similar to: [patch 00/11] x86/vdso: Cleanups, simmplifications and CLOCK_TAI support

On Fri, 14 Sep 2018, Florian Weimer wrote: > On 09/14/2018 03:05 PM, Thomas Gleixner wrote: > > On Fri, 14 Sep 2018, Florian Weimer wrote: > > > > > On 09/14/2018 02:50 PM, Thomas Gleixner wrote: > > > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > > > implementation, which extended the clockid switch case and added yet

On Fri, 14 Sep 2018, Florian Weimer wrote: > On 09/14/2018 02:50 PM, Thomas Gleixner wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different copy of the same code. > > > > Especially the extended switch case is problematic as the compiler

On Fri, Sep 14, 2018 at 2:52 PM Thomas Gleixner <tglx at linutronix.de> wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > implementation, which extended the clockid switch case and added yet > another slightly different copy of the same code. > > Especially the extended switch case is problematic as the compiler tends to > generate a jump

Hi Vitaly, Paolo, Radim, etc., On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > implementation, which extended the clockid switch case and added yet > another slightly different copy of the same code. > > Especially the extended switch case is problematic as the compiler

On Wed, Oct 3, 2018 at 12:01 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > > Hi Vitaly, Paolo, Radim, etc., > > > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > > > > > Matt attempted to add CLOCK_TAI support to the VDSO

On Thu, Oct 4, 2018 at 9:43 AM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Wed, Oct 03, 2018 at 03:32:08PM -0700, Andy Lutomirski wrote: > > On Wed, Oct 3, 2018 at 12:01 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > > > On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > > > > Hi Vitaly, Paolo, Radim,

On Wed, Oct 03, 2018 at 11:22:58AM +0200, Vitaly Kuznetsov wrote: > Andy Lutomirski <luto at kernel.org> writes: > > > Hi Vitaly, Paolo, Radim, etc., > > > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > >> > >> Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > >> implementation,

> On Oct 3, 2018, at 2:22 AM, Vitaly Kuznetsov <vkuznets at redhat.com> wrote: > > Andy Lutomirski <luto at kernel.org> writes: > >> Hi Vitaly, Paolo, Radim, etc., >> >>> On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: >>> >>> Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime()

On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > Hi Vitaly, Paolo, Radim, etc., > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different

On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > Hi Vitaly, Paolo, Radim, etc., > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > > > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() > > implementation, which extended the clockid switch case and added yet > > another slightly different

On Wed, Oct 03, 2018 at 03:32:08PM -0700, Andy Lutomirski wrote: > On Wed, Oct 3, 2018 at 12:01 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > > > Hi Vitaly, Paolo, Radim, etc., > > > > > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de>

On Wed, Oct 03, 2018 at 03:32:08PM -0700, Andy Lutomirski wrote: > On Wed, Oct 3, 2018 at 12:01 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > > > On Tue, Oct 02, 2018 at 10:15:49PM -0700, Andy Lutomirski wrote: > > > Hi Vitaly, Paolo, Radim, etc., > > > > > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de>

Andy Lutomirski <luto at kernel.org> writes: > Hi Vitaly, Paolo, Radim, etc., > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: >> >> Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() >> implementation, which extended the clockid switch case and added yet >> another slightly different copy of the same

Andy Lutomirski <luto at kernel.org> writes: > Hi Vitaly, Paolo, Radim, etc., > > On Fri, Sep 14, 2018 at 5:52 AM Thomas Gleixner <tglx at linutronix.de> wrote: >> >> Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() >> implementation, which extended the clockid switch case and added yet >> another slightly different copy of the same

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

On Fri, 14 Sep 2018, Arnd Bergmann wrote: > On Fri, Sep 14, 2018 at 2:52 PM Thomas Gleixner <tglx at linutronix.de> wrote: > A couple of architectures (s390, ia64, riscv, powerpc, arm64) > implement the vdso as assembler code at the moment, so they > won't be as easy to consolidate (other than outright replacing all > the code). > > The other five: >

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

For better or for worse, I'm trying to understand this code. So far, I've come up with this patch: https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/vdso-tglx&id=14fd71e12b1c4492a06f368f75041f263e6862bf Is it correct, or am I missing some subtlety?

On Sat, Oct 6, 2018 at 1:29 PM Marcelo Tosatti <mtosatti at redhat.com> wrote: > > On Thu, Oct 04, 2018 at 03:15:32PM -0700, Andy Lutomirski wrote: > > For better or for worse, I'm trying to understand this code. So far, > > I've come up with this patch: > > > >