1 /* Assembler macros for 64 bit S/390. 2 Copyright (C) 2001-2022 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 _LINUX_S390_SYSDEP_H 20 #define _LINUX_S390_SYSDEP_H 21 22 #include <sysdeps/s390/s390-64/sysdep.h> 23 #include <sysdeps/unix/sysdep.h> 24 #include <sysdeps/unix/sysv/linux/s390/sysdep.h> 25 #include <sysdeps/unix/sysv/linux/sysdep.h> 26 #include <dl-sysdep.h> /* For RTLD_PRIVATE_ERRNO. */ 27 #include <tls.h> 28 29 /* For Linux we can use the system call table in the header file 30 /usr/include/asm/unistd.h 31 of the kernel. But these symbols do not follow the SYS_* syntax 32 so we have to redefine the `SYS_ify' macro here. */ 33 /* In newer 2.1 kernels __NR_syscall is missing so we define it here. */ 34 #define __NR_syscall 0 35 36 #undef SYS_ify 37 #define SYS_ify(syscall_name) __NR_##syscall_name 38 39 #ifdef __ASSEMBLER__ 40 41 /* Linux uses a negative return value to indicate syscall errors, unlike 42 most Unices, which use the condition codes' carry flag. 43 44 Since version 2.1 the return value of a system call might be negative 45 even if the call succeeded. E.g., the `lseek' system call might return 46 a large offset. Therefore we must not anymore test for < 0, but test 47 for a real error by making sure the value in gpr2 is a real error 48 number. Linus said he will make sure that no syscall returns a value 49 in -1 .. -4095 as a valid result so we can savely test with -4095. */ 50 51 #undef PSEUDO 52 #define PSEUDO(name, syscall_name, args) \ 53 .text; \ 54 ENTRY (name) \ 55 DO_CALL (syscall_name, args); \ 56 lghi %r4,-4095 ; \ 57 clgr %r2,%r4 ; \ 58 jgnl SYSCALL_ERROR_LABEL 59 60 #undef PSEUDO_END 61 #define PSEUDO_END(name) \ 62 SYSCALL_ERROR_HANDLER; \ 63 END (name) 64 65 #undef PSEUDO_NOERRNO 66 #define PSEUDO_NOERRNO(name, syscall_name, args) \ 67 .text; \ 68 ENTRY (name) \ 69 DO_CALL (syscall_name, args) 70 71 #undef PSEUDO_END_NOERRNO 72 #define PSEUDO_END_NOERRNO(name) \ 73 SYSCALL_ERROR_HANDLER; \ 74 END (name) 75 76 #undef PSEUDO_ERRVAL 77 #define PSEUDO_ERRVAL(name, syscall_name, args) \ 78 .text; \ 79 ENTRY (name) \ 80 DO_CALL (syscall_name, args); \ 81 lcgr %r2,%r2 82 83 #undef PSEUDO_END_ERRVAL 84 #define PSEUDO_END_ERRVAL(name) \ 85 SYSCALL_ERROR_HANDLER; \ 86 END (name) 87 88 #undef SYSCALL_ERROR_LABEL 89 #ifndef PIC 90 # undef SYSCALL_ERROR_LABEL 91 # define SYSCALL_ERROR_LABEL syscall_error 92 # define SYSCALL_ERROR_HANDLER 93 #else 94 # if RTLD_PRIVATE_ERRNO 95 # undef SYSCALL_ERROR_LABEL 96 # define SYSCALL_ERROR_LABEL 0f 97 # define SYSCALL_ERROR_HANDLER \ 98 0: larl %r1,rtld_errno; \ 99 lcr %r2,%r2; \ 100 st %r2,0(%r1); \ 101 lghi %r2,-1; \ 102 br %r14 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 larl %r1,SYSCALL_ERROR_ERRNO@indntpoff; \ 114 lg %r1,0(%r1); \ 115 ear %r2,%a0; \ 116 sllg %r2,%r2,32; \ 117 ear %r2,%a1; \ 118 st %r0,0(%r1,%r2); \ 119 lghi %r2,-1; \ 120 br %r14 121 # else 122 # undef SYSCALL_ERROR_LABEL 123 # define SYSCALL_ERROR_LABEL 0f 124 # define SYSCALL_ERROR_HANDLER \ 125 0: larl %r1,_GLOBAL_OFFSET_TABLE_; \ 126 lg %r1,errno@GOT(%r1); \ 127 lcr %r2,%r2; \ 128 st %r2,0(%r1); \ 129 lghi %r2,-1; \ 130 br %r14 131 # endif /* _LIBC_REENTRANT */ 132 #endif /* PIC */ 133 134 /* Linux takes system call arguments in registers: 135 136 syscall number 1 call-clobbered 137 arg 1 2 call-clobbered 138 arg 2 3 call-clobbered 139 arg 3 4 call-clobbered 140 arg 4 5 call-clobbered 141 arg 5 6 call-saved 142 arg 6 7 call-saved 143 144 (Of course a function with say 3 arguments does not have entries for 145 arguments 4 and 5.) 146 For system calls with 6 parameters a stack operation is required 147 to load the 6th parameter to register 7. Call saved register 7 is 148 moved to register 0 and back to avoid an additional stack frame. 149 */ 150 151 #define DO_CALL(syscall, args) \ 152 .if args > 5; \ 153 lgr %r0,%r7; \ 154 lg %r7,160(%r15); \ 155 .endif; \ 156 .if SYS_ify (syscall) < 256; \ 157 svc SYS_ify (syscall); \ 158 .else; \ 159 lghi %r1,SYS_ify (syscall); \ 160 svc 0; \ 161 .endif; \ 162 .if args > 5; \ 163 lgr %r7,%r0; \ 164 .endif 165 166 #define ret \ 167 br 14 168 169 #define ret_NOERRNO \ 170 br 14 171 172 #define ret_ERRVAL \ 173 br 14 174 175 #else 176 177 # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL 178 # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1 179 180 #endif /* __ASSEMBLER__ */ 181 182 /* Pointer mangling support. */ 183 #if IS_IN (rtld) 184 /* We cannot use the thread descriptor because in ld.so we use setjmp 185 earlier than the descriptor is initialized. */ 186 #else 187 /* For the time being just use stack_guard rather than a separate 188 pointer_guard. */ 189 # ifdef __ASSEMBLER__ 190 # define PTR_MANGLE(reg, tmpreg) \ 191 ear tmpreg,%a0; \ 192 sllg tmpreg,tmpreg,32; \ 193 ear tmpreg,%a1; \ 194 xg reg,STACK_GUARD(tmpreg) 195 # define PTR_MANGLE2(reg, tmpreg) \ 196 xg 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