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[Qemu-devel] [PATCH] target-arm/translate-a64.c: Correct unallocated che
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH] target-arm/translate-a64.c: Correct unallocated checks for ldst_excl |
Date: |
Mon, 16 Nov 2015 18:28:51 +0000 |
The checks for the unallocated encodings in the ldst_excl group
(exclusives and load-acquire/store-release) were not correct. This
error meant that in turn we ended up with code attempting to handle
the non-existent case of "non-exclusive load-acquire/store-release
pair". Delete that broken and now unreachable code.
Reported-by: Laurent Desnogues <address@hidden>
Signed-off-by: Peter Maydell <address@hidden>
---
The easiest way to validate that we have the unallocated
conditions correct now is to look at C4.4.6 "load/store exclusive"
in the v8 ARM ARM rev A.3h: our three conditions correspond
to the three "unallocated" rows in the decode table.
PS: Laurent originally reported this way back in 2014:
http://lists.gnu.org/archive/html/qemu-devel/2014-10/msg01255.html
target-arm/translate-a64.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index fe485a4..890ace4 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -1833,7 +1833,8 @@ static void disas_ldst_excl(DisasContext *s, uint32_t
insn)
int size = extract32(insn, 30, 2);
TCGv_i64 tcg_addr;
- if ((!is_excl && !is_lasr) ||
+ if ((!is_excl && !is_pair && !is_lasr) ||
+ (!is_excl && is_pair) ||
(is_pair && size < 2)) {
unallocated_encoding(s);
return;
@@ -1862,15 +1863,6 @@ static void disas_ldst_excl(DisasContext *s, uint32_t
insn)
} else {
do_gpr_ld(s, tcg_rt, tcg_addr, size, false, false);
}
- if (is_pair) {
- TCGv_i64 tcg_rt2 = cpu_reg(s, rt);
- tcg_gen_addi_i64(tcg_addr, tcg_addr, 1 << size);
- if (is_store) {
- do_gpr_st(s, tcg_rt2, tcg_addr, size);
- } else {
- do_gpr_ld(s, tcg_rt2, tcg_addr, size, false, false);
- }
- }
}
}
--
1.9.1
- [Qemu-devel] [PATCH] target-arm/translate-a64.c: Correct unallocated checks for ldst_excl,
Peter Maydell <=