1 /* $OpenBSD: asm.h,v 1.21 2022/01/01 23:47:14 guenther Exp $ */ 2 /* $NetBSD: asm.h,v 1.2 2003/05/02 18:05:47 yamt Exp $ */ 3 4 /*- 5 * Copyright (c) 1990 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * William Jolitz. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)asm.h 5.5 (Berkeley) 5/7/91 36 */ 37 38 #ifndef _MACHINE_ASM_H_ 39 #define _MACHINE_ASM_H_ 40 41 #ifdef __PIC__ 42 #define PIC_PLT(x) x@PLT 43 #define PIC_GOT(x) x@GOTPCREL(%rip) 44 #else 45 #define PIC_PLT(x) x 46 #define PIC_GOT(x) x 47 #endif 48 49 # define _C_LABEL(x) x 50 #define _ASM_LABEL(x) x 51 52 #define CVAROFF(x,y) (_C_LABEL(x)+y)(%rip) 53 54 #ifdef __STDC__ 55 # define __CONCAT(x,y) x ## y 56 # define __STRING(x) #x 57 #else 58 # define __CONCAT(x,y) x/**/y 59 # define __STRING(x) "x" 60 #endif 61 62 /* let kernels and others override entrypoint alignment */ 63 #ifndef _ALIGN_TEXT 64 #define _ALIGN_TEXT .align 16, 0x90 65 #endif 66 #define _ALIGN_TRAPS .align 16, 0xcc 67 68 #define _FENTRY(x) .type x,@function; x: 69 70 /* NB == No Binding: use .globl or .weak as necessary */ 71 #define NENTRY_NB(x) \ 72 .text; _ALIGN_TEXT; _FENTRY(x) 73 #define _ENTRY_NB(x) \ 74 .text; _ALIGN_TRAPS; _FENTRY(x) 75 #define _ENTRY(x) .globl x; _ENTRY_NB(x) 76 #define _NENTRY(x) .globl x; NENTRY_NB(x) 77 78 #ifdef _KERNEL 79 #define KUTEXT .section .kutext, "ax", @progbits 80 81 #define KUTEXT_PAGE_START .pushsection .kutext.page, "a", @progbits 82 #define KTEXT_PAGE_START .pushsection .ktext.page, "ax", @progbits 83 #define KUTEXT_PAGE_END .popsection 84 #define KTEXT_PAGE_END .popsection 85 86 #define IDTVEC(name) \ 87 KUTEXT; _ALIGN_TRAPS; IDTVEC_NOALIGN(name) 88 #define GENTRY(x) .globl x; _FENTRY(x) 89 #define IDTVEC_NOALIGN(name) GENTRY(X ## name) 90 #define KIDTVEC(name) \ 91 .text; _ALIGN_TRAPS; IDTVEC_NOALIGN(name) 92 #define KIDTVEC_FALLTHROUGH(name) \ 93 _ALIGN_TEXT; IDTVEC_NOALIGN(name) 94 #define KUENTRY(x) \ 95 KUTEXT; _ALIGN_TRAPS; GENTRY(x) 96 97 /* Return stack refill, to prevent speculation attacks on natural returns */ 98 #define RET_STACK_REFILL_WITH_RCX \ 99 mov $8,%rcx ; \ 100 _ALIGN_TEXT ; \ 101 3: call 5f ; \ 102 4: pause ; \ 103 lfence ; \ 104 call 4b ; \ 105 _ALIGN_TRAPS ; \ 106 5: call 7f ; \ 107 6: pause ; \ 108 lfence ; \ 109 call 6b ; \ 110 _ALIGN_TRAPS ; \ 111 7: loop 3b ; \ 112 add $(16*8),%rsp 113 114 #endif /* _KERNEL */ 115 116 #ifdef __STDC__ 117 #define CPUVAR(off) %gs:CPU_INFO_ ## off 118 #else 119 #define CPUVAR(off) %gs:CPU_INFO_/**/off 120 #endif 121 122 123 #if defined(PROF) || defined(GPROF) 124 # define _PROF_PROLOGUE \ 125 pushq %rbp; leaq (%rsp),%rbp; call PIC_PLT(__mcount); popq %rbp 126 #else 127 # define _PROF_PROLOGUE 128 #endif 129 130 #if defined(_RET_PROTECTOR) 131 # define RETGUARD_SETUP_OFF(x, reg, off) \ 132 RETGUARD_SYMBOL(x); \ 133 movq (__retguard_ ## x)(%rip), %reg; \ 134 xorq off(%rsp), %reg 135 # define RETGUARD_SETUP(x, reg) \ 136 RETGUARD_SETUP_OFF(x, reg, 0) 137 # define RETGUARD_CHECK(x, reg) \ 138 xorq (%rsp), %reg; \ 139 cmpq (__retguard_ ## x)(%rip), %reg; \ 140 je 66f; \ 141 int3; int3; \ 142 .zero (0xf - ((. + 3 - x) & 0xf)), 0xcc; \ 143 66: 144 # define RETGUARD_PUSH(reg) \ 145 pushq %reg 146 # define RETGUARD_POP(reg) \ 147 popq %reg 148 # define RETGUARD_SYMBOL(x) \ 149 .ifndef __retguard_ ## x; \ 150 .hidden __retguard_ ## x; \ 151 .type __retguard_ ## x,@object; \ 152 .pushsection .openbsd.randomdata.retguard,"aw",@progbits; \ 153 .weak __retguard_ ## x; \ 154 .p2align 3; \ 155 __retguard_ ## x: ; \ 156 .quad 0; \ 157 .size __retguard_ ## x, 8; \ 158 .popsection; \ 159 .endif 160 #else 161 # define RETGUARD_SETUP_OFF(x, reg, off) 162 # define RETGUARD_SETUP(x, reg) 163 # define RETGUARD_CHECK(x, reg) 164 # define RETGUARD_PUSH(reg) 165 # define RETGUARD_POP(reg) 166 # define RETGUARD_SYMBOL(x) 167 #endif 168 169 #define ENTRY(y) _ENTRY(_C_LABEL(y)); _PROF_PROLOGUE 170 #define NENTRY(y) _NENTRY(_C_LABEL(y)) 171 #define ASENTRY(y) _NENTRY(_ASM_LABEL(y)); _PROF_PROLOGUE 172 #define ENTRY_NB(y) _ENTRY_NB(y); _PROF_PROLOGUE 173 #define END(y) .size y, . - y 174 175 #define STRONG_ALIAS(alias,sym) \ 176 .global alias; \ 177 alias = sym 178 #define WEAK_ALIAS(alias,sym) \ 179 .weak alias; \ 180 alias = sym 181 182 /* XXXfvdl do not use stabs here */ 183 #ifdef __STDC__ 184 #define WARN_REFERENCES(sym,msg) \ 185 .stabs msg ## ,30,0,0,0 ; \ 186 .stabs __STRING(_C_LABEL(sym)) ## ,1,0,0,0 187 #else 188 #define WARN_REFERENCES(sym,msg) \ 189 .stabs msg,30,0,0,0 ; \ 190 .stabs __STRING(sym),1,0,0,0 191 #endif /* __STDC__ */ 192 193 /* generic retpoline ("return trampoline") generator */ 194 #define JMP_RETPOLINE(reg) \ 195 call 69f ; \ 196 68: pause ; \ 197 lfence ; \ 198 jmp 68b ; \ 199 _ALIGN_TRAPS ; \ 200 69: mov %reg,(%rsp) ; \ 201 ret ; \ 202 lfence 203 204 #endif /* !_MACHINE_ASM_H_ */ 205