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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBFIp-0003h9-N1; Tue, 02 Apr 2019 09:01:55 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBFIm-0003gj-FQ for linux-arm-kernel@lists.infradead.org; Tue, 02 Apr 2019 09:01:53 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 515C980D; Tue, 2 Apr 2019 02:01:50 -0700 (PDT) Received: from [10.1.196.72] (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E3E233F690; Tue, 2 Apr 2019 02:01:47 -0700 (PDT) Subject: Re: [PATCH 2/5] powerpc: Fix vDSO clock_getres() To: Christophe Leroy , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org References: <20190401115152.32751-1-vincenzo.frascino@arm.com> <20190401115152.32751-3-vincenzo.frascino@arm.com> <5a76f55d-eb0d-fb49-8e59-f0e89e561f7b@c-s.fr> From: Vincenzo Frascino Message-ID: Date: Tue, 2 Apr 2019 10:01:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <5a76f55d-eb0d-fb49-8e59-f0e89e561f7b@c-s.fr> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190402_020152_557318_D0C460BB X-CRM114-Status: GOOD ( 17.99 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Arnd Bergmann , Heiko Carstens , Catalin Marinas , Will Deacon , Paul Mackerras , Greentime Hu , Martin Schwidefsky , Thomas Gleixner , Vincent Chen , Shuah Khan Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 02/04/2019 07:14, Christophe Leroy wrote: > > > On 04/01/2019 11:51 AM, Vincenzo Frascino wrote: >> clock_getres in the vDSO library has to preserve the same behaviour >> of posix_get_hrtimer_res(). >> >> In particular, posix_get_hrtimer_res() does: >> sec = 0; >> ns = hrtimer_resolution; >> and hrtimer_resolution depends on the enablement of the high >> resolution timers that can happen either at compile or at run time. >> >> Fix the powerpc vdso implementation of clock_getres keeping a copy of >> hrtimer_resolution in vdso data and using that directly. >> >> Cc: Benjamin Herrenschmidt >> Cc: Paul Mackerras >> Cc: Michael Ellerman >> Signed-off-by: Vincenzo Frascino >> --- >> arch/powerpc/include/asm/vdso_datapage.h | 2 ++ >> arch/powerpc/kernel/asm-offsets.c | 2 +- >> arch/powerpc/kernel/time.c | 1 + >> arch/powerpc/kernel/vdso32/gettimeofday.S | 22 +++++++++++++++------- >> arch/powerpc/kernel/vdso64/gettimeofday.S | 22 +++++++++++++++------- >> 5 files changed, 34 insertions(+), 15 deletions(-) >> > > [...] > >> diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S >> index 1e0bc5955a40..b21630079496 100644 >> --- a/arch/powerpc/kernel/vdso32/gettimeofday.S >> +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S >> @@ -160,14 +160,21 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) >> cror cr0*4+eq,cr0*4+eq,cr1*4+eq >> bne cr0,99f >> >> - li r3,0 >> - cmpli cr0,r4,0 >> + mflr r12 >> + .cfi_register lr,r12 >> + mr r11,r4 >> + bl __get_datapage@local >> + lwz r5,CLOCK_REALTIME_RES(r3) >> + li r4,0 >> + cmplwi r11,0 /* check if res is NULL */ >> + beq 1f >> + >> + stw r4,TSPC32_TV_SEC(r11) >> + stw r5,TSPC32_TV_NSEC(r11) >> + >> +1: mtlr r12 >> crclr cr0*4+so >> - beqlr >> - lis r5,CLOCK_REALTIME_RES@h >> - ori r5,r5,CLOCK_REALTIME_RES@l >> - stw r3,TSPC32_TV_SEC(r4) >> - stw r5,TSPC32_TV_NSEC(r4) >> + li r3,0 >> blr > > The above can be done simpler, see below > > @@ -160,12 +160,15 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) > cror cr0*4+eq,cr0*4+eq,cr1*4+eq > bne cr0,99f > > + mflr r12 > + .cfi_register lr,r12 > + bl __get_datapage@local > + lwz r5,CLOCK_REALTIME_RES(r3) > + mtlr r12 > li r3,0 > cmpli cr0,r4,0 > crclr cr0*4+so > beqlr > - lis r5,CLOCK_REALTIME_RES@h > - ori r5,r5,CLOCK_REALTIME_RES@l > stw r3,TSPC32_TV_SEC(r4) > stw r5,TSPC32_TV_NSEC(r4) > blr > Thank you for this, I will update my code accordingly before posting v2. > Christophe > >> >> /* >> @@ -175,6 +182,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) >> */ >> 99: >> li r0,__NR_clock_getres >> + .cfi_restore lr >> sc >> blr >> .cfi_endproc >> diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S >> index a4ed9edfd5f0..a7e49bddd475 100644 >> --- a/arch/powerpc/kernel/vdso64/gettimeofday.S >> +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S >> @@ -190,14 +190,21 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) >> cror cr0*4+eq,cr0*4+eq,cr1*4+eq >> bne cr0,99f >> >> - li r3,0 >> - cmpldi cr0,r4,0 >> + mflr r12 >> + .cfi_register lr,r12 >> + mr r11, r4 >> + bl V_LOCAL_FUNC(__get_datapage) >> + lwz r5,CLOCK_REALTIME_RES(r3) >> + li r4,0 >> + cmpldi r11,0 /* check if res is NULL */ >> + beq 1f >> + >> + std r4,TSPC64_TV_SEC(r11) >> + std r5,TSPC64_TV_NSEC(r11) >> + >> +1: mtlr r12 >> crclr cr0*4+so >> - beqlr >> - lis r5,CLOCK_REALTIME_RES@h >> - ori r5,r5,CLOCK_REALTIME_RES@l >> - std r3,TSPC64_TV_SEC(r4) >> - std r5,TSPC64_TV_NSEC(r4) >> + li r3,0 >> blr > > The same type of simplification applies here too. > > Christophe > > >> >> /* >> @@ -205,6 +212,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) >> */ >> 99: >> li r0,__NR_clock_getres >> + .cfi_restore lr >> sc >> blr >> .cfi_endproc >> -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel