f1c2bb8b99
Until now UML had no x86_64 vDSO. So glibc always used the vsyscall page for gettimeday() and friends. Calls to gettimeday() returned falsely the host time and confused some programs. This patch adds a vDSO which turns all __vdso_* calls into a system call so that UML can trap them. As glibc still uses the vsyscall page for static binaries this patch improves the situation only for dynamic binaries. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
/*
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* Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This vDSO turns all calls into a syscall so that UML can trap them.
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*/
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/* Disable profiling for userspace code */
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#define DISABLE_BRANCH_PROFILING
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#include <linux/time.h>
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#include <linux/getcpu.h>
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#include <asm/unistd.h>
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int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
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{
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long ret;
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asm("syscall" : "=a" (ret) :
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"0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
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return ret;
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}
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int clock_gettime(clockid_t, struct timespec *)
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__attribute__((weak, alias("__vdso_clock_gettime")));
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int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
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{
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long ret;
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asm("syscall" : "=a" (ret) :
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"0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
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return ret;
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}
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int gettimeofday(struct timeval *, struct timezone *)
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__attribute__((weak, alias("__vdso_gettimeofday")));
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time_t __vdso_time(time_t *t)
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{
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long secs;
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asm volatile("syscall"
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: "=a" (secs)
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: "0" (__NR_time), "D" (t) : "cc", "r11", "cx", "memory");
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return secs;
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}
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int time(time_t *t) __attribute__((weak, alias("__vdso_time")));
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long
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__vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
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{
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/*
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* UML does not support SMP, we can cheat here. :)
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*/
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if (cpu)
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*cpu = 0;
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if (node)
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*node = 0;
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return 0;
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}
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long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
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__attribute__((weak, alias("__vdso_getcpu")));
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