From patchwork Thu May 23 11:21:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincenzo Frascino X-Patchwork-Id: 10957443 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C86161708 for ; Thu, 23 May 2019 11:21:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B17612848D for ; Thu, 23 May 2019 11:21:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A590828496; Thu, 23 May 2019 11:21:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 825732848D for ; Thu, 23 May 2019 11:21:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729863AbfEWLVa (ORCPT ); Thu, 23 May 2019 07:21:30 -0400 Received: from foss.arm.com ([217.140.101.70]:44248 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729430AbfEWLVa (ORCPT ); Thu, 23 May 2019 07:21:30 -0400 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 7B010341; Thu, 23 May 2019 04:21:29 -0700 (PDT) Received: from e119884-lin.cambridge.arm.com (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1F2DA3F718; Thu, 23 May 2019 04:21:26 -0700 (PDT) From: Vincenzo Frascino To: linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: vincenzo.frascino@arm.com, Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Shuah Khan , Thomas Gleixner , Arnd Bergmann Subject: [PATCH v4 0/3] Fix vDSO clock_getres() Date: Thu, 23 May 2019 12:21:13 +0100 Message-Id: <20190523112116.19233-1-vincenzo.frascino@arm.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. A possible fix is to change the vdso implementation of clock_getres, keeping a copy of hrtimer_resolution in vdso data and using that directly [1]. This patchset implements the proposed fix for arm64, powerpc, s390, nds32 and adds a test to verify that the syscall and the vdso library implementation of clock_getres return the same values. Even if these patches are unified by the same topic, there is no dependency between them, hence they can be merged singularly by each arch maintainer. Note: arm64 and nds32 respective fixes have been merged in 5.2-rc1, hence they have been removed from this series. [1] https://marc.info/?l=linux-arm-kernel&m=155110381930196&w=2 Changes: -------- v4: - Address review comments. v3: - Rebased on 5.2-rc1. - Address review comments. v2: - Rebased on 5.1-rc5. - Addressed review comments. Cc: Christophe Leroy Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Shuah Khan Cc: Thomas Gleixner Cc: Arnd Bergmann Signed-off-by: Vincenzo Frascino Vincenzo Frascino (3): powerpc: Fix vDSO clock_getres() s390: Fix vDSO clock_getres() kselftest: Extend vDSO selftest to clock_getres 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 | 7 +- arch/powerpc/kernel/vdso64/gettimeofday.S | 7 +- arch/s390/include/asm/vdso.h | 1 + arch/s390/kernel/asm-offsets.c | 2 +- arch/s390/kernel/time.c | 1 + arch/s390/kernel/vdso32/clock_getres.S | 12 +- arch/s390/kernel/vdso64/clock_getres.S | 10 +- tools/testing/selftests/vDSO/Makefile | 2 + .../selftests/vDSO/vdso_clock_getres.c | 124 ++++++++++++++++++ 12 files changed, 155 insertions(+), 16 deletions(-) create mode 100644 tools/testing/selftests/vDSO/vdso_clock_getres.c