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SubjectRe: [PATCH] Modify UEFI anti-bricking code
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於 四,2013-06-06 於 05:42 +0000,Matthew Garrett 提到:
> On Thu, 2013-06-06 at 13:05 +0800, joeyli wrote:
>
> > + if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
> > + return EFI_OUT_OF_RESOURCES;
>
> I'd move this up to the top of the function, and just return 0 - there's
> no risk of the firmware causing problems if it's a volatile variable, so
> we should probably just pass it down to the firmware and return an error
> from there.
>

OK, I moved volatile checking to the top of the function.
New version, version 3 diff result like the following.


Thanks a lot for reviewing
Joey Lee

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index cc3cfe8..5ae2eb0 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);
}

/*
@@ -1040,6 +1046,9 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
efi_status_t status;
u64 storage_size, remaining_size, max_size;

+ if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
+ return 0;
+
status = efi.query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);
if (status != EFI_SUCCESS)
@@ -1051,7 +1060,9 @@ 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) {
+
/*
* 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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