Re: [PATCH] Modify UEFI anti-bricking code

From: joeyli
Date: Thu Jun 06 2013 - 01:42:35 EST


æ åï2013-06-06 æ 13:05 +0800ïjoeyli æåï
> æ äï2013-06-05 æ 16:59 +0100ïMatt Fleming æåï
> > On Wed, 05 Jun, at 02:53:27PM, Matthew Garrett wrote:
> > > On Wed, 2013-06-05 at 15:49 +0100, Fleming, Matt wrote:
> > >
> > > > Folks, what do you want me to do with this? Merge it with Matthew's patch?
> > >
> > > Do that and add Joey's signed-off-by?
> >
> > Right, this is what I've got queued up.
> >
> > ---
> >
> > >From 380dcc12ba82f4e10feb6a72207b2e4771d16d8d Mon Sep 17 00:00:00 2001
> > From: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
> > Date: Sat, 1 Jun 2013 16:06:20 -0400
> > Subject: [PATCH] Modify UEFI anti-bricking code
> >
> > This patch reworks the UEFI anti-bricking code, including an effective
> > reversion of cc5a080c and 31ff2f20. It turns out that calling
> > QueryVariableInfo() from boot services results in some firmware
> > implementations jumping to physical addresses even after entering virtual
> > mode, so until we have 1:1 mappings for UEFI runtime space this isn't
> > going to work so well.
> [...]
>
> The follow diff change is base on 380dcc12 patch queued in efi git tree,
> it included Matthew and hpa's suggestions. I fix the attributes of DUMMY
> object to NV/BS/RT and introduced a #define of the minimum reserve flash
> space.
>
> This change works to me on OVMF.
>
>
>
> Thanks a lot!
> Joey Lee
>

Sorry for attached a wrong diff result, it lost a NV/BS/RT attributes
changed in efi_query_variable_store(). The right diff change is
following.


Thanks a lot!
Joey Lee


diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index cc3cfe8..ec8ac97 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -53,6 +53,8 @@

#define EFI_DEBUG 1

+#define EFI_MIN_RESERVE 5120
+
#define EFI_DUMMY_GUID \
EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)

@@ -988,7 +990,11 @@ void __init efi_enter_virtual_mode(void)
kfree(new_memmap);

/* clean DUMMY object */
- efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID, 0, 0, NULL);
+ efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+ EFI_VARIABLE_NON_VOLATILE |
+ EFI_VARIABLE_BOOTSERVICE_ACCESS |
+ EFI_VARIABLE_RUNTIME_ACCESS,
+ 0, NULL);
}

/*
@@ -1051,7 +1057,12 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
* write if permitting it would reduce the available space to under
* 5KB. This figure was provided by Samsung, so should be safe.
*/
- if ((remaining_size - size < 5120) && !efi_no_storage_paranoia) {
+ if ((remaining_size - size < EFI_MIN_RESERVE) &&
+ !efi_no_storage_paranoia) {
+
+ if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
+ return EFI_OUT_OF_RESOURCES;
+
/*
* Triggering garbage collection may require that the firmware
* generate a real EFI_OUT_OF_RESOURCES error. We can force
@@ -1061,7 +1072,10 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
void *dummy = kmalloc(dummy_size, GFP_ATOMIC);

status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
- attributes, dummy_size, dummy);
+ EFI_VARIABLE_NON_VOLATILE |
+ EFI_VARIABLE_BOOTSERVICE_ACCESS |
+ EFI_VARIABLE_RUNTIME_ACCESS,
+ dummy_size, dummy);

if (status == EFI_SUCCESS) {
/*
@@ -1069,7 +1083,10 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
* that we delete it...
*/
efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
- attributes, 0, dummy);
+ EFI_VARIABLE_NON_VOLATILE |
+ EFI_VARIABLE_BOOTSERVICE_ACCESS |
+ EFI_VARIABLE_RUNTIME_ACCESS,
+ 0, dummy);
}

/*
@@ -1085,7 +1102,7 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
/*
* There still isn't enough room, so return an error
*/
- if (remaining_size - size < 5120)
+ if (remaining_size - size < EFI_MIN_RESERVE)
return EFI_OUT_OF_RESOURCES;
}


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