Re: [Xen-devel] [PATCH v2 08/29] ArmVirtualizationPkg: add padding to FDT allocation

[Laszlo Ersek <lersek@xxxxxxxxxx>]

On 01/28/15 17:18, Ard Biesheuvel wrote:
> On 28 January 2015 at 15:13, Olivier Martin <olivier.martin@xxxxxxx> wrote:
>> Same question as last time, would it not be better to have a PCD instead of
>> hardcoded value?
> 
> Ah yes, I remember reading that but failed to take it into account.
> 
>> Some platforms might want to have a larger FDT padding.
>>
> 
> Agreed. Will add it to v3

I think using a FixedPcd will be okay.

With that change, you can add

Reviewed-by: Laszlo Ersek <lersek@xxxxxxxxxx>

Thanks
Laszlo

> 
> 
>>
>>> -----Original Message-----
>>> From: Ard Biesheuvel [mailto:ard.biesheuvel@xxxxxxxxxx]
>>> Sent: 26 January 2015 19:03
>>> To: edk2-devel@xxxxxxxxxxxxxxxxxxxxx; lersek@xxxxxxxxxx; Olivier
>>> Martin; roy.franz@xxxxxxxxxx; leif.lindholm@xxxxxxxxxx;
>>> stefano.stabellini@xxxxxxxxxxxxx; Ian.Campbell@xxxxxxxxxx;
>>> anthony.perard@xxxxxxxxxx; christoffer.dall@xxxxxxxxxx; xen-
>>> devel@xxxxxxxxxxxxx; ilias.biris@xxxxxxxxxx
>>> Cc: Ard Biesheuvel
>>> Subject: [PATCH v2 08/29] ArmVirtualizationPkg: add padding to FDT
>>> allocation
>>>
>>> Our primary user QEMU/mach-virt presents us with a FDT blob padded
>>> to 64 KB with plenty of room to set additional properties. However,
>>> in the general case, we should only add properties after making sure
>>> there is enough room available.
>>>
>>> Contributed-under: TianoCore Contribution Agreement 1.0
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>>> ---
>>>
>>> ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPeiL
>>> ib.c | 17 ++++++++++++++---
>>>  1 file changed, 14 insertions(+), 3 deletions(-)
>>>
>>> diff --git
>>> a/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
>>> iLib.c
>>> b/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
>>> iLib.c
>>> index c500d5964b25..42a87309aebe 100644
>>> ---
>>> a/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
>>> iLib.c
>>> +++
>>> b/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
>>> iLib.c
>>> @@ -24,6 +24,15 @@
>>>  #include <Guid/EarlyPL011BaseAddress.h>
>>>  #include <Guid/FdtHob.h>
>>>
>>> +//
>>> +// We may want to apply some changes to the device tree before passing
>>> it
>>> +// to the OS: for instance, if we find a PL031 RTC node and attach our
>>> +// runtime driver to it, we should disable it in the device tree by
>>> setting
>>> +// its status property to "disabled". Add some padding to make sure
>>> this is
>>> +// possible.
>>> +//
>>> +#define FDT_PADDING   256
>>> +
>>>  EFI_STATUS
>>>  EFIAPI
>>>  PlatformPeim (
>>> @@ -33,6 +42,7 @@ PlatformPeim (
>>>    VOID               *Base;
>>>    VOID               *NewBase;
>>>    UINTN              FdtSize;
>>> +  UINTN              FdtPages;
>>>    UINT64             *FdtHobData;
>>>    UINT64             *UartHobData;
>>>    INT32              Node, Prev;
>>> @@ -47,10 +57,11 @@ PlatformPeim (
>>>    ASSERT (Base != NULL);
>>>    ASSERT (fdt_check_header (Base) == 0);
>>>
>>> -  FdtSize = fdt_totalsize (Base);
>>> -  NewBase = AllocatePages (EFI_SIZE_TO_PAGES (FdtSize));
>>> +  FdtSize = fdt_totalsize (Base) + FDT_PADDING;
>>> +  FdtPages = EFI_SIZE_TO_PAGES (FdtSize);
>>> +  NewBase = AllocatePages (FdtPages);
>>>    ASSERT (NewBase != NULL);
>>> -  CopyMem (NewBase, Base, FdtSize);
>>> +  fdt_open_into (Base, NewBase, EFI_PAGES_TO_SIZE (FdtPages));
>>>
>>>    FdtHobData = BuildGuidHob (&gFdtHobGuid, sizeof *FdtHobData);
>>>    ASSERT (FdtHobData != NULL);
>>> --
>>> 1.8.3.2
>>>
>>
>>
>>
>>


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