From: David Vrabel <david.vrabel@citrix.com>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>, <bp@alien8.de>
Cc: <rusty@rustcorp.com.au>, <x86@kernel.org>,
<linux-kernel@vger.kernel.org>, <luto@amacapital.net>,
<xen-devel@lists.xensource.com>, <david.vrabel@citrix.com>,
<boris.ostrovsky@oracle.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [Xen-devel] [PATCH 1/9] x86/boot: enumerate documentation for the x86 hardware_subarch
Date: Fri, 19 Feb 2016 13:40:33 +0000 [thread overview]
Message-ID: <56C71B51.20109@citrix.com> (raw)
In-Reply-To: <1455887316-9223-2-git-send-email-mcgrof@kernel.org>
On 19/02/16 13:08, Luis R. Rodriguez wrote:
> Although hardware_subarch has been in place since the x86 boot
> protocol 2.07 it hasn't been used much. Enumerate current possible
> values to avoid misuses and help with semantics later at boot
> time should this be used further.
>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
> ---
> arch/x86/include/uapi/asm/bootparam.h | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
> index 329254373479..dbfb9406436b 100644
> --- a/arch/x86/include/uapi/asm/bootparam.h
> +++ b/arch/x86/include/uapi/asm/bootparam.h
> @@ -157,7 +157,37 @@ struct boot_params {
> __u8 _pad9[276]; /* 0xeec */
> } __attribute__((packed));
>
> -enum {
> +/**
> + * enum x86_hardware_subarch - x86 hardware subarchitecture
> + *
> + * The x86 hardware_subarch and hardware_subarch_data were added as of the x86
> + * boot protocol 2.07 to help distinguish and supports custom x86 boot
> + * sequences. This enum represents accepted values for the x86
> + * hardware_subarch. Custom x86 boot sequences (not X86_SUBARCH_PC) do not have
> + * or simply do not make use of natural stubs like BIOS or EFI, the
> + * hardware_subarch can be used on the Linux entry path to revector to a
> + * subarchitecture stub when needed. This subarchitecture stub can be used to
> + * set up Linux boot parameters or for special care to account for nonstandard
> + * handling of page tables.
This documentation reads like a plan for future implementation. Is this
the level of documentation that is needed here?
Also, "revector to a subarchitecture stub" is a rather odd way of saying
"call a subarch-specific stub".
David
next prev parent reply other threads:[~2016-02-19 13:40 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-19 13:08 [PATCH 0/9] x86/init: replace paravirt_enabled() were possible Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 1/9] x86/boot: enumerate documentation for the x86 hardware_subarch Luis R. Rodriguez
2016-02-19 13:19 ` [Xen-devel] " Juergen Gross
2016-02-19 13:40 ` David Vrabel [this message]
2016-02-19 14:40 ` Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 2/9] tools/lguest: make lguest launcher use X86_SUBARCH_LGUEST explicitly Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 3/9] x86/xen: use X86_SUBARCH_XEN for PV guest boots Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 4/9] x86/init: make ebda depend on PC subarch Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 5/9] apm32: remove paravirt_enabled() use Luis R. Rodriguez
2016-02-19 15:08 ` Boris Ostrovsky
2016-02-19 20:58 ` Luis R. Rodriguez
2016-02-19 22:17 ` Boris Ostrovsky
2016-02-20 0:42 ` Luis R. Rodriguez
2016-02-22 14:15 ` Boris Ostrovsky
2016-02-19 13:08 ` [PATCH 6/9] x86/tboot: remove paravirt_enabled() Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 7/9] x86/cpu/intel: replace paravirt_enabled() for f00f work around Luis R. Rodriguez
2016-02-19 13:08 ` [PATCH 8/9] x86/rtc: replace paravirt_enabled() check with subarch check Luis R. Rodriguez
2016-02-19 13:22 ` [Xen-devel] " Juergen Gross
2016-02-19 14:48 ` Luis R. Rodriguez
2016-02-22 6:07 ` Luis R. Rodriguez
2016-02-22 10:27 ` Borislav Petkov
2016-02-22 14:34 ` Boris Ostrovsky
2016-02-22 23:12 ` Luis R. Rodriguez
2016-02-19 13:27 ` David Vrabel
2016-02-19 13:08 ` [PATCH 9/9] pnpbios: replace paravirt_enabled() check with subarch checks Luis R. Rodriguez
2016-02-19 13:34 ` [Xen-devel] [PATCH 0/9] x86/init: replace paravirt_enabled() were possible David Vrabel
2016-02-19 14:36 ` Luis R. Rodriguez
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