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4fbba6fe90
According to [gcc documentation][1], temporary variables must be used for
the desired content to not be call-clobbered.
Fix the Linux inline syscall templates by adding temporary variables,
much like what x86 did before
(commit 381a0c26d7).
Tested with gcc 9.2.0, both cross-compiled and natively on Loongson
3A4000.
[1]: https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html
329 lines
11 KiB
C
329 lines
11 KiB
C
/* Copyright (C) 2000-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _LINUX_MIPS_SYSDEP_H
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#define _LINUX_MIPS_SYSDEP_H 1
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/* There is some commonality. */
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#include <sysdeps/unix/sysv/linux/mips/sysdep.h>
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#include <sysdeps/unix/sysv/linux/sysdep.h>
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#include <sysdeps/unix/mips/mips64/n64/sysdep.h>
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#include <tls.h>
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/* In order to get __set_errno() definition in INLINE_SYSCALL. */
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#ifndef __ASSEMBLER__
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#include <errno.h>
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#endif
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/* For Linux we can use the system call table in the header file
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/usr/include/asm/unistd.h
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of the kernel. But these symbols do not follow the SYS_* syntax
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so we have to redefine the `SYS_ify' macro here. */
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#undef SYS_ify
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#define SYS_ify(syscall_name) __NR_##syscall_name
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#ifdef __ASSEMBLER__
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/* We don't want the label for the error handler to be visible in the symbol
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table when we define it here. */
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# define SYSCALL_ERROR_LABEL 99b
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#else /* ! __ASSEMBLER__ */
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/* Define a macro which expands into the inline wrapper code for a system
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call. */
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#undef INLINE_SYSCALL
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#define INLINE_SYSCALL(name, nr, args...) \
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({ INTERNAL_SYSCALL_DECL (_sc_err); \
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long int result_var = INTERNAL_SYSCALL (name, _sc_err, nr, args); \
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if ( INTERNAL_SYSCALL_ERROR_P (result_var, _sc_err) ) \
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{ \
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__set_errno (INTERNAL_SYSCALL_ERRNO (result_var, _sc_err)); \
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result_var = -1L; \
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} \
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result_var; })
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#undef INTERNAL_SYSCALL_DECL
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#define INTERNAL_SYSCALL_DECL(err) long int err __attribute__ ((unused))
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#undef INTERNAL_SYSCALL_ERROR_P
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#define INTERNAL_SYSCALL_ERROR_P(val, err) ((void) (val), (long int) (err))
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#undef INTERNAL_SYSCALL_ERRNO
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#define INTERNAL_SYSCALL_ERRNO(val, err) ((void) (err), val)
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/* Note that the original Linux syscall restart convention required the
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instruction immediately preceding SYSCALL to initialize $v0 with the
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syscall number. Then if a restart triggered, $v0 would have been
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clobbered by the syscall interrupted, and needed to be reinititalized.
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The kernel would decrement the PC by 4 before switching back to the
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user mode so that $v0 had been reloaded before SYSCALL was executed
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again. This implied the place $v0 was loaded from must have been
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preserved across a syscall, e.g. an immediate, static register, stack
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slot, etc.
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The convention was relaxed in Linux with a change applied to the kernel
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GIT repository as commit 96187fb0bc30cd7919759d371d810e928048249d, that
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first appeared in the 2.6.36 release. Since then the kernel has had
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code that reloads $v0 upon syscall restart and resumes right at the
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SYSCALL instruction, so no special arrangement is needed anymore.
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For backwards compatibility with existing kernel binaries we support
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the old convention by choosing the instruction preceding SYSCALL
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carefully. This also means we have to force a 32-bit encoding of the
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microMIPS MOVE instruction if one is used. */
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#ifdef __mips_micromips
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# define MOVE32 "move32"
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#else
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# define MOVE32 "move"
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#endif
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#undef INTERNAL_SYSCALL
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#define INTERNAL_SYSCALL(name, err, nr, args...) \
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internal_syscall##nr ("li\t%0, %2\t\t\t# " #name "\n\t", \
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"IK" (SYS_ify (name)), \
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0, err, args)
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#undef INTERNAL_SYSCALL_NCS
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#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
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internal_syscall##nr (MOVE32 "\t%0, %2\n\t", \
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"r" (__s0), \
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number, err, args)
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#define internal_syscall0(v0_init, input, number, err, dummy...) \
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({ \
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long int _sys_result; \
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\
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{ \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a3 asm ("$7"); \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set reorder" \
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: "=r" (__v0), "=r" (__a3) \
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: input \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#define internal_syscall1(v0_init, input, number, err, arg1) \
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({ \
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long int _sys_result; \
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\
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{ \
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long int _arg1 = (long int) (arg1); \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a0 asm ("$4") = _arg1; \
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register long int __a3 asm ("$7"); \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set reorder" \
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: "=r" (__v0), "=r" (__a3) \
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: input, "r" (__a0) \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#define internal_syscall2(v0_init, input, number, err, arg1, arg2) \
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({ \
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long int _sys_result; \
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\
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{ \
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long int _arg1 = (long int) (arg1); \
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long int _arg2 = (long int) (arg2); \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a0 asm ("$4") = _arg1; \
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register long int __a1 asm ("$5") = _arg2; \
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register long int __a3 asm ("$7"); \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set\treorder" \
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: "=r" (__v0), "=r" (__a3) \
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: input, "r" (__a0), "r" (__a1) \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#define internal_syscall3(v0_init, input, number, err, \
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arg1, arg2, arg3) \
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({ \
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long int _sys_result; \
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\
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{ \
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long int _arg1 = (long int) (arg1); \
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long int _arg2 = (long int) (arg2); \
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long int _arg3 = (long int) (arg3); \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a0 asm ("$4") = _arg1; \
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register long int __a1 asm ("$5") = _arg2; \
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register long int __a2 asm ("$6") = _arg3; \
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register long int __a3 asm ("$7"); \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set\treorder" \
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: "=r" (__v0), "=r" (__a3) \
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: input, "r" (__a0), "r" (__a1), "r" (__a2) \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#define internal_syscall4(v0_init, input, number, err, \
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arg1, arg2, arg3, arg4) \
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({ \
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long int _sys_result; \
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\
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{ \
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long int _arg1 = (long int) (arg1); \
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long int _arg2 = (long int) (arg2); \
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long int _arg3 = (long int) (arg3); \
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long int _arg4 = (long int) (arg4); \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a0 asm ("$4") = _arg1; \
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register long int __a1 asm ("$5") = _arg2; \
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register long int __a2 asm ("$6") = _arg3; \
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register long int __a3 asm ("$7") = _arg4; \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set\treorder" \
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: "=r" (__v0), "+r" (__a3) \
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: input, "r" (__a0), "r" (__a1), "r" (__a2) \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#define internal_syscall5(v0_init, input, number, err, \
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arg1, arg2, arg3, arg4, arg5) \
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({ \
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long int _sys_result; \
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\
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{ \
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long int _arg1 = (long int) (arg1); \
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long int _arg2 = (long int) (arg2); \
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long int _arg3 = (long int) (arg3); \
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long int _arg4 = (long int) (arg4); \
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long int _arg5 = (long int) (arg5); \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a0 asm ("$4") = _arg1; \
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register long int __a1 asm ("$5") = _arg2; \
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register long int __a2 asm ("$6") = _arg3; \
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register long int __a3 asm ("$7") = _arg4; \
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register long int __a4 asm ("$8") = _arg5; \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set\treorder" \
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: "=r" (__v0), "+r" (__a3) \
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: input, "r" (__a0), "r" (__a1), "r" (__a2), "r" (__a4) \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#define internal_syscall6(v0_init, input, number, err, \
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arg1, arg2, arg3, arg4, arg5, arg6) \
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({ \
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long int _sys_result; \
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\
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{ \
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long int _arg1 = (long int) (arg1); \
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long int _arg2 = (long int) (arg2); \
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long int _arg3 = (long int) (arg3); \
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long int _arg4 = (long int) (arg4); \
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long int _arg5 = (long int) (arg5); \
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long int _arg6 = (long int) (arg6); \
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register long int __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long int __v0 asm ("$2"); \
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register long int __a0 asm ("$4") = _arg1; \
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register long int __a1 asm ("$5") = _arg2; \
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register long int __a2 asm ("$6") = _arg3; \
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register long int __a3 asm ("$7") = _arg4; \
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register long int __a4 asm ("$8") = _arg5; \
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register long int __a5 asm ("$9") = _arg6; \
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__asm__ volatile ( \
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".set\tnoreorder\n\t" \
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v0_init \
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"syscall\n\t" \
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".set\treorder" \
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: "=r" (__v0), "+r" (__a3) \
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: input, "r" (__a0), "r" (__a1), "r" (__a2), "r" (__a4), \
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"r" (__a5) \
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: __SYSCALL_CLOBBERS); \
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err = __a3; \
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_sys_result = __v0; \
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} \
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_sys_result; \
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})
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#if __mips_isa_rev >= 6
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# define __SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12", "$13", \
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"$14", "$15", "$24", "$25", "memory"
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#else
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# define __SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12", "$13", \
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"$14", "$15", "$24", "$25", "hi", "lo", "memory"
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#endif
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#endif /* __ASSEMBLER__ */
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/* Pointer mangling is not yet supported for MIPS. */
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#define PTR_MANGLE(var) (void) (var)
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#define PTR_DEMANGLE(var) (void) (var)
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#endif /* linux/mips/sysdep.h */
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