From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de,
vincenzo.frascino@arm.com, luto@kernel.org
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
x86@kernel.org
Subject: [PATCH v5 4/6] lib/vdso: Allow fixed clock mode
Date: Thu, 30 Jan 2020 16:08:38 +0000 (UTC) [thread overview]
Message-ID: <47500ae9aa628aead4c5b5a71d5279268cdddb48.1580399657.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1580399657.git.christophe.leroy@c-s.fr>
Some architectures have a fixed clocksource which is known at compile
time and cannot be replaced or disabled at runtime, e.g. timebase on
PowerPC. For such cases the clock mode check in the VDSO code is
pointless.
Therefore, give architectures the opportunity to redefine the way
clock_mode is checked by moving the check into an
__arch_vdso_capable() macro.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
lib/vdso/gettimeofday.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 72d65dd50cb4..0b4b71880f22 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -120,12 +120,18 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
cpu_relax();
}
smp_rmb();
+#ifdef __arch_vdso_capable
+ if (unlikely(!__arch_vdso_capable(vd->clock_mode)))
+ return -1;
+#endif
cycles = __arch_get_hw_counter(vd->clock_mode);
ns = vdso_ts->nsec;
last = vd->cycle_last;
+#ifndef __arch_vdso_capable
if (unlikely((s64)cycles < 0))
return -1;
+#endif
ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
ns >>= vd->shift;
--
2.25.0
WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de,
vincenzo.frascino@arm.com, luto@kernel.org
Cc: x86@kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org
Subject: [PATCH v5 4/6] lib/vdso: Allow fixed clock mode
Date: Thu, 30 Jan 2020 16:08:38 +0000 (UTC) [thread overview]
Message-ID: <47500ae9aa628aead4c5b5a71d5279268cdddb48.1580399657.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1580399657.git.christophe.leroy@c-s.fr>
Some architectures have a fixed clocksource which is known at compile
time and cannot be replaced or disabled at runtime, e.g. timebase on
PowerPC. For such cases the clock mode check in the VDSO code is
pointless.
Therefore, give architectures the opportunity to redefine the way
clock_mode is checked by moving the check into an
__arch_vdso_capable() macro.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
lib/vdso/gettimeofday.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 72d65dd50cb4..0b4b71880f22 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -120,12 +120,18 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
cpu_relax();
}
smp_rmb();
+#ifdef __arch_vdso_capable
+ if (unlikely(!__arch_vdso_capable(vd->clock_mode)))
+ return -1;
+#endif
cycles = __arch_get_hw_counter(vd->clock_mode);
ns = vdso_ts->nsec;
last = vd->cycle_last;
+#ifndef __arch_vdso_capable
if (unlikely((s64)cycles < 0))
return -1;
+#endif
ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
ns >>= vd->shift;
--
2.25.0
WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de,
vincenzo.frascino@arm.com, luto@kernel.org
Cc: x86@kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org
Subject: [PATCH v5 4/6] lib/vdso: Allow fixed clock mode
Date: Thu, 30 Jan 2020 16:08:38 +0000 (UTC) [thread overview]
Message-ID: <47500ae9aa628aead4c5b5a71d5279268cdddb48.1580399657.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1580399657.git.christophe.leroy@c-s.fr>
Some architectures have a fixed clocksource which is known at compile
time and cannot be replaced or disabled at runtime, e.g. timebase on
PowerPC. For such cases the clock mode check in the VDSO code is
pointless.
Therefore, give architectures the opportunity to redefine the way
clock_mode is checked by moving the check into an
__arch_vdso_capable() macro.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
lib/vdso/gettimeofday.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 72d65dd50cb4..0b4b71880f22 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -120,12 +120,18 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
cpu_relax();
}
smp_rmb();
+#ifdef __arch_vdso_capable
+ if (unlikely(!__arch_vdso_capable(vd->clock_mode)))
+ return -1;
+#endif
cycles = __arch_get_hw_counter(vd->clock_mode);
ns = vdso_ts->nsec;
last = vd->cycle_last;
+#ifndef __arch_vdso_capable
if (unlikely((s64)cycles < 0))
return -1;
+#endif
ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult);
ns >>= vd->shift;
--
2.25.0
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-01-30 16:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-30 16:08 [PATCH v5 0/6] powerpc: switch VDSO to C implementation Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` [PATCH v5 1/6] powerpc/vdso64: Switch from __get_datapage() to get_datapage inline macro Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` [PATCH v5 2/6] powerpc/vdso: Remove __kernel_datapage_offset and simplify __get_datapage() Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` [PATCH v5 3/6] lib/vdso: Allow architectures to provide the vdso data pointer Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy [this message]
2020-01-30 16:08 ` [PATCH v5 4/6] lib/vdso: Allow fixed clock mode Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` [PATCH v5 5/6] lib/vdso: Allow architectures to override the ns shift operation Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` [PATCH v5 6/6] powerpc/vdso: Switch VDSO to generic C implementation Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-01-30 16:08 ` Christophe Leroy
2020-02-03 11:27 ` kbuild test robot
2020-02-03 11:27 ` kbuild test robot
2020-02-03 11:27 ` kbuild test robot
2020-02-03 11:27 ` kbuild test robot
2020-02-03 11:59 ` Arnd Bergmann
2020-02-03 11:59 ` Arnd Bergmann
2020-02-03 11:59 ` Arnd Bergmann
2020-02-03 11:59 ` Arnd Bergmann
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