b3879a4d3a
The ARM decompressor is finicky when it comes to uninitialized variables with local linkage, the reason being that it may relocate .text and .bss independently when executing from ROM. This is only possible if all references into .bss from .text are absolute, and this happens to be the case for references emitted under -fpic to symbols with external linkage, and so all .bss references must involve symbols with external linkage. When building the ARM stub using clang, the initialized local variable __chunk_size is optimized into a zero-initialized flag that indicates whether chunking is in effect or not. This flag is therefore emitted into .bss, which triggers the ARM decompressor's diagnostics, resulting in a failed build. Under UEFI, we never execute the decompressor from ROM, so the diagnostic makes little sense here. But we can easily work around the issue by making __chunk_size global instead. However, given that the file I/O chunking that is controlled by the __chunk_size variable is intended to work around known bugs on various x86 implementations of UEFI, we can simply make the chunking an x86 specific feature. This is an improvement by itself, and also removes the need to parse the efi= options in the stub entirely. Tested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1486380166-31868-8-git-send-email-ard.biesheuvel@linaro.org [ Small readability edits. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
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| .mailmap | ||
| COPYING | ||
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| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.