The special cases of peek and poke on acrs[15] and the fpc register are not
handled correctly. A poke on acrs[15] will clobber the 4 bytes after the
access registers in the thread_info structure. That happens to be the kernel
stack pointer. A poke on the fpc with an invalid value is not caught by the
validity check. On the next context switch the broken fpc value will cause a
program check in the kernel. Improving the checks in peek and poke fixes
this.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
778959db97