Commit graph

13 commits

Author SHA1 Message Date
H. Peter Anvin
ebe119cd09 x86: Fix movq immediate operand constraints in uaccess.h
The movq instruction, generated by __put_user_asm() when used for
64-bit data, takes a sign-extended immediate ("e") not a zero-extended
immediate ("Z").

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: stable@kernel.org
2009-07-20 23:27:39 -07:00
Linus Torvalds
9063c61fd5 x86, 64-bit: Clean up user address masking
The discussion about using "access_ok()" in get_user_pages_fast() (see
commit 7f81890687: "x86: don't use
'access_ok()' as a range check in get_user_pages_fast()" for details and
end result), made us notice that x86-64 was really being very sloppy
about virtual address checking.

So be way more careful and straightforward about masking x86-64 virtual
addresses:

 - All the VIRTUAL_MASK* variants now cover half of the address
   space, it's not like we can use the full mask on a signed
   integer, and the larger mask just invites mistakes when
   applying it to either half of the 48-bit address space.

 - /proc/kcore's kc_offset_to_vaddr() becomes a lot more
   obvious when it transforms a file offset into a
   (kernel-half) virtual address.

 - Unify/simplify the 32-bit and 64-bit USER_DS definition to
   be based on TASK_SIZE_MAX.

This cleanup and more careful/obvious user virtual address checking also
uncovered a buglet in the x86-64 implementation of strnlen_user(): it
would do an "access_ok()" check on the whole potential area, even if the
string itself was much shorter, and thus return an error even for valid
strings. Our sloppy checking had hidden this.

So this fixes 'strnlen_user()' to do this properly, the same way we
already handled user strings in 'strncpy_from_user()'.  Namely by just
checking the first byte, and then relying on fault handling for the
rest.  That always works, since we impose a guard page that cannot be
mapped at the end of the user space address space (and even if we
didn't, we'd have the address space hole).

Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-20 15:40:00 -07:00
Ingo Molnar
0c87197142 perf_counter, x86: Improve interactions with fast-gup
Improve a few details in perfcounter call-chain recording that
makes use of fast-GUP:

- Use ACCESS_ONCE() to observe the pte value. ptes are fundamentally
  racy and can be changed on another CPU, so we have to be careful
  about how we access them. The PAE branch is already careful with
  read-barriers - but the non-PAE and 64-bit side needs an
  ACCESS_ONCE() to make sure the pte value is observed only once.

- make the checks a bit stricter so that we can feed it any kind of
  cra^H^H^H user-space input ;-)

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-19 16:55:16 +02:00
Hiroshi Shimamoto
18114f6135 x86: uaccess: use errret as error value in __put_user_size()
Impact: cleanup

In __put_user_size() macro errret is used for error value.
But if size is 8, errret isn't passed to__put_user_asm_u64().
This behavior is inconsistent.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-02-04 17:28:21 -08:00
Hiroshi Shimamoto
019a136966 x86: uaccess: fix compilation error on CONFIG_M386
In case of !CONFIG_X86_WP_WORKS_OK, __put_user_size_ex() is not defined.
Add macros for !CONFIG_X86_WP_WORKS_OK case.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29 21:29:02 +01:00
Hiroshi Shimamoto
fe40c0af3c x86: uaccess: introduce try and catch framework
Impact: introduce new uaccess exception handling framework

Introduce {get|put}_user_try and {get|put}_user_catch as new uaccess exception
handling framework.
{get|put}_user_try begins exception block and {get|put}_user_catch(err) ends
the block and gets err if an exception occured in {get|put}_user_ex() in the
block. The exception is stored thread_info->uaccess_err.

The example usage of this framework is below;
int func()
{
	int err = 0;

	get_user_try {
		get_user_ex(...);
		get_user_ex(...);
		:
	} get_user_catch(err);

	return err;
}

Note: get_user_ex() is not clear the value when an exception occurs, it's
different from the behavior of __get_user(), but I think it doesn't matter.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-01-23 17:17:36 -08:00
Hiroshi Shimamoto
cc86c9e0dc x86: uaccess: rename __put_user_u64() to __put_user_asm_u64()
Impact: cleanup

rename __put_user_u64() to __put_user_asm_u64() like __get_user_asm_u64().

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-21 12:34:44 +01:00
Hiroshi Shimamoto
4d5d783896 x86: uaccess: fix style problems
Impact: cleanup

Fix coding style problems in arch/x86/include/asm/uaccess.h.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-21 12:34:44 +01:00
Linus Torvalds
5f34fe1cfc Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
  stacktrace: provide save_stack_trace_tsk() weak alias
  rcu: provide RCU options on non-preempt architectures too
  printk: fix discarding message when recursion_bug
  futex: clean up futex_(un)lock_pi fault handling
  "Tree RCU": scalable classic RCU implementation
  futex: rename field in futex_q to clarify single waiter semantics
  x86/swiotlb: add default swiotlb_arch_range_needs_mapping
  x86/swiotlb: add default phys<->bus conversion
  x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
  x86: add swiotlb allocation functions
  swiotlb: consolidate swiotlb info message printing
  swiotlb: support bouncing of HighMem pages
  swiotlb: factor out copy to/from device
  swiotlb: add arch hook to force mapping
  swiotlb: allow architectures to override phys<->bus<->phys conversions
  swiotlb: add comment where we handle the overflow of a dma mask on 32 bit
  rcu: fix rcutorture behavior during reboot
  resources: skip sanity check of busy resources
  swiotlb: move some definitions to header
  swiotlb: allow architectures to override swiotlb pool allocation
  ...

Fix up trivial conflicts in
  arch/x86/kernel/Makefile
  arch/x86/mm/init_32.c
  include/linux/hardirq.h
as per Ingo's suggestions.
2008-12-30 16:10:19 -08:00
Hiroshi Shimamoto
16855f878d x86: uaccess: return value of __{get|put}_user() can be int
Impact: cleanup

The type of return value of __{get|put}_user() can be int.
There is no user to refer the return value of __{get|put}_user() as long.
This reduces code size a bit on 64-bit.

 $ size vmlinux.*
     text	   data	    bss	    dec	    hex	filename
  4509265	 479988	 673588	5662841	 566879	vmlinux.new
  4511462	 479988	 673588	5665038	 56710e	vmlinux.old

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-12 11:54:43 +01:00
Ingo Molnar
d1a76187a5 Merge commit 'v2.6.28-rc2' into core/locking
Conflicts:
	arch/um/include/asm/system.h
2008-10-28 16:54:49 +01:00
H. Peter Anvin
1965aae3c9 x86: Fix ASM_X86__ header guards
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:23 -07:00
Al Viro
bb8985586b x86, um: ... and asm-x86 move
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:20 -07:00
Renamed from include/asm-x86/uaccess.h (Browse further)