# HG changeset patch
# User Zheng Xu <zheng.xu@linaro.org>
# Date 1464657720 -7200
# Node ID dfaafbaaa2919a033c4c0abdd5830f4ea413bed6
# Parent 499f16ca85ec48d1896a1633730715f32bd62140
Bug 1143022 - Manually mmap on arm64 to ensure high 17 bits are clear. r=ehoogeveen
There might be 48-bit VA on arm64 depending on kernel configuration.
Manually mmap heap memory to align with the assumption made by JS engine.
diff --git a/js/src/gc/Memory.cpp b/js/src/gc/Memory.cpp
--- a/js/src/gc/Memory.cpp
+++ b/js/src/gc/Memory.cpp
@@ -430,17 +430,17 @@ InitMemorySubsystem()
if (pageSize == 0)
pageSize = allocGranularity = size_t(sysconf(_SC_PAGESIZE));
}
static inline void*
MapMemoryAt(void* desired, size_t length, int prot = PROT_READ | PROT_WRITE,
int flags = MAP_PRIVATE | MAP_ANON, int fd = -1, off_t offset = 0)
{
-#if defined(__ia64__) || (defined(__sparc64__) && defined(__NetBSD__))
+#if defined(__ia64__) || (defined(__sparc64__) && defined(__NetBSD__)) || defined(__aarch64__)
MOZ_ASSERT(0xffff800000000000ULL & (uintptr_t(desired) + length - 1) == 0);
#endif
void* region = mmap(desired, length, prot, flags, fd, offset);
if (region == MAP_FAILED)
return nullptr;
/*
* mmap treats the given address as a hint unless the MAP_FIXED flag is
* used (which isn't usually what you want, as this overrides existing
@@ -480,16 +480,51 @@ MapMemory(size_t length, int prot = PROT
* as out of memory.
*/
if ((uintptr_t(region) + (length - 1)) & 0xffff800000000000) {
if (munmap(region, length))
MOZ_ASSERT(errno == ENOMEM);
return nullptr;
}
return region;
+#elif defined(__aarch64__)
+ /*
+ * There might be similar virtual address issue on arm64 which depends on
+ * hardware and kernel configurations. But the work around is slightly
+ * different due to the different mmap behavior.
+ *
+ * TODO: Merge with the above code block if this implementation works for
+ * ia64 and sparc64.
+ */
+ const uintptr_t start = UINT64_C(0x0000070000000000);
+ const uintptr_t end = UINT64_C(0x0000800000000000);
+ const uintptr_t step = ChunkSize;
+ /*
+ * Optimization options if there are too many retries in practice:
+ * 1. Examine /proc/self/maps to find an available address. This file is
+ * not always available, however. In addition, even if we examine
+ * /proc/self/maps, we may still need to retry several times due to
+ * racing with other threads.
+ * 2. Use a global/static variable with lock to track the addresses we have
+ * allocated or tried.
+ */
+ uintptr_t hint;
+ void* region = MAP_FAILED;
+ for (hint = start; region == MAP_FAILED && hint + length <= end; hint += step) {
+ region = mmap((void*)hint, length, prot, flags, fd, offset);
+ if (region != MAP_FAILED) {
+ if ((uintptr_t(region) + (length - 1)) & 0xffff800000000000) {
+ if (munmap(region, length)) {
+ MOZ_ASSERT(errno == ENOMEM);
+ }
+ region = MAP_FAILED;
+ }
+ }
+ }
+ return region == MAP_FAILED ? nullptr : region;
#else
void* region = MozTaggedAnonymousMmap(nullptr, length, prot, flags, fd, offset, "js-gc-heap");
if (region == MAP_FAILED)
return nullptr;
return region;
#endif
}
diff --git a/js/src/jsapi-tests/testGCAllocator.cpp b/js/src/jsapi-tests/testGCAllocator.cpp
--- a/js/src/jsapi-tests/testGCAllocator.cpp
+++ b/js/src/jsapi-tests/testGCAllocator.cpp
@@ -307,48 +307,72 @@ void* mapMemoryAt(void* desired, size_t
void* mapMemory(size_t length) { return nullptr; }
void unmapPages(void* p, size_t size) { }
#elif defined(XP_UNIX)
void*
mapMemoryAt(void* desired, size_t length)
{
-#if defined(__ia64__) || (defined(__sparc64__) && defined(__NetBSD__))
+#if defined(__ia64__) || (defined(__sparc64__) && defined(__NetBSD__)) || defined(__aarch64__)
MOZ_RELEASE_ASSERT(0xffff800000000000ULL & (uintptr_t(desired) + length - 1) == 0);
#endif
void* region = mmap(desired, length, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (region == MAP_FAILED)
return nullptr;
if (region != desired) {
if (munmap(region, length))
MOZ_RELEASE_ASSERT(errno == ENOMEM);
return nullptr;
}
return region;
}
void*
mapMemory(size_t length)
{
- void* hint = nullptr;
+ int prot = PROT_READ | PROT_WRITE;
+ int flags = MAP_PRIVATE | MAP_ANON;
+ int fd = -1;
+ off_t offset = 0;
+ // The test code must be aligned with the implementation in gc/Memory.cpp.
#if defined(__ia64__) || (defined(__sparc64__) && defined(__NetBSD__))
- hint = (void*)0x0000070000000000ULL;
-#endif
- void* region = mmap(hint, length, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
+ void* region = mmap((void*)0x0000070000000000, length, prot, flags, fd, offset);
if (region == MAP_FAILED)
return nullptr;
-#if defined(__ia64__) || (defined(__sparc64__) && defined(__NetBSD__))
- if ((uintptr_t(region) + (length - 1)) & 0xffff800000000000ULL) {
+ if ((uintptr_t(region) + (length - 1)) & 0xffff800000000000) {
if (munmap(region, length))
MOZ_RELEASE_ASSERT(errno == ENOMEM);
return nullptr;
}
+ return region;
+#elif defined(__aarch64__)
+ const uintptr_t start = UINT64_C(0x0000070000000000);
+ const uintptr_t end = UINT64_C(0x0000800000000000);
+ const uintptr_t step = ChunkSize;
+ uintptr_t hint;
+ void* region = MAP_FAILED;
+ for (hint = start; region == MAP_FAILED && hint + length <= end; hint += step) {
+ region = mmap((void*)hint, length, prot, flags, fd, offset);
+ if (region != MAP_FAILED) {
+ if ((uintptr_t(region) + (length - 1)) & 0xffff800000000000) {
+ if (munmap(region, length)) {
+ MOZ_RELEASE_ASSERT(errno == ENOMEM);
+ }
+ region = MAP_FAILED;
+ }
+ }
+ }
+ return region == MAP_FAILED ? nullptr : region;
+#else
+ void* region = mmap(nullptr, length, prot, flags, fd, offset);
+ if (region == MAP_FAILED)
+ return nullptr;
+ return region;
#endif
- return region;
}
void
unmapPages(void* p, size_t size)
{
if (munmap(p, size))
MOZ_RELEASE_ASSERT(errno == ENOMEM);
}