Re: [PATCH v1 06/21] ArmVirtualizationPkg: add padding to FDT allocation

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 26 January 2015 at 11:47, Olivier Martin <olivier.martin@arm.com> wrote:
> I am a bit lost with this patch. I am looking for the definition of
> FDT_PADDING. I cannot find it in the previous patches and in subversion.

It is in the first hunk of *this* patch

> And it looks like it is going to be removed later on as I cannot find it
> anymore in the HEAD of your branch
> https://git.linaro.org/people/ard.biesheuvel/uefi-next.git/shortlog/refs/hea
> ds/linaro-topic-xen.
>
>> -----Original Message-----
>> From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
>> Sent: 23 January 2015 15:03
>> To: edk2-devel@lists.sourceforge.net; lersek@redhat.com; Olivier
>> Martin; roy.franz@linaro.org; leif.lindholm@linaro.org;
>> stefano.stabellini@eu.citrix.com; Ian.Campbell@citrix.com;
>> anthony.perard@citrix.com; christoffer.dall@linaro.org; xen-
>> devel@lists.xen.org; ilias.biris@linaro.org
>> Cc: Ard Biesheuvel
>> Subject: [PATCH v1 06/21] 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@linaro.org>
>> ---
>>  .../Library/PlatformPeiLib/PlatformPeiLib.c             | 17
>> +++++++++++++----
>>  1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git
>> a/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
>> iLib.c
>> b/ArmPlatformPkg/ArmVirtualizationPkg/Library/PlatformPeiLib/PlatformPe
>> iLib.c
>> index f2404f89d152..540474608deb 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


here ^^^


>> +
>>  EFI_STATUS
>>  EFIAPI
>>  PlatformPeim (
>> @@ -32,7 +41,7 @@ PlatformPeim (
>>  {
>>    VOID               *Base;
>>    VOID               *NewBase;
>> -  UINTN              FdtSize;
>> +  UINTN              FdtPages;
>>    UINTN              *FdtHobData;
>>    UINT64             *UartHobData;
>>    INT32              Node, Prev;
>> @@ -46,10 +55,10 @@ PlatformPeim (
>>    Base = (VOID*)(UINTN)PcdGet64 (PcdDeviceTreeInitialBaseAddress);
>>    ASSERT (Base != NULL && fdt_check_header (Base) == 0);
>>
>> -  FdtSize = fdt_totalsize (Base);
>> -  NewBase = AllocatePages (EFI_SIZE_TO_PAGES (FdtSize));
>> +  FdtPages = EFI_SIZE_TO_PAGES (fdt_totalsize (Base) + FDT_PADDING);
>> +  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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