Thanks for your contribution, I submitted Andrew’s fix in revision 15252.
From: Andrew Fish [mailto:afish@apple.com]
Sent: 22 February 2014 18:47
To: edk2-devel@lists.sourceforge.net
Cc: linaro-uefi
Subject: Re: [edk2] Upstream EDK2 broken with latest Linaro toolchain (13.12 onwards)
On Feb 21, 2014, at 11:53 AM, Ryan Harkin <ryan.harkin@linaro.org> wrote:
On 21 February 2014 18:44, Andrew Fish <afish@apple.com> wrote:
On Feb 21, 2014, at 10:17 AM, Laszlo Ersek <lersek@redhat.com> wrote:
On 02/21/14 16:12, Ryan Harkin wrote:
Hi Olivier,
I've just noticed that the upstream EDK2 repository for the FVP AEMv8
model is broken when built with Linaro GCC 13.12 onwards.
The error I see is:
UEFI firmware (version built at 14:54:24 on Feb 21 2014)
add-symbol-file
/linaro/uefi/master/upstream/edk2.git/Build/ArmVExpress-FVP-AArch64/DEBUG_ARMGCC/AARCH64/ArmPlatformPkg/PrePi/PeiMPCore/DEBUG/ArmPlatformPrePiMPCore.dll
0x88000780
Decompress Failed - Not Found
ASSERT_EFI_ERROR (Status = Not Found)
ASSERT /linaro/uefi/master/upstream/edk2.git/ArmPlatformPkg/PrePi/PrePi.c(194):
!EFI_ERROR (Status)
I've tracked the bug as far as function "FfsProcessSection" [1] where
at line 373, it calls into function "ExtractGuidedSectionDecode" [2]
which then calls into "SavedData->ExtractDecodeHandlerTable [Index]".
At that point, I can't work out where it goes.
I can "fix" the problem if I re-org the variables at the top of
FfsProcessSection so that DstBuffer is at the start of the
declarations. That is obviously not a fix. But it will probably hint
at why the subsequent code is broken.
Cheers,
Ryan
[1] EmbeddedPkg/Library/PrePiLib/FwVol.c, line 285
[2] EmbeddedPkg/Library/PrePiExtractGuidedSectionLib/PrePiExtractGuidedSectionLib.c:166
Here's a random shot (could be completely unrelated):
EFI_STATUS
FfsProcessSection (
IN EFI_SECTION_TYPE SectionType,
IN EFI_COMMON_SECTION_HEADER *Section,
IN UINTN SectionSize,
OUT VOID **OutputBuffer
)
{
/* ... */
UINTN DstBufferSize;
/* ... */
You're on AArch64, so UINTN means UINT64.
Note that this "auto" variable is not initialized, hence its contents are indeterminate. Fast forward to the next use:
Status = UefiDecompressGetInfo (
(UINT8 *) ((EFI_COMPRESSION_SECTION *) Section + 1),
(UINT32) SectionLength - sizeof (EFI_COMPRESSION_SECTION),
(UINT32 *) &DstBufferSize,
&ScratchBufferSize
);
} else if (Section->Type == EFI_SECTION_GUID_DEFINED) {
Status = ExtractGuidedSectionGetInfo (
Section,
(UINT32 *) &DstBufferSize,
&ScratchBufferSize,
&SectionAttribute
);
Whichever of these functions is invoked, it fills in only four bytes (UINT32). Then,
DstBuffer = (VOID *)(UINTN)AllocatePages (EFI_SIZE_TO_PAGES (DstBufferSize) + 1);
etc etc etc.
By reordering the local variables, you could be limiting the nonzero garbage in "DstBufferSize" to those four bytes that *are* ultimately overwritten.
I guess initing DstBufferSize to zero is easy enough to try... :)
As you guessed, it was easy to try and it does indeed fix the problem. However....