PKGBUILDs/community/mongodb/0005-ARM-support-for-ASM-operations-in-MongoDB.patch

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2014-02-04 15:38:10 +00:00
From: Robie Basak <robie.basak@canonical.com>
Date: Sat, 20 Apr 2013 22:05:50 -0300
Subject: ARM support for ASM operations in MongoDB
This is a modified version of Jon Masters' ARM patch. I have replaced some of
the calls whose return value semantics didn't quite match the existing x86
assembler.
Original-Author: Jon Masters <jcm@redhat.com>
Origin: http://lists.fedoraproject.org/pipermail/arm/2013-February/005388.html
Last-Update: 2013-03-15
---
src/mongo/platform/atomic_intrinsics_gcc.h | 69 +++++++++++++++++++++++++++++-
src/mongo/platform/bits.h | 2 +-
2 files changed, 68 insertions(+), 3 deletions(-)
diff --git a/src/mongo/platform/atomic_intrinsics_gcc.h b/src/mongo/platform/atomic_intrinsics_gcc.h
index f8f96f0..da36685 100644
--- a/src/mongo/platform/atomic_intrinsics_gcc.h
+++ b/src/mongo/platform/atomic_intrinsics_gcc.h
@@ -14,14 +14,19 @@
*/
/**
- * Implementation of the AtomicIntrinsics<T>::* operations for IA-32 and AMD64 systems using a
- * GCC-compatible compiler toolchain.
+ * Implementation of the AtomicIntrinsics<T>::* operations for IA-32, AMD64, and 32-bit ARM
+ * systems using a GCC-compatible compiler toolchain.
*/
#pragma once
#include <boost/utility.hpp>
+#if defined(__arm__)
+typedef int (__kuser_cmpxchg_t)(int oldval, int newval, volatile int *ptr);
+#define __kuser_cmpxchg (*(__kuser_cmpxchg_t *)0xffff0fc0)
+#endif
+
namespace mongo {
/**
@@ -37,31 +42,58 @@ namespace mongo {
static T compareAndSwap(volatile T* dest, T expected, T newValue) {
T result;
+
+#if defined(__i386__) || defined(__x86_64__)
asm volatile ("lock cmpxchg %[src], %[dest]"
: [dest] "+m" (*dest),
"=a" (result)
: [src] "r" (newValue),
"a" (expected)
: "memory", "cc");
+#endif
+
+#if defined(__arm__)
+ result = __sync_val_compare_and_swap(dest, expected, newValue);
+#endif
+
return result;
}
static T swap(volatile T* dest, T newValue) {
T result = newValue;
+
+#if defined(__i386__) || defined(__x86_64__)
// No need for "lock" prefix on "xchg".
asm volatile ("xchg %[r], %[dest]"
: [dest] "+m" (*dest),
[r] "+r" (result)
:
: "memory");
+#endif
+
+#if defined(__arm__)
+ __sync_synchronize();
+ result = __sync_lock_test_and_set(dest, newValue);
+#endif
+
return result;
}
static T load(volatile const T* value) {
+
+#if defined(__i386__) || defined(__x86_64__)
asm volatile ("mfence" ::: "memory");
T result = *value;
asm volatile ("mfence" ::: "memory");
+#endif
+
+#if defined(__arm__)
+ asm volatile("mcr p15, 0, r0, c7, c10, 5");
+ T result = *value;
+ asm volatile("mcr p15, 0, r0, c7, c10, 5");
+#endif
+
return result;
}
@@ -70,19 +102,44 @@ namespace mongo {
}
static void store(volatile T* dest, T newValue) {
+
+#if defined(__i386__) || defined(__x86_64__)
asm volatile ("mfence" ::: "memory");
*dest = newValue;
asm volatile ("mfence" ::: "memory");
+#endif
+
+#if defined(__arm__)
+ asm volatile("mcr p15, 0, r0, c7, c10, 5");
+ *dest = newValue;
+ asm volatile("mcr p15, 0, r0, c7, c10, 5");
+#endif
+
}
static T fetchAndAdd(volatile T* dest, T increment) {
T result = increment;
+
+#if defined(__i386__) || defined(__x86_64__)
asm volatile ("lock xadd %[src], %[dest]"
: [dest] "+m" (*dest),
[src] "+r" (result)
:
: "memory", "cc");
+#endif
+
+#if defined(__arm__)
+ int old;
+
+ do {
+ old = (int)(*dest);
+ } while(__kuser_cmpxchg((int)old, (int)(old+increment),
+ (volatile int *)dest));
+
+ result = old;
+#endif
+
return result;
}
@@ -105,6 +162,8 @@ namespace mongo {
public:
static T compareAndSwap(volatile T* dest, T expected, T newValue) {
T result = expected;
+
+#if defined(__i386__) || defined(__x86_64__)
asm volatile ("push %%eax\n"
"push %%ebx\n"
"push %%ecx\n"
@@ -125,6 +184,12 @@ namespace mongo {
"D" (&result),
"d" (&newValue)
: "memory", "cc");
+#endif
+
+#if defined(__arm__)
+ result = __sync_val_compare_and_swap(dest, expected, newValue);
+#endif
+
return result;
}
diff --git a/src/mongo/platform/bits.h b/src/mongo/platform/bits.h
index 7afc428..75343dd 100644
--- a/src/mongo/platform/bits.h
+++ b/src/mongo/platform/bits.h
@@ -21,7 +21,7 @@
#if defined(__x86_64__) || defined(__amd64__) || defined(_WIN64)
#define MONGO_PLATFORM_64
-#elif defined(__i386__) || defined(_WIN32)
+#elif defined(__i386__) || defined(_WIN32) || defined(__arm__)
#define MONGO_PLATFORM_32
#else
#error "unknown platform"