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2009-10-06[S390] Add EX_TABLE for addressing exception in usercopy functions.Gerald Schaefer1-6/+8
This patch adds an EX_TABLE entry to mvc{p|s|os} usercopy functions that may be called with KERNEL_DS. In combination with collaborative memory management, kernel pages marked as unused may trigger an adressing exception in the usercopy functions. This fixes an unhandled addressing exception bug where strncpy_from_user() is used with len > strnlen and KERNEL_DS, crossing a page boundary to an unused page. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-02-19[S390] Fix futex_atomic_cmpxchg_std inline assembly.Heiko Carstens1-4/+4
Add missing exception table entry so that the kernel can handle proctection exceptions as well on the cs instruction. Currently only specification exceptions are handled correctly. The missing entry allows user space to crash the kernel. Cc: stable <stable@kernel.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05[S390] Get rid of a lot of sparse warnings.Heiko Carstens1-11/+12
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-01-09[S390] don't call handle_mm_fault() if in an atomic context.Heiko Carstens1-3/+0
There are several places in the futex code where a spin_lock is held and still uaccesses happen. Deadlocks are avoided by increasing the preempt count. The pagefault handler will then not take any locks but will immediately search the fixup tables. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-12-07[PATCH] mm: pagefault_{disable,enable}()Peter Zijlstra1-3/+3
Introduce pagefault_{disable,enable}() and use these where previously we did manual preempt increments/decrements to make the pagefault handler do the atomic thing. Currently they still rely on the increased preempt count, but do not rely on the disabled preemption, this might go away in the future. (NOTE: the extra barrier() in pagefault_disable might fix some holes on machines which have too many registers for their own good) [heiko.carstens@de.ibm.com: s390 fix] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Nick Piggin <npiggin@suse.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-04[S390] Add dynamic size check for usercopy functions.Gerald Schaefer1-52/+15
Use a wrapper for copy_to/from_user to chose the best usercopy method. The mvcos instruction is better for sizes greater than 256 bytes, if mvcos is not available a page table walk is better for sizes greater than 1024 bytes. Also removed the redundant copy_to/from_user_std_small functions. Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-28[S390] user readable uninitialised kernel memory.Martin Schwidefsky1-10/+26
A user space program can read uninitialised kernel memory by appending to a file from a bad address and then reading the result back. The cause is the copy_from_user function that does not clear the remaining bytes of the kernel buffer after it got a fault on the user space address. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-09-20[S390] Make user-copy operations run-time configurable.Gerald Schaefer1-0/+340
Introduces a struct uaccess_ops which allows setting user-copy operations at run-time. Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>