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1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2/*
3 * PowerPC specific definitions for NOLIBC
4 * Copyright (C) 2023 Zhangjin Wu <[email protected]>
5 */
6
7#ifndef _NOLIBC_ARCH_POWERPC_H
8#define _NOLIBC_ARCH_POWERPC_H
9
10#include <linux/unistd.h>
11
12#include "compiler.h"
13#include "crt.h"
14#include "std.h"
15
16/* Syscalls for PowerPC :
17 * - stack is 16-byte aligned
18 * - syscall number is passed in r0
19 * - arguments are in r3, r4, r5, r6, r7, r8, r9
20 * - the system call is performed by calling "sc"
21 * - syscall return comes in r3, and the summary overflow bit is checked
22 * to know if an error occurred, in which case errno is in r3.
23 * - the arguments are cast to long and assigned into the target
24 * registers which are then simply passed as registers to the asm code,
25 * so that we don't have to experience issues with register constraints.
26 */
27
28#define _NOLIBC_SYSCALL_CLOBBERLIST \
29 "memory", "cr0", "ctr", "xer", "r12", "r11", "r10", "r9"
30
31#define __nolibc_syscall0(num) \
32({ \
33 register long _ret __asm__ ("r3"); \
34 register long _num __asm__ ("r0") = (num); \
35 \
36 __asm__ volatile ( \
37 " sc\n" \
38 " bns+ 1f\n" \
39 " neg %0, %0\n" \
40 "1:\n" \
41 : "=r"(_ret), "+r"(_num) \
42 : \
43 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \
44 ); \
45 _ret; \
46})
47
48#define __nolibc_syscall1(num, arg1) \
49({ \
50 register long _ret __asm__ ("r3"); \
51 register long _num __asm__ ("r0") = (num); \
52 register long _arg1 __asm__ ("r3") = (long)(arg1); \
53 \
54 __asm__ volatile ( \
55 " sc\n" \
56 " bns+ 1f\n" \
57 " neg %0, %0\n" \
58 "1:\n" \
59 : "=r"(_ret), "+r"(_num) \
60 : "0"(_arg1) \
61 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4" \
62 ); \
63 _ret; \
64})
65
66
67#define __nolibc_syscall2(num, arg1, arg2) \
68({ \
69 register long _ret __asm__ ("r3"); \
70 register long _num __asm__ ("r0") = (num); \
71 register long _arg1 __asm__ ("r3") = (long)(arg1); \
72 register long _arg2 __asm__ ("r4") = (long)(arg2); \
73 \
74 __asm__ volatile ( \
75 " sc\n" \
76 " bns+ 1f\n" \
77 " neg %0, %0\n" \
78 "1:\n" \
79 : "=r"(_ret), "+r"(_num), "+r"(_arg2) \
80 : "0"(_arg1) \
81 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5" \
82 ); \
83 _ret; \
84})
85
86
87#define __nolibc_syscall3(num, arg1, arg2, arg3) \
88({ \
89 register long _ret __asm__ ("r3"); \
90 register long _num __asm__ ("r0") = (num); \
91 register long _arg1 __asm__ ("r3") = (long)(arg1); \
92 register long _arg2 __asm__ ("r4") = (long)(arg2); \
93 register long _arg3 __asm__ ("r5") = (long)(arg3); \
94 \
95 __asm__ volatile ( \
96 " sc\n" \
97 " bns+ 1f\n" \
98 " neg %0, %0\n" \
99 "1:\n" \
100 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3) \
101 : "0"(_arg1) \
102 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6" \
103 ); \
104 _ret; \
105})
106
107
108#define __nolibc_syscall4(num, arg1, arg2, arg3, arg4) \
109({ \
110 register long _ret __asm__ ("r3"); \
111 register long _num __asm__ ("r0") = (num); \
112 register long _arg1 __asm__ ("r3") = (long)(arg1); \
113 register long _arg2 __asm__ ("r4") = (long)(arg2); \
114 register long _arg3 __asm__ ("r5") = (long)(arg3); \
115 register long _arg4 __asm__ ("r6") = (long)(arg4); \
116 \
117 __asm__ volatile ( \
118 " sc\n" \
119 " bns+ 1f\n" \
120 " neg %0, %0\n" \
121 "1:\n" \
122 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \
123 "+r"(_arg4) \
124 : "0"(_arg1) \
125 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7" \
126 ); \
127 _ret; \
128})
129
130
131#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
132({ \
133 register long _ret __asm__ ("r3"); \
134 register long _num __asm__ ("r0") = (num); \
135 register long _arg1 __asm__ ("r3") = (long)(arg1); \
136 register long _arg2 __asm__ ("r4") = (long)(arg2); \
137 register long _arg3 __asm__ ("r5") = (long)(arg3); \
138 register long _arg4 __asm__ ("r6") = (long)(arg4); \
139 register long _arg5 __asm__ ("r7") = (long)(arg5); \
140 \
141 __asm__ volatile ( \
142 " sc\n" \
143 " bns+ 1f\n" \
144 " neg %0, %0\n" \
145 "1:\n" \
146 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \
147 "+r"(_arg4), "+r"(_arg5) \
148 : "0"(_arg1) \
149 : _NOLIBC_SYSCALL_CLOBBERLIST, "r8" \
150 ); \
151 _ret; \
152})
153
154#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
155({ \
156 register long _ret __asm__ ("r3"); \
157 register long _num __asm__ ("r0") = (num); \
158 register long _arg1 __asm__ ("r3") = (long)(arg1); \
159 register long _arg2 __asm__ ("r4") = (long)(arg2); \
160 register long _arg3 __asm__ ("r5") = (long)(arg3); \
161 register long _arg4 __asm__ ("r6") = (long)(arg4); \
162 register long _arg5 __asm__ ("r7") = (long)(arg5); \
163 register long _arg6 __asm__ ("r8") = (long)(arg6); \
164 \
165 __asm__ volatile ( \
166 " sc\n" \
167 " bns+ 1f\n" \
168 " neg %0, %0\n" \
169 "1:\n" \
170 : "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3), \
171 "+r"(_arg4), "+r"(_arg5), "+r"(_arg6) \
172 : "0"(_arg1) \
173 : _NOLIBC_SYSCALL_CLOBBERLIST \
174 ); \
175 _ret; \
176})
177
178#if !defined(__powerpc64__) && !defined(__clang__)
179/* FIXME: For 32-bit PowerPC, with newer gcc compilers (e.g. gcc 13.1.0),
180 * "omit-frame-pointer" fails with __attribute__((no_stack_protector)) but
181 * works with __attribute__((__optimize__("-fno-stack-protector")))
182 */
183#ifdef __nolibc_no_stack_protector
184#undef __nolibc_no_stack_protector
185#define __nolibc_no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
186#endif
187#endif /* !__powerpc64__ */
188
189#ifndef NOLIBC_NO_RUNTIME
190/* startup code */
191void __attribute__((weak, noreturn)) __nolibc_entrypoint __nolibc_no_stack_protector _start(void)
192{
193#ifdef __powerpc64__
194#if _CALL_ELF == 2
195 /* with -mabi=elfv2, save TOC/GOT pointer to r2
196 * r12 is global entry pointer, we use it to compute TOC from r12
197 * https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf
198 * https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf
199 */
200 __asm__ volatile (
201 "addis 2, 12, .TOC. - _start@ha\n"
202 "addi 2, 2, .TOC. - _start@l\n"
203 );
204#endif /* _CALL_ELF == 2 */
205
206 __asm__ volatile (
207 "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */
208 "li 0, 0\n" /* zero the frame pointer */
209 "stdu 1, -32(1)\n" /* the initial stack frame */
210 "bl _start_c\n" /* transfer to c runtime */
211 );
212#else
213 __asm__ volatile (
214 "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */
215 "li 0, 0\n" /* zero the frame pointer */
216 "stwu 1, -16(1)\n" /* the initial stack frame */
217 "bl _start_c\n" /* transfer to c runtime */
218 );
219#endif
220 __nolibc_entrypoint_epilogue();
221}
222#endif /* NOLIBC_NO_RUNTIME */
223
224#if !defined(__powerpc64__)
225#define __NOLIBC_PAD_64BIT_SYSCALL_ARGUMENT_PAIR
226#endif
227
228#endif /* _NOLIBC_ARCH_POWERPC_H */