aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorTejas Belagod <tejas.belagod@arm.com>2021-04-09 12:21:38 +0100
committerTamar Christina <tamar.christina@arm.com>2021-04-09 12:27:54 +0100
commit52efda8266cb1f8ade0193f45801fdd6e42165ac (patch)
tree90be33f93f897c9524d0cbdb15240eb33f5798ad
parentc3f72de4f53bc3e5f13762633d78d8a7efb8dd79 (diff)
downloadfsf-binutils-gdb-52efda8266cb1f8ade0193f45801fdd6e42165ac.zip
fsf-binutils-gdb-52efda8266cb1f8ade0193f45801fdd6e42165ac.tar.gz
fsf-binutils-gdb-52efda8266cb1f8ade0193f45801fdd6e42165ac.tar.bz2
AArch64: Fix Atomic LD64/ST64 classification.
Patch 1: Fix diagnostics for exclusive load/stores and reclassify Armv8.7-A ST/LD64 Atomics. Following upstream pointing out some inconsistencies in diagnostics, https://sourceware.org/pipermail/binutils/2021-February/115356.html attached is a patch set that fixes the issues. I believe a combination of two patches mainly contributed to these bugs: https://sourceware.org/pipermail/binutils/2020-November/113961.html https://sourceware.org/pipermail/binutils/2018-June/103322.html A summary of what this patch set fixes: For instructions STXR w0,x2,[x0] STLXR w0,x2,[x0] The warning we emit currently is misleading: Warning: unpredictable: identical transfer and status registers --`stlxr w0,x2,[x0]' Warning: unpredictable: identical transfer and status registers --`stxr w0,x2,[x0]' it ought to be: Warning: unpredictable: identical base and status registers --`stlxr w0,x2,[x0]' Warning: unpredictable: identical base and status registers --`stxr w0,x2,[x0]' For instructions: ldaxp x0,x0,[x0] ldxp x0,x0,[x0] The warning we emit is incorrect Warning: unpredictable: identical transfer and status registers --`ldaxp x0,x0,[x0]' Warning: unpredictable: identical transfer and status registers --`ldxp x0,x0,[x0]' it ought to be: Warning: unpredictable load of register pair -- `ldaxp x0,x0,[x0]' Warning: unpredictable load of register pair -- `ldxp x0,x0,[x0]' For instructions stlxp w0, x2, x2, [x0] stxp w0, x2, x2, [x0] We don't emit any warning when it ought to be: Warning: unpredictable: identical base and status registers --`stlxp w0,x2,x2,[x0]' Warning: unpredictable: identical base and status registers --`stxp w0,x2,x2,[x0]' For instructions: st64bv x0, x2, [x0] st64bv x2, x0, [x0] We incorrectly warn when its not necessary. This is because we classify them incorrectly as ldstexcl when it should be lse_atomics in the opcode table. The incorrect classification makes it pick up the warnings from warning on exclusive load/stores. Patch 2: Reclassify Armv8.7-A ST/LD64 Atomics. This patch reclassifies ST64B{V,V0}, LD64B as lse_atomics rather than ldstexcl according to their encoding class as specified in the architecture. This also has the fortunate side-effect of spurious unpredictable warnings getting eliminated. For eg. For instruction: st64bv x0, x2, [x0] We incorrectly warn when its not necessary: Warning: unpredictable: identical transfer and status registers --`st64bv x0,x2,[x0]' This is because we classify them incorrectly as ldstexcl when it should be lse_atomics in the opcode table. The incorrect classification makes it pick up the warnings from warning on exclusive load/stores. This patch fixes it by reclassifying it and no warnings are issued for this instruction. opcodes/ChangeLog: 2021-04-09 Tejas Belagod <tejas.belagod@arm.com> * aarch64-tbl.h (struct aarch64_opcode aarch64_opcode_table): Reclassify LD64/ST64 instructions to lse_atomic instead of ldstexcl.
-rw-r--r--opcodes/ChangeLog5
-rw-r--r--opcodes/aarch64-tbl.h8
2 files changed, 9 insertions, 4 deletions
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index f6c5eef..d2b5435 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,8 @@
+2021-04-09 Tejas Belagod <tejas.belagod@arm.com>
+
+ * aarch64-tbl.h (struct aarch64_opcode aarch64_opcode_table): Reclassify
+ LD64/ST64 instructions to lse_atomic instead of ldstexcl.
+
2021-04-09 Alan Modra <amodra@gmail.com>
* ppc-dis.c (struct dis_private): Add "special".
diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
index f5c3131..4192e54 100644
--- a/opcodes/aarch64-tbl.h
+++ b/opcodes/aarch64-tbl.h
@@ -3646,10 +3646,10 @@ struct aarch64_opcode aarch64_opcode_table[] =
CORE_INSN ("ldrsw", 0x98000000, 0xff000000, loadlit, OP_LDRSW_LIT, OP2 (Rt, ADDR_PCREL19), QL_X_PCREL, 0),
CORE_INSN ("prfm", 0xd8000000, 0xff000000, loadlit, OP_PRFM_LIT, OP2 (PRFOP, ADDR_PCREL19), QL_PRFM_PCREL, 0),
/* Atomic 64-byte load/store in Armv8.7. */
- _LS64_INSN ("ld64b", 0xf83fd000, 0xfffffc00, ldstexcl, OP2 (Rt_LS64, ADDR_SIMPLE), QL_X1NIL, 0),
- _LS64_INSN ("st64b", 0xf83f9000, 0xfffffc00, ldstexcl, OP2 (Rt_LS64, ADDR_SIMPLE), QL_X1NIL, 0),
- _LS64_INSN ("st64bv", 0xf820b000, 0xffe0fc00, ldstexcl, OP3 (Rs, Rt_LS64, ADDR_SIMPLE), QL_X2NIL, 0),
- _LS64_INSN ("st64bv0", 0xf820a000, 0xffe0fc00, ldstexcl, OP3 (Rs, Rt_LS64, ADDR_SIMPLE), QL_X2NIL, 0),
+ _LS64_INSN ("ld64b", 0xf83fd000, 0xfffffc00, lse_atomic, OP2 (Rt_LS64, ADDR_SIMPLE), QL_X1NIL, 0),
+ _LS64_INSN ("st64b", 0xf83f9000, 0xfffffc00, lse_atomic, OP2 (Rt_LS64, ADDR_SIMPLE), QL_X1NIL, 0),
+ _LS64_INSN ("st64bv", 0xf820b000, 0xffe0fc00, lse_atomic, OP3 (Rs, Rt_LS64, ADDR_SIMPLE), QL_X2NIL, 0),
+ _LS64_INSN ("st64bv0", 0xf820a000, 0xffe0fc00, lse_atomic, OP3 (Rs, Rt_LS64, ADDR_SIMPLE), QL_X2NIL, 0),
/* Logical (immediate). */
CORE_INSN ("and", 0x12000000, 0x7f800000, log_imm, 0, OP3 (Rd_SP, Rn, LIMM), QL_R2NIL, F_HAS_ALIAS | F_SF),
CORE_INSN ("bic", 0x12000000, 0x7f800000, log_imm, OP_BIC, OP3 (Rd_SP, Rn, LIMM), QL_R2NIL, F_ALIAS | F_PSEUDO | F_SF),