From: Vincenzo Frascino <vincenzo.frascino@arm.com> To: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org, LAK <linux-arm-kernel@lists.infradead.org>, LKML <linux-kernel@vger.kernel.org>, linux-mips@vger.kernel.org, linux-kselftest@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Arnd Bergmann <arnd@arndb.de>, Russell King <linux@armlinux.org.uk>, Ralf Baechle <ralf@linux-mips.org>, Paul Burton <paul.burton@mips.com>, Daniel Lezcano <daniel.lezcano@linaro.org>, Mark Salyzyn <salyzyn@android.com>, Peter Collingbourne <pcc@google.com>, Shuah Khan <shuah@kernel.org>, Dmitry Safonov <0x7f454c46@gmail.com>, Rasmus Villemoes <linux@rasmusvillemoes.dk>, Huw Davies <huw@codeweavers.com>, Shijith Thotton <sthotton@marvell.com>, Andre Przywara <andre.przywara@arm.com>, Dmitry Safonov <dima@arista.com>, Andrei Vagin <avagin@openvz.org>, Linus Torvalds <torvalds@linux-foundation.org>, Andy Lutomirski <luto@kernel.org>, Michael Kelley <mikelley@microsoft.com>, Sasha Levin <sashal@kernel.org> Subject: Re: [PATCH v7 00/25] Unify vDSOs across more architectures Date: Mon, 24 Jun 2019 14:21:03 +0100 Message-ID: <fdded1ed-9404-c80e-c74e-a61716277bda@arm.com> (raw) In-Reply-To: <alpine.DEB.2.21.1906240142000.32342@nanos.tec.linutronix.de> Hi Thomas, On 24/06/2019 01:34, Thomas Gleixner wrote: > Vincenzo, > > On Fri, 21 Jun 2019, Vincenzo Frascino wrote: >> vDSO (virtual dynamic shared object) is a mechanism that the Linux >> kernel provides as an alternative to system calls to reduce where >> possible the costs in terms of cycles. >> This is possible because certain syscalls like gettimeofday() do >> not write any data and return one or more values that are stored >> in the kernel, which makes relatively safe calling them directly >> as a library function. >> >> Even if the mechanism is pretty much standard, every architecture >> in the last few years ended up implementing their own vDSO library >> in the architectural code. > > .... > >> This implementation contains the portings to the common library for: arm64, >> compat mode for arm64, arm, mips, x86_64, x32, compat mode for x86_64 and >> i386. > > I picked up the core implementation and the ARM64 and x86 conversion. I did > some refinements in several places, coding style, naming conventions, > comments and changelogs including subject prefixes. Please double check! > I tested your changes and they seem OK (git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso). ... > As you can see from the commit dates, this has soaked for some time in a > WIP branch and I did extensive regression testing. So far so good. > > Thanks a lot for going through several iterations. It's a very much > appreciated effort! > It has been a lot of fun and I learned many many things about the vDSOs and the kernel that I did not know before. Thanks to you for your patience and guidance. > Especially with the upcoming time namespaces this will avoid a lot of > duplicated and pointlessly different horrors all over the architecture > space. Any architecture which wants to gain that support needs to convert > to the generic VDSO first. > > As you have become the dude who knows almost everything about VDSO > including all the nasty pitfalls, I propose the patch below. > Thanks for this, it means a lot to me. > Thanks, > > tglx > > 8<------------ > Subject: MAINTAINERS: Add entry for the generic VDSO library > From: Thomas Gleixner <tglx@linutronix.de> > Date: Mon, 24 Jun 2019 02:03:50 +0200 > > Asign the following folks in alphabetic order: > > - Andy for being the VDSO wizard of x86 and in general. He's also the > performance monitor of choice and the code in the generic library is > heavily influenced by his previous x86 VDSO work. > > - Thomas for being the dude who has to deal with any form of time(r) > nonsense anyway > > - Vincenzo for being the poor sod who went through all the different > architecture implementations in order to unify them. A lot of knowledge > gained from VDSO implementation details to the intricacies of taming the > build system. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > MAINTAINERS | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -6665,6 +6665,18 @@ L: kvm@vger.kernel.org > S: Supported > F: drivers/uio/uio_pci_generic.c > > +GENERIC VDSO LIBRARY: > +M: Andy Lutomirksy <luto@kernel.org> > +M: Thomas Gleixner <tglx@linutronix.de> > +M: Vincenzo Frascino <vincenzo.frascino@arm.com> > +L: linux-kernel@vger.kernel.org > +T: git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso > +S: Maintained > +F: lib/vdso > +F: kernel/time/vsyscall.c > +F: include/vdso > +F: include/asm-generic/vdso/vsyscall.h > + > GENWQE (IBM Generic Workqueue Card) > M: Frank Haverkamp <haver@linux.ibm.com> > S: Supported > -- Regards, Vincenzo
next prev parent reply index Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-06-21 9:52 Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 01/25] kernel: Standardize vdso_datapage Vincenzo Frascino 2019-06-24 13:56 ` Catalin Marinas 2019-06-21 9:52 ` [PATCH v7 02/25] kernel: Define gettimeofday vdso common code Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 03/25] kernel: Unify update_vsyscall implementation Vincenzo Frascino 2019-06-21 10:49 ` Huw Davies 2019-06-21 9:52 ` [PATCH v7 04/25] arm64: Substitute gettimeofday with C implementation Vincenzo Frascino 2019-06-24 13:36 ` Will Deacon 2019-06-24 13:59 ` Vincenzo Frascino 2019-06-25 16:18 ` [PATCH 1/3] lib/vdso: Delay mask application in do_hres() Vincenzo Frascino 2019-06-25 16:18 ` [PATCH 2/3] arm64: Fix __arch_get_hw_counter() implementation Vincenzo Frascino 2019-06-25 16:18 ` [PATCH 3/3] arm64: compat: " Vincenzo Frascino 2019-06-25 17:02 ` [PATCH 1/3] lib/vdso: Delay mask application in do_hres() Thomas Gleixner 2019-06-25 18:27 ` Thomas Gleixner 2019-06-25 20:15 ` Andy Lutomirski 2019-06-25 22:24 ` Thomas Gleixner 2019-06-26 6:38 ` Thomas Gleixner 2019-06-26 9:25 ` Vincenzo Frascino 2019-06-26 10:02 ` lib/vdso: Make delta calculation work correctly Thomas Gleixner 2019-06-26 11:08 ` Vincenzo Frascino 2019-06-24 13:58 ` [PATCH v7 04/25] arm64: Substitute gettimeofday with C implementation Catalin Marinas 2019-06-25 15:33 ` Dave Martin 2019-06-26 13:27 ` Vincenzo Frascino 2019-06-26 16:14 ` Dave Martin 2019-06-26 19:01 ` Vincenzo Frascino 2019-06-27 10:01 ` Dave Martin 2019-06-27 10:57 ` Vincenzo Frascino 2019-06-27 11:27 ` Dave Martin 2019-06-27 11:59 ` Vincenzo Frascino 2019-06-27 14:38 ` Dave Martin 2019-06-27 15:34 ` Vincenzo Frascino 2019-06-25 17:43 ` [PATCH] arm64: vdso: Fix compilation with clang < 8 Vincenzo Frascino 2019-06-26 11:36 ` [PATCH v2] arm64: vdso: Fix compilation with clang older then 8 Vincenzo Frascino [not found] ` <CGME20190628130921eucas1p239935b0771032c331911eacc1a69dd2e@eucas1p2.samsung.com> 2019-06-28 13:09 ` [PATCH v7 04/25] arm64: Substitute gettimeofday with C implementation Marek Szyprowski 2019-06-28 14:32 ` Vincenzo Frascino 2019-06-28 16:50 ` Sylwester Nawrocki 2019-06-29 6:58 ` Vincenzo Frascino 2019-07-08 12:57 ` Sylwester Nawrocki 2019-07-08 13:09 ` Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 05/25] arm64: Build vDSO with -ffixed-x18 Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 06/25] arm64: compat: Add missing syscall numbers Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 07/25] arm64: compat: Expose signal related structures Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 08/25] arm64: compat: Generate asm offsets for signals Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 09/25] lib: vdso: Add compat support Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 10/25] arm64: compat: Add vDSO Vincenzo Frascino 2019-06-24 14:00 ` Catalin Marinas 2019-07-10 4:02 ` John Stultz 2019-07-10 6:12 ` Thomas Gleixner 2019-07-10 9:48 ` Vincenzo Frascino 2019-07-10 8:27 ` Will Deacon 2019-07-10 8:58 ` Thomas Gleixner 2019-07-10 9:12 ` Will Deacon 2019-07-10 9:47 ` Vincenzo Frascino 2019-07-10 13:41 ` Vincenzo Frascino 2019-07-10 13:04 ` [PATCH] arm64: vdso: Fix ABI regression in compat vdso Vincenzo Frascino 2019-07-10 13:25 ` Will Deacon 2019-07-10 13:42 ` Vincenzo Frascino 2019-07-10 14:01 ` [PATCH v2] " Vincenzo Frascino 2019-07-10 15:44 ` John Stultz 2019-07-10 15:53 ` Vincenzo Frascino 2019-07-11 9:45 ` Will Deacon 2019-07-11 10:34 ` Thomas Gleixner 2019-07-11 11:32 ` Will Deacon 2019-06-21 9:52 ` [PATCH v7 11/25] arm64: Refactor vDSO code Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 12/25] arm64: compat: vDSO setup for compat layer Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 13/25] arm64: elf: vDSO code page discovery Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 14/25] arm64: compat: Get sigreturn trampolines from vDSO Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 15/25] arm64: Add vDSO compat support Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 16/25] arm: Add support for generic vDSO Vincenzo Frascino 2019-12-04 13:51 ` [PATCH v7 16/25] arm: Add support for generic vDSO (causing crash) Guenter Roeck 2019-12-04 13:58 ` Vincenzo Frascino 2019-12-04 16:16 ` Guenter Roeck 2019-12-04 17:15 ` Vincenzo Frascino 2019-12-04 19:39 ` Guenter Roeck 2019-12-05 9:42 ` Philippe Mathieu-Daudé 2019-12-05 10:00 ` Vincenzo Frascino 2019-12-05 11:02 ` Arnd Bergmann 2019-12-05 14:56 ` Philippe Mathieu-Daudé 2019-06-21 9:52 ` [PATCH v7 17/25] arm: Add clock_getres entry point Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 18/25] arm: Add clock_gettime64 " Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 19/25] mips: Add support for generic vDSO Vincenzo Frascino 2019-07-26 5:15 ` Paul Burton 2019-07-26 16:29 ` [PATCH 0/2] mips: vdso: Fix Makefile Vincenzo Frascino 2019-07-26 16:29 ` [PATCH 1/2] mips: vdso: Fix source path Vincenzo Frascino 2019-07-26 16:29 ` [PATCH 2/2] mips: vdso: Fix flip/flop vdso building bug Vincenzo Frascino 2019-07-28 22:20 ` [PATCH 0/2] mips: vdso: Fix Makefile Paul Burton 2019-06-21 9:52 ` [PATCH v7 20/25] mips: Add clock_getres entry point Vincenzo Frascino 2019-07-26 5:15 ` Paul Burton 2019-06-21 9:52 ` [PATCH v7 21/25] mips: Add clock_gettime64 " Vincenzo Frascino 2019-07-26 5:15 ` Paul Burton 2019-06-21 9:52 ` [PATCH v7 22/25] x86: Add support for generic vDSO Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 23/25] x86: Add clock_getres entry point Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 24/25] x86: Add clock_gettime64 " Vincenzo Frascino 2019-06-21 9:52 ` [PATCH v7 25/25] kselftest: Extend vDSO selftest Vincenzo Frascino 2019-06-24 0:34 ` [PATCH v7 00/25] Unify vDSOs across more architectures Thomas Gleixner 2019-06-24 1:15 ` Andy Lutomirski 2019-06-24 7:42 ` Thomas Gleixner 2019-06-24 13:21 ` Vincenzo Frascino [this message] 2019-06-24 14:18 ` Thomas Gleixner 2019-06-24 14:23 ` Russell King - ARM Linux admin 2019-06-24 14:49 ` Catalin Marinas 2019-06-24 16:20 ` Vincenzo Frascino 2019-10-25 11:42 ` Geert Uytterhoeven 2019-06-24 18:41 ` Paul Burton 2019-06-24 23:16 ` Vincenzo Frascino 2019-06-25 17:11 ` Paul Burton 2019-06-25 17:17 ` Vincenzo Frascino 2019-06-24 12:50 ` Andre Przywara
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