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-rw-r--r--includes/Block.h4
-rw-r--r--includes/Storage.h4
-rw-r--r--rts/Adjustor.c23
-rw-r--r--rts/Linker.c3
-rw-r--r--rts/OSMem.h10
-rw-r--r--rts/RtsUtils.c52
-rw-r--r--rts/RtsUtils.h3
-rw-r--r--rts/Storage.c99
-rw-r--r--rts/posix/OSMem.c52
-rw-r--r--rts/win32/OSMem.c34
10 files changed, 216 insertions, 68 deletions
diff --git a/includes/Block.h b/includes/Block.h
index d1705ad686..408088087a 100644
--- a/includes/Block.h
+++ b/includes/Block.h
@@ -85,8 +85,10 @@ typedef struct bdescr_ {
#define BF_PINNED 4
/* Block is part of a compacted generation */
#define BF_COMPACTED 8
-/* Block is free, and on the free list */
+/* Block is free, and on the free list (TODO: is this used?) */
#define BF_FREE 16
+/* Block is executable */
+#define BF_EXEC 32
/* Finding the block descriptor for a given block -------------------------- */
diff --git a/includes/Storage.h b/includes/Storage.h
index 3a6bb2fde1..1886e0921e 100644
--- a/includes/Storage.h
+++ b/includes/Storage.h
@@ -166,6 +166,10 @@ doYouWantToGC( void )
return (alloc_blocks >= alloc_blocks_lim);
}
+/* memory allocator for executable memory */
+extern void *allocateExec (nat bytes);
+extern void freeExec (void *p);
+
/* -----------------------------------------------------------------------------
Performing Garbage Collection
diff --git a/rts/Adjustor.c b/rts/Adjustor.c
index fc4182e731..4b042a17b2 100644
--- a/rts/Adjustor.c
+++ b/rts/Adjustor.c
@@ -40,6 +40,7 @@ Haskell side.
#include "Rts.h"
#include "RtsExternal.h"
#include "RtsUtils.h"
+#include "Storage.h"
#include <stdlib.h>
#if defined(_WIN32)
@@ -266,7 +267,7 @@ createAdjustor(int cconv, StgStablePtr hptr,
<c>: ff e0 jmp %eax # and jump to it.
# the callee cleans up the stack
*/
- adjustor = stgMallocBytesRWX(14);
+ adjustor = allocateExec(14);
{
unsigned char *const adj_code = (unsigned char *)adjustor;
adj_code[0x00] = (unsigned char)0x58; /* popl %eax */
@@ -311,7 +312,7 @@ createAdjustor(int cconv, StgStablePtr hptr,
That's (thankfully) the case here with the restricted set of
return types that we support.
*/
- adjustor = stgMallocBytesRWX(17);
+ adjustor = allocateExec(17);
{
unsigned char *const adj_code = (unsigned char *)adjustor;
@@ -340,7 +341,7 @@ createAdjustor(int cconv, StgStablePtr hptr,
We offload most of the work to AdjustorAsm.S.
*/
- AdjustorStub *adjustorStub = stgMallocBytesRWX(sizeof(AdjustorStub));
+ AdjustorStub *adjustorStub = allocateExec(sizeof(AdjustorStub));
adjustor = adjustorStub;
extern void adjustorCode(void);
@@ -443,7 +444,7 @@ createAdjustor(int cconv, StgStablePtr hptr,
}
if (i < 6) {
- adjustor = stgMallocBytesRWX(0x30);
+ adjustor = allocateExec(0x30);
*(StgInt32 *)adjustor = 0x49c1894d;
*(StgInt32 *)(adjustor+0x4) = 0x8948c889;
@@ -457,7 +458,7 @@ createAdjustor(int cconv, StgStablePtr hptr,
}
else
{
- adjustor = stgMallocBytesRWX(0x40);
+ adjustor = allocateExec(0x40);
*(StgInt32 *)adjustor = 0x35ff5141;
*(StgInt32 *)(adjustor+0x4) = 0x00000020;
@@ -504,7 +505,7 @@ createAdjustor(int cconv, StgStablePtr hptr,
similarly, and local variables should be accessed via %fp, not %sp. In a
nutshell: This should work! (Famous last words! :-)
*/
- adjustor = stgMallocBytesRWX(4*(11+1));
+ adjustor = allocateExec(4*(11+1));
{
unsigned long *const adj_code = (unsigned long *)adjustor;
@@ -581,7 +582,7 @@ TODO: Depending on how much allocation overhead stgMallocBytes uses for
4 bytes (getting rid of the nop), hence saving memory. [ccshan]
*/
ASSERT(((StgWord64)wptr & 3) == 0);
- adjustor = stgMallocBytesRWX(48);
+ adjustor = allocateExec(48);
{
StgWord64 *const code = (StgWord64 *)adjustor;
@@ -686,7 +687,7 @@ TODO: Depending on how much allocation overhead stgMallocBytes uses for
*/
// allocate space for at most 4 insns per parameter
// plus 14 more instructions.
- adjustor = stgMallocBytesRWX(4 * (4*n + 14));
+ adjustor = allocateExec(4 * (4*n + 14));
code = (unsigned*)adjustor;
*code++ = 0x48000008; // b *+8
@@ -845,7 +846,7 @@ TODO: Depending on how much allocation overhead stgMallocBytes uses for
#ifdef FUNDESCS
adjustorStub = stgMallocBytes(sizeof(AdjustorStub), "createAdjustor");
#else
- adjustorStub = stgMallocBytesRWX(sizeof(AdjustorStub));
+ adjustorStub = allocateExec(sizeof(AdjustorStub));
#endif
adjustor = adjustorStub;
@@ -1088,7 +1089,7 @@ if ( *(unsigned char*)ptr != 0xe8 ) {
#endif
*((unsigned char*)ptr) = '\0';
- stgFree(ptr);
+ freeExec(ptr);
}
@@ -1101,7 +1102,7 @@ void
initAdjustor(void)
{
#if defined(i386_HOST_ARCH) && defined(openbsd_HOST_OS)
- obscure_ccall_ret_code_dyn = stgMallocBytesRWX(4);
+ obscure_ccall_ret_code_dyn = allocateExec(4);
obscure_ccall_ret_code_dyn[0] = ((unsigned char *)obscure_ccall_ret_code)[0];
obscure_ccall_ret_code_dyn[1] = ((unsigned char *)obscure_ccall_ret_code)[1];
obscure_ccall_ret_code_dyn[2] = ((unsigned char *)obscure_ccall_ret_code)[2];
diff --git a/rts/Linker.c b/rts/Linker.c
index 4aca3978b9..3cfd2a8f91 100644
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -707,7 +707,8 @@ typedef struct _RtsSymbolVal {
SymX(stg_interp_constr6_entry) \
SymX(stg_interp_constr7_entry) \
SymX(stg_interp_constr8_entry) \
- SymX(stgMallocBytesRWX) \
+ SymX(allocateExec) \
+ SymX(freeExec) \
SymX(getAllocations) \
SymX(revertCAFs) \
SymX(RtsFlags) \
diff --git a/rts/OSMem.h b/rts/OSMem.h
new file mode 100644
index 0000000000..417f106948
--- /dev/null
+++ b/rts/OSMem.h
@@ -0,0 +1,10 @@
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The University of Glasgow 2006
+ *
+ * OS-specific memory management
+ *
+ * ---------------------------------------------------------------------------*/
+
+lnat getPageSize (void);
+void setExecutable (void *p, lnat len, rtsBool exec);
diff --git a/rts/RtsUtils.c b/rts/RtsUtils.c
index af68905707..bf02c328fb 100644
--- a/rts/RtsUtils.c
+++ b/rts/RtsUtils.c
@@ -39,19 +39,6 @@
#include <pthread.h>
#endif
-#if defined(openbsd_HOST_OS) || defined(linux_HOST_OS) || defined(darwin_HOST_OS)
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-
-/* no C99 header stdint.h on OpenBSD? */
-#if defined(openbsd_HOST_OS)
-typedef unsigned long my_uintptr_t;
-#else
-#include <stdint.h>
-typedef uintptr_t my_uintptr_t;
-#endif
-#endif
#if defined(_WIN32)
#include <windows.h>
@@ -325,42 +312,3 @@ int genericRaise(int sig) {
return raise(sig);
#endif
}
-
-/* -----------------------------------------------------------------------------
- Allocating executable memory
- -------------------------------------------------------------------------- */
-
-/* Heavily arch-specific, I'm afraid.. */
-
-/*
- * Allocate len bytes which are readable, writable, and executable.
- *
- * ToDo: If this turns out to be a performance bottleneck, one could
- * e.g. cache the last VirtualProtect/mprotect-ed region and do
- * nothing in case of a cache hit.
- */
-void*
-stgMallocBytesRWX(int len)
-{
- void *addr = stgMallocBytes(len, "mallocBytesRWX");
-#if defined(i386_HOST_ARCH) && defined(_WIN32)
- /* This could be necessary for processors which distinguish between READ and
- EXECUTE memory accesses, e.g. Itaniums. */
- DWORD dwOldProtect = 0;
- if (VirtualProtect (addr, len, PAGE_EXECUTE_READWRITE, &dwOldProtect) == 0) {
- barf("mallocBytesRWX: failed to protect 0x%p; error=%lu; old protection: %lu\n",
- addr, (unsigned long)GetLastError(), (unsigned long)dwOldProtect);
- }
-#elif defined(openbsd_HOST_OS) || defined(linux_HOST_OS) || defined(darwin_HOST_OS)
- /* malloced memory isn't executable by default on OpenBSD */
- my_uintptr_t pageSize = sysconf(_SC_PAGESIZE);
- my_uintptr_t mask = ~(pageSize - 1);
- my_uintptr_t startOfFirstPage = ((my_uintptr_t)addr ) & mask;
- my_uintptr_t startOfLastPage = ((my_uintptr_t)addr + len - 1) & mask;
- my_uintptr_t size = startOfLastPage - startOfFirstPage + pageSize;
- if (mprotect((void*)startOfFirstPage, (size_t)size, PROT_EXEC | PROT_READ | PROT_WRITE) != 0) {
- barf("mallocBytesRWX: failed to protect 0x%p\n", addr);
- }
-#endif
- return addr;
-}
diff --git a/rts/RtsUtils.h b/rts/RtsUtils.h
index 96a5f0d82f..93139367b3 100644
--- a/rts/RtsUtils.h
+++ b/rts/RtsUtils.h
@@ -16,9 +16,6 @@
extern void *stgMallocBytes(int n, char *msg)
GNUC3_ATTRIBUTE(__malloc__);
-extern void* stgMallocBytesRWX(int len)
- GNUC3_ATTRIBUTE(__malloc__);
-
extern void *stgReallocBytes(void *p, int n, char *msg);
extern void *stgCallocBytes(int n, int m, char *msg)
diff --git a/rts/Storage.c b/rts/Storage.c
index 974be45f10..ee860e27a2 100644
--- a/rts/Storage.c
+++ b/rts/Storage.c
@@ -22,6 +22,7 @@
#include "Storage.h"
#include "Schedule.h"
#include "RetainerProfile.h" // for counting memory blocks (memInventory)
+#include "OSMem.h"
#include <stdlib.h>
#include <string.h>
@@ -968,6 +969,99 @@ calcNeeded(void)
return needed;
}
+/* ----------------------------------------------------------------------------
+ Executable memory
+
+ Executable memory must be managed separately from non-executable
+ memory. Most OSs these days require you to jump through hoops to
+ dynamically allocate executable memory, due to various security
+ measures.
+
+ Here we provide a small memory allocator for executable memory.
+ Memory is managed with a page granularity; we allocate linearly
+ in the page, and when the page is emptied (all objects on the page
+ are free) we free the page again, not forgetting to make it
+ non-executable.
+ ------------------------------------------------------------------------- */
+
+static bdescr *exec_block;
+
+void *allocateExec (nat bytes)
+{
+ void *ret;
+ nat n;
+
+ ACQUIRE_SM_LOCK;
+
+ // round up to words.
+ n = (bytes + sizeof(W_) + 1) / sizeof(W_);
+
+ if (n+1 > BLOCK_SIZE_W) {
+ barf("allocateExec: can't handle large objects");
+ }
+
+ if (exec_block == NULL ||
+ exec_block->free + n + 1 > exec_block->start + BLOCK_SIZE_W) {
+ bdescr *bd;
+ lnat pagesize = getPageSize();
+ bd = allocGroup(stg_max(1, pagesize / BLOCK_SIZE));
+ IF_DEBUG(gc, debugBelch("allocate exec block %p\n", bd->start));
+ bd->gen_no = 0;
+ bd->flags = BF_EXEC;
+ bd->link = exec_block;
+ if (exec_block != NULL) {
+ exec_block->u.back = bd;
+ }
+ bd->u.back = NULL;
+ setExecutable(bd->start, bd->blocks * BLOCK_SIZE, rtsTrue);
+ exec_block = bd;
+ }
+ *(exec_block->free) = n; // store the size of this chunk
+ exec_block->gen_no += n; // gen_no stores the number of words allocated
+ ret = exec_block->free + 1;
+ exec_block->free += n + 1;
+
+ RELEASE_SM_LOCK
+ return ret;
+}
+
+void freeExec (void *addr)
+{
+ StgPtr p = (StgPtr)addr - 1;
+ bdescr *bd = Bdescr((StgPtr)p);
+
+ if ((bd->flags & BF_EXEC) == 0) {
+ barf("freeExec: not executable");
+ }
+
+ if (*(StgPtr)p == 0) {
+ barf("freeExec: already free?");
+ }
+
+ ACQUIRE_SM_LOCK;
+
+ bd->gen_no -= *(StgPtr)p;
+ *(StgPtr)p = 0;
+
+ // Free the block if it is empty, but not if it is the block at
+ // the head of the queue.
+ if (bd->gen_no == 0 && bd != exec_block) {
+ IF_DEBUG(gc, debugBelch("free exec block %p\n", bd->start));
+ if (bd->u.back) {
+ bd->u.back->link = bd->link;
+ } else {
+ exec_block = bd->link;
+ }
+ if (bd->link) {
+ bd->link->u.back = bd->u.back;
+ }
+ setExecutable(bd->start, bd->blocks * BLOCK_SIZE, rtsFalse);
+ freeGroup(bd);
+ }
+
+ RELEASE_SM_LOCK
+}
+
/* -----------------------------------------------------------------------------
Debugging
@@ -1048,6 +1142,11 @@ memInventory(void)
// count the blocks allocated by the arena allocator
total_blocks += arenaBlocks();
+ // count the blocks containing executable memory
+ for (bd = exec_block; bd; bd = bd->link) {
+ total_blocks += bd->blocks;
+ }
+
/* count the blocks on the free list */
free_blocks = countFreeList();
diff --git a/rts/posix/OSMem.c b/rts/posix/OSMem.c
new file mode 100644
index 0000000000..6e8337bdc6
--- /dev/null
+++ b/rts/posix/OSMem.c
@@ -0,0 +1,52 @@
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The University of Glasgow 2006
+ *
+ * OS-specific memory management
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include "Rts.h"
+#include "OSMem.h"
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+
+/* no C99 header stdint.h on OpenBSD? */
+#if defined(openbsd_HOST_OS)
+typedef unsigned long my_uintptr_t;
+#else
+#include <stdint.h>
+typedef uintptr_t my_uintptr_t;
+#endif
+
+lnat getPageSize (void)
+{
+ static lnat pageSize = 0;
+ if (pageSize) {
+ return pageSize;
+ } else {
+ long ret;
+ ret = sysconf(_SC_PAGESIZE);
+ if (ret == -1) {
+ barf("getPageSize: cannot get page size");
+ }
+ return ret;
+ }
+}
+
+void setExecutable (void *p, lnat len, rtsBool exec)
+{
+ my_uintptr_t pageSize = getPageSize();
+
+ /* malloced memory isn't executable by default on OpenBSD */
+ my_uintptr_t mask = ~(pageSize - 1);
+ my_uintptr_t startOfFirstPage = ((my_uintptr_t)p ) & mask;
+ my_uintptr_t startOfLastPage = ((my_uintptr_t)p + len - 1) & mask;
+ my_uintptr_t size = startOfLastPage - startOfFirstPage + pageSize;
+ if (mprotect((void*)startOfFirstPage, (size_t)size,
+ (exec ? PROT_EXEC : 0) | PROT_READ | PROT_WRITE) != 0) {
+ barf("makeExecutable: failed to protect 0x%p\n", p);
+ }
+}
diff --git a/rts/win32/OSMem.c b/rts/win32/OSMem.c
new file mode 100644
index 0000000000..fe69a341e8
--- /dev/null
+++ b/rts/win32/OSMem.c
@@ -0,0 +1,34 @@
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The University of Glasgow 2006
+ *
+ * OS-specific memory management
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include <windows.h>
+
+lnat getPageSize (void)
+{
+ static lnat pagesize = 0;
+ if (pagesize) {
+ return pagesize;
+ } else {
+ SYSTEM_INFO sSysInfo;
+ GetSystemInfo(&sSysInfo);
+ pagesize = sSysInfo.dwPageSize;
+ return pagesize;
+ }
+}
+
+void setExecutable (void *p, lnat len, rtsBool exec)
+{
+ DWORD dwOldProtect = 0;
+ if (VirtualProtect (addr, len,
+ exec ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE,
+ &dwOldProtect) == 0)
+ {
+ barf("makeExecutable: failed to protect 0x%p; error=%lu; old protection: %lu\n",
+ addr, (unsigned long)GetLastError(), (unsigned long)dwOldProtect);
+ }
+}
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