linux-kernel - Re: [PATCH v3 08/15] x86/acpi/cstate: Improve Intel Family model checks

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Message-ID: <CAJZ5v0iRxdpr9Lc9XJDbN5KbO6Ch=TEG39PC53gQJOTW_L9hnw@mail.gmail.com>
Date: Thu, 20 Feb 2025 20:20:06 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Sohil Mehta <sohil.mehta@...el.com>
Cc: x86@...nel.org, Dave Hansen <dave.hansen@...ux.intel.com>, 
	Tony Luck <tony.luck@...el.com>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Thomas Gleixner <tglx@...utronix.de>, 
	Borislav Petkov <bp@...en8.de>, "H . Peter Anvin" <hpa@...or.com>, "Rafael J . Wysocki" <rafael@...nel.org>, 
	Len Brown <lenb@...nel.org>, Andy Lutomirski <luto@...nel.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, Jean Delvare <jdelvare@...e.com>, 
	Guenter Roeck <linux@...ck-us.net>, Zhang Rui <rui.zhang@...el.com>, 
	Andrew Cooper <andrew.cooper3@...rix.com>, David Laight <david.laight.linux@...il.com>, 
	Dapeng Mi <dapeng1.mi@...ux.intel.com>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org, 
	linux-pm@...r.kernel.org
Subject: Re: [PATCH v3 08/15] x86/acpi/cstate: Improve Intel Family model checks

On Wed, Feb 19, 2025 at 8:29 PM Sohil Mehta <sohil.mehta@...el.com> wrote:
>
> Update the Intel Family checks to consistently use Family 15 instead of
> Family 0xF. Also, get rid of one of last usages of x86_model by using
> the new VFM checks.
>
> Update the incorrect comment since the check has changed[1][2] since the
> initial commit ee1ca48fae7e ("ACPI: Disable ARB_DISABLE on platforms
> where it is not needed").
>
> [1]: commit 3e2ada5867b7 ("ACPI: fix Compaq Evo N800c (Pentium 4m) boot
> hang regression") removed the P4 - Family 15.
>
> [2]: commit 03a05ed11529 ("ACPI: Use the ARB_DISABLE for the CPU which
> model id is less than 0x0f.") got rid of CORE_YONAH - Family 6, model E.
>
> Signed-off-by: Sohil Mehta <sohil.mehta@...el.com>
> Acked-by: Dave Hansen <dave.hansen@...ux.intel.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

and I'm assuming that this series will go in via x86.

Thanks!

> ---
> v3: Pick up Dave's Ack.
> v2: Improve commit message.
> ---
>  arch/x86/include/asm/intel-family.h | 3 +++
>  arch/x86/kernel/acpi/cstate.c       | 8 ++++----
>  2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h
> index 9e6a13f03f0e..deb17c9c21e5 100644
> --- a/arch/x86/include/asm/intel-family.h
> +++ b/arch/x86/include/asm/intel-family.h
> @@ -187,6 +187,9 @@
>  #define INTEL_XEON_PHI_KNL             IFM(6, 0x57) /* Knights Landing */
>  #define INTEL_XEON_PHI_KNM             IFM(6, 0x85) /* Knights Mill */
>
> +/* Notational marker denoting the last Family 6 model */
> +#define INTEL_FAM6_LAST                        IFM(6, 0xFF)
> +
>  /* Family 15 - NetBurst */
>  #define INTEL_P4_WILLAMETTE            IFM(15, 0x01) /* Also Xeon Foster */
>  #define INTEL_P4_PRESCOTT              IFM(15, 0x03)
> diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
> index 5854f0b8f0f1..444602a0a3dd 100644
> --- a/arch/x86/kernel/acpi/cstate.c
> +++ b/arch/x86/kernel/acpi/cstate.c
> @@ -13,6 +13,7 @@
>  #include <linux/sched.h>
>
>  #include <acpi/processor.h>
> +#include <asm/cpu_device_id.h>
>  #include <asm/cpuid.h>
>  #include <asm/mwait.h>
>  #include <asm/special_insns.h>
> @@ -47,12 +48,11 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
>         /*
>          * On all recent Intel platforms, ARB_DISABLE is a nop.
>          * So, set bm_control to zero to indicate that ARB_DISABLE
> -        * is not required while entering C3 type state on
> -        * P4, Core and beyond CPUs
> +        * is not required while entering C3 type state.
>          */
>         if (c->x86_vendor == X86_VENDOR_INTEL &&
> -           (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
> -                       flags->bm_control = 0;
> +           (c->x86 > 15 || (c->x86_vfm >= INTEL_CORE2_MEROM && c->x86_vfm <= INTEL_FAM6_LAST)))
> +               flags->bm_control = 0;
>
>         if (c->x86_vendor == X86_VENDOR_CENTAUR) {
>                 if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&
> --
> 2.43.0
>