optimally conditional on [__PIC__].
(TLS_DO_SET_THREAD_AREA): New macro, implement inline syscall
without touching errno, and use latest modify_ldt-like interface.
(TLS_SETUP_GS_SEGMENT): Use that instead of INLINE_SYSCALL.
* sysdeps/i386/useldt.h (DO_MODIFY_LDT): Set %gs in this macro.
(DO_SET_THREAD_AREA): New macro, uses current syscall interface with
existing %gs value as the segment to set.
(INIT_THREAD_SELF): Rewritten using those. Use set_thread_area only
under [HAVE_TLS_SUPPORT] so we can rely on the initialization done
by the first thread's early TLS setup.
+2002-08-16 Roland McGrath <roland@redhat.com>
+
+ * sysdeps/i386/tls.h (TLS_DO_MODIFY_LDT): Rewrite asm to use %ebx
+ optimally conditional on [__PIC__].
+ (TLS_DO_SET_THREAD_AREA): New macro, implement inline syscall
+ without touching errno, and use latest modify_ldt-like interface.
+ (TLS_SETUP_GS_SEGMENT): Use that instead of INLINE_SYSCALL.
+ * sysdeps/i386/useldt.h (DO_MODIFY_LDT): Set %gs in this macro.
+ (DO_SET_THREAD_AREA): New macro, uses current syscall interface with
+ existing %gs value as the segment to set.
+ (INIT_THREAD_SELF): Rewritten using those. Use set_thread_area only
+ under [HAVE_TLS_SUPPORT] so we can rely on the initialization done
+ by the first thread's early TLS setup.
+
2002-08-15 Roland McGrath <roland@redhat.com>
* sysdeps/i386/tls.h (TLS_INIT_TP): Use statement expression and
# define GET_DTV(descr) \
(((tcbhead_t *) (descr))->dtv)
+# ifdef __PIC__
+# define TLS_EBX_ARG "r"
+# define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
+# else
+# define TLS_EBX_ARG "b"
+# define TLS_LOAD_EBX
+# endif
+
# define TLS_DO_MODIFY_LDT(descr, nr) \
({ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \
1, 0, 0, 0, 0, 1, 0 }; \
int result; \
- asm volatile ( \
- "pushl %%ebx\n\t" \
- "movl $1, %%ebx\n\t" \
- "int $0x80\n\t" \
- "popl %%ebx" \
- : "=a" (result) \
- : "0" (__NR_modify_ldt), \
- /* The extra argument with the "m" constraint is necessary \
- to let the compiler know that we are accessing LDT_ENTRY here. */\
- "m" (ldt_entry), "c" (&ldt_entry), "d" (sizeof (ldt_entry))); \
+ asm volatile (TLS_LOAD_EBX \
+ "int $0x80\n\t" \
+ TLS_LOAD_EBX \
+ : "=a" (result) \
+ : "0" (__NR_modify_ldt), \
+ /* The extra argument with the "m" constraint is necessary \
+ to let the compiler know that we are accessing LDT_ENTRY \
+ here. */ \
+ "m" (ldt_entry), TLS_EBX_ARG (1), "c" (&ldt_entry), \
+ "d" (sizeof (ldt_entry))); \
__builtin_expect (result, 0) != 0 ? -1 : nr * 8 + 7; \
})
+# define TLS_DO_SET_THREAD_AREA(descr) \
+({ \
+ struct modify_ldt_ldt_s ldt_entry = \
+ { -1, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \
+ 1, 0, 0, 0, 0, 1, 0 }; \
+ int result; \
+ asm volatile (TLS_LOAD_EBX \
+ "int $0x80\n\t" \
+ TLS_LOAD_EBX \
+ : "=a" (result), "=m" (ldt_entry.entry_number) \
+ : "0" (__NR_set_thread_area), \
+ /* The extra argument with the "m" constraint is necessary \
+ to let the compiler know that we are accessing LDT_ENTRY \
+ here. */ \
+ TLS_EBX_ARG (&ldt_entry), "m" (ldt_entry)); \
+ __builtin_expect (result, 0) == 0 ? ldt_entry.entry_number : -1; \
+})
+
# ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
-# define TLS_SETUP_GS_SEGMENT(descr) \
- INLINE_SYSCALL (set_thread_area, 2, descr, 1)
+# define TLS_SETUP_GS_SEGMENT(descr) TLS_DO_SET_THREAD_AREA (descr)
# elif defined __NR_set_thread_area
# define TLS_SETUP_GS_SEGMENT(descr) \
- ({ int __seg = INLINE_SYSCALL (set_thread_area, 2, descr, 1); \
+ ({ int __seg = TLS_DO_SET_THREAD_AREA (descr); \
__seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
# else
-# define TLS_SETUP_GS_SEGMENT(descr) \
- TLS_DO_MODIFY_LDT (descr, 0)
+# define TLS_SETUP_GS_SEGMENT(descr) TLS_DO_MODIFY_LDT ((descr), 0)
# endif
/* Code to initially initialize the thread pointer. This might need
__self; \
})
-#define DO_MODIFY_LDT(descr, nr) \
+
+/* Initialize the thread-unique value. Two possible ways to do it. */
+
+#define DO_MODIFY_LDT(descr, nr) \
({ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, (unsigned long int) descr, sizeof (struct _pthread_descr_struct), \
1, 0, 0, 0, 0, 1, 0 }; \
if (__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) \
abort (); \
- nr * 8 + 7; \
+ asm ("movw %w0, %%gs" : : "q" (nr * 8 + 7)); \
})
-/* Initialize the thread-unique value. */
-#ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
-#define INIT_THREAD_SELF(descr, nr) \
-{ \
- int __gs = INLINE_SYSCALL (set_thread_area, 2, descr, 1); \
- if (__gs == -1) \
- abort (); \
- __asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
-}
-#elif defined __NR_set_thread_area
+/* When using the new set_thread_area call, we don't need to change %gs
+ because we inherited the value set up in the main thread by TLS setup.
+ We need to extract that value and set up the same segment in this
+ thread. */
+# define DO_SET_THREAD_AREA(descr) \
+({ \
+ int __gs; \
+ struct modify_ldt_ldt_s ldt_entry = \
+ { ({ asm ("movw %%gs, %w0" : "=q" (__gs)); __gs >> 2; }), \
+ (unsigned long int) descr, sizeof (struct _pthread_descr_struct), \
+ 1, 0, 0, 0, 0, 1, 0 }; \
+ __builtin_expect (INLINE_SYSCALL (set_thread_area, 1, &ldt_entry) == 0, 1) \
+ ? __gs : -1; \
+})
+#if defined __ASSUME_SET_THREAD_AREA_SYSCALL && defined HAVE_TLS_SUPPORT
+# define INIT_THREAD_SELF(descr, nr) DO_SET_THREAD_AREA (descr)
+#elif defined __NR_set_thread_area && defined HAVE_TLS_SUPPORT
+# define INIT_THREAD_SELF(descr, nr) \
+({ \
+ if (__builtin_expect (__have_no_set_thread_area, 0) \
+ || (DO_SET_THREAD_AREA (descr) == -1 \
+ && (__have_no_set_thread_area = 1))) \
+ DO_MODIFY_LDT (descr, nr); \
+})
/* Defined in pspinlock.c. */
extern int __have_no_set_thread_area;
-
-#define INIT_THREAD_SELF(descr, nr) \
-{ \
- int __gs = -1; \
- if (! __builtin_expect (__have_no_set_thread_area, 0)) \
- { \
- if ((__gs = INLINE_SYSCALL (set_thread_area, 2, descr, 1)) == -1 \
- && errno == ENOSYS) \
- __have_no_set_thread_area = 1; \
- } \
- if (__builtin_expect (__gs == -1, 0)) \
- __gs = DO_MODIFY_LDT (descr, nr); \
- __asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
-}
#else
-#define INIT_THREAD_SELF(descr, nr) \
-{ \
- int __gs = DO_MODIFY_LDT (descr, nr); \
- __asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
-}
+# define INIT_THREAD_SELF(descr, nr) DO_MODIFY_LDT (descr, nr)
#endif
/* Free resources associated with thread descriptor. */
projects / thirdparty / glibc.git / commitdiff
