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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
parent
c88b47593a
commit
25cb6eb229
@ -1,3 +1,17 @@
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2002-08-16 Roland McGrath <roland@redhat.com>
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* sysdeps/i386/tls.h (TLS_DO_MODIFY_LDT): Rewrite asm to use %ebx
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optimally conditional on [__PIC__].
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(TLS_DO_SET_THREAD_AREA): New macro, implement inline syscall
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without touching errno, and use latest modify_ldt-like interface.
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(TLS_SETUP_GS_SEGMENT): Use that instead of INLINE_SYSCALL.
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* sysdeps/i386/useldt.h (DO_MODIFY_LDT): Set %gs in this macro.
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(DO_SET_THREAD_AREA): New macro, uses current syscall interface with
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existing %gs value as the segment to set.
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(INIT_THREAD_SELF): Rewritten using those. Use set_thread_area only
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under [HAVE_TLS_SUPPORT] so we can rely on the initialization done
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by the first thread's early TLS setup.
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2002-08-15 Roland McGrath <roland@redhat.com>
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* sysdeps/i386/tls.h (TLS_INIT_TP): Use statement expression and
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@ -88,35 +88,59 @@ typedef struct
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# define GET_DTV(descr) \
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(((tcbhead_t *) (descr))->dtv)
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# ifdef __PIC__
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# define TLS_EBX_ARG "r"
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# define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
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# else
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# define TLS_EBX_ARG "b"
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# define TLS_LOAD_EBX
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# endif
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# define TLS_DO_MODIFY_LDT(descr, nr) \
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({ \
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struct modify_ldt_ldt_s ldt_entry = \
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{ nr, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \
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1, 0, 0, 0, 0, 1, 0 }; \
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int result; \
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asm volatile ( \
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"pushl %%ebx\n\t" \
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"movl $1, %%ebx\n\t" \
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"int $0x80\n\t" \
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"popl %%ebx" \
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: "=a" (result) \
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: "0" (__NR_modify_ldt), \
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/* The extra argument with the "m" constraint is necessary \
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to let the compiler know that we are accessing LDT_ENTRY here. */\
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"m" (ldt_entry), "c" (&ldt_entry), "d" (sizeof (ldt_entry))); \
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asm volatile (TLS_LOAD_EBX \
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"int $0x80\n\t" \
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TLS_LOAD_EBX \
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: "=a" (result) \
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: "0" (__NR_modify_ldt), \
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/* The extra argument with the "m" constraint is necessary \
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to let the compiler know that we are accessing LDT_ENTRY \
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here. */ \
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"m" (ldt_entry), TLS_EBX_ARG (1), "c" (&ldt_entry), \
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"d" (sizeof (ldt_entry))); \
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__builtin_expect (result, 0) != 0 ? -1 : nr * 8 + 7; \
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})
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# define TLS_DO_SET_THREAD_AREA(descr) \
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({ \
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struct modify_ldt_ldt_s ldt_entry = \
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{ -1, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \
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1, 0, 0, 0, 0, 1, 0 }; \
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int result; \
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asm volatile (TLS_LOAD_EBX \
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"int $0x80\n\t" \
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TLS_LOAD_EBX \
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: "=a" (result), "=m" (ldt_entry.entry_number) \
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: "0" (__NR_set_thread_area), \
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/* The extra argument with the "m" constraint is necessary \
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to let the compiler know that we are accessing LDT_ENTRY \
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here. */ \
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TLS_EBX_ARG (&ldt_entry), "m" (ldt_entry)); \
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__builtin_expect (result, 0) == 0 ? ldt_entry.entry_number : -1; \
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})
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# ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
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# define TLS_SETUP_GS_SEGMENT(descr) \
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INLINE_SYSCALL (set_thread_area, 2, descr, 1)
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# define TLS_SETUP_GS_SEGMENT(descr) TLS_DO_SET_THREAD_AREA (descr)
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# elif defined __NR_set_thread_area
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# define TLS_SETUP_GS_SEGMENT(descr) \
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({ int __seg = INLINE_SYSCALL (set_thread_area, 2, descr, 1); \
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({ int __seg = TLS_DO_SET_THREAD_AREA (descr); \
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__seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
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# else
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# define TLS_SETUP_GS_SEGMENT(descr) \
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TLS_DO_MODIFY_LDT (descr, 0)
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# define TLS_SETUP_GS_SEGMENT(descr) TLS_DO_MODIFY_LDT ((descr), 0)
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# endif
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/* Code to initially initialize the thread pointer. This might need
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@ -62,49 +62,48 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
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__self; \
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})
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#define DO_MODIFY_LDT(descr, nr) \
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/* Initialize the thread-unique value. Two possible ways to do it. */
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#define DO_MODIFY_LDT(descr, nr) \
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({ \
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struct modify_ldt_ldt_s ldt_entry = \
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{ nr, (unsigned long int) descr, sizeof (struct _pthread_descr_struct), \
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1, 0, 0, 0, 0, 1, 0 }; \
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if (__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) \
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abort (); \
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nr * 8 + 7; \
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asm ("movw %w0, %%gs" : : "q" (nr * 8 + 7)); \
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})
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/* Initialize the thread-unique value. */
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#ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
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#define INIT_THREAD_SELF(descr, nr) \
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{ \
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int __gs = INLINE_SYSCALL (set_thread_area, 2, descr, 1); \
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if (__gs == -1) \
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abort (); \
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__asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
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}
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#elif defined __NR_set_thread_area
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/* When using the new set_thread_area call, we don't need to change %gs
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because we inherited the value set up in the main thread by TLS setup.
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We need to extract that value and set up the same segment in this
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thread. */
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# define DO_SET_THREAD_AREA(descr) \
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({ \
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int __gs; \
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struct modify_ldt_ldt_s ldt_entry = \
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{ ({ asm ("movw %%gs, %w0" : "=q" (__gs)); __gs >> 2; }), \
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(unsigned long int) descr, sizeof (struct _pthread_descr_struct), \
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1, 0, 0, 0, 0, 1, 0 }; \
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__builtin_expect (INLINE_SYSCALL (set_thread_area, 1, &ldt_entry) == 0, 1) \
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? __gs : -1; \
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})
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#if defined __ASSUME_SET_THREAD_AREA_SYSCALL && defined HAVE_TLS_SUPPORT
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# define INIT_THREAD_SELF(descr, nr) DO_SET_THREAD_AREA (descr)
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#elif defined __NR_set_thread_area && defined HAVE_TLS_SUPPORT
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# define INIT_THREAD_SELF(descr, nr) \
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({ \
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if (__builtin_expect (__have_no_set_thread_area, 0) \
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|| (DO_SET_THREAD_AREA (descr) == -1 \
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&& (__have_no_set_thread_area = 1))) \
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DO_MODIFY_LDT (descr, nr); \
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})
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/* Defined in pspinlock.c. */
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extern int __have_no_set_thread_area;
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#define INIT_THREAD_SELF(descr, nr) \
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{ \
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int __gs = -1; \
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if (! __builtin_expect (__have_no_set_thread_area, 0)) \
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{ \
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if ((__gs = INLINE_SYSCALL (set_thread_area, 2, descr, 1)) == -1 \
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&& errno == ENOSYS) \
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__have_no_set_thread_area = 1; \
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} \
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if (__builtin_expect (__gs == -1, 0)) \
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__gs = DO_MODIFY_LDT (descr, nr); \
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__asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
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}
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#else
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#define INIT_THREAD_SELF(descr, nr) \
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{ \
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int __gs = DO_MODIFY_LDT (descr, nr); \
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__asm__ __volatile__ ("movw %w0, %%gs" : : "q" (__gs)); \
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}
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# define INIT_THREAD_SELF(descr, nr) DO_MODIFY_LDT (descr, nr)
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#endif
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/* Free resources associated with thread descriptor. */
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