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-rw-r--r--sysdeps/i386/dl-tlsdesc.S290
1 files changed, 290 insertions, 0 deletions
diff --git a/sysdeps/i386/dl-tlsdesc.S b/sysdeps/i386/dl-tlsdesc.S
new file mode 100644
index 0000000000..db5005d9f4
--- /dev/null
+++ b/sysdeps/i386/dl-tlsdesc.S
@@ -0,0 +1,290 @@
+/* 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)
+	call	__i686.get_pc_thunk.bx
+	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
+	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
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-11-29 16:39:40 +0000