linux-kernel - Re: [PATCH 10/11] EFI: Runtime services virtual mapping

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Date:	Fri, 1 Nov 2013 11:25:51 +0800
From:	Dave Young <dyoung@...hat.com>
To:	Borislav Petkov <bp@...en8.de>,
	Matt Fleming <matt@...sole-pimps.org>
Cc:	Linux EFI <linux-efi@...r.kernel.org>,
	Borislav Petkov <bp@...e.de>, "H. Peter Anvin" <hpa@...or.com>,
	James Bottomley <James.Bottomley@...senPartnership.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Vivek Goyal <vgoyal@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, X86 ML <x86@...nel.org>
Subject: Re: [PATCH 10/11] EFI: Runtime services virtual mapping

On 10/31/13 at 05:25pm, Borislav Petkov wrote:
> From: Borislav Petkov <bp@...e.de>
> 
> We map the EFI regions needed for runtime services non-contiguously,
> with preserved alignment on virtual addresses starting from -4G down
> for a total max space of 64G. This way, we provide for stable runtime
> services addresses across kernels so that a kexec'd kernel can still use
> them.
> 
> Thus, they're mapped in a separate pagetable so that we don't pollute
> the kernel namespace.
> 
> Add an efi= kernel command line parameter for passing miscellaneous
> options and chicken bits from the command line.
> 
> While at it, add a chicken bit called "efi=old_map" which can be used as
> a fallback to the old runtime services mapping method in case there's
> some b0rkage with a particular EFI implementation (haha, it is hard to
> hold up the sarcasm here...).
> 
> Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.
> 
> Signed-off-by: Borislav Petkov <bp@...e.de>
> ---
>  Documentation/kernel-parameters.txt  |   6 ++
>  Documentation/x86/x86_64/mm.txt      |   7 +++
>  arch/x86/include/asm/efi.h           |  64 ++++++++++++++------
>  arch/x86/include/asm/pgtable_types.h |   3 +-
>  arch/x86/platform/efi/efi.c          |  94 +++++++++++++++++++++---------
>  arch/x86/platform/efi/efi_32.c       |   9 ++-
>  arch/x86/platform/efi/efi_64.c       | 109 +++++++++++++++++++++++++++++++++++
>  arch/x86/platform/efi/efi_stub_64.S  |  54 +++++++++++++++++
>  include/linux/efi.h                  |   1 +
>  9 files changed, 300 insertions(+), 47 deletions(-)
> 

Hi,

This one still does not apply:

[dave@...kstar linux-2.6]$ git am ~/Mail/bp/new/*
Applying: efi: Simplify EFI_DEBUG
Applying: x86, pageattr: Lookup address in an arbitrary PGD
Applying: x86, pageattr: Add a PGD pagetable populating function
Applying: x86, pageattr: Add a PUD pagetable populating function
Applying: x86, pageattr: Add a PMD pagetable populating function
Applying: x86, pageattr: Add a PTE pagetable populating function
Applying: x86, pageattr: Add a PUD error unwinding path
Applying: x86, pageattr: Add last levels of error path
Applying: x86, cpa: Map in an arbitrary pgd
Applying: EFI: Runtime services virtual mapping
error: patch failed: arch/x86/platform/efi/efi.c:808
error: arch/x86/platform/efi/efi.c: patch does not apply
Patch failed at 0010 EFI: Runtime services virtual mapping
The copy of the patch that failed is found in:
   /home/dave/git/linux-2.6/.git/rebase-apply/patch
When you have resolved this problem, run "git am --resolved".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

I found the reason, here is the diff of the efi.c
between (linus tree + matt next) and the one in matt next:

--- efi.c.linus-tree	2013-11-01 11:16:44.731554778 +0800
+++ efi.c.matt-next	2013-11-01 11:17:41.662316832 +0800
@@ -806,13 +806,10 @@ void __init efi_enter_virtual_mode(void)
 
 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 		md = p;
-		if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
-#ifdef CONFIG_X86_64
-			if (md->type != EFI_BOOT_SERVICES_CODE &&
-			    md->type != EFI_BOOT_SERVICES_DATA)
-#endif
-				continue;
-		}
+		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+		    md->type != EFI_BOOT_SERVICES_CODE &&
+		    md->type != EFI_BOOT_SERVICES_DATA)
+			continue;
 
 		size = md->num_pages << EFI_PAGE_SHIFT;
 		end = md->phys_addr + size;

The conflict is caused by missing one commit in matt's efi next tree:

commit 700870119f49084da004ab588ea2b799689efaf7
Author: Josh Boyer <jwboyer@...hat.com>
Date:   Thu Apr 18 07:51:34 2013 -0700

    x86, efi: Don't map Boot Services on i386
    
    Add patch to fix 32bit EFI service mapping (rhbz 726701)
    
    Multiple people are reporting hitting the following WARNING on i386,
    
      WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440()
      Modules linked in:
      Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95

--
Thanks
Dave
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