1/* Assembler macros for x86-64.
2 Copyright (C) 2001-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _X86_64_SYSDEP_H
20#define _X86_64_SYSDEP_H 1
21
22#include <sysdeps/x86/sysdep.h>
23#include <x86-lp_size.h>
24
25/* __CET__ is defined by GCC with Control-Flow Protection values:
26
27enum cf_protection_level
28{
29 CF_NONE = 0,
30 CF_BRANCH = 1 << 0,
31 CF_RETURN = 1 << 1,
32 CF_FULL = CF_BRANCH | CF_RETURN,
33 CF_SET = 1 << 2
34};
35*/
36
37/* Set if CF_BRANCH (IBT) is enabled. */
38#define X86_FEATURE_1_IBT (1U << 0)
39/* Set if CF_RETURN (SHSTK) is enabled. */
40#define X86_FEATURE_1_SHSTK (1U << 1)
41
42#ifdef __CET__
43# define CET_ENABLED 1
44# define SHSTK_ENABLED (__CET__ & X86_FEATURE_1_SHSTK)
45#else
46# define CET_ENABLED 0
47# define SHSTK_ENABLED 0
48#endif
49
50#ifdef __ASSEMBLER__
51
52/* Syntactic details of assembler. */
53
54#ifdef _CET_ENDBR
55# define _CET_NOTRACK notrack
56#else
57# define _CET_ENDBR
58# define _CET_NOTRACK
59#endif
60
61/* Define an entry point visible from C. */
62#define ENTRY_P2ALIGN(name, alignment) \
63 .globl C_SYMBOL_NAME(name); \
64 .type C_SYMBOL_NAME(name),@function; \
65 .align ALIGNARG(alignment); \
66 C_LABEL(name) \
67 cfi_startproc; \
68 _CET_ENDBR; \
69 CALL_MCOUNT
70
71/* This macro is for setting proper CFI with DW_CFA_expression describing
72 the register as saved relative to %rsp instead of relative to the CFA.
73 Expression is DW_OP_drop, DW_OP_breg7 (%rsp is register 7), sleb128 offset
74 from %rsp. */
75#define cfi_offset_rel_rsp(regn, off) .cfi_escape 0x10, regn, 0x4, 0x13, \
76 0x77, off & 0x7F | 0x80, off >> 7
77
78/* If compiled for profiling, call `mcount' at the start of each function. */
79#ifdef PROF
80/* The mcount code relies on a normal frame pointer being on the stack
81 to locate our caller, so push one just for its benefit. */
82#define CALL_MCOUNT \
83 pushq %rbp; \
84 cfi_adjust_cfa_offset(8); \
85 movq %rsp, %rbp; \
86 cfi_def_cfa_register(%rbp); \
87 call JUMPTARGET(mcount); \
88 popq %rbp; \
89 cfi_def_cfa(rsp,8);
90#else
91#define CALL_MCOUNT /* Do nothing. */
92#endif
93
94#define PSEUDO(name, syscall_name, args) \
95lose: \
96 jmp JUMPTARGET(syscall_error) \
97 .globl syscall_error; \
98 ENTRY (name) \
99 DO_CALL (syscall_name, args); \
100 jb lose
101
102#undef JUMPTARGET
103#ifdef SHARED
104# ifdef BIND_NOW
105# define JUMPTARGET(name) *name##@GOTPCREL(%rip)
106# else
107# define JUMPTARGET(name) name##@PLT
108# endif
109#else
110/* For static archives, branch to target directly. */
111# define JUMPTARGET(name) name
112#endif
113
114/* Instruction to operate on long and pointer. */
115#define LP_OP(insn) insn##q
116
117/* Assembler address directive. */
118#define ASM_ADDR .quad
119
120/* Registers to hold long and pointer. */
121#define RAX_LP rax
122#define RBP_LP rbp
123#define RBX_LP rbx
124#define RCX_LP rcx
125#define RDI_LP rdi
126#define RDX_LP rdx
127#define RSI_LP rsi
128#define RSP_LP rsp
129#define R8_LP r8
130#define R9_LP r9
131#define R10_LP r10
132#define R11_LP r11
133#define R12_LP r12
134#define R13_LP r13
135#define R14_LP r14
136#define R15_LP r15
137
138/* Zero upper vector registers and return with xtest. NB: Use VZEROALL
139 to avoid RTM abort triggered by VZEROUPPER inside transactionally. */
140#define ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST \
141 xtest; \
142 jnz 1f; \
143 vzeroupper; \
144 ret; \
1451: \
146 vzeroall; \
147 ret
148
149/* Can be used to replace vzeroupper that is not directly before a
150 return. This is useful when hoisting a vzeroupper from multiple
151 return paths to decrease the total number of vzerouppers and code
152 size. */
153#define COND_VZEROUPPER_XTEST \
154 xtest; \
155 jz 1f; \
156 vzeroall; \
157 jmp 2f; \
1581: \
159 vzeroupper; \
1602:
161
162/* In RTM define this as COND_VZEROUPPER_XTEST. */
163#ifndef COND_VZEROUPPER
164# define COND_VZEROUPPER vzeroupper
165#endif
166
167/* Zero upper vector registers and return. */
168#ifndef ZERO_UPPER_VEC_REGISTERS_RETURN
169# define ZERO_UPPER_VEC_REGISTERS_RETURN \
170 VZEROUPPER; \
171 ret
172#endif
173
174#ifndef VZEROUPPER_RETURN
175# define VZEROUPPER_RETURN VZEROUPPER; ret
176#endif
177
178#else /* __ASSEMBLER__ */
179
180/* Instruction to operate on long and pointer. */
181#define LP_OP(insn) #insn "q"
182
183/* Assembler address directive. */
184#define ASM_ADDR ".quad"
185
186/* Registers to hold long and pointer. */
187#define RAX_LP "rax"
188#define RBP_LP "rbp"
189#define RBX_LP "rbx"
190#define RCX_LP "rcx"
191#define RDI_LP "rdi"
192#define RDX_LP "rdx"
193#define RSI_LP "rsi"
194#define RSP_LP "rsp"
195#define R8_LP "r8"
196#define R9_LP "r9"
197#define R10_LP "r10"
198#define R11_LP "r11"
199#define R12_LP "r12"
200#define R13_LP "r13"
201#define R14_LP "r14"
202#define R15_LP "r15"
203
204#endif /* __ASSEMBLER__ */
205
206#endif /* _X86_64_SYSDEP_H */
207

source code of glibc/sysdeps/x86_64/sysdep.h