sysdeps/i386/dl-tlsdesc.S - nest-cam/v366/glibc - Git at Google

 /* Thread-local storage handling in the ELF dynamic linker.  i386 version.
    Copyright (C) 2004, 2005, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.

    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    The GNU C Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, write to the Free
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */

 #include <sysdep.h>
 #include <tls.h>
 #include "tlsdesc.h"

 	.text

      /* This function is used to compute the TP offset for symbols in
 	Static TLS, i.e., whose TP offset is the same for all
 	threads.

 	The incoming %eax points to the TLS descriptor, such that
 	0(%eax) points to _dl_tlsdesc_return itself, and 4(%eax) holds
 	the TP offset of the symbol corresponding to the object
 	denoted by the argument.  */

 	.hidden _dl_tlsdesc_return
 	.global	_dl_tlsdesc_return
 	.type	_dl_tlsdesc_return,@function
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_return:
 	movl	4(%eax), %eax
 	ret
 	cfi_endproc
 	.size	_dl_tlsdesc_return, .-_dl_tlsdesc_return

      /* This function is used for undefined weak TLS symbols, for
 	which the base address (i.e., disregarding any addend) should
 	resolve to NULL.

 	%eax points to the TLS descriptor, such that 0(%eax) points to
 	_dl_tlsdesc_undefweak itself, and 4(%eax) holds the addend.
 	We return the addend minus the TP, such that, when the caller
 	adds TP, it gets the addend back.  If that's zero, as usual,
 	that's most likely a NULL pointer.  */

 	.hidden _dl_tlsdesc_undefweak
 	.global	_dl_tlsdesc_undefweak
 	.type	_dl_tlsdesc_undefweak,@function
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_undefweak:
 	movl	4(%eax), %eax
 	subl	%gs:0, %eax
 	ret
 	cfi_endproc
 	.size	_dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak

 #ifdef SHARED
 	.hidden _dl_tlsdesc_dynamic
 	.global	_dl_tlsdesc_dynamic
 	.type	_dl_tlsdesc_dynamic,@function

      /* This function is used for symbols that need dynamic TLS.

 	%eax points to the TLS descriptor, such that 0(%eax) points to
 	_dl_tlsdesc_dynamic itself, and 4(%eax) points to a struct
 	tlsdesc_dynamic_arg object.  It must return in %eax the offset
 	between the thread pointer and the object denoted by the
 	argument, without clobbering any registers.

 	The assembly code that follows is a rendition of the following
 	C code, hand-optimized a little bit.

 ptrdiff_t
 __attribute__ ((__regparm__ (1)))
 _dl_tlsdesc_dynamic (struct tlsdesc *tdp)
 {
   struct tlsdesc_dynamic_arg *td = tdp->arg;
   dtv_t *dtv = *(dtv_t **)((char *)__thread_pointer + DTV_OFFSET);
   if (__builtin_expect (td->gen_count <= dtv[0].counter
 			&& (dtv[td->tlsinfo.ti_module].pointer.val
 			    != TLS_DTV_UNALLOCATED),
 			1))
     return dtv[td->tlsinfo.ti_module].pointer.val + td->tlsinfo.ti_offset
       - __thread_pointer;

   return ___tls_get_addr (&td->tlsinfo) - __thread_pointer;
 }
 */
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_dynamic:
 	/* Like all TLS resolvers, preserve call-clobbered registers.
 	   We need two scratch regs anyway.  */
 	subl	$28, %esp
 	cfi_adjust_cfa_offset (28)
 	movl	%ecx, 20(%esp)
 	movl	%edx, 24(%esp)
 	movl	TLSDESC_ARG(%eax), %eax
 	movl	%gs:DTV_OFFSET, %edx
 	movl	TLSDESC_GEN_COUNT(%eax), %ecx
 	cmpl	(%edx), %ecx
 	ja	.Lslow
 	movl	TLSDESC_MODID(%eax), %ecx
 	movl	(%edx,%ecx,8), %edx
 	cmpl	$-1, %edx
 	je	.Lslow
 	movl	TLSDESC_MODOFF(%eax), %eax
 	addl	%edx, %eax
 .Lret:
 	movl	20(%esp), %ecx
 	subl	%gs:0, %eax
 	movl	24(%esp), %edx
 	addl	$28, %esp
 	cfi_adjust_cfa_offset (-28)
 	ret
 	.p2align 4,,7
 .Lslow:
 	cfi_adjust_cfa_offset (28)
 	movl	%ebx, 16(%esp)
 	LOAD_PIC_REG (bx)
 	call	___tls_get_addr@PLT
 	movl	16(%esp), %ebx
 	jmp	.Lret
 	cfi_endproc
 	.size	_dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
 #endif /* SHARED */

      /* This function is a wrapper for a lazy resolver for TLS_DESC
 	REL relocations that reference the *ABS* segment in their own
 	link maps.  %ebx points to the caller's GOT.  %eax points to a
 	TLS descriptor, such that 0(%eax) holds the address of the
 	resolver wrapper itself (unless some other thread beat us to
 	it) and 4(%eax) holds the addend in the relocation.

 	When the actual resolver returns, it will have adjusted the
 	TLS descriptor such that we can tail-call it for it to return
 	the TP offset of the symbol.  */

 	.hidden _dl_tlsdesc_resolve_abs_plus_addend
 	.global	_dl_tlsdesc_resolve_abs_plus_addend
 	.type	_dl_tlsdesc_resolve_abs_plus_addend,@function
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_resolve_abs_plus_addend:
 0:
 	pushl	%eax
 	cfi_adjust_cfa_offset (4)
 	pushl	%ecx
 	cfi_adjust_cfa_offset (4)
 	pushl	%edx
 	cfi_adjust_cfa_offset (4)
 	movl	$1f - 0b, %ecx
 	movl	4(%ebx), %edx
 	call	_dl_tlsdesc_resolve_abs_plus_addend_fixup
 1:
 	popl	%edx
 	cfi_adjust_cfa_offset (-4)
 	popl	%ecx
 	cfi_adjust_cfa_offset (-4)
 	popl	%eax
 	cfi_adjust_cfa_offset (-4)
 	jmp	*(%eax)
 	cfi_endproc
 	.size	_dl_tlsdesc_resolve_abs_plus_addend, .-_dl_tlsdesc_resolve_abs_plus_addend

      /* This function is a wrapper for a lazy resolver for TLS_DESC
 	REL relocations that had zero addends.  %ebx points to the
 	caller's GOT.  %eax points to a TLS descriptor, such that
 	0(%eax) holds the address of the resolver wrapper itself
 	(unless some other thread beat us to it) and 4(%eax) holds a
 	pointer to the relocation.

 	When the actual resolver returns, it will have adjusted the
 	TLS descriptor such that we can tail-call it for it to return
 	the TP offset of the symbol.  */

 	.hidden _dl_tlsdesc_resolve_rel
 	.global	_dl_tlsdesc_resolve_rel
 	.type	_dl_tlsdesc_resolve_rel,@function
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_resolve_rel:
 0:
 	pushl	%eax
 	cfi_adjust_cfa_offset (4)
 	pushl	%ecx
 	cfi_adjust_cfa_offset (4)
 	pushl	%edx
 	cfi_adjust_cfa_offset (4)
 	movl	$1f - 0b, %ecx
 	movl	4(%ebx), %edx
 	call	_dl_tlsdesc_resolve_rel_fixup
 1:
 	popl	%edx
 	cfi_adjust_cfa_offset (-4)
 	popl	%ecx
 	cfi_adjust_cfa_offset (-4)
 	popl	%eax
 	cfi_adjust_cfa_offset (-4)
 	jmp	*(%eax)
 	cfi_endproc
 	.size	_dl_tlsdesc_resolve_rel, .-_dl_tlsdesc_resolve_rel

      /* This function is a wrapper for a lazy resolver for TLS_DESC
 	RELA relocations.  %ebx points to the caller's GOT.  %eax
 	points to a TLS descriptor, such that 0(%eax) holds the
 	address of the resolver wrapper itself (unless some other
 	thread beat us to it) and 4(%eax) holds a pointer to the
 	relocation.

 	When the actual resolver returns, it will have adjusted the
 	TLS descriptor such that we can tail-call it for it to return
 	the TP offset of the symbol.  */

 	.hidden _dl_tlsdesc_resolve_rela
 	.global	_dl_tlsdesc_resolve_rela
 	.type	_dl_tlsdesc_resolve_rela,@function
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_resolve_rela:
 0:
 	pushl	%eax
 	cfi_adjust_cfa_offset (4)
 	pushl	%ecx
 	cfi_adjust_cfa_offset (4)
 	pushl	%edx
 	cfi_adjust_cfa_offset (4)
 	movl	$1f - 0b, %ecx
 	movl	4(%ebx), %edx
 	call	_dl_tlsdesc_resolve_rela_fixup
 1:
 	popl	%edx
 	cfi_adjust_cfa_offset (-4)
 	popl	%ecx
 	cfi_adjust_cfa_offset (-4)
 	popl	%eax
 	cfi_adjust_cfa_offset (-4)
 	jmp	*(%eax)
 	cfi_endproc
 	.size	_dl_tlsdesc_resolve_rela, .-_dl_tlsdesc_resolve_rela

      /* This function is a placeholder for lazy resolving of TLS
 	relocations.  Once some thread starts resolving a TLS
 	relocation, it sets up the TLS descriptor to use this
 	resolver, such that other threads that would attempt to
 	resolve it concurrently may skip the call to the original lazy
 	resolver and go straight to a condition wait.

 	When the actual resolver returns, it will have adjusted the
 	TLS descriptor such that we can tail-call it for it to return
 	the TP offset of the symbol.  */

 	.hidden _dl_tlsdesc_resolve_hold
 	.global	_dl_tlsdesc_resolve_hold
 	.type	_dl_tlsdesc_resolve_hold,@function
 	cfi_startproc
 	.align 16
 _dl_tlsdesc_resolve_hold:
 0:
 	pushl	%eax
 	cfi_adjust_cfa_offset (4)
 	pushl	%ecx
 	cfi_adjust_cfa_offset (4)
 	pushl	%edx
 	cfi_adjust_cfa_offset (4)
 	movl	$1f - 0b, %ecx
 	movl	4(%ebx), %edx
 	call	_dl_tlsdesc_resolve_hold_fixup
 1:
 	popl	%edx
 	cfi_adjust_cfa_offset (-4)
 	popl	%ecx
 	cfi_adjust_cfa_offset (-4)
 	popl	%eax
 	cfi_adjust_cfa_offset (-4)
 	jmp	*(%eax)
 	cfi_endproc
 	.size	_dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold
	/* Thread-local storage handling in the ELF dynamic linker. i386 version.
	Copyright (C) 2004, 2005, 2008 Free Software Foundation, Inc.
	This file is part of the GNU C Library.

	The GNU C Library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	The GNU C Library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with the GNU C Library; if not, write to the Free
	Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
	02111-1307 USA. */

	#include <sysdep.h>
	#include <tls.h>
	#include "tlsdesc.h"

	.text

	/* This function is used to compute the TP offset for symbols in
	Static TLS, i.e., whose TP offset is the same for all
	threads.

	The incoming %eax points to the TLS descriptor, such that
	0(%eax) points to _dl_tlsdesc_return itself, and 4(%eax) holds
	the TP offset of the symbol corresponding to the object
	denoted by the argument. */

	.hidden _dl_tlsdesc_return
	.global _dl_tlsdesc_return
	.type _dl_tlsdesc_return,@function
	cfi_startproc
	.align 16
	_dl_tlsdesc_return:
	movl 4(%eax), %eax
	ret
	cfi_endproc
	.size _dl_tlsdesc_return, .-_dl_tlsdesc_return

	/* This function is used for undefined weak TLS symbols, for
	which the base address (i.e., disregarding any addend) should
	resolve to NULL.

	%eax points to the TLS descriptor, such that 0(%eax) points to
	_dl_tlsdesc_undefweak itself, and 4(%eax) holds the addend.
	We return the addend minus the TP, such that, when the caller
	adds TP, it gets the addend back. If that's zero, as usual,
	that's most likely a NULL pointer. */

	.hidden _dl_tlsdesc_undefweak
	.global _dl_tlsdesc_undefweak
	.type _dl_tlsdesc_undefweak,@function
	cfi_startproc
	.align 16
	_dl_tlsdesc_undefweak:
	movl 4(%eax), %eax
	subl %gs:0, %eax
	ret
	cfi_endproc
	.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak

	#ifdef SHARED
	.hidden _dl_tlsdesc_dynamic
	.global _dl_tlsdesc_dynamic
	.type _dl_tlsdesc_dynamic,@function

	/* This function is used for symbols that need dynamic TLS.

	%eax points to the TLS descriptor, such that 0(%eax) points to
	_dl_tlsdesc_dynamic itself, and 4(%eax) points to a struct
	tlsdesc_dynamic_arg object. It must return in %eax the offset
	between the thread pointer and the object denoted by the
	argument, without clobbering any registers.

	The assembly code that follows is a rendition of the following
	C code, hand-optimized a little bit.

	ptrdiff_t
	__attribute__ ((__regparm__ (1)))
	_dl_tlsdesc_dynamic (struct tlsdesc *tdp)
	{
	struct tlsdesc_dynamic_arg *td = tdp->arg;
	dtv_t dtv = (dtv_t *)((char )__thread_pointer + DTV_OFFSET);
	if (__builtin_expect (td->gen_count <= dtv[0].counter
	&& (dtv[td->tlsinfo.ti_module].pointer.val
	!= TLS_DTV_UNALLOCATED),
	1))
	return dtv[td->tlsinfo.ti_module].pointer.val + td->tlsinfo.ti_offset
	- __thread_pointer;

	return ___tls_get_addr (&td->tlsinfo) - __thread_pointer;
	}
	*/
	cfi_startproc
	.align 16
	_dl_tlsdesc_dynamic:
	/* Like all TLS resolvers, preserve call-clobbered registers.
	We need two scratch regs anyway. */
	subl $28, %esp
	cfi_adjust_cfa_offset (28)
	movl %ecx, 20(%esp)
	movl %edx, 24(%esp)
	movl TLSDESC_ARG(%eax), %eax
	movl %gs:DTV_OFFSET, %edx
	movl TLSDESC_GEN_COUNT(%eax), %ecx
	cmpl (%edx), %ecx
	ja .Lslow
	movl TLSDESC_MODID(%eax), %ecx
	movl (%edx,%ecx,8), %edx
	cmpl $-1, %edx
	je .Lslow
	movl TLSDESC_MODOFF(%eax), %eax
	addl %edx, %eax
	.Lret:
	movl 20(%esp), %ecx
	subl %gs:0, %eax
	movl 24(%esp), %edx
	addl $28, %esp
	cfi_adjust_cfa_offset (-28)
	ret
	.p2align 4,,7
	.Lslow:
	cfi_adjust_cfa_offset (28)
	movl %ebx, 16(%esp)
	LOAD_PIC_REG (bx)
	call ___tls_get_addr@PLT
	movl 16(%esp), %ebx
	jmp .Lret
	cfi_endproc
	.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
	#endif /* SHARED */

	/* This function is a wrapper for a lazy resolver for TLS_DESC
	REL relocations that reference the ABS segment in their own
	link maps. %ebx points to the caller's GOT. %eax points to a
	TLS descriptor, such that 0(%eax) holds the address of the
	resolver wrapper itself (unless some other thread beat us to
	it) and 4(%eax) holds the addend in the relocation.

	When the actual resolver returns, it will have adjusted the
	TLS descriptor such that we can tail-call it for it to return
	the TP offset of the symbol. */

	.hidden _dl_tlsdesc_resolve_abs_plus_addend
	.global _dl_tlsdesc_resolve_abs_plus_addend
	.type _dl_tlsdesc_resolve_abs_plus_addend,@function
	cfi_startproc
	.align 16
	_dl_tlsdesc_resolve_abs_plus_addend:
	0:
	pushl %eax
	cfi_adjust_cfa_offset (4)
	pushl %ecx
	cfi_adjust_cfa_offset (4)
	pushl %edx
	cfi_adjust_cfa_offset (4)
	movl $1f - 0b, %ecx
	movl 4(%ebx), %edx
	call _dl_tlsdesc_resolve_abs_plus_addend_fixup
	1:
	popl %edx
	cfi_adjust_cfa_offset (-4)
	popl %ecx
	cfi_adjust_cfa_offset (-4)
	popl %eax
	cfi_adjust_cfa_offset (-4)
	jmp *(%eax)
	cfi_endproc
	.size _dl_tlsdesc_resolve_abs_plus_addend, .-_dl_tlsdesc_resolve_abs_plus_addend

	/* This function is a wrapper for a lazy resolver for TLS_DESC
	REL relocations that had zero addends. %ebx points to the
	caller's GOT. %eax points to a TLS descriptor, such that
	0(%eax) holds the address of the resolver wrapper itself
	(unless some other thread beat us to it) and 4(%eax) holds a
	pointer to the relocation.

	When the actual resolver returns, it will have adjusted the
	TLS descriptor such that we can tail-call it for it to return
	the TP offset of the symbol. */

	.hidden _dl_tlsdesc_resolve_rel
	.global _dl_tlsdesc_resolve_rel
	.type _dl_tlsdesc_resolve_rel,@function
	cfi_startproc
	.align 16
	_dl_tlsdesc_resolve_rel:
	0:
	pushl %eax
	cfi_adjust_cfa_offset (4)
	pushl %ecx
	cfi_adjust_cfa_offset (4)
	pushl %edx
	cfi_adjust_cfa_offset (4)
	movl $1f - 0b, %ecx
	movl 4(%ebx), %edx
	call _dl_tlsdesc_resolve_rel_fixup
	1:
	popl %edx
	cfi_adjust_cfa_offset (-4)
	popl %ecx
	cfi_adjust_cfa_offset (-4)
	popl %eax
	cfi_adjust_cfa_offset (-4)
	jmp *(%eax)
	cfi_endproc
	.size _dl_tlsdesc_resolve_rel, .-_dl_tlsdesc_resolve_rel

	/* This function is a wrapper for a lazy resolver for TLS_DESC
	RELA relocations. %ebx points to the caller's GOT. %eax
	points to a TLS descriptor, such that 0(%eax) holds the
	address of the resolver wrapper itself (unless some other
	thread beat us to it) and 4(%eax) holds a pointer to the
	relocation.

	When the actual resolver returns, it will have adjusted the
	TLS descriptor such that we can tail-call it for it to return
	the TP offset of the symbol. */

	.hidden _dl_tlsdesc_resolve_rela
	.global _dl_tlsdesc_resolve_rela
	.type _dl_tlsdesc_resolve_rela,@function
	cfi_startproc
	.align 16
	_dl_tlsdesc_resolve_rela:
	0:
	pushl %eax
	cfi_adjust_cfa_offset (4)
	pushl %ecx
	cfi_adjust_cfa_offset (4)
	pushl %edx
	cfi_adjust_cfa_offset (4)
	movl $1f - 0b, %ecx
	movl 4(%ebx), %edx
	call _dl_tlsdesc_resolve_rela_fixup
	1:
	popl %edx
	cfi_adjust_cfa_offset (-4)
	popl %ecx
	cfi_adjust_cfa_offset (-4)
	popl %eax
	cfi_adjust_cfa_offset (-4)
	jmp *(%eax)
	cfi_endproc
	.size _dl_tlsdesc_resolve_rela, .-_dl_tlsdesc_resolve_rela

	/* This function is a placeholder for lazy resolving of TLS
	relocations. Once some thread starts resolving a TLS
	relocation, it sets up the TLS descriptor to use this
	resolver, such that other threads that would attempt to
	resolve it concurrently may skip the call to the original lazy
	resolver and go straight to a condition wait.

	When the actual resolver returns, it will have adjusted the
	TLS descriptor such that we can tail-call it for it to return
	the TP offset of the symbol. */

	.hidden _dl_tlsdesc_resolve_hold
	.global _dl_tlsdesc_resolve_hold
	.type _dl_tlsdesc_resolve_hold,@function
	cfi_startproc
	.align 16
	_dl_tlsdesc_resolve_hold:
	0:
	pushl %eax
	cfi_adjust_cfa_offset (4)
	pushl %ecx
	cfi_adjust_cfa_offset (4)
	pushl %edx
	cfi_adjust_cfa_offset (4)
	movl $1f - 0b, %ecx
	movl 4(%ebx), %edx
	call _dl_tlsdesc_resolve_hold_fixup
	1:
	popl %edx
	cfi_adjust_cfa_offset (-4)
	popl %ecx
	cfi_adjust_cfa_offset (-4)
	popl %eax
	cfi_adjust_cfa_offset (-4)
	jmp *(%eax)
	cfi_endproc
	.size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold