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From c4a8eebdbaea9eef3f4422497196627485de920e Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Wed, 24 Mar 2021 00:32:09 -0700
Subject: [PATCH] compiler-rt: Use mcr based barrier on armv6
dsb is an armv7 instruction and wont work when we are building for armv6.
Upstream-Status: Pending
Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
compiler-rt/lib/builtins/arm/sync-ops.h | 8 ++++----
compiler-rt/lib/builtins/assembly.h | 8 ++++++++
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/compiler-rt/lib/builtins/arm/sync-ops.h b/compiler-rt/lib/builtins/arm/sync-ops.h
index c9623249e5d2..7a26170741ad 100644
--- a/compiler-rt/lib/builtins/arm/sync-ops.h
+++ b/compiler-rt/lib/builtins/arm/sync-ops.h
@@ -19,14 +19,14 @@
.thumb; \
.syntax unified; \
DEFINE_COMPILERRT_THUMB_FUNCTION(__sync_fetch_and_##op) \
- dmb; \
+ DMB; \
mov r12, r0; \
LOCAL_LABEL(tryatomic_##op) : ldrex r0, [r12]; \
op(r2, r0, r1); \
strex r3, r2, [r12]; \
cmp r3, #0; \
bne LOCAL_LABEL(tryatomic_##op); \
- dmb; \
+ DMB; \
bx lr
#define SYNC_OP_8(op) \
@@ -35,14 +35,14 @@
.syntax unified; \
DEFINE_COMPILERRT_THUMB_FUNCTION(__sync_fetch_and_##op) \
push {r4, r5, r6, lr}; \
- dmb; \
+ DMB; \
mov r12, r0; \
LOCAL_LABEL(tryatomic_##op) : ldrexd r0, r1, [r12]; \
op(r4, r5, r0, r1, r2, r3); \
strexd r6, r4, r5, [r12]; \
cmp r6, #0; \
bne LOCAL_LABEL(tryatomic_##op); \
- dmb; \
+ DMB; \
pop { r4, r5, r6, pc }
#define MINMAX_4(rD, rN, rM, cmp_kind) \
diff --git a/compiler-rt/lib/builtins/assembly.h b/compiler-rt/lib/builtins/assembly.h
index 69a3d8620f92..60bac86df218 100644
--- a/compiler-rt/lib/builtins/assembly.h
+++ b/compiler-rt/lib/builtins/assembly.h
@@ -189,6 +189,14 @@
JMP(ip)
#endif
+#if __ARM_ARCH >= 7
+#define DMB dmb
+#elif __ARM_ARCH >= 6
+#define DMB mcr p15, #0, r0, c7, c10, #5
+#else
+#error Only use this with ARMv6+
+#endif
+
#if defined(USE_THUMB_2)
#define WIDE(op) op.w
#else
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