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b39d84adff
This patch adds support for using the implementations of gettimeofday()
and clock_gettime() provided by the kernel in the VDSO. The VDSO will
always provide clock_gettime() as CLOCK_{REALTIME,MONOTONIC}_COARSE can
be implemented regardless of platform. CLOCK_{REALTIME,MONOTONIC}, along
with gettimeofday(), are only implemented on platforms which make use of
either the CP0 count or GIC as their clocksource. On other platforms,
the VDSO does not provide the __vdso_gettimeofday symbol, as it is
never useful.
The VDSO functions return ENOSYS when they encounter an unsupported
request, in which case glibc should fall back to the standard syscall.
Tested with upstream kernel 4.5 and QEMU emulating Malta.
./vdsotest gettimeofday bench
gettimeofday: syscall: 1021 nsec/call
gettimeofday: libc: 262 nsec/call
gettimeofday: vdso: 174 nsec/call
* sysdeps/unix/sysv/linux/mips/Makefile (sysdep_routines):
Include dl-vdso.
* sysdeps/unix/sysv/linux/mips/Versions: Add
__vdso_clock_gettime.
* sysdeps/unix/sysv/linux/mips/init-first.c: New file.
* sysdeps/unix/sysv/linux/mips/libc-vdso.h: New file.
* sysdeps/unix/sysv/linux/mips/mips32/sysdep.h:
(INTERNAL_VSYSCALL_CALL): Define to be compatible with MIPS
definitions of INTERNAL_SYSCALL_{ERROR_P,ERRNO}.
(HAVE_CLOCK_GETTIME_VSYSCALL): Define.
(HAVE_GETTIMEOFDAY_VSYSCALL): Define.
* sysdeps/unix/sysv/linux/mips/mips64/n32/sysdep.h: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/sysdep.h: Likewise.
322 lines
10 KiB
C
322 lines
10 KiB
C
/* Copyright (C) 2000-2016 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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<http://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/sysdep.h>
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#include <sysdeps/unix/mips/mips64/n32/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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/* Convert X to a long long, without losing any bits if it is one
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already or warning if it is a 32-bit pointer. */
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#define ARGIFY(X) ((long long) (__typeof__ ((X) - (X))) (X))
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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 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 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) (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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __a0 asm ("$4") = ARGIFY (arg1); \
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register long long __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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __a0 asm ("$4") = ARGIFY (arg1); \
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register long long __a1 asm ("$5") = ARGIFY (arg2); \
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register long long __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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __a0 asm ("$4") = ARGIFY (arg1); \
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register long long __a1 asm ("$5") = ARGIFY (arg2); \
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register long long __a2 asm ("$6") = ARGIFY (arg3); \
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register long long __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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __a0 asm ("$4") = ARGIFY (arg1); \
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register long long __a1 asm ("$5") = ARGIFY (arg2); \
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register long long __a2 asm ("$6") = ARGIFY (arg3); \
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register long long __a3 asm ("$7") = ARGIFY (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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __a0 asm ("$4") = ARGIFY (arg1); \
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register long long __a1 asm ("$5") = ARGIFY (arg2); \
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register long long __a2 asm ("$6") = ARGIFY (arg3); \
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register long long __a3 asm ("$7") = ARGIFY (arg4); \
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register long long __a4 asm ("$8") = ARGIFY (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 _sys_result; \
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\
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{ \
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register long long __s0 asm ("$16") __attribute__ ((unused)) \
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= (number); \
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register long long __v0 asm ("$2"); \
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register long long __a0 asm ("$4") = ARGIFY (arg1); \
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register long long __a1 asm ("$5") = ARGIFY (arg2); \
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register long long __a2 asm ("$6") = ARGIFY (arg3); \
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register long long __a3 asm ("$7") = ARGIFY (arg4); \
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register long long __a4 asm ("$8") = ARGIFY (arg5); \
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register long long __a5 asm ("$9") = ARGIFY (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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#define __SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12", "$13", \
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"$14", "$15", "$24", "$25", "hi", "lo", "memory"
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/* Standard MIPS syscalls have an error flag, and return a positive errno
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when the error flag is set. Emulate this behaviour for vsyscalls so that
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the INTERNAL_SYSCALL_{ERROR_P,ERRNO} macros work correctly. */
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#define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...) \
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({ \
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long _ret = funcptr (args); \
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err = ((unsigned long) (_ret) >= (unsigned long) -4095L); \
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if (err) \
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_ret = -_ret; \
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_ret; \
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})
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/* List of system calls which are supported as vsyscalls. */
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#define HAVE_CLOCK_GETTIME_VSYSCALL 1
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#define HAVE_GETTIMEOFDAY_VSYSCALL 1
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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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