80b489ebba
It's unnecessary and it reportedly breaks the build on arm64 GNU/Linux.
Reviewed-on: https://go-review.googlesource.com/30978
From-SVN: r241084
103 lines
3.0 KiB
C
103 lines
3.0 KiB
C
/* clone_linux.c -- consistent wrapper around Linux clone syscall
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Copyright 2016 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include <errno.h>
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#include <sys/syscall.h>
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#include "runtime.h"
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long rawClone (unsigned long flags, void *child_stack, void *ptid,
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void *ctid, void *regs)
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__asm__ (GOSYM_PREFIX "syscall.rawClone")
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__attribute__ ((no_split_stack));
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long
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rawClone (unsigned long flags, void *child_stack, void *ptid, void *ctid, void *regs)
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{
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#if defined(__arc__) || defined(__aarch64__) || defined(__arm__) || defined(__mips__) || defined(__hppa__) || defined(__powerpc__) || defined(__score__) || defined(__i386__) || defined(__xtensa__)
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// CLONE_BACKWARDS
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return syscall(__NR_clone, flags, child_stack, ptid, regs, ctid);
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#elif defined(__s390__) || defined(__cris__)
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// CLONE_BACKWARDS2
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return syscall(__NR_clone, child_stack, flags, ptid, ctid, regs);
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#elif defined(__microblaze__)
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// CLONE_BACKWARDS3
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return syscall(__NR_clone, flags, child_stack, 0, ptid, ctid, regs);
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#elif defined(__sparc__)
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/* SPARC has a unique return value convention:
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Parent --> %o0 == child's pid, %o1 == 0
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Child --> %o0 == parent's pid, %o1 == 1
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Translate this to look like a normal clone. */
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# if defined(__arch64__)
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# define SYSCALL_STRING \
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"ta 0x6d;" \
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"bcc,pt %%xcc, 1f;" \
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" mov 0, %%g1;" \
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"sub %%g0, %%o0, %%o0;" \
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"mov 1, %%g1;" \
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"1:"
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# define SYSCALL_CLOBBERS \
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"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
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"f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
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"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
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"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
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"f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \
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"f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \
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"cc", "memory"
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# else /* __arch64__ */
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# define SYSCALL_STRING \
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"ta 0x10;" \
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"bcc 1f;" \
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" mov 0, %%g1;" \
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"sub %%g0, %%o0, %%o0;" \
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"mov 1, %%g1;" \
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"1:"
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# define SYSCALL_CLOBBERS \
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"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
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"f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
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"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
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"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
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"cc", "memory"
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# endif /* __arch64__ */
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register long o0 __asm__ ("o0") = (long)flags;
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register long o1 __asm__ ("o1") = (long)child_stack;
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register long o2 __asm__ ("o2") = (long)ptid;
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register long o3 __asm__ ("o3") = (long)ctid;
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register long o4 __asm__ ("o4") = (long)regs;
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register long g1 __asm__ ("g1") = __NR_clone;
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__asm __volatile (SYSCALL_STRING :
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"=r" (g1), "=r" (o0), "=r" (o1) :
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"0" (g1), "1" (o0), "2" (o1),
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"r" (o2), "r" (o3), "r" (o4) :
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SYSCALL_CLOBBERS);
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if (__builtin_expect(g1 != 0, 0))
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{
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errno = -o0;
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o0 = -1L;
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}
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else
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o0 &= (o1 - 1);
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return o0;
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#else
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return syscall(__NR_clone, flags, child_stack, ptid, ctid, regs);
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#endif
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}
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