From: Michael Kelley <mikelley@microsoft.com>
To: Vincenzo Frascino <vincenzo.frascino@arm.com>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@vger.kernel.org>
Cc: Shuah Khan <shuah@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Huw Davies <huw@codeweavers.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Will Deacon <will.deacon@arm.com>,
Russell King <linux@armlinux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
Mark Salyzyn <salyzyn@android.com>,
Paul Burton <paul.burton@mips.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Collingbourne <pcc@google.com>
Subject: RE: [PATCH v6 18/19] x86: Add support for generic vDSO
Date: Thu, 30 May 2019 15:41:13 +0000 [thread overview]
Message-ID: <BYAPR21MB1221D54FCEC97509EEF7395CD7180@BYAPR21MB1221.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20190530141531.43462-19-vincenzo.frascino@arm.com>
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
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-05-30 15:41 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 14:15 [PATCH v6 00/19] Unify vDSOs across more architectures Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 01/19] kernel: Standardize vdso_datapage Vincenzo Frascino
2019-05-31 8:16 ` Arnd Bergmann
2019-06-04 12:05 ` Vincenzo Frascino
2019-06-10 17:47 ` Huw Davies
2019-06-10 9:27 ` Huw Davies
2019-06-10 10:17 ` Vincenzo Frascino
2019-06-10 10:31 ` Huw Davies
2019-06-10 11:07 ` Vincenzo Frascino
2019-06-10 11:37 ` Huw Davies
2019-05-30 14:15 ` [PATCH v6 02/19] kernel: Define gettimeofday vdso common code Vincenzo Frascino
2019-05-31 8:19 ` Arnd Bergmann
2019-06-04 12:08 ` Vincenzo Frascino
2019-06-10 9:31 ` Huw Davies
2019-06-10 10:18 ` Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 03/19] kernel: Unify update_vsyscall implementation Vincenzo Frascino
2019-06-10 9:34 ` Huw Davies
2019-06-10 10:19 ` Vincenzo Frascino
2019-06-14 11:10 ` Thomas Gleixner
2019-06-14 12:15 ` Vincenzo Frascino
2019-06-14 12:19 ` Thomas Gleixner
2019-06-14 12:25 ` Vincenzo Frascino
2019-06-14 13:07 ` Thomas Gleixner
2019-05-30 14:15 ` [PATCH v6 04/19] arm64: Substitute gettimeofday with C implementation Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 05/19] arm64: Build vDSO with -ffixed-x18 Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 06/19] arm64: compat: Add missing syscall numbers Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 07/19] arm64: compat: Expose signal related structures Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 08/19] arm64: compat: Generate asm offsets for signals Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 09/19] lib: vdso: Add compat support Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 10/19] arm64: compat: Add vDSO Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 11/19] arm64: Refactor vDSO code Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 12/19] arm64: compat: vDSO setup for compat layer Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 13/19] arm64: elf: vDSO code page discovery Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 14/19] arm64: compat: Get sigreturn trampolines from vDSO Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 15/19] arm64: Add vDSO compat support Vincenzo Frascino
2019-06-01 9:38 ` Catalin Marinas
2019-06-04 12:10 ` Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 16/19] arm: Add support for generic vDSO Vincenzo Frascino
2019-05-31 8:32 ` Arnd Bergmann
2019-05-30 14:15 ` [PATCH v6 17/19] mips: " Vincenzo Frascino
2019-05-31 8:34 ` Arnd Bergmann
2019-06-03 14:54 ` Mark Salyzyn
2019-06-03 17:07 ` Arnd Bergmann
2019-05-30 14:15 ` [PATCH v6 18/19] x86: " Vincenzo Frascino
2019-05-30 15:41 ` Michael Kelley [this message]
2019-06-04 12:13 ` Vincenzo Frascino
2019-06-14 11:15 ` Thomas Gleixner
2019-06-14 21:17 ` Sasha Levin
2019-06-22 14:46 ` Thomas Gleixner
2019-06-23 19:09 ` Sasha Levin
2019-06-23 21:58 ` Stephen Rothwell
2019-06-24 0:24 ` Sasha Levin
2019-06-24 1:20 ` Stephen Rothwell
2019-06-23 22:12 ` Thomas Gleixner
2019-06-24 0:04 ` Michael Kelley
2019-06-24 0:25 ` Thomas Gleixner
2019-06-28 18:40 ` Michael Kelley
2019-05-30 14:15 ` [PATCH v6 19/19] kselftest: Extend vDSO selftest Vincenzo Frascino
2019-05-31 8:53 ` Arnd Bergmann
2019-05-31 8:46 ` [PATCH v6 00/19] Unify vDSOs across more architectures Arnd Bergmann
2019-06-04 12:04 ` Vincenzo Frascino
2019-06-04 12:12 ` Arnd Bergmann
2019-06-05 14:32 ` Vincenzo Frascino
2019-06-14 12:16 ` Thomas Gleixner
2019-06-14 12:19 ` Vincenzo Frascino
2019-06-20 6:17 ` Shijith Thotton
2019-06-20 8:55 ` Vincenzo Frascino
2019-06-20 16:27 ` Andre Przywara
2019-06-21 9:11 ` Vincenzo Frascino
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BYAPR21MB1221D54FCEC97509EEF7395CD7180@BYAPR21MB1221.namprd21.prod.outlook.com \
--to=mikelley@microsoft.com \
--cc=0x7f454c46@gmail.com \
--cc=arnd@arndb.de \
--cc=catalin.marinas@arm.com \
--cc=daniel.lezcano@linaro.org \
--cc=huw@codeweavers.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=linux@rasmusvillemoes.dk \
--cc=paul.burton@mips.com \
--cc=pcc@google.com \
--cc=ralf@linux-mips.org \
--cc=salyzyn@android.com \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=vincenzo.frascino@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).