mozilla-aarch64-48bit-va.patch
branchfirefox47
changeset 919 6838f0c032f8
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mozilla-aarch64-48bit-va.patch	Tue Jun 14 22:13:50 2016 +0200
@@ -0,0 +1,170 @@
+
+# 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);
+ }
+