| Message ID | 20190530141531.43462-19-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Unify vDSOs across more architectures | expand |
From: Vincenzo Frascino <vincenzo.frascino@arm.com> On Thursday, May 30, 2019 7:16 AM > > The x86 vDSO library requires some adaptations to take advantage of the > newly introduced generic vDSO library. > > Introduce the following changes: > - Modification of vdso.c to be compliant with the common vdso datapage > - Use of lib/vdso for gettimeofday > > Cc: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> > > > diff --git a/arch/x86/include/asm/mshyperv-tsc.h b/arch/x86/include/asm/mshyperv-tsc.h > new file mode 100644 > index 000000000000..99c98ccea0bf > --- /dev/null > +++ b/arch/x86/include/asm/mshyperv-tsc.h > @@ -0,0 +1,76 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_X86_MSHYPER_TSCPAGE_H > +#define _ASM_X86_MSHYPER_TSCPAGE_H > + > +#include <asm/hyperv-tlfs.h> > + > +#ifdef CONFIG_HYPERV_TSCPAGE > +struct ms_hyperv_tsc_page *hv_get_tsc_page(void); > +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, > + u64 *cur_tsc) > +{ > + u64 scale, offset; > + u32 sequence; > + > + /* > + * The protocol for reading Hyper-V TSC page is specified in Hypervisor > + * Top-Level Functional Specification ver. 3.0 and above. To get the > + * reference time we must do the following: > + * - READ ReferenceTscSequence > + * A special '0' value indicates the time source is unreliable and we > + * need to use something else. The currently published specification > + * versions (up to 4.0b) contain a mistake and wrongly claim '-1' > + * instead of '0' as the special value, see commit c35b82ef0294. > + * - ReferenceTime = > + * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset > + * - READ ReferenceTscSequence again. In case its value has changed > + * since our first reading we need to discard ReferenceTime and repeat > + * the whole sequence as the hypervisor was updating the page in > + * between. > + */ > + do { > + sequence = READ_ONCE(tsc_pg->tsc_sequence); > + if (!sequence) > + return U64_MAX; > + /* > + * Make sure we read sequence before we read other values from > + * TSC page. > + */ > + smp_rmb(); > + > + scale = READ_ONCE(tsc_pg->tsc_scale); > + offset = READ_ONCE(tsc_pg->tsc_offset); > + *cur_tsc = rdtsc_ordered(); > + > + /* > + * Make sure we read sequence after we read all other values > + * from TSC page. > + */ > + smp_rmb(); > + > + } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); > + > + return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; > +} > + > +static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) > +{ > + u64 cur_tsc; > + > + return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); > +} > + > +#else > +static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) > +{ > + return NULL; > +} > + > +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, > + u64 *cur_tsc) > +{ > + BUG(); > + return U64_MAX; > +} > +#endif > +#endif > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index cc60e617931c..db095a992f3e 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -7,6 +7,7 @@ > #include <linux/nmi.h> > #include <asm/io.h> > #include <asm/hyperv-tlfs.h> > +#include <asm/mshyperv-tsc.h> > #include <asm/nospec-branch.h> > > #define VP_INVAL U32_MAX > @@ -387,73 +388,4 @@ static inline int hyperv_flush_guest_mapping_range(u64 as, > } > #endif /* CONFIG_HYPERV */ > > -#ifdef CONFIG_HYPERV_TSCPAGE > -struct ms_hyperv_tsc_page *hv_get_tsc_page(void); > -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, > - u64 *cur_tsc) > -{ > - u64 scale, offset; > - u32 sequence; > - > - /* > - * The protocol for reading Hyper-V TSC page is specified in Hypervisor > - * Top-Level Functional Specification ver. 3.0 and above. To get the > - * reference time we must do the following: > - * - READ ReferenceTscSequence > - * A special '0' value indicates the time source is unreliable and we > - * need to use something else. The currently published specification > - * versions (up to 4.0b) contain a mistake and wrongly claim '-1' > - * instead of '0' as the special value, see commit c35b82ef0294. > - * - ReferenceTime = > - * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset > - * - READ ReferenceTscSequence again. In case its value has changed > - * since our first reading we need to discard ReferenceTime and repeat > - * the whole sequence as the hypervisor was updating the page in > - * between. > - */ > - do { > - sequence = READ_ONCE(tsc_pg->tsc_sequence); > - if (!sequence) > - return U64_MAX; > - /* > - * Make sure we read sequence before we read other values from > - * TSC page. > - */ > - smp_rmb(); > - > - scale = READ_ONCE(tsc_pg->tsc_scale); > - offset = READ_ONCE(tsc_pg->tsc_offset); > - *cur_tsc = rdtsc_ordered(); > - > - /* > - * Make sure we read sequence after we read all other values > - * from TSC page. > - */ > - smp_rmb(); > - > - } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); > - > - return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; > -} > - > -static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) > -{ > - u64 cur_tsc; > - > - return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); > -} > - > -#else > -static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) > -{ > - return NULL; > -} > - > -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, > - u64 *cur_tsc) > -{ > - BUG(); > - return U64_MAX; > -} > -#endif > #endif Vincenzo -- these changes for Hyper-V are a subset of a larger patch set I have that moves all of the Hyper-V clock/timer code into a separate clocksource driver in drivers/clocksource, with an include file in includes/clocksource. That new include file should be able to work instead of your new mshyperv-tsc.h. It also has the benefit of being ISA neutral, so it will work with my in-progress patch set to support Linux on Hyper-V on ARM64. See https://lkml.org/lkml/2019/5/27/231 for the new clocksource driver patch set. Michael
Hi Michael, On 30/05/2019 16:41, Michael Kelley wrote: > From: Vincenzo Frascino <vincenzo.frascino@arm.com> On Thursday, May 30, 2019 7:16 AM >> >> The x86 vDSO library requires some adaptations to take advantage of the >> newly introduced generic vDSO library. >> >> Introduce the following changes: >> - Modification of vdso.c to be compliant with the common vdso datapage >> - Use of lib/vdso for gettimeofday >> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> >> >> >> diff --git a/arch/x86/include/asm/mshyperv-tsc.h b/arch/x86/include/asm/mshyperv-tsc.h >> new file mode 100644 >> index 000000000000..99c98ccea0bf >> --- /dev/null >> +++ b/arch/x86/include/asm/mshyperv-tsc.h >> @@ -0,0 +1,76 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +#ifndef _ASM_X86_MSHYPER_TSCPAGE_H >> +#define _ASM_X86_MSHYPER_TSCPAGE_H >> + >> +#include <asm/hyperv-tlfs.h> >> + >> +#ifdef CONFIG_HYPERV_TSCPAGE >> +struct ms_hyperv_tsc_page *hv_get_tsc_page(void); >> +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, >> + u64 *cur_tsc) >> +{ >> + u64 scale, offset; >> + u32 sequence; >> + >> + /* >> + * The protocol for reading Hyper-V TSC page is specified in Hypervisor >> + * Top-Level Functional Specification ver. 3.0 and above. To get the >> + * reference time we must do the following: >> + * - READ ReferenceTscSequence >> + * A special '0' value indicates the time source is unreliable and we >> + * need to use something else. The currently published specification >> + * versions (up to 4.0b) contain a mistake and wrongly claim '-1' >> + * instead of '0' as the special value, see commit c35b82ef0294. >> + * - ReferenceTime = >> + * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset >> + * - READ ReferenceTscSequence again. In case its value has changed >> + * since our first reading we need to discard ReferenceTime and repeat >> + * the whole sequence as the hypervisor was updating the page in >> + * between. >> + */ >> + do { >> + sequence = READ_ONCE(tsc_pg->tsc_sequence); >> + if (!sequence) >> + return U64_MAX; >> + /* >> + * Make sure we read sequence before we read other values from >> + * TSC page. >> + */ >> + smp_rmb(); >> + >> + scale = READ_ONCE(tsc_pg->tsc_scale); >> + offset = READ_ONCE(tsc_pg->tsc_offset); >> + *cur_tsc = rdtsc_ordered(); >> + >> + /* >> + * Make sure we read sequence after we read all other values >> + * from TSC page. >> + */ >> + smp_rmb(); >> + >> + } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); >> + >> + return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; >> +} >> + >> +static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) >> +{ >> + u64 cur_tsc; >> + >> + return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); >> +} >> + >> +#else >> +static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) >> +{ >> + return NULL; >> +} >> + >> +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, >> + u64 *cur_tsc) >> +{ >> + BUG(); >> + return U64_MAX; >> +} >> +#endif >> +#endif >> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h >> index cc60e617931c..db095a992f3e 100644 >> --- a/arch/x86/include/asm/mshyperv.h >> +++ b/arch/x86/include/asm/mshyperv.h >> @@ -7,6 +7,7 @@ >> #include <linux/nmi.h> >> #include <asm/io.h> >> #include <asm/hyperv-tlfs.h> >> +#include <asm/mshyperv-tsc.h> >> #include <asm/nospec-branch.h> >> >> #define VP_INVAL U32_MAX >> @@ -387,73 +388,4 @@ static inline int hyperv_flush_guest_mapping_range(u64 as, >> } >> #endif /* CONFIG_HYPERV */ >> >> -#ifdef CONFIG_HYPERV_TSCPAGE >> -struct ms_hyperv_tsc_page *hv_get_tsc_page(void); >> -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, >> - u64 *cur_tsc) >> -{ >> - u64 scale, offset; >> - u32 sequence; >> - >> - /* >> - * The protocol for reading Hyper-V TSC page is specified in Hypervisor >> - * Top-Level Functional Specification ver. 3.0 and above. To get the >> - * reference time we must do the following: >> - * - READ ReferenceTscSequence >> - * A special '0' value indicates the time source is unreliable and we >> - * need to use something else. The currently published specification >> - * versions (up to 4.0b) contain a mistake and wrongly claim '-1' >> - * instead of '0' as the special value, see commit c35b82ef0294. >> - * - ReferenceTime = >> - * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset >> - * - READ ReferenceTscSequence again. In case its value has changed >> - * since our first reading we need to discard ReferenceTime and repeat >> - * the whole sequence as the hypervisor was updating the page in >> - * between. >> - */ >> - do { >> - sequence = READ_ONCE(tsc_pg->tsc_sequence); >> - if (!sequence) >> - return U64_MAX; >> - /* >> - * Make sure we read sequence before we read other values from >> - * TSC page. >> - */ >> - smp_rmb(); >> - >> - scale = READ_ONCE(tsc_pg->tsc_scale); >> - offset = READ_ONCE(tsc_pg->tsc_offset); >> - *cur_tsc = rdtsc_ordered(); >> - >> - /* >> - * Make sure we read sequence after we read all other values >> - * from TSC page. >> - */ >> - smp_rmb(); >> - >> - } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); >> - >> - return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; >> -} >> - >> -static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) >> -{ >> - u64 cur_tsc; >> - >> - return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); >> -} >> - >> -#else >> -static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) >> -{ >> - return NULL; >> -} >> - >> -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, >> - u64 *cur_tsc) >> -{ >> - BUG(); >> - return U64_MAX; >> -} >> -#endif >> #endif > > Vincenzo -- these changes for Hyper-V are a subset of a larger patch set > I have that moves all of the Hyper-V clock/timer code into a separate > clocksource driver in drivers/clocksource, with an include file in > includes/clocksource. That new include file should be able to work > instead of your new mshyperv-tsc.h. It also has the benefit of being > ISA neutral, so it will work with my in-progress patch set to support > Linux on Hyper-V on ARM64. See https://lkml.org/lkml/2019/5/27/231 > for the new clocksource driver patch set. > Thank you for pointing this out, I will rebase my changes on your patches. > Michael >
On Thu, 30 May 2019, Michael Kelley wrote: > Vincenzo -- these changes for Hyper-V are a subset of a larger patch set > I have that moves all of the Hyper-V clock/timer code into a separate > clocksource driver in drivers/clocksource, with an include file in > includes/clocksource. That new include file should be able to work > instead of your new mshyperv-tsc.h. It also has the benefit of being > ISA neutral, so it will work with my in-progress patch set to support > Linux on Hyper-V on ARM64. See https://lkml.org/lkml/2019/5/27/231 > for the new clocksource driver patch set. Grrr. That's queued in hyperv-next for whatever reasons. Sasha, can you please provide me the branch to pull from so I can have a common base for all the various changes floating around? Thanks, tglx
On Fri, Jun 14, 2019 at 01:15:23PM +0200, Thomas Gleixner wrote: >On Thu, 30 May 2019, Michael Kelley wrote: >> Vincenzo -- these changes for Hyper-V are a subset of a larger patch set >> I have that moves all of the Hyper-V clock/timer code into a separate >> clocksource driver in drivers/clocksource, with an include file in >> includes/clocksource. That new include file should be able to work >> instead of your new mshyperv-tsc.h. It also has the benefit of being >> ISA neutral, so it will work with my in-progress patch set to support >> Linux on Hyper-V on ARM64. See https://lkml.org/lkml/2019/5/27/231 >> for the new clocksource driver patch set. > >Grrr. That's queued in hyperv-next for whatever reasons. I queue up our future pull requests there to give them some soaking in -next. >Sasha, can you please provide me the branch to pull from so I can have a >common base for all the various changes floating around? I'll send you a unified pull request for these changes. -- Thanks, Sasha
On Fri, 14 Jun 2019, Sasha Levin wrote: > On Fri, Jun 14, 2019 at 01:15:23PM +0200, Thomas Gleixner wrote: > > On Thu, 30 May 2019, Michael Kelley wrote: > > > Vincenzo -- these changes for Hyper-V are a subset of a larger patch set > > > I have that moves all of the Hyper-V clock/timer code into a separate > > > clocksource driver in drivers/clocksource, with an include file in > > > includes/clocksource. That new include file should be able to work > > > instead of your new mshyperv-tsc.h. It also has the benefit of being > > > ISA neutral, so it will work with my in-progress patch set to support > > > Linux on Hyper-V on ARM64. See https://lkml.org/lkml/2019/5/27/231 > > > for the new clocksource driver patch set. > > > > Grrr. That's queued in hyperv-next for whatever reasons. > > I queue up our future pull requests there to give them some soaking in > -next. What? You queue completely unreviewed stuff which touches two other subsystems to let it soak in next? > > Sasha, can you please provide me the branch to pull from so I can have a > > common base for all the various changes floating around? > > I'll send you a unified pull request for these changes. Which has not materialized yet. TBH, I'm pretty grumpy about those clocksource changes. Here is the diffstat: MAINTAINERS | 2 arch/x86/entry/vdso/vclock_gettime.c | 1 arch/x86/entry/vdso/vma.c | 2 arch/x86/hyperv/hv_init.c | 91 --------- arch/x86/include/asm/hyperv-tlfs.h | 6 arch/x86/include/asm/mshyperv.h | 81 +------- arch/x86/kernel/cpu/mshyperv.c | 2 arch/x86/kvm/x86.c | 1 drivers/clocksource/Makefile | 1 drivers/clocksource/hyperv_timer.c | 322 +++++++++++++++++++++++++++++++++++ drivers/hv/Kconfig | 3 drivers/hv/hv.c | 156 ---------------- drivers/hv/hv_util.c | 1 drivers/hv/hyperv_vmbus.h | 3 drivers/hv/vmbus_drv.c | 42 ++-- include/clocksource/hyperv_timer.h | 105 +++++++++++ While the world and some more people have been CC'ed on those patches, neither the clocksource nor the x86 maintainer have been. When I gave Vincenzo the advise to base his code on that hyper-v branch, I expected that I find the related patches in my mail backlog. No, they have not been there because I was not on CC. Folks, please stop chosing Cc lists as you like. We have well established rules for that. And please stop queueing random unreviewed patches in next. Next is not a playground for not ready and unreviewed stuff. No, the hyper-v inbreed Reviewed-by is not sufficient for anything x86 and clocksource related. After chasing and looking at those patches, which have horrible subject lines and changelogs btw, I was not able to judge quickly whether that stuff is self contained or not. So no, I fixed up the fallout and rebased Vincenzos VDSO stuff on mainline w/o those hyperv changes simply because if they are not self contained they will break bisection badly. I'm going to push out the VDSO series later today. That will nicely break in combination with the hyper-next branch. Stephen, please drop that and do not try to handle the fallout. That stuff needs to go through the proper channels or at least be acked/reviewed by the relevant maintainers. So the hyper-v folks can rebase themself and post it proper. Yours grumpy, tglx
On Sat, Jun 22, 2019 at 04:46:28PM +0200, Thomas Gleixner wrote: >On Fri, 14 Jun 2019, Sasha Levin wrote: >> On Fri, Jun 14, 2019 at 01:15:23PM +0200, Thomas Gleixner wrote: >> > On Thu, 30 May 2019, Michael Kelley wrote: >> > > Vincenzo -- these changes for Hyper-V are a subset of a larger patch set >> > > I have that moves all of the Hyper-V clock/timer code into a separate >> > > clocksource driver in drivers/clocksource, with an include file in >> > > includes/clocksource. That new include file should be able to work >> > > instead of your new mshyperv-tsc.h. It also has the benefit of being >> > > ISA neutral, so it will work with my in-progress patch set to support >> > > Linux on Hyper-V on ARM64. See https://lkml.org/lkml/2019/5/27/231 >> > > for the new clocksource driver patch set. >> > >> > Grrr. That's queued in hyperv-next for whatever reasons. >> >> I queue up our future pull requests there to give them some soaking in >> -next. > >What? You queue completely unreviewed stuff which touches two other >subsystems to let it soak in next? It was out on LKML for 2+ weeks before I've pulled it in. As it mostly touches hyperv bits I felt comfortable to give it time in -next (but not actually to try and merge it until it gets a few acks). >> > Sasha, can you please provide me the branch to pull from so I can have a >> > common base for all the various changes floating around? >> >> I'll send you a unified pull request for these changes. > >Which has not materialized yet. Appologies about this. I ended up with way more travel than I would have liked (writing this from an airport). I've reset our hyperv-next branch to remove these 3 commits until we figure this out. >TBH, I'm pretty grumpy about those clocksource changes. Here is the >diffstat: > > MAINTAINERS | 2 > arch/x86/entry/vdso/vclock_gettime.c | 1 > arch/x86/entry/vdso/vma.c | 2 > arch/x86/hyperv/hv_init.c | 91 --------- > arch/x86/include/asm/hyperv-tlfs.h | 6 > arch/x86/include/asm/mshyperv.h | 81 +------- > arch/x86/kernel/cpu/mshyperv.c | 2 > arch/x86/kvm/x86.c | 1 > drivers/clocksource/Makefile | 1 > drivers/clocksource/hyperv_timer.c | 322 +++++++++++++++++++++++++++++++++++ > drivers/hv/Kconfig | 3 > drivers/hv/hv.c | 156 ---------------- > drivers/hv/hv_util.c | 1 > drivers/hv/hyperv_vmbus.h | 3 > drivers/hv/vmbus_drv.c | 42 ++-- > include/clocksource/hyperv_timer.h | 105 +++++++++++ > >While the world and some more people have been CC'ed on those patches, >neither the clocksource nor the x86 maintainer have been. > >When I gave Vincenzo the advise to base his code on that hyper-v branch, I >expected that I find the related patches in my mail backlog. No, they have >not been there because I was not on CC. > >Folks, please stop chosing Cc lists as you like. We have well established >rules for that. And please stop queueing random unreviewed patches in >next. Next is not a playground for not ready and unreviewed stuff. No, the >hyper-v inbreed Reviewed-by is not sufficient for anything x86 and >clocksource related. I'm sorry for this, you were supposed to be Cc'ed on these patches and I see that you were not. >After chasing and looking at those patches, which have horrible subject >lines and changelogs btw, I was not able to judge quickly whether that >stuff is self contained or not. So no, I fixed up the fallout and rebased >Vincenzos VDSO stuff on mainline w/o those hyperv changes simply because if >they are not self contained they will break bisection badly. > >I'm going to push out the VDSO series later today. That will nicely break >in combination with the hyper-next branch. Stephen, please drop that and do >not try to handle the fallout. That stuff needs to go through the proper >channels or at least be acked/reviewed by the relevant maintainers. So the >hyper-v folks can rebase themself and post it proper. Okay, thank you. We'll rebase and resend. -- Thanks, Sasha
Hi Sasha, On Sun, 23 Jun 2019 15:09:29 -0400 Sasha Levin <sashal@kernel.org> wrote: > > Appologies about this. I ended up with way more travel than I would have > liked (writing this from an airport). I've reset our hyperv-next branch > to remove these 3 commits until we figure this out. But not pushed out, yet?
Sasha, On Sun, 23 Jun 2019, Sasha Levin wrote: > On Sat, Jun 22, 2019 at 04:46:28PM +0200, Thomas Gleixner wrote: > > Folks, please stop chosing Cc lists as you like. We have well established > > rules for that. And please stop queueing random unreviewed patches in > > next. Next is not a playground for not ready and unreviewed stuff. No, the > > hyper-v inbreed Reviewed-by is not sufficient for anything x86 and > > clocksource related. > > I'm sorry for this, you were supposed to be Cc'ed on these patches and I > see that you were not. All good. I've vented steam and am back to normal pressure :) > > After chasing and looking at those patches, which have horrible subject > > lines and changelogs btw, I was not able to judge quickly whether that > > stuff is self contained or not. So no, I fixed up the fallout and rebased > > Vincenzos VDSO stuff on mainline w/o those hyperv changes simply because if > > they are not self contained they will break bisection badly. > > > > I'm going to push out the VDSO series later today. That will nicely break Not yet, but soon :) > > in combination with the hyper-next branch. Stephen, please drop that and do > > not try to handle the fallout. That stuff needs to go through the proper > > channels or at least be acked/reviewed by the relevant maintainers. So the > > hyper-v folks can rebase themself and post it proper. > > Okay, thank you. We'll rebase and resend. I have no objections if you collect hyper-v stuff, quite the contrary, but changes which touch other subsystems need to be coordinated upfront. That's all I'm asking for. Btw, that clocksource stuff looks good code wise, just the change logs need some care and after the VDSO stuff hits next we need to sort out the logistics. I hope these changes are completely self contained. If not we'll find a solution. Thanks, tglx
From: Thomas Gleixner <tglx@linutronix.de> Sent: Sunday, June 23, 2019 3:13 PM > > I have no objections if you collect hyper-v stuff, quite the contrary, but > changes which touch other subsystems need to be coordinated upfront. That's > all I'm asking for. > > Btw, that clocksource stuff looks good code wise, just the change logs need > some care and after the VDSO stuff hits next we need to sort out the > logistics. I hope these changes are completely self contained. If not we'll > find a solution. > In my view, the only thing that potentially needs a solution is where the Hyper-V clock code used by VDSO ends up in the code tree. I think the right long term place is include/clocksource/hyperv_timer.h. That location is architecture neutral, and the same Hyper-V clock code will be shared by the Hyper-V on ARM64 support that's in process. Vincenzo's patch set creates a new file arch/x86/include/asm/mshyperv-tsc.h, which I will want to move when creating the separate Hyper-V clocksource driver. If you're OK with that file existing for a release and then going away, that's fine. Alternatively, put the code in include/clocksource/hyperv_timer.h now as part of the VDSO patch set so it's in the right place from the start. My subsequent patch set will add a few additional tweaks to remove x86-isms and fully integrate with the separate Hyper-V clocksource driver. Michael
On Mon, Jun 24, 2019 at 07:58:34AM +1000, Stephen Rothwell wrote: >Hi Sasha, > >On Sun, 23 Jun 2019 15:09:29 -0400 Sasha Levin <sashal@kernel.org> wrote: >> >> Appologies about this. I ended up with way more travel than I would have >> liked (writing this from an airport). I've reset our hyperv-next branch >> to remove these 3 commits until we figure this out. > >But not pushed out, yet? Pushed now. For some reason the airport wifi was blocking ssh :/ -- Thanks, Sasha
On Mon, 24 Jun 2019, Michael Kelley wrote: > From: Thomas Gleixner <tglx@linutronix.de> Sent: Sunday, June 23, 2019 3:13 PM > > > > I have no objections if you collect hyper-v stuff, quite the contrary, but > > changes which touch other subsystems need to be coordinated upfront. That's > > all I'm asking for. > > > > Btw, that clocksource stuff looks good code wise, just the change logs need > > some care and after the VDSO stuff hits next we need to sort out the > > logistics. I hope these changes are completely self contained. If not we'll > > find a solution. > > > > In my view, the only thing that potentially needs a solution is where the > Hyper-V clock code used by VDSO ends up in the code tree. I think the > right long term place is include/clocksource/hyperv_timer.h. That location > is architecture neutral, and the same Hyper-V clock code will be shared by > the Hyper-V on ARM64 support that's in process. > > Vincenzo's patch set creates a new file arch/x86/include/asm/mshyperv-tsc.h, > which I will want to move when creating the separate Hyper-V clocksource > driver. If you're OK with that file existing for a release and then going away, > that's fine. Alternatively, put the code in include/clocksource/hyperv_timer.h > now as part of the VDSO patch set so it's in the right place from the start. My > subsequent patch set will add a few additional tweaks to remove x86-isms > and fully integrate with the separate Hyper-V clocksource driver. I don't care whether this goes into 5.3 or later. If you can provide me rebased self contained patches on top of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso I'm happy to pull them in on top. Thanks, tglx
Hi Sasha, On Sun, 23 Jun 2019 20:24:30 -0400 Sasha Levin <sashal@kernel.org> wrote: > > Pushed now. For some reason the airport wifi was blocking ssh :/ Thanks.
From: Thomas Gleixner <tglx@linutronix.de> Sent: Sunday, June 23, 2019 5:25 PM > > I don't care whether this goes into 5.3 or later. If you can provide me > rebased self contained patches on top of > > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso > > I'm happy to pull them in on top. > I've sent out "v4" of the patch set to create a Hyper-V clocksource, based on the above tree. It is contained to Hyper-V code, plus updating a #include statement in two of the VDSO files and in one KVM file. If the KVM file update is problematic, the patch set can just wait until 5.3-rc1. Michael
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2bbbd4d1ba31..51a98d6eae8e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -17,6 +17,7 @@ config X86_32 select HAVE_DEBUG_STACKOVERFLOW select MODULES_USE_ELF_REL select OLD_SIGACTION + select GENERIC_VDSO_32 config X86_64 def_bool y @@ -121,6 +122,7 @@ config X86 select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL + select GENERIC_GETTIMEOFDAY select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 select HAVE_ACPI_APEI if ACPI select HAVE_ACPI_APEI_NMI if ACPI @@ -202,6 +204,7 @@ config X86 select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_USER_RETURN_NOTIFIER + select HAVE_GENERIC_VDSO select HOTPLUG_SMT if SMP select IRQ_FORCED_THREADING select NEED_SG_DMA_LENGTH diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 42fe42e82baf..39106111be86 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -3,6 +3,12 @@ # Building vDSO images for x86. # +# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before +# the inclusion of generic Makefile. +ARCH_REL_TYPE_ABS := R_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE| +ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE +include $(srctree)/lib/vdso/Makefile + KBUILD_CFLAGS += $(DISABLE_LTO) KASAN_SANITIZE := n UBSAN_SANITIZE := n @@ -51,6 +57,7 @@ VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ $(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE $(call if_changed,vdso) + $(call if_changed,vdso_check) HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi hostprogs-y += vdso2c @@ -121,6 +128,7 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE $(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE $(call if_changed,vdso) + $(call if_changed,vdso_check) CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1 @@ -160,6 +168,7 @@ $(obj)/vdso32.so.dbg: FORCE \ $(obj)/vdso32/system_call.o \ $(obj)/vdso32/sigreturn.o $(call if_changed,vdso) + $(call if_changed,vdso_check) # # The DSO images are built using a special linker script. diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 98c7d12b945c..39268f941878 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -1,240 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 /* - * Copyright 2006 Andi Kleen, SUSE Labs. - * Subject to the GNU Public License, v.2 - * * Fast user context implementation of clock_gettime, gettimeofday, and time. * + * Copyright 2019 ARM Limited + * Copyright 2006 Andi Kleen, SUSE Labs. * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net> * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany - * - * The code should have no internal unresolved relocations. - * Check with readelf after changing. */ - -#include <uapi/linux/time.h> -#include <asm/vgtod.h> -#include <asm/vvar.h> -#include <asm/unistd.h> -#include <asm/msr.h> -#include <asm/pvclock.h> -#include <asm/mshyperv.h> -#include <linux/math64.h> #include <linux/time.h> -#include <linux/kernel.h> +#include <linux/types.h> -#define gtod (&VVAR(vsyscall_gtod_data)) +#include "../../../../lib/vdso/gettimeofday.c" -extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts); -extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz); +extern int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz); extern time_t __vdso_time(time_t *t); -#ifdef CONFIG_PARAVIRT_CLOCK -extern u8 pvclock_page[PAGE_SIZE] - __attribute__((visibility("hidden"))); -#endif - -#ifdef CONFIG_HYPERV_TSCPAGE -extern u8 hvclock_page[PAGE_SIZE] - __attribute__((visibility("hidden"))); -#endif - -#ifndef BUILD_VDSO32 - -notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) -{ - long ret; - asm ("syscall" : "=a" (ret), "=m" (*ts) : - "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : - "rcx", "r11"); - return ret; -} - -#else - -notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) +notrace int __vdso_gettimeofday(struct __kernel_old_timeval *tv, + struct timezone *tz) { - long ret; - - asm ( - "mov %%ebx, %%edx \n" - "mov %[clock], %%ebx \n" - "call __kernel_vsyscall \n" - "mov %%edx, %%ebx \n" - : "=a" (ret), "=m" (*ts) - : "0" (__NR_clock_gettime), [clock] "g" (clock), "c" (ts) - : "edx"); - return ret; + return __cvdso_gettimeofday(tv, tz); } +int gettimeofday(struct __kernel_old_timeval *, struct timezone *) + __attribute__((weak, alias("__vdso_gettimeofday"))); -#endif - -#ifdef CONFIG_PARAVIRT_CLOCK -static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void) +notrace time_t __vdso_time(time_t *t) { - return (const struct pvclock_vsyscall_time_info *)&pvclock_page; + return __cvdso_time(t); } +time_t time(time_t *t) + __attribute__((weak, alias("__vdso_time"))); -static notrace u64 vread_pvclock(void) -{ - const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti; - u32 version; - u64 ret; - - /* - * Note: The kernel and hypervisor must guarantee that cpu ID - * number maps 1:1 to per-CPU pvclock time info. - * - * Because the hypervisor is entirely unaware of guest userspace - * preemption, it cannot guarantee that per-CPU pvclock time - * info is updated if the underlying CPU changes or that that - * version is increased whenever underlying CPU changes. - * - * On KVM, we are guaranteed that pvti updates for any vCPU are - * atomic as seen by *all* vCPUs. This is an even stronger - * guarantee than we get with a normal seqlock. - * - * On Xen, we don't appear to have that guarantee, but Xen still - * supplies a valid seqlock using the version field. - * - * We only do pvclock vdso timing at all if - * PVCLOCK_TSC_STABLE_BIT is set, and we interpret that bit to - * mean that all vCPUs have matching pvti and that the TSC is - * synced, so we can just look at vCPU 0's pvti. - */ - - do { - version = pvclock_read_begin(pvti); - - if (unlikely(!(pvti->flags & PVCLOCK_TSC_STABLE_BIT))) - return U64_MAX; - - ret = __pvclock_read_cycles(pvti, rdtsc_ordered()); - } while (pvclock_read_retry(pvti, version)); - - return ret; -} -#endif -#ifdef CONFIG_HYPERV_TSCPAGE -static notrace u64 vread_hvclock(void) -{ - const struct ms_hyperv_tsc_page *tsc_pg = - (const struct ms_hyperv_tsc_page *)&hvclock_page; - return hv_read_tsc_page(tsc_pg); -} -#endif +#if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64) +/* both 64-bit and x32 use these */ +extern int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts); +extern int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res); -notrace static inline u64 vgetcyc(int mode) +notrace int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) { - if (mode == VCLOCK_TSC) - return (u64)rdtsc_ordered(); -#ifdef CONFIG_PARAVIRT_CLOCK - else if (mode == VCLOCK_PVCLOCK) - return vread_pvclock(); -#endif -#ifdef CONFIG_HYPERV_TSCPAGE - else if (mode == VCLOCK_HVCLOCK) - return vread_hvclock(); -#endif - return U64_MAX; + return __cvdso_clock_gettime(clock, ts); } +int clock_gettime(clockid_t, struct __kernel_timespec *) + __attribute__((weak, alias("__vdso_clock_gettime"))); -notrace static int do_hres(clockid_t clk, struct timespec *ts) +notrace int __vdso_clock_getres(clockid_t clock, + struct __kernel_timespec *res) { - struct vgtod_ts *base = >od->basetime[clk]; - u64 cycles, last, sec, ns; - unsigned int seq; - - do { - seq = gtod_read_begin(gtod); - cycles = vgetcyc(gtod->vclock_mode); - ns = base->nsec; - last = gtod->cycle_last; - if (unlikely((s64)cycles < 0)) - return vdso_fallback_gettime(clk, ts); - if (cycles > last) - ns += (cycles - last) * gtod->mult; - ns >>= gtod->shift; - sec = base->sec; - } while (unlikely(gtod_read_retry(gtod, seq))); - - /* - * Do this outside the loop: a race inside the loop could result - * in __iter_div_u64_rem() being extremely slow. - */ - ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); - ts->tv_nsec = ns; - - return 0; + return __cvdso_clock_getres(clock, res); } +int clock_getres(clockid_t, struct __kernel_timespec *) + __attribute__((weak, alias("__vdso_clock_getres"))); -notrace static void do_coarse(clockid_t clk, struct timespec *ts) -{ - struct vgtod_ts *base = >od->basetime[clk]; - unsigned int seq; - - do { - seq = gtod_read_begin(gtod); - ts->tv_sec = base->sec; - ts->tv_nsec = base->nsec; - } while (unlikely(gtod_read_retry(gtod, seq))); -} +#else +/* i386 only */ +extern int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts); +extern int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts); +extern int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res); -notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts) +notrace int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts) { - unsigned int msk; - - /* Sort out negative (CPU/FD) and invalid clocks */ - if (unlikely((unsigned int) clock >= MAX_CLOCKS)) - return vdso_fallback_gettime(clock, ts); - - /* - * Convert the clockid to a bitmask and use it to check which - * clocks are handled in the VDSO directly. - */ - msk = 1U << clock; - if (likely(msk & VGTOD_HRES)) { - return do_hres(clock, ts); - } else if (msk & VGTOD_COARSE) { - do_coarse(clock, ts); - return 0; - } - return vdso_fallback_gettime(clock, ts); + return __cvdso_clock_gettime32(clock, ts); } - -int clock_gettime(clockid_t, struct timespec *) +int clock_gettime(clockid_t, struct old_timespec32 *) __attribute__((weak, alias("__vdso_clock_gettime"))); -notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) +notrace int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts) { - if (likely(tv != NULL)) { - struct timespec *ts = (struct timespec *) tv; - - do_hres(CLOCK_REALTIME, ts); - tv->tv_usec /= 1000; - } - if (unlikely(tz != NULL)) { - tz->tz_minuteswest = gtod->tz_minuteswest; - tz->tz_dsttime = gtod->tz_dsttime; - } - - return 0; + return __cvdso_clock_gettime(clock, ts); } -int gettimeofday(struct timeval *, struct timezone *) - __attribute__((weak, alias("__vdso_gettimeofday"))); +int clock_gettime64(clockid_t, struct __kernel_timespec *) + __attribute__((weak, alias("__vdso_clock_gettime64"))); -/* - * This will break when the xtime seconds get inaccurate, but that is - * unlikely - */ -notrace time_t __vdso_time(time_t *t) +notrace int __vdso_clock_getres(clockid_t clock, + struct old_timespec32 *res) { - /* This is atomic on x86 so we don't need any locks. */ - time_t result = READ_ONCE(gtod->basetime[CLOCK_REALTIME].sec); - - if (t) - *t = result; - return result; + return __cvdso_clock_getres_time32(clock, res); } -time_t time(time_t *t) - __attribute__((weak, alias("__vdso_time"))); +int clock_getres(clockid_t, struct old_timespec32 *) + __attribute__((weak, alias("__vdso_clock_getres"))); +#endif diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S index d3a2dce4cfa9..36b644e16272 100644 --- a/arch/x86/entry/vdso/vdso.lds.S +++ b/arch/x86/entry/vdso/vdso.lds.S @@ -25,6 +25,8 @@ VERSION { __vdso_getcpu; time; __vdso_time; + clock_getres; + __vdso_clock_getres; local: *; }; } diff --git a/arch/x86/entry/vdso/vdso32/vdso32.lds.S b/arch/x86/entry/vdso/vdso32/vdso32.lds.S index 422764a81d32..c7720995ab1a 100644 --- a/arch/x86/entry/vdso/vdso32/vdso32.lds.S +++ b/arch/x86/entry/vdso/vdso32/vdso32.lds.S @@ -26,6 +26,8 @@ VERSION __vdso_clock_gettime; __vdso_gettimeofday; __vdso_time; + __vdso_clock_getres; + __vdso_clock_gettime64; }; LINUX_2.5 { diff --git a/arch/x86/entry/vdso/vdsox32.lds.S b/arch/x86/entry/vdso/vdsox32.lds.S index 05cd1c5c4a15..16a8050a4fb6 100644 --- a/arch/x86/entry/vdso/vdsox32.lds.S +++ b/arch/x86/entry/vdso/vdsox32.lds.S @@ -21,6 +21,7 @@ VERSION { __vdso_gettimeofday; __vdso_getcpu; __vdso_time; + __vdso_clock_getres; local: *; }; } diff --git a/arch/x86/entry/vsyscall/Makefile b/arch/x86/entry/vsyscall/Makefile index 1ac4dd116c26..93c1b3e949a7 100644 --- a/arch/x86/entry/vsyscall/Makefile +++ b/arch/x86/entry/vsyscall/Makefile @@ -2,7 +2,5 @@ # # Makefile for the x86 low level vsyscall code # -obj-y := vsyscall_gtod.o - obj-$(CONFIG_X86_VSYSCALL_EMULATION) += vsyscall_64.o vsyscall_emu_64.o diff --git a/arch/x86/entry/vsyscall/vsyscall_gtod.c b/arch/x86/entry/vsyscall/vsyscall_gtod.c deleted file mode 100644 index cfcdba082feb..000000000000 --- a/arch/x86/entry/vsyscall/vsyscall_gtod.c +++ /dev/null @@ -1,83 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE - * Copyright 2003 Andi Kleen, SuSE Labs. - * - * Modified for x86 32 bit architecture by - * Stefani Seibold <stefani@seibold.net> - * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany - * - * Thanks to hpa@transmeta.com for some useful hint. - * Special thanks to Ingo Molnar for his early experience with - * a different vsyscall implementation for Linux/IA32 and for the name. - * - */ - -#include <linux/timekeeper_internal.h> -#include <asm/vgtod.h> -#include <asm/vvar.h> - -int vclocks_used __read_mostly; - -DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data); - -void update_vsyscall_tz(void) -{ - vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest; - vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime; -} - -void update_vsyscall(struct timekeeper *tk) -{ - int vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode; - struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data; - struct vgtod_ts *base; - u64 nsec; - - /* Mark the new vclock used. */ - BUILD_BUG_ON(VCLOCK_MAX >= 32); - WRITE_ONCE(vclocks_used, READ_ONCE(vclocks_used) | (1 << vclock_mode)); - - gtod_write_begin(vdata); - - /* copy vsyscall data */ - vdata->vclock_mode = vclock_mode; - vdata->cycle_last = tk->tkr_mono.cycle_last; - vdata->mask = tk->tkr_mono.mask; - vdata->mult = tk->tkr_mono.mult; - vdata->shift = tk->tkr_mono.shift; - - base = &vdata->basetime[CLOCK_REALTIME]; - base->sec = tk->xtime_sec; - base->nsec = tk->tkr_mono.xtime_nsec; - - base = &vdata->basetime[CLOCK_TAI]; - base->sec = tk->xtime_sec + (s64)tk->tai_offset; - base->nsec = tk->tkr_mono.xtime_nsec; - - base = &vdata->basetime[CLOCK_MONOTONIC]; - base->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - nsec = tk->tkr_mono.xtime_nsec; - nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift); - while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { - nsec -= ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift; - base->sec++; - } - base->nsec = nsec; - - base = &vdata->basetime[CLOCK_REALTIME_COARSE]; - base->sec = tk->xtime_sec; - base->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; - - base = &vdata->basetime[CLOCK_MONOTONIC_COARSE]; - base->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; - nsec += tk->wall_to_monotonic.tv_nsec; - while (nsec >= NSEC_PER_SEC) { - nsec -= NSEC_PER_SEC; - base->sec++; - } - base->nsec = nsec; - - gtod_write_end(vdata); -} diff --git a/arch/x86/include/asm/mshyperv-tsc.h b/arch/x86/include/asm/mshyperv-tsc.h new file mode 100644 index 000000000000..99c98ccea0bf --- /dev/null +++ b/arch/x86/include/asm/mshyperv-tsc.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_MSHYPER_TSCPAGE_H +#define _ASM_X86_MSHYPER_TSCPAGE_H + +#include <asm/hyperv-tlfs.h> + +#ifdef CONFIG_HYPERV_TSCPAGE +struct ms_hyperv_tsc_page *hv_get_tsc_page(void); +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, + u64 *cur_tsc) +{ + u64 scale, offset; + u32 sequence; + + /* + * The protocol for reading Hyper-V TSC page is specified in Hypervisor + * Top-Level Functional Specification ver. 3.0 and above. To get the + * reference time we must do the following: + * - READ ReferenceTscSequence + * A special '0' value indicates the time source is unreliable and we + * need to use something else. The currently published specification + * versions (up to 4.0b) contain a mistake and wrongly claim '-1' + * instead of '0' as the special value, see commit c35b82ef0294. + * - ReferenceTime = + * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset + * - READ ReferenceTscSequence again. In case its value has changed + * since our first reading we need to discard ReferenceTime and repeat + * the whole sequence as the hypervisor was updating the page in + * between. + */ + do { + sequence = READ_ONCE(tsc_pg->tsc_sequence); + if (!sequence) + return U64_MAX; + /* + * Make sure we read sequence before we read other values from + * TSC page. + */ + smp_rmb(); + + scale = READ_ONCE(tsc_pg->tsc_scale); + offset = READ_ONCE(tsc_pg->tsc_offset); + *cur_tsc = rdtsc_ordered(); + + /* + * Make sure we read sequence after we read all other values + * from TSC page. + */ + smp_rmb(); + + } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); + + return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; +} + +static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) +{ + u64 cur_tsc; + + return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); +} + +#else +static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) +{ + return NULL; +} + +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, + u64 *cur_tsc) +{ + BUG(); + return U64_MAX; +} +#endif +#endif diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index cc60e617931c..db095a992f3e 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -7,6 +7,7 @@ #include <linux/nmi.h> #include <asm/io.h> #include <asm/hyperv-tlfs.h> +#include <asm/mshyperv-tsc.h> #include <asm/nospec-branch.h> #define VP_INVAL U32_MAX @@ -387,73 +388,4 @@ static inline int hyperv_flush_guest_mapping_range(u64 as, } #endif /* CONFIG_HYPERV */ -#ifdef CONFIG_HYPERV_TSCPAGE -struct ms_hyperv_tsc_page *hv_get_tsc_page(void); -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, - u64 *cur_tsc) -{ - u64 scale, offset; - u32 sequence; - - /* - * The protocol for reading Hyper-V TSC page is specified in Hypervisor - * Top-Level Functional Specification ver. 3.0 and above. To get the - * reference time we must do the following: - * - READ ReferenceTscSequence - * A special '0' value indicates the time source is unreliable and we - * need to use something else. The currently published specification - * versions (up to 4.0b) contain a mistake and wrongly claim '-1' - * instead of '0' as the special value, see commit c35b82ef0294. - * - ReferenceTime = - * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset - * - READ ReferenceTscSequence again. In case its value has changed - * since our first reading we need to discard ReferenceTime and repeat - * the whole sequence as the hypervisor was updating the page in - * between. - */ - do { - sequence = READ_ONCE(tsc_pg->tsc_sequence); - if (!sequence) - return U64_MAX; - /* - * Make sure we read sequence before we read other values from - * TSC page. - */ - smp_rmb(); - - scale = READ_ONCE(tsc_pg->tsc_scale); - offset = READ_ONCE(tsc_pg->tsc_offset); - *cur_tsc = rdtsc_ordered(); - - /* - * Make sure we read sequence after we read all other values - * from TSC page. - */ - smp_rmb(); - - } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); - - return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; -} - -static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) -{ - u64 cur_tsc; - - return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); -} - -#else -static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) -{ - return NULL; -} - -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, - u64 *cur_tsc) -{ - BUG(); - return U64_MAX; -} -#endif #endif diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index b6033680d458..19b695ff2c68 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -2,7 +2,7 @@ #ifndef _ASM_X86_PVCLOCK_H #define _ASM_X86_PVCLOCK_H -#include <linux/clocksource.h> +#include <asm/clocksource.h> #include <asm/pvclock-abi.h> /* some helper functions for xen and kvm pv clock sources */ diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h new file mode 100644 index 000000000000..45608b1d6ff8 --- /dev/null +++ b/arch/x86/include/asm/vdso/gettimeofday.h @@ -0,0 +1,203 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Fast user context implementation of clock_gettime, gettimeofday, and time. + * + * Copyright (C) 2019 ARM Limited. + * Copyright 2006 Andi Kleen, SUSE Labs. + * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net> + * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany + */ +#ifndef __ASM_VDSO_GETTIMEOFDAY_H +#define __ASM_VDSO_GETTIMEOFDAY_H + +#ifndef __ASSEMBLY__ + +#include <uapi/linux/time.h> +#include <asm/vgtod.h> +#include <asm/vvar.h> +#include <asm/unistd.h> +#include <asm/msr.h> +#include <asm/pvclock.h> +#include <asm/mshyperv-tsc.h> + +#define __vdso_data (VVAR(_vdso_data)) + +#define VDSO_HAS_TIME 1 + +#ifdef CONFIG_PARAVIRT_CLOCK +extern u8 pvclock_page[PAGE_SIZE] + __attribute__((visibility("hidden"))); +#endif + +#ifdef CONFIG_HYPERV_TSCPAGE +extern u8 hvclock_page[PAGE_SIZE] + __attribute__((visibility("hidden"))); +#endif + +#ifndef BUILD_VDSO32 + +static __always_inline notrace long clock_gettime_fallback( + clockid_t _clkid, + struct __kernel_timespec *_ts) +{ + long ret; + asm ("syscall" : "=a" (ret), "=m" (*_ts) : + "0" (__NR_clock_gettime), "D" (_clkid), "S" (_ts) : + "rcx", "r11"); + return ret; +} + +static __always_inline notrace long gettimeofday_fallback( + struct __kernel_old_timeval *_tv, + struct timezone *_tz) +{ + long ret; + asm("syscall" : "=a" (ret) : + "0" (__NR_gettimeofday), "D" (_tv), "S" (_tz) : "memory"); + return ret; +} + +static __always_inline notrace long clock_getres_fallback( + clockid_t _clkid, + struct __kernel_timespec *_ts) +{ + long ret; + asm ("syscall" : "=a" (ret), "=m" (*_ts) : + "0" (__NR_clock_getres), "D" (_clkid), "S" (_ts) : + "rcx", "r11"); + return ret; +} + +#else + +static __always_inline notrace long clock_gettime_fallback( + clockid_t _clkid, + struct __kernel_timespec *_ts) +{ + long ret; + + asm ( + "mov %%ebx, %%edx \n" + "mov %[clock], %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret), "=m" (*_ts) + : "0" (__NR_clock_gettime64), [clock] "g" (_clkid), "c" (_ts) + : "edx"); + return ret; +} + +static __always_inline notrace long gettimeofday_fallback( + struct __kernel_old_timeval *_tv, + struct timezone *_tz) +{ + long ret; + asm( + "mov %%ebx, %%edx \n" + "mov %2, %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret) + : "0" (__NR_gettimeofday), "g" (_tv), "c" (_tz) + : "memory", "edx"); + return ret; +} + +static __always_inline notrace long clock_getres_fallback( + clockid_t _clkid, + struct __kernel_timespec *_ts) +{ + long ret; + + asm ( + "mov %%ebx, %%edx \n" + "mov %[clock], %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret), "=m" (*_ts) + : "0" (__NR_clock_getres_time64), [clock] "g" (_clkid), "c" (_ts) + : "edx"); + return ret; +} + +#endif + +#ifdef CONFIG_PARAVIRT_CLOCK +static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void) +{ + return (const struct pvclock_vsyscall_time_info *)&pvclock_page; +} + +static notrace u64 vread_pvclock(void) +{ + const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti; + u32 version; + u64 ret; + + /* + * Note: The kernel and hypervisor must guarantee that cpu ID + * number maps 1:1 to per-CPU pvclock time info. + * + * Because the hypervisor is entirely unaware of guest userspace + * preemption, it cannot guarantee that per-CPU pvclock time + * info is updated if the underlying CPU changes or that that + * version is increased whenever underlying CPU changes. + * + * On KVM, we are guaranteed that pvti updates for any vCPU are + * atomic as seen by *all* vCPUs. This is an even stronger + * guarantee than we get with a normal seqlock. + * + * On Xen, we don't appear to have that guarantee, but Xen still + * supplies a valid seqlock using the version field. + * + * We only do pvclock vdso timing at all if + * PVCLOCK_TSC_STABLE_BIT is set, and we interpret that bit to + * mean that all vCPUs have matching pvti and that the TSC is + * synced, so we can just look at vCPU 0's pvti. + */ + + do { + version = pvclock_read_begin(pvti); + + if (unlikely(!(pvti->flags & PVCLOCK_TSC_STABLE_BIT))) + return U64_MAX; + + ret = __pvclock_read_cycles(pvti, rdtsc_ordered()); + } while (pvclock_read_retry(pvti, version)); + + return ret; +} +#endif +#ifdef CONFIG_HYPERV_TSCPAGE +static notrace u64 vread_hvclock(void) +{ + const struct ms_hyperv_tsc_page *tsc_pg = + (const struct ms_hyperv_tsc_page *)&hvclock_page; + + return hv_read_tsc_page(tsc_pg); +} +#endif + +notrace static inline u64 __arch_get_hw_counter(s32 clock_mode) +{ + if (clock_mode == VCLOCK_TSC) + return (u64)rdtsc_ordered(); +#ifdef CONFIG_PARAVIRT_CLOCK + else if (clock_mode == VCLOCK_PVCLOCK) + return vread_pvclock(); +#endif +#ifdef CONFIG_HYPERV_TSCPAGE + else if (clock_mode == VCLOCK_HVCLOCK) + return vread_hvclock(); +#endif + return U64_MAX; +} + +static __always_inline notrace const struct vdso_data *__arch_get_vdso_data(void) +{ + return __vdso_data; +} + +#endif /* !__ASSEMBLY__ */ + +#endif /* __ASM_VDSO_GETTIMEOFDAY_H */ diff --git a/arch/x86/include/asm/vdso/vsyscall.h b/arch/x86/include/asm/vdso/vsyscall.h new file mode 100644 index 000000000000..0026ab2123ce --- /dev/null +++ b/arch/x86/include/asm/vdso/vsyscall.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_VDSO_VSYSCALL_H +#define __ASM_VDSO_VSYSCALL_H + +#ifndef __ASSEMBLY__ + +#include <linux/hrtimer.h> +#include <linux/timekeeper_internal.h> +#include <vdso/datapage.h> +#include <asm/vgtod.h> +#include <asm/vvar.h> + +int vclocks_used __read_mostly; + +DEFINE_VVAR(struct vdso_data, _vdso_data); +/* + * Update the vDSO data page to keep in sync with kernel timekeeping. + */ +static __always_inline +struct vdso_data *__x86_get_k_vdso_data(void) +{ + return _vdso_data; +} +#define __arch_get_k_vdso_data __x86_get_k_vdso_data + +static __always_inline +int __x86_get_clock_mode(struct timekeeper *tk) +{ + int vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode; + + /* Mark the new vclock used. */ + BUILD_BUG_ON(VCLOCK_MAX >= 32); + WRITE_ONCE(vclocks_used, READ_ONCE(vclocks_used) | (1 << vclock_mode)); + + return vclock_mode; +} +#define __arch_get_clock_mode __x86_get_clock_mode + +/* The asm-generic header needs to be included after the definitions above */ +#include <asm-generic/vdso/vsyscall.h> + +#endif /* !__ASSEMBLY__ */ + +#endif /* __ASM_VDSO_VSYSCALL_H */ diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h index 913a133f8e6f..a2638c6124ed 100644 --- a/arch/x86/include/asm/vgtod.h +++ b/arch/x86/include/asm/vgtod.h @@ -3,7 +3,9 @@ #define _ASM_X86_VGTOD_H #include <linux/compiler.h> -#include <linux/clocksource.h> +#include <asm/clocksource.h> +#include <vdso/datapage.h> +#include <vdso/helpers.h> #include <uapi/linux/time.h> @@ -13,81 +15,10 @@ typedef u64 gtod_long_t; typedef unsigned long gtod_long_t; #endif -/* - * There is one of these objects in the vvar page for each - * vDSO-accelerated clockid. For high-resolution clocks, this encodes - * the time corresponding to vsyscall_gtod_data.cycle_last. For coarse - * clocks, this encodes the actual time. - * - * To confuse the reader, for high-resolution clocks, nsec is left-shifted - * by vsyscall_gtod_data.shift. - */ -struct vgtod_ts { - u64 sec; - u64 nsec; -}; - -#define VGTOD_BASES (CLOCK_TAI + 1) -#define VGTOD_HRES (BIT(CLOCK_REALTIME) | BIT(CLOCK_MONOTONIC) | BIT(CLOCK_TAI)) -#define VGTOD_COARSE (BIT(CLOCK_REALTIME_COARSE) | BIT(CLOCK_MONOTONIC_COARSE)) - -/* - * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time - * so be carefull by modifying this structure. - */ -struct vsyscall_gtod_data { - unsigned int seq; - - int vclock_mode; - u64 cycle_last; - u64 mask; - u32 mult; - u32 shift; - - struct vgtod_ts basetime[VGTOD_BASES]; - - int tz_minuteswest; - int tz_dsttime; -}; -extern struct vsyscall_gtod_data vsyscall_gtod_data; - extern int vclocks_used; static inline bool vclock_was_used(int vclock) { return READ_ONCE(vclocks_used) & (1 << vclock); } -static inline unsigned int gtod_read_begin(const struct vsyscall_gtod_data *s) -{ - unsigned int ret; - -repeat: - ret = READ_ONCE(s->seq); - if (unlikely(ret & 1)) { - cpu_relax(); - goto repeat; - } - smp_rmb(); - return ret; -} - -static inline int gtod_read_retry(const struct vsyscall_gtod_data *s, - unsigned int start) -{ - smp_rmb(); - return unlikely(s->seq != start); -} - -static inline void gtod_write_begin(struct vsyscall_gtod_data *s) -{ - ++s->seq; - smp_wmb(); -} - -static inline void gtod_write_end(struct vsyscall_gtod_data *s) -{ - smp_wmb(); - ++s->seq; -} - #endif /* _ASM_X86_VGTOD_H */ diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 3f32dfc2ab73..2dbde48f27a9 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -32,19 +32,20 @@ extern char __vvar_page; #define DECLARE_VVAR(offset, type, name) \ - extern type vvar_ ## name __attribute__((visibility("hidden"))); + extern type vvar_ ## name[CS_BASES] \ + __attribute__((visibility("hidden"))); #define VVAR(name) (vvar_ ## name) #define DEFINE_VVAR(type, name) \ - type name \ + type name[CS_BASES] \ __attribute__((section(".vvar_" #name), aligned(16))) __visible #endif /* DECLARE_VVAR(offset, type, name) */ -DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data) +DECLARE_VVAR(128, struct vdso_data, _vdso_data) #undef DECLARE_VVAR diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 0ff3e294d0e5..10125358b9c4 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -3,6 +3,7 @@ */ +#include <linux/clocksource.h> #include <linux/kernel.h> #include <linux/percpu.h> #include <linux/notifier.h>
The x86 vDSO library requires some adaptations to take advantage of the newly introduced generic vDSO library. Introduce the following changes: - Modification of vdso.c to be compliant with the common vdso datapage - Use of lib/vdso for gettimeofday Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/x86/Kconfig | 3 + arch/x86/entry/vdso/Makefile | 9 + arch/x86/entry/vdso/vclock_gettime.c | 251 +++++------------------ arch/x86/entry/vdso/vdso.lds.S | 2 + arch/x86/entry/vdso/vdso32/vdso32.lds.S | 2 + arch/x86/entry/vdso/vdsox32.lds.S | 1 + arch/x86/entry/vsyscall/Makefile | 2 - arch/x86/entry/vsyscall/vsyscall_gtod.c | 83 -------- arch/x86/include/asm/mshyperv-tsc.h | 76 +++++++ arch/x86/include/asm/mshyperv.h | 70 +------ arch/x86/include/asm/pvclock.h | 2 +- arch/x86/include/asm/vdso/gettimeofday.h | 203 ++++++++++++++++++ arch/x86/include/asm/vdso/vsyscall.h | 44 ++++ arch/x86/include/asm/vgtod.h | 75 +------ arch/x86/include/asm/vvar.h | 7 +- arch/x86/kernel/pvclock.c | 1 + 16 files changed, 396 insertions(+), 435 deletions(-) delete mode 100644 arch/x86/entry/vsyscall/vsyscall_gtod.c create mode 100644 arch/x86/include/asm/mshyperv-tsc.h create mode 100644 arch/x86/include/asm/vdso/gettimeofday.h create mode 100644 arch/x86/include/asm/vdso/vsyscall.h