/* Thread-local storage handling in the ELF dynamic linker.  x86_64 version.

   Copyright (C) 2004-2018 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, see

   <http://www.gnu.org/licenses/>.  */

#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 %rax points to the TLS descriptor, such that

	0(%rax) points to _dl_tlsdesc_return itself, and 8(%rax) 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:

	_CET_ENDBR

	movq	8(%rax), %rax

	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.

	%rax points to the TLS descriptor, such that 0(%rax) points to

	_dl_tlsdesc_undefweak itself, and 8(%rax) 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:

	_CET_ENDBR

	movq	8(%rax), %rax

	subq	%fs:0, %rax

	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

     /* %rax points to the TLS descriptor, such that 0(%rax) points to

	_dl_tlsdesc_dynamic itself, and 8(%rax) points to a struct

	tlsdesc_dynamic_arg object.  It must return in %rax 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

_dl_tlsdesc_dynamic (register struct tlsdesc *tdp asm ("%rax"))

{

  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_internal (&td->tlsinfo) - __thread_pointer;

}

*/

	cfi_startproc

	.align 16

_dl_tlsdesc_dynamic:

	_CET_ENDBR

	/* Preserve call-clobbered registers that we modify.

	   We need two scratch regs anyway.  */

	movq	%rsi, -16(%rsp)

	movq	%fs:DTV_OFFSET, %rsi

	movq	%rdi, -8(%rsp)

	movq	TLSDESC_ARG(%rax), %rdi

	movq	(%rsi), %rax

	cmpq	%rax, TLSDESC_GEN_COUNT(%rdi)

	ja	.Lslow

	movq	TLSDESC_MODID(%rdi), %rax

	salq	$4, %rax

	movq	(%rax,%rsi), %rax

	cmpq	$-1, %rax

	je	.Lslow

	addq	TLSDESC_MODOFF(%rdi), %rax

.Lret:

	movq	-16(%rsp), %rsi

	subq	%fs:0, %rax

	movq	-8(%rsp), %rdi

	ret

.Lslow:

	/* Besides rdi and rsi, saved above, save rdx, rcx, r8, r9,

	   r10 and r11.  Also, align the stack, that's off by 8 bytes.	*/

	subq	$72, %rsp

	cfi_adjust_cfa_offset (72)

	movq	%rdx, 8(%rsp)

	movq	%rcx, 16(%rsp)

	movq	%r8, 24(%rsp)

	movq	%r9, 32(%rsp)

	movq	%r10, 40(%rsp)

	movq	%r11, 48(%rsp)

	/* %rdi already points to the tlsinfo data structure.  */

#ifdef NO_RTLD_HIDDEN

	call	JUMPTARGET (__tls_get_addr)

#else

	call	HIDDEN_JUMPTARGET (__tls_get_addr)

#endif

	movq	8(%rsp), %rdx

	movq	16(%rsp), %rcx

	movq	24(%rsp), %r8

	movq	32(%rsp), %r9

	movq	40(%rsp), %r10

	movq	48(%rsp), %r11

	addq	$72, %rsp

	cfi_adjust_cfa_offset (-72)

	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

	RELA relocations.  The incoming 0(%rsp) points to the caller's

	link map, pushed by the dynamic object's internal lazy TLS

	resolver front-end before tail-calling us.  We need to pop it

	ourselves.  %rax points to a TLS descriptor, such that 0(%rax)

	holds the address of the internal resolver front-end (unless

	some other thread beat us to resolving it) and 8(%rax) 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

	/* The PLT entry will have pushed the link_map pointer.  */

_dl_tlsdesc_resolve_rela:

	_CET_ENDBR

	cfi_adjust_cfa_offset (8)

	/* Save all call-clobbered registers.  Add 8 bytes for push in

	   the PLT entry to align the stack.  */

	subq	$80, %rsp

	cfi_adjust_cfa_offset (80)

	movq	%rax, (%rsp)

	movq	%rdi, 8(%rsp)

	movq	%rax, %rdi	/* Pass tlsdesc* in %rdi.  */

	movq	%rsi, 16(%rsp)

	movq	80(%rsp), %rsi	/* Pass link_map* in %rsi.  */

	movq	%r8, 24(%rsp)

	movq	%r9, 32(%rsp)

	movq	%r10, 40(%rsp)

	movq	%r11, 48(%rsp)

	movq	%rdx, 56(%rsp)

	movq	%rcx, 64(%rsp)

	call	_dl_tlsdesc_resolve_rela_fixup

	movq	(%rsp), %rax

	movq	8(%rsp), %rdi

	movq	16(%rsp), %rsi

	movq	24(%rsp), %r8

	movq	32(%rsp), %r9

	movq	40(%rsp), %r10

	movq	48(%rsp), %r11

	movq	56(%rsp), %rdx

	movq	64(%rsp), %rcx

	addq	$88, %rsp

	cfi_adjust_cfa_offset (-88)

	jmp	*(%rax)

	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:

	_CET_ENDBR

	/* Save all call-clobbered registers.  */

	subq	$72, %rsp

	cfi_adjust_cfa_offset (72)

	movq	%rax, (%rsp)

	movq	%rdi, 8(%rsp)

	movq	%rax, %rdi	/* Pass tlsdesc* in %rdi.  */

	movq	%rsi, 16(%rsp)

	/* Pass _dl_tlsdesc_resolve_hold's address in %rsi.  */

	leaq	. - _dl_tlsdesc_resolve_hold(%rip), %rsi

	movq	%r8, 24(%rsp)

	movq	%r9, 32(%rsp)

	movq	%r10, 40(%rsp)

	movq	%r11, 48(%rsp)

	movq	%rdx, 56(%rsp)

	movq	%rcx, 64(%rsp)

	call	_dl_tlsdesc_resolve_hold_fixup

1:

	movq	(%rsp), %rax

	movq	8(%rsp), %rdi

	movq	16(%rsp), %rsi

	movq	24(%rsp), %r8

	movq	32(%rsp), %r9

	movq	40(%rsp), %r10

	movq	48(%rsp), %r11

	movq	56(%rsp), %rdx

	movq	64(%rsp), %rcx

	addq	$72, %rsp

	cfi_adjust_cfa_offset (-72)

	jmp	*(%rax)

	cfi_endproc

	.size	_dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold