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SubjectRe: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
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On Thu, 2011-09-01 at 14:55 +0800, Zhang, Rui wrote: 
> From: Zhang Rui <rui.zhang@intel.com>
> Date: Wed, 31 Aug 2011 09:59:01 +0800
> Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
>
> set_memory_uc uses __pa() to translate the virtual address to the physical address.
> This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
>
oops, wrong patch was attached.

here is the correct patch.

From: Zhang Rui <rui.zhang@intel.com>
Date: Wed, 31 Aug 2011 09:59:01 +0800
Subject: Do not use __pa() to get the physical address of an ioremapped memory range.

set_memory_uc uses __pa() to translate the virtual address to the physical address.
This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.

<1>[ 0.029956] BUG: unable to handle kernel paging request at f7f22280
<1>[ 0.042049] IP: [<c10257b9>] reserve_ram_pages_type+0x89/0x210
<4>[ 0.053465] *pdpt = 0000000001978001 *pde = 0000000001ffb067 *pte = 0000000000000000
<0>[ 0.068781] Oops: 0000 [#1] PREEMPT SMP
<4>[ 0.076441] Modules linked in:
<4>[ 0.082399]
<4>[ 0.085304] Pid: 0, comm: swapper Not tainted 3.0.0-acpi-efi-0805 #3
<4>[ 0.098067] EIP: 0060:[<c10257b9>] EFLAGS: 00010202 CPU: 0
<4>[ 0.108810] EIP is at reserve_ram_pages_type+0x89/0x210
<4>[ 0.119022] EAX: 0070e280 EBX: 38714000 ECX: f7814000 EDX: 00000000
<4>[ 0.131284] ESI: 00000000 EDI: 38715000 EBP: c189fef0 ESP: c189fea8
<4>[ 0.143543] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
<0>[ 0.154099] Process swapper (pid: 0, ti=c189e000 task=c18bbe60 task.ti=c189e000)
<0>[ 0.168576] Stack:
<4>[ 0.172475] 80000200 ff108000 00000000 c189ff00 00038714 00000000 00000000 c189fed0
<4>[ 0.187623] c104f8ca 00038714 00000000 00038715 00000000 00000000 00038715 00000000
<4>[ 0.202777] 00000010 38715000 c189ff48 c1025aff 38715000 00000000 00000010 00000000
<0>[ 0.217930] Call Trace:
<4>[ 0.222722] [<c104f8ca>] ? page_is_ram+0x1a/0x40
<4>[ 0.231916] [<c1025aff>] reserve_memtype+0xdf/0x2f0
<4>[ 0.241622] [<c1024dc9>] set_memory_uc+0x49/0xa0
<4>[ 0.250818] [<c19334d0>] efi_enter_virtual_mode+0x1c2/0x3aa
<4>[ 0.261887] [<c19216d4>] start_kernel+0x291/0x2f2
<4>[ 0.271245] [<c19211c7>] ? loglevel+0x1b/0x1b
<4>[ 0.279929] [<c19210bf>] i386_start_kernel+0xbf/0xc8
---

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 3ae4128..89586fe 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -44,6 +44,7 @@
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/x86_init.h>
+#include <asm/pat.h>

#define EFI_DEBUG 1
#define PFX "EFI: "
@@ -687,7 +688,13 @@ void __init efi_enter_virtual_mode(void)
addr = md->virt_addr;
npages = md->num_pages;
memrange_efi_to_native(&addr, &npages);
- set_memory_uc(addr, npages);
+ if (reserve_memtype(md->phys_addr, md->phys_addr + npages * PAGE_SIZE,
+ _PAGE_CACHE_UC_MINUS, NULL)) {
+ printk(KERN_ERR PFX "failed to reserve region as uncacheable\n");
+ } else if (_set_memory_uc(addr, npages)) {
+ printk(KERN_ERR PFX "failed to set region to uncacheable\n");
+ free_memtype(md->phys_addr, md->phys_addr + npages * PAGE_SIZE);
+ }
}

systab = (u64) (unsigned long) efi_phys.systab;







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