f839e5f1ce
When a page is not present, we get non-access data TLB faults from the fdc and fic instructions in flush_user_dcache_range_asm and flush_user_icache_range_asm. When these occur, the cache line is not invalidated and potentially we get memory corruption. The problem was hidden by the nullification of the flush instructions. These faults also affect performance. With pa8800/pa8900 processors, there will be 32 faults per 4 KB page since the cache line is 128 bytes. There will be more faults with earlier processors. The problem is fixed by using flush_cache_pages(). It does the flush using a tmp alias mapping. The flush_cache_pages() call in flush_cache_range() flushed too large a range. V2: Remove unnecessary preempt_disable() and preempt_enable() calls. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.