Initial support for Interlocked on arm/arm64

Added initial implementation for RhpLockCmpXchg32 and RhpLockCmpXchg64
for arm64. The arm version is not implemented yet.

4 files changed, 82 insertions, 0 deletions

diff --git a/src/Native/Runtime/arm/Interlocked.S b/src/Native/Runtime/arm/Interlocked.S
new file mode 100644
index 000000000..c6eb31e12
--- /dev/null
+++ b/src/Native/Runtime/arm/Interlocked.S
@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information. 
+//
+
+// TODO: Implement InterLocked routines
+#include <unixasmmacros.inc>
+
+// WARNING: Code in EHHelpers.cpp makes assumptions about this helper, in particular:
+// - Function "InWriteBarrierHelper" assumes an AV due to passed in null pointer will happen at RhpLockCmpXchg32AVLocation
+// - Function "UnwindWriteBarrierToCaller" assumes the stack contains just the pushed return address
+// r0 = destination address
+// r1 = value
+// r2 = comparand
+LEAF_ENTRY RhpLockCmpXchg32, _TEXT
+ALTERNATE_ENTRY RhpLockCmpXchg32AVLocation
+    bx      lr
+LEAF_END RhpLockCmpXchg32, _TEXT
+
+
+// WARNING: Code in EHHelpers.cpp makes assumptions about this helper, in particular:
+// - Function "InWriteBarrierHelper" assumes an AV due to passed in null pointer will happen at RhpLockCmpXchg64AVLocation
+// - Function "UnwindWriteBarrierToCaller" assumes the stack contains just the pushed return address
+// r0 = destination address
+// r1 = value
+// r2 = comparand
+LEAF_ENTRY RhpLockCmpXchg64, _TEXT
+ALTERNATE_ENTRY RhpLockCmpXchg64AVLocation
+	bx	lr
+LEAF_END RhpLockCmpXchg64, _TEXT
diff --git a/src/Native/Runtime/arm64/Interlocked.S b/src/Native/Runtime/arm64/Interlocked.S
new file mode 100644
index 000000000..aa70733c7
--- /dev/null
+++ b/src/Native/Runtime/arm64/Interlocked.S
@@ -0,0 +1,43 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information. 
+//
+
+#include <unixasmmacros.inc>
+
+// WARNING: Code in EHHelpers.cpp makes assumptions about this helper, in particular:
+// - Function "InWriteBarrierHelper" assumes an AV due to passed in null pointer will happen at RhpLockCmpXchg32AVLocation
+// - Function "UnwindWriteBarrierToCaller" assumes the stack contains just the pushed return address
+// x0 = destination address
+// w1 = value
+// w2 = comparand
+LEAF_ENTRY RhpLockCmpXchg32, _TEXT
+    mov     x8, x0          // Save value of x0 into x8 as x0 is used for the return value
+ALTERNATE_ENTRY RhpLockCmpXchg32AVLocation
+1: // loop
+    ldaxr   w0, [x8]        // w0 = *x8
+    cmp     w0, w2 
+    bne     2f              // if (w0 != w2) goto exit
+    stlxr   w9, w1, [x8]    // if (w0 == w2) { try *x8 = w1 and goto loop if failed or goto exit }
+    cbnz    w9, 1b
+2: // exit
+    ret
+LEAF_END RhpLockCmpXchg32, _TEXT
+
+// WARNING: Code in EHHelpers.cpp makes assumptions about this helper, in particular:
+// - Function "InWriteBarrierHelper" assumes an AV due to passed in null pointer will happen at RhpLockCmpXchg64AVLocation
+// - Function "UnwindWriteBarrierToCaller" assumes the stack contains just the pushed return address
+// x0 = destination address
+// x1 = value
+// x2 = comparand
+LEAF_ENTRY RhpLockCmpXchg64, _TEXT
+    mov     x8, x0          // Save value of x0 into x8 as x0 is used for the return value
+ALTERNATE_ENTRY RhpLockCmpXchg64AVLocation
+1: // loop
+    ldaxr   x0, [x8]        // x0 = *x8
+    cmp     x0, x2 
+    bne     2f              // if (x0 != x2) goto exit
+    stlxr   w9, x1, [x8]    // if (x0 == x2) { try *x8 = x1 and goto loop if failed or goto exit }
+    cbnz    w9, 1b
+2: // exit
+    ret
+LEAF_END RhpLockCmpXchg64, _TEXT
diff --git a/src/Native/Runtime/unix/unixasmmacrosarm.inc b/src/Native/Runtime/unix/unixasmmacrosarm.inc
index 837ffd788..4aa8729d3 100644
--- a/src/Native/Runtime/unix/unixasmmacrosarm.inc
+++ b/src/Native/Runtime/unix/unixasmmacrosarm.inc
@@ -20,6 +20,11 @@
 C_FUNC(\Name):
 .endm
 
+.macro ALTERNATE_ENTRY Name
+        .global C_FUNC(\Name)
+C_FUNC(\Name):
+.endm
+
 .macro LEAF_ENTRY Name, Section
         .thumb_func
         .global C_FUNC(\Name)
diff --git a/src/Native/Runtime/unix/unixasmmacrosarm64.inc b/src/Native/Runtime/unix/unixasmmacrosarm64.inc
index 12c6c3648..1619592c5 100644
--- a/src/Native/Runtime/unix/unixasmmacrosarm64.inc
+++ b/src/Native/Runtime/unix/unixasmmacrosarm64.inc
@@ -19,6 +19,11 @@
 C_FUNC(\Name):
 .endm
 
+.macro ALTERNATE_ENTRY Name
+        .global C_FUNC(\Name)
+C_FUNC(\Name):
+.endm
+
 .macro LEAF_ENTRY Name, Section
         .global C_FUNC(\Name)
         .type \Name, %function