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lib/vdso: Move fallback invocation to the callers

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To allow syscall fallbacks using the legacy 32bit syscall for 32bit VDSO
builds, move the fallback invocation out into the callers.

Split the common code out of __cvdso_clock_gettime/getres() and invoke the
syscall fallback in the 64bit and 32bit variants.

Preparatory work for using legacy syscalls in 32bit VDSO. No functional
change.

Fixes: 00b26474c2 ("lib/vdso: Provide generic VDSO implementation")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20190728131648.695579736@linutronix.de
This commit is contained in:
Thomas Gleixner 2019-07-28 15:12:53 +02:00
parent a9446a906f
commit 502a590a17
1 changed files with 36 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
lib/vdso/gettimeofday.c
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@ -51,7 +51,7 @@ static int do_hres(const struct vdso_data *vd, clockid_t clk,
ns = vdso_ts->nsec;
last = vd->cycle_last;
if (unlikely((s64)cycles < 0))
return clock_gettime_fallback(clk, ts);
return -1;
ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
ns >>= vd->shift;
@ -82,14 +82,14 @@ static void do_coarse(const struct vdso_data *vd, clockid_t clk,
}
static __maybe_unused int
__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
__cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts)
{
const struct vdso_data *vd = __arch_get_vdso_data();
u32 msk;
/* Check for negative values or invalid clocks */
if (unlikely((u32) clock >= MAX_CLOCKS))
goto fallback;
return -1;
/*
* Convert the clockid to a bitmask and use it to check which
@ -104,9 +104,17 @@ __cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
} else if (msk & VDSO_RAW) {
return do_hres(&vd[CS_RAW], clock, ts);
}
return -1;
}
fallback:
return clock_gettime_fallback(clock, ts);
static __maybe_unused int
__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
{
int ret = __cvdso_clock_gettime_common(clock, ts);
if (unlikely(ret))
return clock_gettime_fallback(clock, ts);
return 0;
}
static __maybe_unused int
@ -115,9 +123,12 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
struct __kernel_timespec ts;
int ret;
ret = __cvdso_clock_gettime(clock, &ts);
ret = __cvdso_clock_gettime_common(clock, &ts);
if (ret == 0) {
if (unlikely(ret))
ret = clock_gettime_fallback(clock, &ts);
if (likely(!ret)) {
res->tv_sec = ts.tv_sec;
res->tv_nsec = ts.tv_nsec;
}
@ -163,17 +174,18 @@ static __maybe_unused time_t __cvdso_time(time_t *time)
#ifdef VDSO_HAS_CLOCK_GETRES
static __maybe_unused
int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res)
{
const struct vdso_data *vd = __arch_get_vdso_data();
u64 ns;
u64 hrtimer_res;
u32 msk;
u64 hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
u64 ns;
/* Check for negative values or invalid clocks */
if (unlikely((u32) clock >= MAX_CLOCKS))
goto fallback;
return -1;
hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);
/*
* Convert the clockid to a bitmask and use it to check which
* clocks are handled in the VDSO directly.
@ -195,16 +207,22 @@ int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
*/
ns = hrtimer_res;
} else {
goto fallback;
return -1;
}
res->tv_sec = 0;
res->tv_nsec = ns;
return 0;
}
fallback:
return clock_getres_fallback(clock, res);
int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
{
int ret = __cvdso_clock_getres_common(clock, res);
if (unlikely(ret))
return clock_getres_fallback(clock, res);
return 0;
}
static __maybe_unused int
@ -213,13 +231,14 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
struct __kernel_timespec ts;
int ret;
ret = __cvdso_clock_getres(clock, &ts);
ret = __cvdso_clock_getres_common(clock, &ts);
if (unlikely(ret))
ret = clock_getres_fallback(clock, &ts);
if (ret == 0) {
if (likely(!ret)) {
res->tv_sec = ts.tv_sec;
res->tv_nsec = ts.tv_nsec;
}
return ret;
}
#endif /* VDSO_HAS_CLOCK_GETRES */