1 /* clone_linux.c -- consistent wrapper around Linux clone syscall
2
3 Copyright 2016 The Go Authors. All rights reserved.
4 Use of this source code is governed by a BSD-style
5 license that can be found in the LICENSE file. */
6
7 #include <errno.h>
8 #include <sys/syscall.h>
9
10 #include "runtime.h"
11
12 long rawClone (unsigned long flags, void *child_stack, void *ptid,
13 void *ctid, void *regs)
14 __asm__ (GOSYM_PREFIX "syscall.rawClone")
15 __attribute__ ((no_split_stack));
16
17 long
rawClone(unsigned long flags,void * child_stack,void * ptid,void * ctid,void * regs)18 rawClone (unsigned long flags, void *child_stack, void *ptid, void *ctid, void *regs)
19 {
20 #if defined(__arc__) || defined(__aarch64__) || defined(__arm__) || defined(__mips__) || defined(__hppa__) || defined(__powerpc__) || defined(__score__) || defined(__i386__) || defined(__xtensa__)
21 // CLONE_BACKWARDS
22 return syscall(__NR_clone, flags, child_stack, ptid, regs, ctid);
23 #elif defined(__s390__) || defined(__cris__)
24 // CLONE_BACKWARDS2
25 return syscall(__NR_clone, child_stack, flags, ptid, ctid, regs);
26 #elif defined(__microblaze__)
27 // CLONE_BACKWARDS3
28 return syscall(__NR_clone, flags, child_stack, 0, ptid, ctid, regs);
29 #elif defined(__sparc__)
30
31 /* SPARC has a unique return value convention:
32
33 Parent --> %o0 == child's pid, %o1 == 0
34 Child --> %o0 == parent's pid, %o1 == 1
35
36 Translate this to look like a normal clone. */
37
38 # if defined(__arch64__)
39
40 # define SYSCALL_STRING \
41 "ta 0x6d;" \
42 "bcc,pt %%xcc, 1f;" \
43 " mov 0, %%g1;" \
44 "sub %%g0, %%o0, %%o0;" \
45 "mov 1, %%g1;" \
46 "1:"
47
48 # define SYSCALL_CLOBBERS \
49 "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
50 "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
51 "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
52 "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
53 "f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \
54 "f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \
55 "cc", "memory"
56
57 # else /* __arch64__ */
58
59 # define SYSCALL_STRING \
60 "ta 0x10;" \
61 "bcc 1f;" \
62 " mov 0, %%g1;" \
63 "sub %%g0, %%o0, %%o0;" \
64 "mov 1, %%g1;" \
65 "1:"
66
67 # define SYSCALL_CLOBBERS \
68 "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
69 "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
70 "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
71 "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
72 "cc", "memory"
73
74 # endif /* __arch64__ */
75
76 register long o0 __asm__ ("o0") = (long)flags;
77 register long o1 __asm__ ("o1") = (long)child_stack;
78 register long o2 __asm__ ("o2") = (long)ptid;
79 register long o3 __asm__ ("o3") = (long)ctid;
80 register long o4 __asm__ ("o4") = (long)regs;
81 register long g1 __asm__ ("g1") = __NR_clone;
82
83 __asm __volatile (SYSCALL_STRING :
84 "=r" (g1), "=r" (o0), "=r" (o1) :
85 "0" (g1), "1" (o0), "2" (o1),
86 "r" (o2), "r" (o3), "r" (o4) :
87 SYSCALL_CLOBBERS);
88
89 if (__builtin_expect(g1 != 0, 0))
90 {
91 errno = -o0;
92 o0 = -1L;
93 }
94 else
95 o0 &= (o1 - 1);
96
97 return o0;
98
99 #else
100 return syscall(__NR_clone, flags, child_stack, ptid, ctid, regs);
101 #endif
102 }
103