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/* RSEQ_* accessors. i386 version.
Copyright (C) 2002-2025 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/>. */
#define __RSEQ_GETMEM(member) \
({ __typeof (RSEQ_SELF()->member) __value; \
if (sizeof (__value) == 1) \
asm volatile ("movb %%gs:%P2(%3),%b0" \
: "=q" (__value) \
: "0" (0), "i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
else if (sizeof (__value) == 4) \
asm volatile ("movl %%gs:%P1(%2),%0" \
: "=r" (__value) \
: "i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
else /* 8 */ \
{ \
asm volatile ("movl %%gs:%P1(%2),%%eax\n\t" \
"movl %%gs:4+%P1(%2),%%edx" \
: "=&A" (__value) \
: "i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
} \
__value; })
/* Read member of the RSEQ area directly. */
#define RSEQ_GETMEM(member) \
({ \
_Static_assert (sizeof (RSEQ_SELF()->member) == 1 \
|| sizeof (RSEQ_SELF()->member) == 4 \
|| sizeof (RSEQ_SELF()->member) == 8, \
"size of rseq data"); \
__RSEQ_GETMEM(member); })
/* Read member of the RSEQ area directly, with single-copy atomicity semantics.
Static assert for types >= 64 bits since they can't be loaded atomically on
x86-32. */
#define RSEQ_GETMEM_ONCE(member) \
({ \
_Static_assert (sizeof (RSEQ_SELF()->member) == 1 \
|| sizeof (RSEQ_SELF()->member) == 4, \
"size of rseq data"); \
__RSEQ_GETMEM(member); })
#define __RSEQ_SETMEM(member, value) \
({ \
if (sizeof (RSEQ_SELF()->member) == 1) \
asm volatile ("movb %b0,%%gs:%P1(%2)" : \
: "iq" (value), \
"i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
else if (sizeof (RSEQ_SELF()->member) == 4) \
asm volatile ("movl %0,%%gs:%P1(%2)" : \
: "ir" (value), \
"i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
else /* 8 */ \
{ \
asm volatile ("movl %%eax,%%gs:%P1(%2)\n\t" \
"movl %%edx,%%gs:4+%P1(%2)" : \
: "A" ((uint64_t) cast_to_integer (value)), \
"i" (offsetof (struct rseq_area, member)), \
"r" (__rseq_offset)); \
}})
/* Set member of the RSEQ area directly. */
#define RSEQ_SETMEM(member, value) \
({ \
_Static_assert (sizeof (RSEQ_SELF()->member) == 1 \
|| sizeof (RSEQ_SELF()->member) == 4 \
|| sizeof (RSEQ_SELF()->member) == 8, \
"size of rseq data"); \
__RSEQ_SETMEM(member, value); })
/* Set member of the RSEQ area directly, with single-copy atomicity semantics.
Static assert for types >= 64 bits since they can't be stored atomically on
x86-32. */
#define RSEQ_SETMEM_ONCE(member, value) \
({ \
_Static_assert (sizeof (RSEQ_SELF()->member) == 1 \
|| sizeof (RSEQ_SELF()->member) == 4, \
"size of rseq data"); \
__RSEQ_SETMEM(member, value); })
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