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avoid use of __sysctl on Darwin
- From: gkeating at apple dot com (Geoffrey Keating)
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 28 Sep 2006 00:02:55 -0700 (PDT)
- Subject: avoid use of __sysctl on Darwin
Apparently, __sysctl is not a published ABI and so should not be used.
The patch also removes some duplication.
Bootstrapped & tested on powerpc-darwin8.
--
- Geoffrey Keating <geoffk@apple.com>
===File ~/patches/gcc-executestacknosysctl.patch============
2006-09-27 Geoffrey Keating <geoffk@apple.com>
* config/darwin.h (ENABLE_EXECUTE_STACK): New, use getpagesize not
__sysctl.
* config/rs6000/darwin.h (ENABLE_EXECUTE_STACK): Remove.
* config/i386/darwin.h (ENABLE_EXECUTE_STACK): Remove.
Index: config/darwin.h
===================================================================
--- config/darwin.h (revision 117268)
+++ config/darwin.h (working copy)
@@ -886,4 +886,42 @@
#define TARGET_ASM_OUTPUT_ANCHOR NULL
#endif
+/* Attempt to turn on execute permission for the stack. This may be
+ used by INITIALIZE_TRAMPOLINE of the target needs it (that is,
+ if the target machine can change execute permissions on a page).
+
+ There is no way to query the execute permission of the stack, so
+ we always issue the mprotect() call.
+
+ Unfortunately it is not possible to make this namespace-clean.
+
+ Also note that no errors should be emitted by this code; it is
+ considered dangerous for library calls to send messages to
+ stdout/stderr. */
+
+#define ENABLE_EXECUTE_STACK \
+extern void __enable_execute_stack (void *); \
+void \
+__enable_execute_stack (void *addr) \
+{ \
+ extern int mprotect (void *, size_t, int); \
+ extern int getpagesize (void); \
+ static int size; \
+ static long mask; \
+ \
+ char *page, *end; \
+ \
+ if (size == 0) \
+ { \
+ size = getpagesize(); \
+ mask = ~((long) size - 1); \
+ } \
+ \
+ page = (char *) (((long) addr) & mask); \
+ end = (char *) ((((long) (addr + (TARGET_64BIT ? 48 : 40))) & mask) + size); \
+ \
+ /* 7 == PROT_READ | PROT_WRITE | PROT_EXEC */ \
+ (void) mprotect (page, end - page, 7); \
+}
+
#endif /* CONFIG_DARWIN_H */
Index: config/rs6000/darwin.h
===================================================================
--- config/rs6000/darwin.h (revision 117268)
+++ config/rs6000/darwin.h (working copy)
@@ -441,50 +441,3 @@
(TARGET_64BIT \
|| (darwin_macosx_version_min \
&& strverscmp (darwin_macosx_version_min, "10.3") >= 0))
-
-/* Attempt to turn on execute permission for the stack. This may be
- used by INITIALIZE_TRAMPOLINE of the target needs it (that is,
- if the target machine can change execute permissions on a page).
-
- There is no way to query the execute permission of the stack, so
- we always issue the mprotect() call.
-
- Note that we go out of our way to use namespace-non-invasive calls
- here. Unfortunately, there is no libc-internal name for mprotect().
-
- Also note that no errors should be emitted by this code; it is
- considered dangerous for library calls to send messages to
- stdout/stderr. */
-
-#define ENABLE_EXECUTE_STACK \
-extern void __enable_execute_stack (void *); \
-void \
-__enable_execute_stack (void *addr) \
-{ \
- extern int mprotect (void *, size_t, int); \
- extern int __sysctl (int *, unsigned int, void *, size_t *, \
- void *, size_t); \
- \
- static int size; \
- static long mask; \
- \
- char *page, *end; \
- \
- if (size == 0) \
- { \
- int mib[2]; \
- size_t len; \
- \
- mib[0] = 6; /* CTL_HW */ \
- mib[1] = 7; /* HW_PAGESIZE */ \
- len = sizeof (size); \
- (void) __sysctl (mib, 2, &size, &len, NULL, 0); \
- mask = ~((long) size - 1); \
- } \
- \
- page = (char *) (((long) addr) & mask); \
- end = (char *) ((((long) (addr + (TARGET_64BIT ? 48 : 40))) & mask) + size); \
- \
- /* 7 == PROT_READ | PROT_WRITE | PROT_EXEC */ \
- (void) mprotect (page, end - page, 7); \
-}
Index: config/i386/darwin.h
===================================================================
--- config/i386/darwin.h (revision 117268)
+++ config/i386/darwin.h (working copy)
@@ -204,53 +204,6 @@
: (n) >= 11 && (n) <= 18 ? (n) + 1 \
: (n))
-/* Attempt to turn on execute permission for the stack. This may be
- used by INITIALIZE_TRAMPOLINE of the target needs it (that is,
- if the target machine can change execute permissions on a page).
-
- There is no way to query the execute permission of the stack, so
- we always issue the mprotect() call.
-
- Note that we go out of our way to use namespace-non-invasive calls
- here. Unfortunately, there is no libc-internal name for mprotect().
-
- Also note that no errors should be emitted by this code; it is
- considered dangerous for library calls to send messages to
- stdout/stderr. */
-
-#define ENABLE_EXECUTE_STACK \
-extern void __enable_execute_stack (void *); \
-void \
-__enable_execute_stack (void *addr) \
-{ \
- extern int mprotect (void *, size_t, int); \
- extern int __sysctl (int *, unsigned int, void *, size_t *, \
- void *, size_t); \
- \
- static int size; \
- static long mask; \
- \
- char *page, *end; \
- \
- if (size == 0) \
- { \
- int mib[2]; \
- size_t len; \
- \
- mib[0] = 6; /* CTL_HW */ \
- mib[1] = 7; /* HW_PAGESIZE */ \
- len = sizeof (size); \
- (void) __sysctl (mib, 2, &size, &len, NULL, 0); \
- mask = ~((long) size - 1); \
- } \
- \
- page = (char *) (((long) addr) & mask); \
- end = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
- \
- /* 7 == PROT_READ | PROT_WRITE | PROT_EXEC */ \
- (void) mprotect (page, end - page, 7); \
-}
-
#undef REGISTER_TARGET_PRAGMAS
#define REGISTER_TARGET_PRAGMAS() DARWIN_REGISTER_TARGET_PRAGMAS()
============================================================