linux-kernel - Re: [PATCH] Fix left over EFI cache mapping problems

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Message-Id: <1203050886.30010.19.camel@caritas-dev.intel.com>
Date:	Fri, 15 Feb 2008 12:48:06 +0800
From:	"Huang, Ying" <ying.huang@...el.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Andi Kleen <andi@...stfloor.org>, torvalds@...l.org,
	tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix left over EFI cache mapping problems

On Thu, 2008-02-14 at 17:12 +0100, Ingo Molnar wrote: 
> this is indeed a bug (we change the attributes for a larger area than 
> needed), but your fix is unclean. Find below a cleaner solution.
> 
> Ying, if you agree with this fix could you please test and ACK it before 
> we push it to Linus? (this fix is also in the latest x86.git#mm)

I think the patch following may be better, because it is possible that
the EFI_PAGE_SHIFT and PAGE_SHIFT are different.

Best Regards,
Huang Ying

-------------------------> 
The EFI-runtime mapping code changed a larger memory area than it
should have, due to a pages/bytes parameter mixup.

noticed by Andi Kleen.

This patch has been tested on Intel x86 platform with EFI 32/64.

Signed-off-by: Huang Ying <ying.huang@...el.com>

---
 arch/x86/kernel/efi.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/arch/x86/kernel/efi.c
+++ b/arch/x86/kernel/efi.c
@@ -386,12 +386,13 @@ static void __init runtime_code_page_mke
 
 	/* Make EFI runtime service code area executable */
 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
-		md = p;
+		unsigned long num_pages;
 
+		md = p;
 		if (md->type != EFI_RUNTIME_SERVICES_CODE)
 			continue;
-
-		set_memory_x(md->virt_addr, md->num_pages << EFI_PAGE_SHIFT);
+		num_pages = (md->num_pages << EFI_PAGE_SHIFT) >> PAGE_SHIFT;
+		set_memory_x(md->virt_addr, num_pages);
 	}
 }
 
@@ -434,7 +435,7 @@ void __init efi_enter_virtual_mode(void)
 		}
 
 		if (!(md->attribute & EFI_MEMORY_WB))
-			set_memory_uc(md->virt_addr, size);
+			set_memory_uc(md->virt_addr, size >> PAGE_SHIFT);
 
 		systab = (u64) (unsigned long) efi_phys.systab;
 		if (md->phys_addr <= systab && systab < end) {

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