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pa_memcpy() is the major memcpy implementation in the parisc kernel which is used to do any kind of userspace/kernel memory copies. Al Viro noticed various bugs in the implementation of pa_mempcy(), most notably that in case of faults it may report back to have copied more bytes than it actually did. Fixing those bugs is quite hard in the C-implementation, because the compiler is messing around with the registers and we are not guaranteed that specific variables are always in the same processor registers. This makes proper fault handling complicated. This patch implements pa_memcpy() in assembler. That way we have correct fault handling and adding a 64-bit copy routine was quite easy. Runtime tested with 32- and 64bit kernels. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: <stable@vger.kernel.org> # v4.9+ Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
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.