x86_64: prepare shared kernel/vsyscall.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 0 insertions, 349 deletions

diff --git a/arch/x86_64/kernel/vsyscall.c b/arch/x86_64/kernel/vsyscall.c
deleted file mode 100644
index 06c34949bfdc..000000000000
--- a/arch/x86_64/kernel/vsyscall.c
+++ /dev/null
@@ -1,349 +0,0 @@
-/*
- *  linux/arch/x86_64/kernel/vsyscall.c
- *
- *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- *  Copyright 2003 Andi Kleen, SuSE Labs.
- *
- *  Thanks to hpa@transmeta.com for some useful hint.
- *  Special thanks to Ingo Molnar for his early experience with
- *  a different vsyscall implementation for Linux/IA32 and for the name.
- *
- *  vsyscall 1 is located at -10Mbyte, vsyscall 2 is located
- *  at virtual address -10Mbyte+1024bytes etc... There are at max 4
- *  vsyscalls. One vsyscall can reserve more than 1 slot to avoid
- *  jumping out of line if necessary. We cannot add more with this
- *  mechanism because older kernels won't return -ENOSYS.
- *  If we want more than four we need a vDSO.
- *
- *  Note: the concept clashes with user mode linux. If you use UML and
- *  want per guest time just set the kernel.vsyscall64 sysctl to 0.
- */
-
-#include <linux/time.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/timer.h>
-#include <linux/seqlock.h>
-#include <linux/jiffies.h>
-#include <linux/sysctl.h>
-#include <linux/clocksource.h>
-#include <linux/getcpu.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-#include <linux/notifier.h>
-
-#include <asm/vsyscall.h>
-#include <asm/pgtable.h>
-#include <asm/page.h>
-#include <asm/unistd.h>
-#include <asm/fixmap.h>
-#include <asm/errno.h>
-#include <asm/io.h>
-#include <asm/segment.h>
-#include <asm/desc.h>
-#include <asm/topology.h>
-#include <asm/vgtod.h>
-
-#define __vsyscall(nr) __attribute__ ((unused,__section__(".vsyscall_" #nr)))
-#define __syscall_clobber "r11","rcx","memory"
-#define __pa_vsymbol(x)                 \
-        ({unsigned long v;              \
-        extern char __vsyscall_0;       \
-          asm("" : "=r" (v) : "0" (x)); \
-          ((v - VSYSCALL_FIRST_PAGE) + __pa_symbol(&__vsyscall_0)); })
-
-/*
- * vsyscall_gtod_data contains data that is :
- * - readonly from vsyscalls
- * - writen by timer interrupt or systcl (/proc/sys/kernel/vsyscall64)
- * Try to keep this structure as small as possible to avoid cache line ping pongs
- */
-int __vgetcpu_mode __section_vgetcpu_mode;
-
-struct vsyscall_gtod_data __vsyscall_gtod_data __section_vsyscall_gtod_data =
-{
-        .lock = SEQLOCK_UNLOCKED,
-        .sysctl_enabled = 1,
-};
-
-void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
-{
-        unsigned long flags;
-
-        write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
-        /* copy vsyscall data */
-        vsyscall_gtod_data.clock.vread = clock->vread;
-        vsyscall_gtod_data.clock.cycle_last = clock->cycle_last;
-        vsyscall_gtod_data.clock.mask = clock->mask;
-        vsyscall_gtod_data.clock.mult = clock->mult;
-        vsyscall_gtod_data.clock.shift = clock->shift;
-        vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec;
-        vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
-        vsyscall_gtod_data.sys_tz = sys_tz;
-        vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
-        vsyscall_gtod_data.wall_to_monotonic = wall_to_monotonic;
-        write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
-}
-
-/* RED-PEN may want to readd seq locking, but then the variable should be
- * write-once.
- */
-static __always_inline void do_get_tz(struct timezone * tz)
-{
-        *tz = __vsyscall_gtod_data.sys_tz;
-}
-
-static __always_inline int gettimeofday(struct timeval *tv, struct timezone *tz)
-{
-        int ret;
-        asm volatile("vsysc2: syscall"
-                : "=a" (ret)
-                : "0" (__NR_gettimeofday),"D" (tv),"S" (tz)
-                : __syscall_clobber );
-        return ret;
-}
-
-static __always_inline long time_syscall(long *t)
-{
-        long secs;
-        asm volatile("vsysc1: syscall"
-                : "=a" (secs)
-                : "0" (__NR_time),"D" (t) : __syscall_clobber);
-        return secs;
-}
-
-static __always_inline void do_vgettimeofday(struct timeval * tv)
-{
-        cycle_t now, base, mask, cycle_delta;
-        unsigned seq;
-        unsigned long mult, shift, nsec;
-        cycle_t (*vread)(void);
-        do {
-                seq = read_seqbegin(&__vsyscall_gtod_data.lock);
-
-                vread = __vsyscall_gtod_data.clock.vread;
-                if (unlikely(!__vsyscall_gtod_data.sysctl_enabled || !vread)) {
-                        gettimeofday(tv,NULL);
-                        return;
-                }
-                now = vread();
-                base = __vsyscall_gtod_data.clock.cycle_last;
-                mask = __vsyscall_gtod_data.clock.mask;
-                mult = __vsyscall_gtod_data.clock.mult;
-                shift = __vsyscall_gtod_data.clock.shift;
-
-                tv->tv_sec = __vsyscall_gtod_data.wall_time_sec;
-                nsec = __vsyscall_gtod_data.wall_time_nsec;
-        } while (read_seqretry(&__vsyscall_gtod_data.lock, seq));
-
-        /* calculate interval: */
-        cycle_delta = (now - base) & mask;
-        /* convert to nsecs: */
-        nsec += (cycle_delta * mult) >> shift;
-
-        while (nsec >= NSEC_PER_SEC) {
-                tv->tv_sec += 1;
-                nsec -= NSEC_PER_SEC;
-        }
-        tv->tv_usec = nsec / NSEC_PER_USEC;
-}
-
-int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
-{
-        if (tv)
-                do_vgettimeofday(tv);
-        if (tz)
-                do_get_tz(tz);
-        return 0;
-}
-
-/* This will break when the xtime seconds get inaccurate, but that is
- * unlikely */
-time_t __vsyscall(1) vtime(time_t *t)
-{
-        struct timeval tv;
-        time_t result;
-        if (unlikely(!__vsyscall_gtod_data.sysctl_enabled))
-                return time_syscall(t);
-
-        vgettimeofday(&tv, 0);
-        result = tv.tv_sec;
-        if (t)
-                *t = result;
-        return result;
-}
-
-/* Fast way to get current CPU and node.
-   This helps to do per node and per CPU caches in user space.
-   The result is not guaranteed without CPU affinity, but usually
-   works out because the scheduler tries to keep a thread on the same
-   CPU.
-
-   tcache must point to a two element sized long array.
-   All arguments can be NULL. */
-long __vsyscall(2)
-vgetcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
-{
-        unsigned int dummy, p;
-        unsigned long j = 0;
-
-        /* Fast cache - only recompute value once per jiffies and avoid
-           relatively costly rdtscp/cpuid otherwise.
-           This works because the scheduler usually keeps the process
-           on the same CPU and this syscall doesn't guarantee its
-           results anyways.
-           We do this here because otherwise user space would do it on
-           its own in a likely inferior way (no access to jiffies).
-           If you don't like it pass NULL. */
-        if (tcache && tcache->blob[0] == (j = __jiffies)) {
-                p = tcache->blob[1];
-        } else if (__vgetcpu_mode == VGETCPU_RDTSCP) {
-                /* Load per CPU data from RDTSCP */
-                rdtscp(dummy, dummy, p);
-        } else {
-                /* Load per CPU data from GDT */
-                asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
-        }
-        if (tcache) {
-                tcache->blob[0] = j;
-                tcache->blob[1] = p;
-        }
-        if (cpu)
-                *cpu = p & 0xfff;
-        if (node)
-                *node = p >> 12;
-        return 0;
-}
-
-long __vsyscall(3) venosys_1(void)
-{
-        return -ENOSYS;
-}
-
-#ifdef CONFIG_SYSCTL
-
-#define SYSCALL 0x050f
-#define NOP2    0x9090
-
-/*
- * NOP out syscall in vsyscall page when not needed.
- */
-static int vsyscall_sysctl_change(ctl_table *ctl, int write, struct file * filp,
-                        void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-        extern u16 vsysc1, vsysc2;
-        u16 __iomem *map1;
-        u16 __iomem *map2;
-        int ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
-        if (!write)
-                return ret;
-        /* gcc has some trouble with __va(__pa()), so just do it this
-           way. */
-        map1 = ioremap(__pa_vsymbol(&vsysc1), 2);
-        if (!map1)
-                return -ENOMEM;
-        map2 = ioremap(__pa_vsymbol(&vsysc2), 2);
-        if (!map2) {
-                ret = -ENOMEM;
-                goto out;
-        }
-        if (!vsyscall_gtod_data.sysctl_enabled) {
-                writew(SYSCALL, map1);
-                writew(SYSCALL, map2);
-        } else {
-                writew(NOP2, map1);
-                writew(NOP2, map2);
-        }
-        iounmap(map2);
-out:
-        iounmap(map1);
-        return ret;
-}
-
-static int vsyscall_sysctl_nostrat(ctl_table *t, int __user *name, int nlen,
-                                void __user *oldval, size_t __user *oldlenp,
-                                void __user *newval, size_t newlen)
-{
-        return -ENOSYS;
-}
-
-static ctl_table kernel_table2[] = {
-        { .ctl_name = 99, .procname = "vsyscall64",
-          .data = &vsyscall_gtod_data.sysctl_enabled, .maxlen = sizeof(int),
-          .mode = 0644,
-          .strategy = vsyscall_sysctl_nostrat,
-          .proc_handler = vsyscall_sysctl_change },
-        {}
-};
-
-static ctl_table kernel_root_table2[] = {
-        { .ctl_name = CTL_KERN, .procname = "kernel", .mode = 0555,
-          .child = kernel_table2 },
-        {}
-};
-
-#endif
-
-/* Assume __initcall executes before all user space. Hopefully kmod
-   doesn't violate that. We'll find out if it does. */
-static void __cpuinit vsyscall_set_cpu(int cpu)
-{
-        unsigned long *d;
-        unsigned long node = 0;
-#ifdef CONFIG_NUMA
-        node = cpu_to_node[cpu];
-#endif
-        if (cpu_has(&cpu_data[cpu], X86_FEATURE_RDTSCP))
-                write_rdtscp_aux((node << 12) | cpu);
-
-        /* Store cpu number in limit so that it can be loaded quickly
-           in user space in vgetcpu.
-           12 bits for the CPU and 8 bits for the node. */
-        d = (unsigned long *)(cpu_gdt(cpu) + GDT_ENTRY_PER_CPU);
-        *d = 0x0f40000000000ULL;
-        *d |= cpu;
-        *d |= (node & 0xf) << 12;
-        *d |= (node >> 4) << 48;
-}
-
-static void __cpuinit cpu_vsyscall_init(void *arg)
-{
-        /* preemption should be already off */
-        vsyscall_set_cpu(raw_smp_processor_id());
-}
-
-static int __cpuinit
-cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
-{
-        long cpu = (long)arg;
-        if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
-                smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 0, 1);
-        return NOTIFY_DONE;
-}
-
-static void __init map_vsyscall(void)
-{
-        extern char __vsyscall_0;
-        unsigned long physaddr_page0 = __pa_symbol(&__vsyscall_0);
-
-        /* Note that VSYSCALL_MAPPED_PAGES must agree with the code below. */
-        __set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_page0, PAGE_KERNEL_VSYSCALL);
-}
-
-static int __init vsyscall_init(void)
-{
-        BUG_ON(((unsigned long) &vgettimeofday !=
-                        VSYSCALL_ADDR(__NR_vgettimeofday)));
-        BUG_ON((unsigned long) &vtime != VSYSCALL_ADDR(__NR_vtime));
-        BUG_ON((VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE)));
-        BUG_ON((unsigned long) &vgetcpu != VSYSCALL_ADDR(__NR_vgetcpu));
-        map_vsyscall();
-#ifdef CONFIG_SYSCTL
-        register_sysctl_table(kernel_root_table2);
-#endif
-        on_each_cpu(cpu_vsyscall_init, NULL, 0, 1);
-        hotcpu_notifier(cpu_vsyscall_notifier, 0);
-        return 0;
-}
-
-__initcall(vsyscall_init);