1 /* Assembler macros for 64 bit S/390.
2 Copyright (C) 2001-2023 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 safely 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 lghi %r1,SYS_ify (syscall); \
157 svc 0; \
158 .if args > 5; \
159 lgr %r7,%r0; \
160 .endif
161
162 #define ret \
163 br 14
164
165 #define ret_NOERRNO \
166 br 14
167
168 #define ret_ERRVAL \
169 br 14
170
171 #else
172
173 # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
174 # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
175
176 #endif /* __ASSEMBLER__ */
177
178 #endif /* _LINUX_S390_SYSDEP_H */