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/* Thread-local storage handling in the ELF dynamic linker. s390 version.
Copyright (C) 2003-2021 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
<https://www.gnu.org/licenses/>. */
/* Type used for the representation of TLS information in the GOT. */
typedef struct
{
unsigned long int ti_module;
unsigned long int ti_offset;
} tls_index;
#ifdef SHARED
extern unsigned long __tls_get_offset (unsigned long got_offset);
# if IS_IN (rtld)
# include <shlib-compat.h>
/* dl-tls.c declares __tls_get_addr as an exported symbol if it is not defined
as a macro. It seems suitable to do that in the generic code because all
architectures other than s390 export __tls_get_addr. The declaration causes
problems in s390 though, so we define __tls_get_addr here to avoid declaring
__tls_get_addr again. */
# define __tls_get_addr __tls_get_addr
extern void *__tls_get_addr (tls_index *ti) attribute_hidden;
/* Make a temporary alias of __tls_get_addr to remove the hidden
attribute. Then export __tls_get_addr as __tls_get_addr_internal
for use from libc. We do not want to export __tls_get_addr, but we
do need to use it from libc when looking up the address of a TLS
variable. We don't use __tls_get_offset because it requires r12 to
be setup and that might not always be true. Either way it's more
optimal to use __tls_get_addr directly (that's what
__tls_get_offset does anyways). */
strong_alias (__tls_get_addr, __tls_get_addr_internal_tmp);
versioned_symbol (ld, __tls_get_addr_internal_tmp,
__tls_get_addr_internal, GLIBC_PRIVATE);
/* The special thing about the s390 TLS ABI is that we do not have the
standard __tls_get_addr function but the __tls_get_offset function
which differs in two important aspects:
1) __tls_get_offset gets a got offset instead of a pointer to the
tls_index structure
2) __tls_get_offset returns the offset of the requested variable to
the thread descriptor instead of a pointer to the variable.
*/
# ifdef __s390x__
__asm__("\n\
.text\n\
.globl __tls_get_offset\n\
.type __tls_get_offset, @function\n\
.align 4\n\
__tls_get_offset:\n\
la %r2,0(%r2,%r12)\n\
jg __tls_get_addr\n\
");
# elif defined __s390__
__asm__("\n\
.text\n\
.globl __tls_get_offset\n\
.type __tls_get_offset, @function\n\
.align 4\n\
__tls_get_offset:\n\
basr %r3,0\n\
0: la %r2,0(%r2,%r12)\n\
l %r4,1f-0b(%r3)\n\
b 0(%r4,%r3)\n\
1: .long __tls_get_addr - 0b\n\
");
# endif
# else /* IS_IN (rtld) */
extern void *__tls_get_addr_internal (tls_index *ti);
# endif /* !IS_IN (rtld) */
# define GET_ADDR_OFFSET \
(ti->ti_offset - (unsigned long) __builtin_thread_pointer ())
/* Use the privately exported __tls_get_addr_internal instead of
__tls_get_offset in order to avoid the __tls_get_offset special
linkage requiring the GOT pointer to be set up in r12. The
compiler will take care of setting up r12 only if itself issued the
__tls_get_offset call. */
# define __TLS_GET_ADDR(__ti) \
({ __tls_get_addr_internal (__ti) \
+ (unsigned long) __builtin_thread_pointer (); })
#endif
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