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author | Nick Kralevich <nnk@google.com> | 2010-05-06 15:05:52 -0700 |
---|---|---|
committer | Nick Kralevich <nnk@google.com> | 2010-05-07 16:35:52 -0700 |
commit | beeeee705bcf16d705748713ea40dca3486cc7b7 (patch) | |
tree | 028ac0bfc7ec987b2c2747cde9d02dc7f4b3b626 | |
parent | 4e226a5006a5c64385b6c88a36c6a4044bd6ffdd (diff) | |
download | system_core-beeeee705bcf16d705748713ea40dca3486cc7b7.zip system_core-beeeee705bcf16d705748713ea40dca3486cc7b7.tar.gz system_core-beeeee705bcf16d705748713ea40dca3486cc7b7.tar.bz2 |
Allow pixelflinger to work when NX (No Execute) is enabled.
Instead of allocating memory from the (non executable) heap,
allocate memory using mspace and ensure that we use mprotect
to mark it as PROT_EXEC. This allows pixelflinger to
continue to work even when NX protections are enabled.
Testing: Using the ApiDemos market app, verify that
Apidemos -> Graphics -> OpenGL ES -> GLSurfaceView
works when "adb shell setprop debug.egl.hw 0" is set.
Change-Id: Ib569cd2543c6fa25688ee76325a712bc2347450b
-rw-r--r-- | libpixelflinger/codeflinger/CodeCache.cpp | 34 | ||||
-rw-r--r-- | libpixelflinger/codeflinger/CodeCache.h | 6 |
2 files changed, 33 insertions, 7 deletions
diff --git a/libpixelflinger/codeflinger/CodeCache.cpp b/libpixelflinger/codeflinger/CodeCache.cpp index 29410c8..5877ff4 100644 --- a/libpixelflinger/codeflinger/CodeCache.cpp +++ b/libpixelflinger/codeflinger/CodeCache.cpp @@ -19,6 +19,8 @@ #include <assert.h> #include <stdio.h> #include <stdlib.h> +#include <unistd.h> +#include <sys/mman.h> #include <cutils/log.h> #include <cutils/atomic.h> @@ -39,15 +41,14 @@ namespace android { Assembly::Assembly(size_t size) : mCount(1), mSize(0) { - mBase = (uint32_t*)malloc(size); - if (mBase) { - mSize = size; - } + mBase = (uint32_t*)mspace_malloc(getMspace(), size); + mSize = size; + ensureMbaseExecutable(); } Assembly::~Assembly() { - free(mBase); + mspace_free(getMspace(), mBase); } void Assembly::incStrong(const void*) const @@ -75,11 +76,32 @@ uint32_t* Assembly::base() const ssize_t Assembly::resize(size_t newSize) { - mBase = (uint32_t*)realloc(mBase, newSize); + mBase = (uint32_t*)mspace_realloc(getMspace(), mBase, newSize); mSize = newSize; + ensureMbaseExecutable(); return size(); } +mspace Assembly::getMspace() +{ + static mspace msp = create_contiguous_mspace(2 * 1024, 1024 * 1024, /*locked=*/ false); + return msp; +} + +void Assembly::ensureMbaseExecutable() +{ + long pagesize = sysconf(_SC_PAGESIZE); + long pagemask = ~(pagesize - 1); // assumes pagesize is a power of 2 + + uint32_t* pageStart = (uint32_t*) (((uintptr_t) mBase) & pagemask); + size_t adjustedLength = mBase - pageStart + mSize; + + if (mBase && mprotect(pageStart, adjustedLength, PROT_READ | PROT_WRITE | PROT_EXEC) != 0) { + mspace_free(getMspace(), mBase); + mBase = NULL; + } +} + // ---------------------------------------------------------------------------- CodeCache::CodeCache(size_t size) diff --git a/libpixelflinger/codeflinger/CodeCache.h b/libpixelflinger/codeflinger/CodeCache.h index 8ff1366..aaafd26 100644 --- a/libpixelflinger/codeflinger/CodeCache.h +++ b/libpixelflinger/codeflinger/CodeCache.h @@ -22,6 +22,7 @@ #include <stdint.h> #include <pthread.h> #include <sys/types.h> +#include <cutils/mspace.h> #include "tinyutils/KeyedVector.h" #include "tinyutils/smartpointer.h" @@ -67,9 +68,12 @@ public: typedef void weakref_type; private: + static mspace getMspace(); + void ensureMbaseExecutable(); + mutable int32_t mCount; uint32_t* mBase; - ssize_t mSize; + size_t mSize; }; // ---------------------------------------------------------------------------- |