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/*
* Copyright (C) 2017 Waldemar Brodkorb <wbx@uclibc-ng.org>
* Ported from GNU C Library
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/* Thread-local storage handling in the ELF dynamic linker.
AArch64 version.
Copyright (C) 2011-2017 Free Software Foundation, Inc.
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>
#if defined __UCLIBC_HAS_TLS__
#include <tls.h>
#include "tlsdesc.h"
#define PTR_REG(n) x##n
#define PTR_LOG_SIZE 3
#define PTR_SIZE (1<<PTR_LOG_SIZE)
#define NSAVEDQREGPAIRS 16
#define SAVE_Q_REGISTERS \
stp q0, q1, [sp, #-32*NSAVEDQREGPAIRS]!; \
cfi_adjust_cfa_offset (32*NSAVEDQREGPAIRS); \
stp q2, q3, [sp, #32*1]; \
stp q4, q5, [sp, #32*2]; \
stp q6, q7, [sp, #32*3]; \
stp q8, q9, [sp, #32*4]; \
stp q10, q11, [sp, #32*5]; \
stp q12, q13, [sp, #32*6]; \
stp q14, q15, [sp, #32*7]; \
stp q16, q17, [sp, #32*8]; \
stp q18, q19, [sp, #32*9]; \
stp q20, q21, [sp, #32*10]; \
stp q22, q23, [sp, #32*11]; \
stp q24, q25, [sp, #32*12]; \
stp q26, q27, [sp, #32*13]; \
stp q28, q29, [sp, #32*14]; \
stp q30, q31, [sp, #32*15];
#define RESTORE_Q_REGISTERS \
ldp q2, q3, [sp, #32*1]; \
ldp q4, q5, [sp, #32*2]; \
ldp q6, q7, [sp, #32*3]; \
ldp q8, q9, [sp, #32*4]; \
ldp q10, q11, [sp, #32*5]; \
ldp q12, q13, [sp, #32*6]; \
ldp q14, q15, [sp, #32*7]; \
ldp q16, q17, [sp, #32*8]; \
ldp q18, q19, [sp, #32*9]; \
ldp q20, q21, [sp, #32*10]; \
ldp q22, q23, [sp, #32*11]; \
ldp q24, q25, [sp, #32*12]; \
ldp q26, q27, [sp, #32*13]; \
ldp q28, q29, [sp, #32*14]; \
ldp q30, q31, [sp, #32*15]; \
ldp q0, q1, [sp], #32*NSAVEDQREGPAIRS; \
cfi_adjust_cfa_offset (-32*NSAVEDQREGPAIRS);
.text
/* Compute the thread pointer offset for symbols in the static
TLS block. The offset is the same for all threads.
Prototype:
_dl_tlsdesc_return (tlsdesc *) ;
*/
.hidden _dl_tlsdesc_return
.global _dl_tlsdesc_return
.type _dl_tlsdesc_return,%function
.align 2
_dl_tlsdesc_return:
ldr x0,[x0,#8]
ret
.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
#ifdef SHARED
/* Handler for dynamic TLS symbols.
Prototype:
_dl_tlsdesc_dynamic (tlsdesc *) ;
The second word of the descriptor points to a
tlsdesc_dynamic_arg structure.
Returns the offset between the thread pointer and the
object referenced by the argument.
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 + TCBHEAD_DTV);
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;
}
*/
.hidden _dl_tlsdesc_dynamic
.global _dl_tlsdesc_dynamic
.type _dl_tlsdesc_dynamic,%function
cfi_startproc
.align 2
_dl_tlsdesc_dynamic:
# define NSAVEXREGPAIRS 2
stp x29, x30, [sp,#-(32+16*NSAVEXREGPAIRS)]!
cfi_adjust_cfa_offset (32+16*NSAVEXREGPAIRS)
mov x29, sp
/* Save just enough registers to support fast path, if we fall
into slow path we will save additional registers. */
stp x1, x2, [sp, #32+16*0]
stp x3, x4, [sp, #32+16*1]
mrs x4, tpidr_el0
/* The ldar here happens after the load from [x0] at the call site
(that is generated by the compiler as part of the TLS access ABI),
so it reads the same value (this function is the final value of
td->entry) and thus it synchronizes with the release store to
td->entry in _dl_tlsdesc_resolve_rela_fixup ensuring that the load
from [x0,#PTR_SIZE] here happens after the initialization of td->arg. */
ldar PTR_REG (zr), [x0]
ldr PTR_REG (1), [x0,#TLSDESC_ARG]
ldr PTR_REG (0), [x4,#TCBHEAD_DTV]
ldr PTR_REG (3), [x1,#TLSDESC_GEN_COUNT]
ldr PTR_REG (2), [x0,#DTV_COUNTER]
cmp PTR_REG (3), PTR_REG (2)
b.hi 2f
ldr PTR_REG (2), [x1,#TLSDESC_MODID]
add PTR_REG (0), PTR_REG (0), PTR_REG (2), lsl #(PTR_LOG_SIZE + 1)
ldr PTR_REG (0), [x0] /* Load val member of DTV entry. */
cmp x0, #TLS_DTV_UNALLOCATED
b.eq 2f
ldr PTR_REG (1), [x1,#TLSDESC_MODOFF]
add PTR_REG (0), PTR_REG (0), PTR_REG (1)
sub PTR_REG (0), PTR_REG (0), PTR_REG (4)
1:
ldp x1, x2, [sp, #32+16*0]
ldp x3, x4, [sp, #32+16*1]
ldp x29, x30, [sp], #(32+16*NSAVEXREGPAIRS)
cfi_adjust_cfa_offset (-32-16*NSAVEXREGPAIRS)
# undef NSAVEXREGPAIRS
ret
2:
/* This is the slow path. We need to call __tls_get_addr() which
means we need to save and restore all the register that the
callee will trash. */
/* Save the remaining registers that we must treat as caller save. */
# define NSAVEXREGPAIRS 7
stp x5, x6, [sp, #-16*NSAVEXREGPAIRS]!
cfi_adjust_cfa_offset (16*NSAVEXREGPAIRS)
stp x7, x8, [sp, #16*1]
stp x9, x10, [sp, #16*2]
stp x11, x12, [sp, #16*3]
stp x13, x14, [sp, #16*4]
stp x15, x16, [sp, #16*5]
stp x17, x18, [sp, #16*6]
SAVE_Q_REGISTERS
mov x0, x1
bl __tls_get_addr
mrs x1, tpidr_el0
sub PTR_REG (0), PTR_REG (0), PTR_REG (1)
RESTORE_Q_REGISTERS
ldp x7, x8, [sp, #16*1]
ldp x9, x10, [sp, #16*2]
ldp x11, x12, [sp, #16*3]
ldp x13, x14, [sp, #16*4]
ldp x15, x16, [sp, #16*5]
ldp x17, x18, [sp, #16*6]
ldp x5, x6, [sp], #16*NSAVEXREGPAIRS
cfi_adjust_cfa_offset (-16*NSAVEXREGPAIRS)
b 1b
cfi_endproc
.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
# undef NSAVEXREGPAIRS
#endif // SHARED
#endif // __UCLIBC_HAS_TLS__
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