archive mirror
 help / color / mirror / Atom feed
From: Josh Triplett <>
To: "H. Peter Anvin" <>
Cc: Matt Fleming <>,,
	Thomas Gleixner <>,
	Ingo Molnar <>,, Len Brown <>,
	Olof Johansson <>, Matthew Garrett <>,
	David Howells <>,
	Rusty Russell <>,
	Jim Cromie <>,
	Peter Zijlstra <>,
	Pawel Moll <>,, linux-efi <>
Subject: Re: [PATCH 0/3] Fix ACPI BGRT support for images located in EFI boot services memory
Date: Tue, 4 Sep 2012 12:45:23 -0700	[thread overview]
Message-ID: <20120904194523.GA5064@jtriplet-mobl1> (raw)
In-Reply-To: <>

On Tue, Sep 04, 2012 at 11:10:54AM -0700, H. Peter Anvin wrote:
> On 09/04/2012 10:59 AM, Josh Triplett wrote:
> >
> >Unfortunately not.  We need enough of ACPI available to go read the
> >BGRT to know what to copy, so we need to defer freeing boot services
> >code until after we initialize ACPI (and thus everything ACPI needs,
> >which includes EFI since ACPI looks for root tables there).
> >
> >>I wouldn't be surprised if some implementations got really cranky if
> >>we accessed boot services data after we installed a new virtual memory
> >>map.
> >
> >Note that I've carefully accessed the boot services data *through* the
> >new virtual memory map, which should work fine.
> >
> There are some platforms which have bugs in this area, so there are
> other reasons to defer freeing up boot memory until as late in the
> boot process as we can possibly get away with.
> free_initmem() is presuambly the place that makes most sense.

You're suggesting a call from free_initmem() to
efi_free_boot_services()?  Or, from init_post() right before the call to

> This
> is EFI-specific but not x86-specific, let's not commingle those
> concepts, please...

init/main.c already calls the x86-specific efi_enter_virtual_mode
(defined in arch/x86/platform/efi/efi.c), and I split the call to the
x86-specific efi_free_boot_services out of that.  Neither of those
functions exists on non-x86 platforms, and thus I mirrored the #ifdef
currently wrapped around efi_enter_virtual_mode for the new call to
efi_free_boot_services.  While it might make sense for that code to
exist on non-x86 EFI platforms, it currently doesn't.  At best, I could
add static inline stubs to linux/efi.h for those functions to avoid the
ifdefs, but as far as I can tell the same issue applies to quite a few
more functions in efi.h.

Would you like me to add the static inline stubs for the couple of
functions called from init/main.c, or leave the #ifdefs?

- Josh Triplett

  reply	other threads:[~2012-09-04 19:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-30 21:28 [PATCH 0/3] Fix ACPI BGRT support for images located in EFI boot services memory Josh Triplett
2012-08-30 21:28 ` [PATCH 1/3] efi: Defer freeing boot services memory until after ACPI init Josh Triplett
2012-08-30 21:28 ` [PATCH 2/3] efi: Add a function to look up existing IO memory mappings Josh Triplett
2012-08-30 21:28 ` [PATCH 3/3] efi: Fix the ACPI BGRT driver for images located in EFI boot services memory Josh Triplett
2012-09-04 14:27 ` [PATCH 0/3] Fix ACPI BGRT support " Matt Fleming
2012-09-04 17:59   ` Josh Triplett
2012-09-04 18:10     ` H. Peter Anvin
2012-09-04 19:45       ` Josh Triplett [this message]
2012-09-04 20:24         ` H. Peter Anvin
2012-09-04 20:29           ` Josh Triplett
2012-09-04 20:11     ` Matt Fleming

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20120904194523.GA5064@jtriplet-mobl1 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

* 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).