1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ 2/* 3 * PowerPC specific definitions for NOLIBC 4 * Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org> 5 */ 6 7#ifndef _NOLIBC_ARCH_POWERPC_H 8#define _NOLIBC_ARCH_POWERPC_H 9 10#include "compiler.h" 11#include "crt.h" 12 13/* Syscalls for PowerPC : 14 * - stack is 16-byte aligned 15 * - syscall number is passed in r0 16 * - arguments are in r3, r4, r5, r6, r7, r8, r9 17 * - the system call is performed by calling "sc" 18 * - syscall return comes in r3, and the summary overflow bit is checked 19 * to know if an error occurred, in which case errno is in r3. 20 * - the arguments are cast to long and assigned into the target 21 * registers which are then simply passed as registers to the asm code, 22 * so that we don't have to experience issues with register constraints. 23 */ 24 25#define _NOLIBC_SYSCALL_CLOBBERLIST \ 26 "memory", "cr0", "r12", "r11", "r10", "r9" 27 28#define my_syscall0(num) \ 29({ \ 30 register long _ret __asm__ ("r3"); \ 31 register long _num __asm__ ("r0") = (num); \ 32 \ 33 __asm__ volatile ( \ 34 " sc\n" \ 35 " bns+ 1f\n" \ 36 " neg %0, %0\n" \ 37 "1:\n" \ 38 : "=r"(_ret), "+r"(_num) \ 39 : \ 40 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \ 41 ); \ 42 _ret; \ 43}) 44 45#define my_syscall1(num, arg1) \ 46({ \ 47 register long _ret __asm__ ("r3"); \ 48 register long _num __asm__ ("r0") = (num); \ 49 register long _arg1 __asm__ ("r3") = (long)(arg1); \ 50 \ 51 __asm__ volatile ( \ 52 " sc\n" \ 53 " bns+ 1f\n" \ 54 " neg %0, %0\n" \ 55 "1:\n" \ 56 : "=r"(_ret), "+r"(_num) \ 57 : "0"(_arg1) \ 58 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \ 59 ); \ 60 _ret; \ 61}) 62 63 64#define my_syscall2(num, arg1, arg2) \ 65({ \ 66 register long _ret __asm__ ("r3"); \ 67 register long _num __asm__ ("r0") = (num); \ 68 register long _arg1 __asm__ ("r3") = (long)(arg1); \ 69 register long _arg2 __asm__ ("r4") = (long)(arg2); \ 70 \ 71 __asm__ volatile ( \ 72 " sc\n" \ 73 " bns+ 1f\n" \ 74 " neg %0, %0\n" \ 75 "1:\n" \ 76 : "=r"(_ret), "+r"(_num), "+r"(_arg2) \ 77 : "0"(_arg1) \ 78 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5" \ 79 ); \ 80 _ret; \ 81}) 82 83 84#define my_syscall3(num, arg1, arg2, arg3) \ 85({ \ 86 register long _ret __asm__ ("r3"); \ 87 register long _num __asm__ ("r0") = (num); \ 88 register long _arg1 __asm__ ("r3") = (long)(arg1); \ 89 register long _arg2 __asm__ ("r4") = (long)(arg2); \ 90 register long _arg3 __asm__ ("r5") = (long)(arg3); \ 91 \ 92 __asm__ volatile ( \ 93 " sc\n" \ 94 " bns+ 1f\n" \ 95 " neg %0, %0\n" \ 96 "1:\n" \ 97 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3) \ 98 : "0"(_arg1) \ 99 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6" \ 100 ); \ 101 _ret; \ 102}) 103 104 105#define my_syscall4(num, arg1, arg2, arg3, arg4) \ 106({ \ 107 register long _ret __asm__ ("r3"); \ 108 register long _num __asm__ ("r0") = (num); \ 109 register long _arg1 __asm__ ("r3") = (long)(arg1); \ 110 register long _arg2 __asm__ ("r4") = (long)(arg2); \ 111 register long _arg3 __asm__ ("r5") = (long)(arg3); \ 112 register long _arg4 __asm__ ("r6") = (long)(arg4); \ 113 \ 114 __asm__ volatile ( \ 115 " sc\n" \ 116 " bns+ 1f\n" \ 117 " neg %0, %0\n" \ 118 "1:\n" \ 119 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \ 120 "+r"(_arg4) \ 121 : "0"(_arg1) \ 122 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7" \ 123 ); \ 124 _ret; \ 125}) 126 127 128#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ 129({ \ 130 register long _ret __asm__ ("r3"); \ 131 register long _num __asm__ ("r0") = (num); \ 132 register long _arg1 __asm__ ("r3") = (long)(arg1); \ 133 register long _arg2 __asm__ ("r4") = (long)(arg2); \ 134 register long _arg3 __asm__ ("r5") = (long)(arg3); \ 135 register long _arg4 __asm__ ("r6") = (long)(arg4); \ 136 register long _arg5 __asm__ ("r7") = (long)(arg5); \ 137 \ 138 __asm__ volatile ( \ 139 " sc\n" \ 140 " bns+ 1f\n" \ 141 " neg %0, %0\n" \ 142 "1:\n" \ 143 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \ 144 "+r"(_arg4), "+r"(_arg5) \ 145 : "0"(_arg1) \ 146 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8" \ 147 ); \ 148 _ret; \ 149}) 150 151#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ 152({ \ 153 register long _ret __asm__ ("r3"); \ 154 register long _num __asm__ ("r0") = (num); \ 155 register long _arg1 __asm__ ("r3") = (long)(arg1); \ 156 register long _arg2 __asm__ ("r4") = (long)(arg2); \ 157 register long _arg3 __asm__ ("r5") = (long)(arg3); \ 158 register long _arg4 __asm__ ("r6") = (long)(arg4); \ 159 register long _arg5 __asm__ ("r7") = (long)(arg5); \ 160 register long _arg6 __asm__ ("r8") = (long)(arg6); \ 161 \ 162 __asm__ volatile ( \ 163 " sc\n" \ 164 " bns+ 1f\n" \ 165 " neg %0, %0\n" \ 166 "1:\n" \ 167 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \ 168 "+r"(_arg4), "+r"(_arg5), "+r"(_arg6) \ 169 : "0"(_arg1) \ 170 : _NOLIBC_SYSCALL_CLOBBERLIST \ 171 ); \ 172 _ret; \ 173}) 174 175#ifndef __powerpc64__ 176/* FIXME: For 32-bit PowerPC, with newer gcc compilers (e.g. gcc 13.1.0), 177 * "omit-frame-pointer" fails with __attribute__((no_stack_protector)) but 178 * works with __attribute__((__optimize__("-fno-stack-protector"))) 179 */ 180#ifdef __no_stack_protector 181#undef __no_stack_protector 182#define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector"))) 183#endif 184#endif /* !__powerpc64__ */ 185 186/* startup code */ 187void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void) 188{ 189#ifdef __powerpc64__ 190#if _CALL_ELF == 2 191 /* with -mabi=elfv2, save TOC/GOT pointer to r2 192 * r12 is global entry pointer, we use it to compute TOC from r12 193 * https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf 194 * https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf 195 */ 196 __asm__ volatile ( 197 "addis 2, 12, .TOC. - _start@ha\n" 198 "addi 2, 2, .TOC. - _start@l\n" 199 ); 200#endif /* _CALL_ELF == 2 */ 201 202 __asm__ volatile ( 203 "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */ 204 "clrrdi 1, 1, 4\n" /* align the stack to 16 bytes */ 205 "li 0, 0\n" /* zero the frame pointer */ 206 "stdu 1, -32(1)\n" /* the initial stack frame */ 207 "bl _start_c\n" /* transfer to c runtime */ 208 ); 209#else 210 __asm__ volatile ( 211 "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */ 212 "clrrwi 1, 1, 4\n" /* align the stack to 16 bytes */ 213 "li 0, 0\n" /* zero the frame pointer */ 214 "stwu 1, -16(1)\n" /* the initial stack frame */ 215 "bl _start_c\n" /* transfer to c runtime */ 216 ); 217#endif 218 __builtin_unreachable(); 219} 220 221#endif /* _NOLIBC_ARCH_POWERPC_H */ 222