (args[0] >> 8)
+ tcg_out_ld32_12(s, COND_AL, 0, 15, 0);
+ else
+ tcg_out_dat_imm(s, COND_AL, ARITH_MOV, 0, 0, args[0]);
+ tcg_out_goto(s, COND_AL, (tcg_target_ulong) tb_ret_addr);
+ if (args[0] >> 8) {
+ *ld_ptr = (uint8_t) (s->code_ptr - ld_ptr) - 8;
+ tcg_out32(s, args[0]);
+ }
+ }
#endif
break;
case INDEX_op_goto_tb:
if (s->tb_jmp_offset) {
/* Direct jump method */
-#if 1
+#if defined(USE_DIRECT_JUMP)
s->tb_jmp_offset[args[0]] = s->code_ptr - s->code_buf;
tcg_out_b(s, COND_AL, 8);
#else
reply other threads:[~2008-12-01 2:17 UTC|newest]
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