From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 4/6] ARM64: arch_timer: configure and enable event stream
Date: Tue, 20 Aug 2013 17:16:58 +0100 [thread overview]
Message-ID: <20130820161658.GD27819@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <52137CD5.7010201@arm.com>
On Tue, Aug 20, 2013 at 03:27:33PM +0100, Sudeep KarkadaNagesha wrote:
> On 20/08/13 14:27, Will Deacon wrote:
> > On Tue, Aug 13, 2013 at 06:29:42PM +0100, Sudeep KarkadaNagesha wrote:
> >> diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
> >> index 6d4482f..effd8f9 100644
> >> --- a/arch/arm64/include/asm/hwcap.h
> >> +++ b/arch/arm64/include/asm/hwcap.h
> >> @@ -30,6 +30,7 @@
> >> #define COMPAT_HWCAP_IDIVA (1 << 17)
> >> #define COMPAT_HWCAP_IDIVT (1 << 18)
> >> #define COMPAT_HWCAP_IDIV (COMPAT_HWCAP_IDIVA|COMPAT_HWCAP_IDIVT)
> >> +#define COMPAT_HWCAP_EVTSTRM (1 << 21)
> >
> > Looking at the context, we should also add COMPAT_HWCAP_LPAE as a separate
> > patch (not part of this series).
> >
> Ok make sense, I can do that. IIUC even this needs at least under some
> config option, assuming can't be dynamic ?
I'm not sure I follow you... if you're asking whether the LPAE HWCAP should
be dynamic for ARMv8, then no, since the capabilities offered by LPAE are
included in ARMv8 as far as userspace is concerned.
> >> #ifndef __ASSEMBLY__
> >> /*
> >> @@ -41,7 +42,8 @@
> >> COMPAT_HWCAP_FAST_MULT|COMPAT_HWCAP_EDSP|\
> >> COMPAT_HWCAP_TLS|COMPAT_HWCAP_VFP|\
> >> COMPAT_HWCAP_VFPv3|COMPAT_HWCAP_VFPv4|\
> >> - COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV)
> >> + COMPAT_HWCAP_NEON|COMPAT_HWCAP_IDIV|\
> >> + COMPAT_HWCAP_EVTSTRM)
> >
> > So here you're hardcoding COMPAT_HWCAP_EVTSTRM in the COMPAT_ELF_HWCAP, yet
> > we only enable the native one from the arch-timer driver. The question then is
> > "Can we rely on the event-stream working for AArch64?". If so, we don't need
> > the native hwcap at all. If not, then we need to make the compat hwcap
> > dynamic.
>
> How about something like this ? I am not sure if
> arch/arm64/kernel/setup.c is apt place for compat_elf_hwcap though.
Looks like the right sort of idea, yes. I can't think of a better place to
put it. You could adjust it slightly so that COMPAT_ELF_HWCAP stays like it
is, with an extra '| compat_dyn_elf_hwcap' on the end, but I have no real
preference.
Will
next prev parent reply other threads:[~2013-08-20 16:16 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-18 17:06 [PATCH 0/4] ARM/ARM64 architected timer updates Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 1/4] drivers: clocksource: configure event stream for ARM arch timer Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 2/4] ARM: arch_timer: add macros for bits in control register Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 3/4] ARM/ARM64: arch_timer: remove __cpuinit attribute for arch_counter_set_user_access Sudeep KarkadaNagesha
2013-06-18 17:58 ` Sudeep KarkadaNagesha
2013-06-18 17:07 ` [PATCH 4/4] drivers: clocksource: add CPU PM notifier for ARM architected timer Sudeep KarkadaNagesha
2013-07-02 16:09 ` Jon Medhurst (Tixy)
2013-07-02 17:24 ` Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 0/3] ARM/ARM64 architected timer updates Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 1/3] drivers: clocksource: configure event stream for ARM arch timer Sudeep KarkadaNagesha
2013-07-23 10:23 ` Catalin Marinas
2013-07-23 10:33 ` Will Deacon
2013-07-23 11:12 ` Catalin Marinas
2013-07-25 9:45 ` [PATCH v3 " Sudeep KarkadaNagesha
2013-08-12 13:32 ` Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 2/3] ARM: arch_timer: add macros for bits in control register Sudeep KarkadaNagesha
2013-07-22 11:21 ` [PATCH v2 3/3] drivers: clocksource: add CPU PM notifier for ARM architected timer Sudeep KarkadaNagesha
2013-08-02 9:32 ` [PATCH v2 0/3] ARM/ARM64 architected timer updates Sudeep KarkadaNagesha
2013-08-02 9:48 ` Daniel Lezcano
2013-08-02 9:55 ` Sudeep KarkadaNagesha
2013-08-02 12:12 ` Daniel Lezcano
2013-08-05 16:25 ` Sudeep KarkadaNagesha
2013-08-06 8:09 ` Daniel Lezcano
2013-08-06 9:01 ` Sudeep KarkadaNagesha
2013-08-12 13:16 ` Daniel Lezcano
2013-08-13 17:29 ` [PATCH v3 0/6] " Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 1/6] ARM/ARM64: arch_timer: add macros for bits in control register Sudeep KarkadaNagesha
2013-08-14 8:50 ` Daniel Lezcano
2013-08-14 9:03 ` Marc Zyngier
2013-08-14 9:23 ` Daniel Lezcano
2013-08-13 17:29 ` [PATCH v3 2/6] drivers: clocksource: configure event stream for ARM arch timer Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 3/6] ARM: arch_timer: configure and enable event stream Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 4/6] ARM64: " Sudeep KarkadaNagesha
2013-08-20 13:27 ` Will Deacon
2013-08-20 14:27 ` Sudeep KarkadaNagesha
2013-08-20 16:16 ` Will Deacon [this message]
2013-08-20 16:23 ` Sudeep KarkadaNagesha
2013-08-20 17:08 ` Sudeep KarkadaNagesha
2013-08-21 17:52 ` Will Deacon
2013-08-13 17:29 ` [PATCH v3 5/6] drivers: clocksource: enable hwcaps for event stream on ARM arch timer Sudeep KarkadaNagesha
2013-08-13 17:29 ` [PATCH v3 6/6] drivers: clocksource: add CPU PM notifier for ARM architected timer Sudeep KarkadaNagesha
2013-08-14 9:08 ` [PATCH v3 0/6] ARM/ARM64 architected timer updates Daniel Lezcano
2013-08-14 9:17 ` Sudeep KarkadaNagesha
2013-08-14 10:51 ` Daniel Lezcano
2013-08-14 11:03 ` Sudeep KarkadaNagesha
2013-08-14 15:00 ` Daniel Lezcano
2013-08-20 17:14 ` Sudeep KarkadaNagesha
2013-08-23 9:26 ` Catalin Marinas
2013-08-23 9:57 ` Sudeep KarkadaNagesha
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