/* RSEQ_* accessors. x86_64 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 . */ /* Read member of the RSEQ area directly, with single-copy atomicity semantics. */ #define RSEQ_GETMEM_ONCE(member) \ ({ __typeof (RSEQ_SELF()->member) __value; \ _Static_assert (sizeof (__value) == 1 \ || sizeof (__value) == 4 \ || sizeof (__value) == 8, \ "size of rseq data"); \ if (sizeof (__value) == 1) \ asm volatile ("movb %%fs:%P2(%q3),%b0" \ : "=q" (__value) \ : "0" (0), "i" (offsetof (struct rseq_area, member)), \ "r" ((long long int) __rseq_offset)); \ else if (sizeof (__value) == 4) \ asm volatile ("movl %%fs:%P1(%q2),%0" \ : "=r" (__value) \ : "i" (offsetof (struct rseq_area, member)), \ "r" ((long long int) __rseq_offset)); \ else /* 8 */ \ { \ asm volatile ("movq %%fs:%P1(%q2),%q0" \ : "=r" (__value) \ : "i" (offsetof (struct rseq_area, member)), \ "r" ((long long int) __rseq_offset)); \ } \ __value; }) /* Read member of the RSEQ area directly. */ #define RSEQ_GETMEM(member) RSEQ_GETMEM_ONCE(member) /* Set member of the RSEQ area directly, with single-copy atomicity semantics. */ #define RSEQ_SETMEM_ONCE(member, value) \ ({ \ _Static_assert (sizeof (RSEQ_SELF()->member) == 1 \ || sizeof (RSEQ_SELF()->member) == 4 \ || sizeof (RSEQ_SELF()->member) == 8, \ "size of rseq data"); \ if (sizeof (RSEQ_SELF()->member) == 1) \ asm volatile ("movb %b0,%%fs:%P1(%q2)" : \ : "iq" (value), \ "i" (offsetof (struct rseq_area, member)), \ "r" ((long long int) __rseq_offset)); \ else if (sizeof (RSEQ_SELF()->member) == 4) \ asm volatile ("movl %0,%%fs:%P1(%q2)" : \ : IMM_MODE (value), \ "i" (offsetof (struct rseq_area, member)), \ "r" ((long long int) __rseq_offset)); \ else /* 8 */ \ { \ /* Since movq takes a signed 32-bit immediate or a register source \ operand, use "er" constraint for 32-bit signed integer constant \ or register. */ \ asm volatile ("movq %q0,%%fs:%P1(%q2)" : \ : "er" ((uint64_t) cast_to_integer (value)), \ "i" (offsetof (struct rseq_area, member)), \ "r" ((long long int) __rseq_offset)); \ }}) /* Set member of the RSEQ area directly. */ #define RSEQ_SETMEM(member, value) RSEQ_SETMEM_ONCE(member, value)