1 files changed, 162 insertions, 94 deletions

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index eb5d7a56f8d4..16d686171e9a 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -4,6 +4,9 @@
  *
  * Fast user context implementation of clock_gettime, gettimeofday, and time.
  *
+ * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
+ *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
+ *
  * The code should have no internal unresolved relocations.
  * Check with readelf after changing.
  */
@@ -11,56 +14,55 @@
 /* Disable profiling for userspace code: */
 #define DISABLE_BRANCH_PROFILING
 
-#include <linux/kernel.h>
-#include <linux/posix-timers.h>
-#include <linux/time.h>
-#include <linux/string.h>
-#include <asm/vsyscall.h>
-#include <asm/fixmap.h>
+#include <uapi/linux/time.h>
 #include <asm/vgtod.h>
-#include <asm/timex.h>
 #include <asm/hpet.h>
+#include <asm/vvar.h>
 #include <asm/unistd.h>
-#include <asm/io.h>
-#include <asm/pvclock.h>
+#include <asm/msr.h>
+#include <linux/math64.h>
+#include <linux/time.h>
 
 #define gtod (&VVAR(vsyscall_gtod_data))
 
-notrace static cycle_t vread_tsc(void)
+extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
+extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
+extern time_t __vdso_time(time_t *t);
+
+#ifdef CONFIG_HPET_TIMER
+static inline u32 read_hpet_counter(const volatile void *addr)
 {
-        cycle_t ret;
-        u64 last;
+        return *(const volatile u32 *) (addr + HPET_COUNTER);
+}
+#endif
 
-        /*
-         * Empirically, a fence (of type that depends on the CPU)
-         * before rdtsc is enough to ensure that rdtsc is ordered
-         * with respect to loads.  The various CPU manuals are unclear
-         * as to whether rdtsc can be reordered with later loads,
-         * but no one has ever seen it happen.
-         */
-        rdtsc_barrier();
-        ret = (cycle_t)vget_cycles();
+#ifndef BUILD_VDSO32
 
-        last = VVAR(vsyscall_gtod_data).clock.cycle_last;
+#include <linux/kernel.h>
+#include <asm/vsyscall.h>
+#include <asm/fixmap.h>
+#include <asm/pvclock.h>
 
-        if (likely(ret >= last))
-                return ret;
+static notrace cycle_t vread_hpet(void)
+{
+        return read_hpet_counter((const void *)fix_to_virt(VSYSCALL_HPET));
+}
 
-        /*
-         * GCC likes to generate cmov here, but this branch is extremely
-         * predictable (it's just a funciton of time and the likely is
-         * very likely) and there's a data dependence, so force GCC
-         * to generate a branch instead.  I don't barrier() because
-         * we don't actually need a barrier, and if this function
-         * ever gets inlined it will generate worse code.
-         */
-        asm volatile ("");
-        return last;
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+{
+        long ret;
+        asm("syscall" : "=a" (ret) :
+            "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
+        return ret;
 }
 
-static notrace cycle_t vread_hpet(void)
+notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
 {
-        return readl((const void __iomem *)fix_to_virt(VSYSCALL_HPET) + HPET_COUNTER);
+        long ret;
+
+        asm("syscall" : "=a" (ret) :
+            "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
+        return ret;
 }
 
 #ifdef CONFIG_PARAVIRT_CLOCK
@@ -124,7 +126,7 @@ static notrace cycle_t vread_pvclock(int *mode)
                 *mode = VCLOCK_NONE;
 
         /* refer to tsc.c read_tsc() comment for rationale */
-        last = VVAR(vsyscall_gtod_data).clock.cycle_last;
+        last = gtod->cycle_last;
 
         if (likely(ret >= last))
                 return ret;
@@ -133,11 +135,30 @@ static notrace cycle_t vread_pvclock(int *mode)
 }
 #endif
 
+#else
+
+extern u8 hpet_page
+        __attribute__((visibility("hidden")));
+
+#ifdef CONFIG_HPET_TIMER
+static notrace cycle_t vread_hpet(void)
+{
+        return read_hpet_counter((const void *)(&hpet_page));
+}
+#endif
+
 notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
 {
         long ret;
-        asm("syscall" : "=a" (ret) :
-            "0" (__NR_clock_gettime),"D" (clock), "S" (ts) : "memory");
+
+        asm(
+                "mov %%ebx, %%edx \n"
+                "mov %2, %%ebx \n"
+                "call VDSO32_vsyscall \n"
+                "mov %%edx, %%ebx \n"
+                : "=a" (ret)
+                : "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
+                : "memory", "edx");
         return ret;
 }
 
@@ -145,28 +166,79 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
 {
         long ret;
 
-        asm("syscall" : "=a" (ret) :
-            "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
+        asm(
+                "mov %%ebx, %%edx \n"
+                "mov %2, %%ebx \n"
+                "call VDSO32_vsyscall \n"
+                "mov %%edx, %%ebx \n"
+                : "=a" (ret)
+                : "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
+                : "memory", "edx");
         return ret;
 }
 
+#ifdef CONFIG_PARAVIRT_CLOCK
+
+static notrace cycle_t vread_pvclock(int *mode)
+{
+        *mode = VCLOCK_NONE;
+        return 0;
+}
+#endif
+
+#endif
+
+notrace static cycle_t vread_tsc(void)
+{
+        cycle_t ret;
+        u64 last;
+
+        /*
+         * Empirically, a fence (of type that depends on the CPU)
+         * before rdtsc is enough to ensure that rdtsc is ordered
+         * with respect to loads.  The various CPU manuals are unclear
+         * as to whether rdtsc can be reordered with later loads,
+         * but no one has ever seen it happen.
+         */
+        rdtsc_barrier();
+        ret = (cycle_t)__native_read_tsc();
+
+        last = gtod->cycle_last;
+
+        if (likely(ret >= last))
+                return ret;
+
+        /*
+         * GCC likes to generate cmov here, but this branch is extremely
+         * predictable (it's just a funciton of time and the likely is
+         * very likely) and there's a data dependence, so force GCC
+         * to generate a branch instead.  I don't barrier() because
+         * we don't actually need a barrier, and if this function
+         * ever gets inlined it will generate worse code.
+         */
+        asm volatile ("");
+        return last;
+}
 
 notrace static inline u64 vgetsns(int *mode)
 {
-        long v;
+        u64 v;
         cycles_t cycles;
-        if (gtod->clock.vclock_mode == VCLOCK_TSC)
+
+        if (gtod->vclock_mode == VCLOCK_TSC)
                 cycles = vread_tsc();
-        else if (gtod->clock.vclock_mode == VCLOCK_HPET)
+#ifdef CONFIG_HPET_TIMER
+        else if (gtod->vclock_mode == VCLOCK_HPET)
                 cycles = vread_hpet();
+#endif
 #ifdef CONFIG_PARAVIRT_CLOCK
-        else if (gtod->clock.vclock_mode == VCLOCK_PVCLOCK)
+        else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
                 cycles = vread_pvclock(mode);
 #endif
         else
                 return 0;
-        v = (cycles - gtod->clock.cycle_last) & gtod->clock.mask;
-        return v * gtod->clock.mult;
+        v = (cycles - gtod->cycle_last) & gtod->mask;
+        return v * gtod->mult;
 }
 
 /* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
@@ -176,106 +248,102 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
         u64 ns;
         int mode;
 
-        ts->tv_nsec = 0;
         do {
-                seq = raw_read_seqcount_begin(&gtod->seq);
-                mode = gtod->clock.vclock_mode;
+                seq = gtod_read_begin(gtod);
+                mode = gtod->vclock_mode;
                 ts->tv_sec = gtod->wall_time_sec;
                 ns = gtod->wall_time_snsec;
                 ns += vgetsns(&mode);
-                ns >>= gtod->clock.shift;
-        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
+                ns >>= gtod->shift;
+        } while (unlikely(gtod_read_retry(gtod, seq)));
+
+        ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+        ts->tv_nsec = ns;
 
-        timespec_add_ns(ts, ns);
         return mode;
 }
 
-notrace static int do_monotonic(struct timespec *ts)
+notrace static int __always_inline do_monotonic(struct timespec *ts)
 {
         unsigned long seq;
         u64 ns;
         int mode;
 
-        ts->tv_nsec = 0;
         do {
-                seq = raw_read_seqcount_begin(&gtod->seq);
-                mode = gtod->clock.vclock_mode;
+                seq = gtod_read_begin(gtod);
+                mode = gtod->vclock_mode;
                 ts->tv_sec = gtod->monotonic_time_sec;
                 ns = gtod->monotonic_time_snsec;
                 ns += vgetsns(&mode);
-                ns >>= gtod->clock.shift;
-        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-        timespec_add_ns(ts, ns);
+                ns >>= gtod->shift;
+        } while (unlikely(gtod_read_retry(gtod, seq)));
+
+        ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+        ts->tv_nsec = ns;
 
         return mode;
 }
 
-notrace static int do_realtime_coarse(struct timespec *ts)
+notrace static void do_realtime_coarse(struct timespec *ts)
 {
         unsigned long seq;
         do {
-                seq = raw_read_seqcount_begin(&gtod->seq);
-                ts->tv_sec = gtod->wall_time_coarse.tv_sec;
-                ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
-        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-        return 0;
+                seq = gtod_read_begin(gtod);
+                ts->tv_sec = gtod->wall_time_coarse_sec;
+                ts->tv_nsec = gtod->wall_time_coarse_nsec;
+        } while (unlikely(gtod_read_retry(gtod, seq)));
 }
 
-notrace static int do_monotonic_coarse(struct timespec *ts)
+notrace static void do_monotonic_coarse(struct timespec *ts)
 {
         unsigned long seq;
         do {
-                seq = raw_read_seqcount_begin(&gtod->seq);
-                ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
-                ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
-        } while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
-
-        return 0;
+                seq = gtod_read_begin(gtod);
+                ts->tv_sec = gtod->monotonic_time_coarse_sec;
+                ts->tv_nsec = gtod->monotonic_time_coarse_nsec;
+        } while (unlikely(gtod_read_retry(gtod, seq)));
 }
 
 notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
 {
-        int ret = VCLOCK_NONE;
-
         switch (clock) {
         case CLOCK_REALTIME:
-                ret = do_realtime(ts);
+                if (do_realtime(ts) == VCLOCK_NONE)
+                        goto fallback;
                 break;
         case CLOCK_MONOTONIC:
-                ret = do_monotonic(ts);
+                if (do_monotonic(ts) == VCLOCK_NONE)
+                        goto fallback;
                 break;
         case CLOCK_REALTIME_COARSE:
-                return do_realtime_coarse(ts);
+                do_realtime_coarse(ts);
+                break;
         case CLOCK_MONOTONIC_COARSE:
-                return do_monotonic_coarse(ts);
+                do_monotonic_coarse(ts);
+                break;
+        default:
+                goto fallback;
         }
 
-        if (ret == VCLOCK_NONE)
-                return vdso_fallback_gettime(clock, ts);
         return 0;
+fallback:
+        return vdso_fallback_gettime(clock, ts);
 }
 int clock_gettime(clockid_t, struct timespec *)
         __attribute__((weak, alias("__vdso_clock_gettime")));
 
 notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
-        long ret = VCLOCK_NONE;
-
         if (likely(tv != NULL)) {
-                BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
-                             offsetof(struct timespec, tv_nsec) ||
-                             sizeof(*tv) != sizeof(struct timespec));
-                ret = do_realtime((struct timespec *)tv);
+                if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
+                        return vdso_fallback_gtod(tv, tz);
                 tv->tv_usec /= 1000;
         }
         if (unlikely(tz != NULL)) {
-                /* Avoid memcpy. Some old compilers fail to inline it */
-                tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;
-                tz->tz_dsttime = gtod->sys_tz.tz_dsttime;
+                tz->tz_minuteswest = gtod->tz_minuteswest;
+                tz->tz_dsttime = gtod->tz_dsttime;
         }
 
-        if (ret == VCLOCK_NONE)
-                return vdso_fallback_gtod(tv, tz);
         return 0;
 }
 int gettimeofday(struct timeval *, struct timezone *)
@@ -287,8 +355,8 @@ int gettimeofday(struct timeval *, struct timezone *)
  */
 notrace time_t __vdso_time(time_t *t)
 {
-        /* This is atomic on x86_64 so we don't need any locks. */
-        time_t result = ACCESS_ONCE(VVAR(vsyscall_gtod_data).wall_time_sec);
+        /* This is atomic on x86 so we don't need any locks. */
+        time_t result = ACCESS_ONCE(gtod->wall_time_sec);
 
         if (t)
                 *t = result;