Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751379Ab3HTO1O (ORCPT ); Tue, 20 Aug 2013 10:27:14 -0400 Received: from service87.mimecast.com ([91.220.42.44]:50960 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751045Ab3HTO1N convert rfc822-to-8bit (ORCPT ); Tue, 20 Aug 2013 10:27:13 -0400 Message-ID: <52137CD5.7010201@arm.com> Date: Tue, 20 Aug 2013 15:27:33 +0100 From: Sudeep KarkadaNagesha User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: Will Deacon CC: Sudeep KarkadaNagesha , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Lorenzo Pieralisi , Catalin Marinas , Thomas Gleixner , Daniel Lezcano Subject: Re: [PATCH v3 4/6] ARM64: arch_timer: configure and enable event stream References: <1374492082-13686-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1376414984-14182-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1376414984-14182-5-git-send-email-Sudeep.KarkadaNagesha@arm.com> <20130820132712.GE26129@mudshark.cambridge.arm.com> In-Reply-To: <20130820132712.GE26129@mudshark.cambridge.arm.com> X-OriginalArrivalTime: 20 Aug 2013 14:27:10.0303 (UTC) FILETIME=[5B126EF0:01CE9DB1] X-MC-Unique: 113082015271001701 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5950 Lines: 166 On 20/08/13 14:27, Will Deacon wrote: > Hi Sudeep, > > Couple of comments inline... > > On Tue, Aug 13, 2013 at 06:29:42PM +0100, Sudeep KarkadaNagesha wrote: >> From: Sudeep KarkadaNagesha >> >> This patch configures the event stream frequency and enables it. >> It also adds the hwcaps as well as compat-specific definitions to >> the user to detect this event stream feature. >> >> Cc: Catalin Marinas >> Reviewed-by: Lorenzo Pieralisi >> Signed-off-by: Will Deacon >> [sudeep: moving ARM/ARM64 changes into separate patches] >> Signed-off-by: Sudeep KarkadaNagesha >> --- >> arch/arm64/include/asm/arch_timer.h | 12 ++++++++++-- >> arch/arm64/include/asm/hwcap.h | 4 +++- >> arch/arm64/include/uapi/asm/hwcap.h | 1 + >> arch/arm64/kernel/setup.c | 1 + >> 4 files changed, 15 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h >> index 69f5c8e..43f322a 100644 >> --- a/arch/arm64/include/asm/arch_timer.h >> +++ b/arch/arm64/include/asm/arch_timer.h >> @@ -106,14 +106,22 @@ static inline void arch_counter_set_user_access(int divider) >> /* Disable user access to the timers and the physical counter. */ >> cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN >> | ARCH_TIMER_USR_VT_ACCESS_EN >> + | ARCH_TIMER_EVT_TRIGGER_MASK >> | ARCH_TIMER_USR_PCT_ACCESS_EN); >> >> - /* Enable user access to the virtual counter. */ >> - cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN; >> + /* Enable event stream and user access to the virtual counter */ >> + cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT) >> + | ARCH_TIMER_VIRT_EVT_EN >> + | ARCH_TIMER_USR_VCT_ACCESS_EN; >> >> asm volatile("msr cntkctl_el1, %0" : : "r" (cntkctl)); >> } >> >> +static inline void arch_timer_set_hwcap_evtstrm(void) >> +{ >> + elf_hwcap |= HWCAP_EVTSTRM; >> +} >> + >> static inline u64 arch_counter_get_cntvct(void) >> { >> u64 cval; >> 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 ? >> #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. ------>8-------- diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index 43f322a..a7d33a8 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -120,6 +120,9 @@ static inline void arch_counter_set_user_access(int divider) static inline void arch_timer_set_hwcap_evtstrm(void) { elf_hwcap |= HWCAP_EVTSTRM; +#ifdef CONFIG_COMPAT + compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM; +#endif } static inline u64 arch_counter_get_cntvct(void) diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index effd8f9..9633db0 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -32,19 +32,24 @@ #define COMPAT_HWCAP_IDIV (COMPAT_HWCAP_IDIVA|COMPAT_HWCAP_IDIVT) #define COMPAT_HWCAP_EVTSTRM (1 << 21) +#define COMPAT_ELF_HWCAP_DEFAULT \ + (COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\ + 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) #ifndef __ASSEMBLY__ /* * This yields a mask that user programs can use to figure out what * instruction set this cpu supports. */ #define ELF_HWCAP (elf_hwcap) -#define COMPAT_ELF_HWCAP (COMPAT_HWCAP_HALF|COMPAT_HWCAP_THUMB|\ - 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_EVTSTRM) - extern unsigned int elf_hwcap; + +#ifdef CONFIG_COMPAT +#define COMPAT_ELF_HWCAP (compat_elf_hwcap) +extern unsigned int compat_elf_hwcap; +#endif + #endif #endif diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 1111833..990fc98 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -60,6 +60,11 @@ EXPORT_SYMBOL(processor_id); unsigned int elf_hwcap __read_mostly; EXPORT_SYMBOL_GPL(elf_hwcap); +#ifdef CONFIG_COMPAT +unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT; +EXPORT_SYMBOL_GPL(compat_elf_hwcap); +#endif + static const char *cpu_name; static const char *machine_name; phys_addr_t __fdt_pointer __initdata; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/