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* 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.
This commit is contained in:
Roland McGrath 2002-08-16 20:16:38 +00:00
parent c88b47593a
commit 25cb6eb229
3 changed files with 83 additions and 46 deletions
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14
linuxthreads/ChangeLog
View File

@ -1,3 +1,17 @@
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> 2002-08-15 Roland McGrath <roland@redhat.com>
* sysdeps/i386/tls.h (TLS_INIT_TP): Use statement expression and * sysdeps/i386/tls.h (TLS_INIT_TP): Use statement expression and

46
linuxthreads/sysdeps/i386/tls.h
View File

@ -88,35 +88,59 @@ typedef struct
# define GET_DTV(descr) \ # define GET_DTV(descr) \
(((tcbhead_t *) (descr))->dtv) (((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) \ # define TLS_DO_MODIFY_LDT(descr, nr) \
({ \ ({ \
struct modify_ldt_ldt_s ldt_entry = \ struct modify_ldt_ldt_s ldt_entry = \
{ nr, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \ { nr, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \
1, 0, 0, 0, 0, 1, 0 }; \ 1, 0, 0, 0, 0, 1, 0 }; \
int result; \ int result; \
asm volatile ( \ asm volatile (TLS_LOAD_EBX \
"pushl %%ebx\n\t" \
"movl $1, %%ebx\n\t" \
"int $0x80\n\t" \ "int $0x80\n\t" \
"popl %%ebx" \ TLS_LOAD_EBX \
: "=a" (result) \ : "=a" (result) \
: "0" (__NR_modify_ldt), \ : "0" (__NR_modify_ldt), \
/* The extra argument with the "m" constraint is necessary \ /* The extra argument with the "m" constraint is necessary \
to let the compiler know that we are accessing LDT_ENTRY here. */\ to let the compiler know that we are accessing LDT_ENTRY \
"m" (ldt_entry), "c" (&ldt_entry), "d" (sizeof (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; \ __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 # ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
# define TLS_SETUP_GS_SEGMENT(descr) \ # define TLS_SETUP_GS_SEGMENT(descr) TLS_DO_SET_THREAD_AREA (descr)
INLINE_SYSCALL (set_thread_area, 2, descr, 1)
# elif defined __NR_set_thread_area # elif defined __NR_set_thread_area
# define TLS_SETUP_GS_SEGMENT(descr) \ # 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; }) __seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
# else # else
# define TLS_SETUP_GS_SEGMENT(descr) \ # define TLS_SETUP_GS_SEGMENT(descr) TLS_DO_MODIFY_LDT ((descr), 0)
TLS_DO_MODIFY_LDT (descr, 0)
# endif # endif
/* Code to initially initialize the thread pointer. This might need /* Code to initially initialize the thread pointer. This might need

59
linuxthreads/sysdeps/i386/useldt.h
View File

@ -62,6 +62,9 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
__self; \ __self; \
}) })
/* Initialize the thread-unique value. Two possible ways to do it. */
#define DO_MODIFY_LDT(descr, nr) \ #define DO_MODIFY_LDT(descr, nr) \
({ \ ({ \
struct modify_ldt_ldt_s ldt_entry = \ struct modify_ldt_ldt_s ldt_entry = \
@ -69,42 +72,38 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
1, 0, 0, 0, 0, 1, 0 }; \ 1, 0, 0, 0, 0, 1, 0 }; \
if (__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) \ if (__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) \
abort (); \ abort (); \
nr * 8 + 7; \ asm ("movw %w0, %%gs" : : "q" (nr * 8 + 7)); \
}) })
/* Initialize the thread-unique value. */ /* When using the new set_thread_area call, we don't need to change %gs
#ifdef __ASSUME_SET_THREAD_AREA_SYSCALL because we inherited the value set up in the main thread by TLS setup.
#define INIT_THREAD_SELF(descr, nr) \ We need to extract that value and set up the same segment in this
{ \ thread. */
int __gs = INLINE_SYSCALL (set_thread_area, 2, descr, 1); \ # define DO_SET_THREAD_AREA(descr) \
if (__gs == -1) \ ({ \
abort (); \ int __gs; \
__asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \ struct modify_ldt_ldt_s ldt_entry = \
} { ({ asm ("movw %%gs, %w0" : "=q" (__gs)); __gs >> 2; }), \
#elif defined __NR_set_thread_area (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. */ /* Defined in pspinlock.c. */
extern int __have_no_set_thread_area; 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 #else
#define INIT_THREAD_SELF(descr, nr) \ # define INIT_THREAD_SELF(descr, nr) DO_MODIFY_LDT (descr, nr)
{ \
int __gs = DO_MODIFY_LDT (descr, nr); \
__asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
}
#endif #endif
/* Free resources associated with thread descriptor. */ /* Free resources associated with thread descriptor. */