107 lines
4 KiB
Diff
107 lines
4 KiB
Diff
|
From a0c0f32299419359b44ac0f880c1ea9073ae51e1 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Zheng Xu <zheng.xu@linaro.org>
|
||
|
|
Date: Fri, 02 Sep 2016 17:40:05 +0800
|
||
|
|
Subject: [PATCH] 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.
|
||
|
|
|
||
|
|
Change-Id: Ic5d2b2fe4b758b3c87cc0688348af7e71a991146
|
||
|
|
---
|
||
|
|
|
||
|
|
diff --git a/js/src/gc/Memory.cpp b/js/src/gc/Memory.cpp
|
||
|
|
index 5b386a2..38101cf 100644
|
||
|
|
--- a/js/src/gc/Memory.cpp
|
||
|
|
+++ b/js/src/gc/Memory.cpp
|
||
|
|
@@ -309,6 +309,75 @@
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
+static inline void *
|
||
|
|
+MapMemory(size_t length, int prot, int flags, int fd, off_t offset)
|
||
|
|
+{
|
||
|
|
+#if defined(__ia64__)
|
||
|
|
+ /*
|
||
|
|
+ * The JS engine assumes that all allocated pointers have their high 17 bits clear,
|
||
|
|
+ * which ia64's mmap doesn't support directly. However, we can emulate it by passing
|
||
|
|
+ * mmap an "addr" parameter with those bits clear. The mmap will return that address,
|
||
|
|
+ * or the nearest available memory above that address, providing a near-guarantee
|
||
|
|
+ * that those bits are clear. If they are not, we return NULL below to indicate
|
||
|
|
+ * out-of-memory.
|
||
|
|
+ *
|
||
|
|
+ * The addr is chosen as 0x0000070000000000, which still allows about 120TB of virtual
|
||
|
|
+ * address space.
|
||
|
|
+ *
|
||
|
|
+ * See Bug 589735 for more information.
|
||
|
|
+ */
|
||
|
|
+ void *region = mmap((void*)0x0000070000000000, length, prot, flags, fd, offset);
|
||
|
|
+ if (region == MAP_FAILED)
|
||
|
|
+ return MAP_FAILED;
|
||
|
|
+ /*
|
||
|
|
+ * If the allocated memory doesn't have its upper 17 bits clear, consider it
|
||
|
|
+ * as out of memory.
|
||
|
|
+ */
|
||
|
|
+ if ((uintptr_t(region) + (length - 1)) & 0xffff800000000000) {
|
||
|
|
+ JS_ALWAYS_TRUE(0 == munmap(region, length));
|
||
|
|
+ return MAP_FAILED;
|
||
|
|
+ }
|
||
|
|
+ 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 = (uintptr_t)(0x0000070000000000UL);
|
||
|
|
+ const uintptr_t end = (uintptr_t)(0x0000800000000000UL);
|
||
|
|
+ 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 ? NULL : region;
|
||
|
|
+#else
|
||
|
|
+ return mmap(NULL, length, prot, flags, fd, offset);
|
||
|
|
+#endif
|
||
|
|
+}
|
||
|
|
+
|
||
|
|
void *
|
||
|
|
MapAlignedPages(size_t size, size_t alignment)
|
||
|
|
{
|
||
|
|
@@ -322,12 +391,12 @@
|
||
|
|
|
||
|
|
/* Special case: If we want page alignment, no further work is needed. */
|
||
|
|
if (alignment == PageSize) {
|
||
|
|
- return mmap(NULL, size, prot, flags, -1, 0);
|
||
|
|
+ return MapMemory(size, prot, flags, -1, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Overallocate and unmap the region's edges. */
|
||
|
|
size_t reqSize = Min(size + 2 * alignment, 2 * size);
|
||
|
|
- void *region = mmap(NULL, reqSize, prot, flags, -1, 0);
|
||
|
|
+ void *region = MapMemory(reqSize, prot, flags, -1, 0);
|
||
|
|
if (region == MAP_FAILED)
|
||
|
|
return NULL;
|
||
|
|
|