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Message-Id: <20180618150613.10322-13-salyzyn@android.com>
Date: Mon, 18 Jun 2018 08:05:58 -0700
From: Mark Salyzyn <salyzyn@...roid.com>
To: linux-kernel@...r.kernel.org
Cc: Mark Salyzyn <salyzyn@...roid.com>,
James Morse <james.morse@....com>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Andy Lutomirski <luto@...capital.net>,
Dmitry Safonov <dsafonov@...tuozzo.com>,
John Stultz <john.stultz@...aro.org>,
Mark Rutland <mark.rutland@....com>,
Laura Abbott <labbott@...hat.com>,
Kees Cook <keescook@...omium.org>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Andy Gross <andy.gross@...aro.org>,
Kevin Brodsky <kevin.brodsky@....com>,
Andrew Pinski <apinski@...ium.com>,
Thomas Gleixner <tglx@...utronix.de>,
linux-arm-kernel@...ts.infradead.org,
Jeremy Linton <Jeremy.Linton@....com>,
Mark Salyzyn <salyzyn@...gle.com>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Ingo Molnar <mingo@...nel.org>
Subject: RESEND [PATCH v5 12/12] lib: vdso: do not expose gettimeofday, if no arch supported timer
Take an effort to recode the arm64 vdso code from assembler to C
previously submitted by Andrew Pinski <apinski@...ium.com>, rework
it for use in both arm and arm64, overlapping any optimizations
for each architecture. But instead of landing it in arm64, land the
result into lib/vdso and unify both implementations to simplify
future maintenance.
If ARCH_PROVIDES_TIMER is not defined, do not expose gettimeofday.
libc will default directly to syscall. Also ifdef clock_gettime
switch cases and stubs if not supported and other unused components.
Signed-off-by: Mark Salyzyn <salyzyn@...roid.com>
Cc: James Morse <james.morse@....com>
Cc: Russell King <linux@...linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Dmitry Safonov <dsafonov@...tuozzo.com>
Cc: John Stultz <john.stultz@...aro.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Laura Abbott <labbott@...hat.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Andy Gross <andy.gross@...aro.org>
Cc: Kevin Brodsky <kevin.brodsky@....com>
Cc: Andrew Pinski <apinski@...ium.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org
Cc: Jeremy Linton <Jeremy.Linton@....com>
v3:
- do not expose gettimeofday if arch does not support user space timer.
v4:
- update commit message to reflect overall reasoning of patch series.
v5:
- rebase
---
lib/vdso/vgettimeofday.c | 52 ++++++++++++++++------------------------
1 file changed, 20 insertions(+), 32 deletions(-)
diff --git a/lib/vdso/vgettimeofday.c b/lib/vdso/vgettimeofday.c
index 4c3af7bc6499..54e519c99c4b 100644
--- a/lib/vdso/vgettimeofday.c
+++ b/lib/vdso/vgettimeofday.c
@@ -30,7 +30,9 @@
#include "compiler.h"
#include "datapage.h"
+#ifdef ARCH_PROVIDES_TIMER
DEFINE_FALLBACK(gettimeofday, struct timeval *, tv, struct timezone *, tz)
+#endif
DEFINE_FALLBACK(clock_gettime, clockid_t, clock, struct timespec *, ts)
DEFINE_FALLBACK(clock_getres, clockid_t, clock, struct timespec *, ts)
@@ -292,30 +294,6 @@ static notrace int do_boottime(const struct vdso_data *vd, struct timespec *ts)
return 0;
}
-#else /* ARCH_PROVIDES_TIMER */
-
-static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts)
-{
- return -1;
-}
-
-static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
-{
- return -1;
-}
-
-static notrace int do_monotonic_raw(const struct vdso_data *vd,
- struct timespec *ts)
-{
- return -1;
-}
-
-static notrace int do_boottime(const struct vdso_data *vd,
- struct timespec *ts)
-{
- return -1;
-}
-
#endif /* ARCH_PROVIDES_TIMER */
notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
@@ -329,6 +307,7 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
case CLOCK_MONOTONIC_COARSE:
do_monotonic_coarse(vd, ts);
break;
+#ifdef ARCH_PROVIDES_TIMER
case CLOCK_REALTIME:
if (do_realtime(vd, ts))
goto fallback;
@@ -345,6 +324,7 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
if (do_boottime(vd, ts))
goto fallback;
break;
+#endif
default:
goto fallback;
}
@@ -354,6 +334,7 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
return clock_gettime_fallback(clock, ts);
}
+#ifdef ARCH_PROVIDES_TIMER
notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
const struct vdso_data *vd = __get_datapage();
@@ -375,21 +356,28 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
return 0;
}
+#endif
int __vdso_clock_getres(clockid_t clock, struct timespec *res)
{
long nsec;
- if (clock == CLOCK_REALTIME ||
- clock == CLOCK_BOOTTIME ||
- clock == CLOCK_MONOTONIC ||
- clock == CLOCK_MONOTONIC_RAW)
- nsec = MONOTONIC_RES_NSEC;
- else if (clock == CLOCK_REALTIME_COARSE ||
- clock == CLOCK_MONOTONIC_COARSE)
+ switch (clock) {
+ case CLOCK_REALTIME_COARSE:
+ case CLOCK_MONOTONIC_COARSE:
nsec = LOW_RES_NSEC;
- else
+ break;
+#ifdef ARCH_PROVIDES_TIMER
+ case CLOCK_REALTIME:
+ case CLOCK_MONOTONIC:
+ case CLOCK_MONOTONIC_RAW:
+ case CLOCK_BOOTTIME:
+ nsec = MONOTONIC_RES_NSEC;
+ break;
+#endif
+ default:
return clock_getres_fallback(clock, res);
+ }
if (likely(res != NULL)) {
res->tv_sec = 0;
--
2.18.0.rc1.244.gcf134e6275-goog
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