1 /* Copyright (C) 2000-2022 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 #ifndef _LINUX_S390_SYSDEP_H 19 #define _LINUX_S390_SYSDEP_H 20 21 #include <sysdeps/s390/s390-32/sysdep.h> 22 #include <sysdeps/unix/sysdep.h> 23 #include <sysdeps/unix/sysv/linux/s390/sysdep.h> 24 #include <sysdeps/unix/sysv/linux/sysdep.h> 25 #include <dl-sysdep.h> /* For RTLD_PRIVATE_ERRNO. */ 26 #include <tls.h> 27 28 /* For Linux we can use the system call table in the header file 29 /usr/include/asm/unistd.h 30 of the kernel. But these symbols do not follow the SYS_* syntax 31 so we have to redefine the `SYS_ify' macro here. */ 32 /* in newer 2.1 kernels __NR_syscall is missing so we define it here */ 33 #define __NR_syscall 0 34 35 #ifdef __ASSEMBLER__ 36 37 /* Linux uses a negative return value to indicate syscall errors, unlike 38 most Unices, which use the condition codes' carry flag. 39 40 Since version 2.1 the return value of a system call might be negative 41 even if the call succeeded. E.g., the `lseek' system call might return 42 a large offset. Therefore we must not anymore test for < 0, but test 43 for a real error by making sure the value in gpr2 is a real error 44 number. Linus said he will make sure that no syscall returns a value 45 in -1 .. -4095 as a valid result so we can savely test with -4095. */ 46 47 #undef PSEUDO 48 #define PSEUDO(name, syscall_name, args) \ 49 .text; \ 50 ENTRY (name) \ 51 DO_CALL (syscall_name, args); \ 52 lhi %r4,-4095 ; \ 53 clr %r2,%r4 ; \ 54 jnl SYSCALL_ERROR_LABEL 55 56 #undef PSEUDO_END 57 #define PSEUDO_END(name) \ 58 SYSCALL_ERROR_HANDLER; \ 59 END (name) 60 61 #undef PSEUDO_NOERRNO 62 #define PSEUDO_NOERRNO(name, syscall_name, args) \ 63 .text; \ 64 ENTRY (name) \ 65 DO_CALL (syscall_name, args) 66 67 #undef PSEUDO_END_NOERRNO 68 #define PSEUDO_END_NOERRNO(name) \ 69 END (name) 70 71 #undef PSEUDO_ERRVAL 72 #define PSEUDO_ERRVAL(name, syscall_name, args) \ 73 .text; \ 74 ENTRY (name) \ 75 DO_CALL (syscall_name, args); \ 76 lcr %r2,%r2 77 78 #undef PSEUDO_END_ERRVAL 79 #define PSEUDO_END_ERRVAL(name) \ 80 END (name) 81 82 #undef SYSCALL_ERROR_LABEL 83 #ifndef PIC 84 # undef SYSCALL_ERROR_LABEL 85 # define SYSCALL_ERROR_LABEL 0f 86 # define SYSCALL_ERROR_HANDLER \ 87 0: basr %r1,0; \ 88 1: l %r1,2f-1b(%r1); \ 89 br %r1; \ 90 2: .long syscall_error 91 #else 92 # if RTLD_PRIVATE_ERRNO 93 # undef SYSCALL_ERROR_LABEL 94 # define SYSCALL_ERROR_LABEL 0f 95 # define SYSCALL_ERROR_HANDLER \ 96 0: basr %r1,0; \ 97 1: al %r1,2f-1b(%r1); \ 98 lcr %r2,%r2; \ 99 st %r2,0(%r1); \ 100 lhi %r2,-1; \ 101 br %r14; \ 102 2: .long rtld_errno-1b 103 # elif defined _LIBC_REENTRANT 104 # if IS_IN (libc) 105 # define SYSCALL_ERROR_ERRNO __libc_errno 106 # else 107 # define SYSCALL_ERROR_ERRNO errno 108 # endif 109 # undef SYSCALL_ERROR_LABEL 110 # define SYSCALL_ERROR_LABEL 0f 111 # define SYSCALL_ERROR_HANDLER \ 112 0: lcr %r0,%r2; \ 113 basr %r1,0; \ 114 1: al %r1,2f-1b(%r1); \ 115 l %r1,SYSCALL_ERROR_ERRNO@gotntpoff(%r1); \ 116 ear %r2,%a0; \ 117 st %r0,0(%r1,%r2); \ 118 lhi %r2,-1; \ 119 br %r14; \ 120 2: .long _GLOBAL_OFFSET_TABLE_-1b 121 # else 122 # undef SYSCALL_ERROR_LABEL 123 # define SYSCALL_ERROR_LABEL 0f 124 # define SYSCALL_ERROR_HANDLER \ 125 0: basr %r1,0; \ 126 1: al %r1,2f-1b(%r1); \ 127 l %r1,errno@GOT(%r1); \ 128 lcr %r2,%r2; \ 129 st %r2,0(%r1); \ 130 lhi %r2,-1; \ 131 br %r14; \ 132 2: .long _GLOBAL_OFFSET_TABLE_-1b 133 # endif /* _LIBC_REENTRANT */ 134 #endif /* PIC */ 135 136 /* Linux takes system call arguments in registers: 137 138 syscall number 1 call-clobbered 139 arg 1 2 call-clobbered 140 arg 2 3 call-clobbered 141 arg 3 4 call-clobbered 142 arg 4 5 call-clobbered 143 arg 5 6 call-saved 144 arg 6 7 call-saved 145 146 (Of course a function with say 3 arguments does not have entries for 147 arguments 4 and 5.) 148 For system calls with 6 parameters a stack operation is required 149 to load the 6th parameter to register 7. Call saved register 7 is 150 moved to register 0 and back to avoid an additional stack frame. 151 */ 152 153 #define DO_CALL(syscall, args) \ 154 .if args > 5; \ 155 lr %r0,%r7; \ 156 l %r7,96(%r15); \ 157 .endif; \ 158 .if SYS_ify (syscall) < 256; \ 159 svc SYS_ify (syscall); \ 160 .else; \ 161 lhi %r1,SYS_ify (syscall); \ 162 svc 0; \ 163 .endif; \ 164 .if args > 5; \ 165 lr %r7,%r0; \ 166 .endif 167 168 #define ret \ 169 br 14 170 171 #define ret_NOERRNO \ 172 br 14 173 174 #define ret_ERRVAL \ 175 br 14 176 177 #else 178 179 # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL 180 # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1 181 182 #endif /* __ASSEMBLER__ */ 183 184 /* Pointer mangling support. */ 185 #if IS_IN (rtld) 186 /* We cannot use the thread descriptor because in ld.so we use setjmp 187 earlier than the descriptor is initialized. */ 188 #else 189 /* For the time being just use stack_guard rather than a separate 190 pointer_guard. */ 191 # ifdef __ASSEMBLER__ 192 # define PTR_MANGLE(reg, tmpreg) \ 193 ear tmpreg,%a0; \ 194 x reg,STACK_GUARD(tmpreg) 195 # define PTR_MANGLE2(reg, tmpreg) \ 196 x reg,STACK_GUARD(tmpreg) 197 # define PTR_DEMANGLE(reg, tmpreg) PTR_MANGLE (reg, tmpreg) 198 # else 199 # define PTR_MANGLE(var) \ 200 (var) = (void *) ((uintptr_t) (var) ^ THREAD_GET_POINTER_GUARD ()) 201 # define PTR_DEMANGLE(var) PTR_MANGLE (var) 202 # endif 203 #endif 204 205 #endif /* _LINUX_S390_SYSDEP_H */ 206