linux-stable.git/arch/parisc/kernel, branch v5.3 Linux kernel stable tree parisc: fix race condition in patching code 2019-07-31T14:20:57+00:00 Sven Schnelle svens@stackframe.org 2019-07-23T20:37:54+00:00 740f05f30a8c49ec63668055d28feedd906d3c50 Assume the following ftrace code sequence that was patched in earlier by ftrace_make_call(): PAGE A: ffc: addr of ftrace_caller() PAGE B: 000: 0x6fc10080 /* stw,ma r1,40(sp) */ 004: 0x48213fd1 /* ldw -18(r1),r1 */ 008: 0xe820c002 /* bv,n r0(r1) */ 00c: 0xe83f1fdf /* b,l,n .-c,r1 */ When a Code sequences that is to be patched spans a page break, we might have already cleared the part on the PAGE A. If an interrupt is coming in during the remap of the fixed mapping to PAGE B, it might execute the patched function with only parts of the FTRACE code cleared. To prevent this, clear the jump to our mini trampoline first, and clear the remaining parts after this. This might also happen when patch_text() patches a function that it calls during remap. Signed-off-by: Sven Schnelle <svens@stackframe.org> Cc: <stable@vger.kernel.org> # 5.2+ Signed-off-by: Helge Deller <deller@gmx.de> 
Assume the following ftrace code sequence that was patched in earlier by
ftrace_make_call():

PAGE A:
ffc:	addr of ftrace_caller()
PAGE B:
000:	0x6fc10080 /* stw,ma r1,40(sp) */
004:	0x48213fd1 /* ldw -18(r1),r1 */
008:	0xe820c002 /* bv,n r0(r1) */
00c:	0xe83f1fdf /* b,l,n .-c,r1 */

When a Code sequences that is to be patched spans a page break, we might
have already cleared the part on the PAGE A. If an interrupt is coming in
during the remap of the fixed mapping to PAGE B, it might execute the
patched function with only parts of the FTRACE code cleared. To prevent
this, clear the jump to our mini trampoline first, and clear the remaining
parts after this. This might also happen when patch_text() patches a
function that it calls during remap.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Cc: <stable@vger.kernel.org> # 5.2+
Signed-off-by: Helge Deller <deller@gmx.de>
parisc: Flush ITLB in flush_tlb_all_local() only on split TLB machines 2019-07-21T09:03:02+00:00 Helge Deller deller@gmx.de 2019-07-20T22:55:48+00:00 69245c97560b40f88c609b078f4b51c5be81d88b flush_tlb_all_local() flushes the ITLB and DTLB of the CPU. In case the machine does not have separate ITLBs and DTLBs, use the alternative functionality to replace the code which flushes the ITLB with nops while keeping the code which flushes the DTLB. Signed-off-by: Helge Deller <deller@gmx.de> 
flush_tlb_all_local() flushes the ITLB and DTLB of the CPU.
In case the machine does not have separate ITLBs and DTLBs, use the
alternative functionality to replace the code which flushes the ITLB
with nops while keeping the code which flushes the DTLB.

Signed-off-by: Helge Deller <deller@gmx.de>
parisc: Wire up clone3 syscall 2019-07-17T21:11:28+00:00 Helge Deller deller@gmx.de 2019-07-15T20:33:26+00:00 45800fb45139284f0db4f5ac7fbbf5dad81e4172 Signed-off-by: Helge Deller <deller@gmx.de> Tested-by: Sven Schnelle <svens@stackframe.org> Acked-by: Christian Brauner <christian@brauner.io> 
Signed-off-by: Helge Deller <deller@gmx.de>
Tested-by: Sven Schnelle <svens@stackframe.org>
Acked-by: Christian Brauner <christian@brauner.io>
parisc: Avoid kernel panic triggered by invalid kprobe 2019-07-17T21:11:28+00:00 Helge Deller deller@gmx.de 2019-07-16T19:16:26+00:00 59a783dbc0d5fd6792aabff933055373b6dcbf2a When running gdb I was able to trigger this kernel panic: Kernel Fault: Code=26 (Data memory access rights trap) at addr 0000000000000060 CPU: 0 PID: 1401 Comm: gdb-crash Not tainted 5.2.0-rc7-64bit+ #1053 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001000000000000001111 Not tainted r00-03 000000000804000f 0000000040dee1a0 0000000040c78cf0 00000000b8d50160 r04-07 0000000040d2b1a0 000000004360a098 00000000bbbe87b8 0000000000000003 r08-11 00000000fac20a70 00000000fac24160 00000000fac1bbe0 0000000000000000 r12-15 00000000fabfb79a 00000000fac244a4 0000000000010000 0000000000000001 r16-19 00000000bbbe87b8 00000000f8f02910 0000000000010034 0000000000000000 r20-23 00000000fac24630 00000000fac24630 000000006474e552 00000000fac1aa52 r24-27 0000000000000028 00000000bbbe87b8 00000000bbbe87b8 0000000040d2b1a0 r28-31 0000000000000000 00000000b8d501c0 00000000b8d501f0 0000000003424000 sr00-03 0000000000423000 0000000000000000 0000000000000000 0000000000423000 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 0000000040c78cf0 0000000040c78cf4 IIR: 539f00c0 ISR: 0000000000000000 IOR: 0000000000000060 CPU: 0 CR30: 00000000b8d50000 CR31: 00000000d22345e2 ORIG_R28: 0000000040250798 IAOQ[0]: parisc_kprobe_ss_handler+0x58/0x170 IAOQ[1]: parisc_kprobe_ss_handler+0x5c/0x170 RP(r2): parisc_kprobe_ss_handler+0x58/0x170 Backtrace: [<0000000040206ff8>] handle_interruption+0x178/0xbb8 Kernel panic - not syncing: Kernel Fault Avoid this panic by checking the return value of kprobe_running() and skip kprobe if none is currently active. Cc: <stable@vger.kernel.org> # v5.2 Acked-by: Sven Schnelle <svens@stackframe.org> Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Helge Deller <deller@gmx.de> 
When running gdb I was able to trigger this kernel panic:

 Kernel Fault: Code=26 (Data memory access rights trap) at addr 0000000000000060
 CPU: 0 PID: 1401 Comm: gdb-crash Not tainted 5.2.0-rc7-64bit+ #1053

      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
 PSW: 00001000000001000000000000001111 Not tainted
 r00-03  000000000804000f 0000000040dee1a0 0000000040c78cf0 00000000b8d50160
 r04-07  0000000040d2b1a0 000000004360a098 00000000bbbe87b8 0000000000000003
 r08-11  00000000fac20a70 00000000fac24160 00000000fac1bbe0 0000000000000000
 r12-15  00000000fabfb79a 00000000fac244a4 0000000000010000 0000000000000001
 r16-19  00000000bbbe87b8 00000000f8f02910 0000000000010034 0000000000000000
 r20-23  00000000fac24630 00000000fac24630 000000006474e552 00000000fac1aa52
 r24-27  0000000000000028 00000000bbbe87b8 00000000bbbe87b8 0000000040d2b1a0
 r28-31  0000000000000000 00000000b8d501c0 00000000b8d501f0 0000000003424000
 sr00-03  0000000000423000 0000000000000000 0000000000000000 0000000000423000
 sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

 IASQ: 0000000000000000 0000000000000000 IAOQ: 0000000040c78cf0 0000000040c78cf4
  IIR: 539f00c0    ISR: 0000000000000000  IOR: 0000000000000060
  CPU:        0   CR30: 00000000b8d50000 CR31: 00000000d22345e2
  ORIG_R28: 0000000040250798
  IAOQ[0]: parisc_kprobe_ss_handler+0x58/0x170
  IAOQ[1]: parisc_kprobe_ss_handler+0x5c/0x170
  RP(r2): parisc_kprobe_ss_handler+0x58/0x170
 Backtrace:
  [<0000000040206ff8>] handle_interruption+0x178/0xbb8
 Kernel panic - not syncing: Kernel Fault

Avoid this panic by checking the return value of kprobe_running() and
skip kprobe if none is currently active.

Cc: <stable@vger.kernel.org> # v5.2
Acked-by: Sven Schnelle <svens@stackframe.org>
Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Helge Deller <deller@gmx.de>
parisc: Ensure userspace privilege for ptraced processes in regset functions 2019-07-17T21:11:27+00:00 Helge Deller deller@gmx.de 2019-07-04T01:44:17+00:00 34c32fc603311a72cb558e5e337555434f64c27b On parisc the privilege level of a process is stored in the lowest two bits of the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0 for the kernel and privilege level 3 for user-space. So userspace should not be allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege level to e.g. 0 to try to gain kernel privileges. This patch prevents such modifications in the regset support functions by always setting the two lowest bits to one (which relates to privilege level 3 for user-space) if IAOQ0 or IAOQ1 are modified via ptrace regset calls. Link: https://bugs.gentoo.org/481768 Cc: <stable@vger.kernel.org> # v4.7+ Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Helge Deller <deller@gmx.de> 
On parisc the privilege level of a process is stored in the lowest two bits of
the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0
for the kernel and privilege level 3 for user-space. So userspace should not be
allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege
level to e.g. 0 to try to gain kernel privileges.

This patch prevents such modifications in the regset support functions by
always setting the two lowest bits to one (which relates to privilege level 3
for user-space) if IAOQ0 or IAOQ1 are modified via ptrace regset calls.

Link: https://bugs.gentoo.org/481768
Cc: <stable@vger.kernel.org> # v4.7+
Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Helge Deller <deller@gmx.de>
parisc: Fix kernel panic due invalid values in IAOQ0 or IAOQ1 2019-07-17T21:11:27+00:00 Helge Deller deller@gmx.de 2019-07-16T19:43:11+00:00 10835c854685393a921b68f529bf740fa7c9984d On parisc the privilege level of a process is stored in the lowest two bits of the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0 for the kernel and privilege level 3 for user-space. So userspace should not be allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege level to e.g. 0 to try to gain kernel privileges. This patch prevents such modifications by always setting the two lowest bits to one (which relates to privilege level 3 for user-space) if IAOQ0 or IAOQ1 are modified via ptrace calls in the native and compat ptrace paths. Link: https://bugs.gentoo.org/481768 Reported-by: Jeroen Roovers <jer@gentoo.org> Cc: <stable@vger.kernel.org> Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Helge Deller <deller@gmx.de> 
On parisc the privilege level of a process is stored in the lowest two bits of
the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0
for the kernel and privilege level 3 for user-space. So userspace should not be
allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege
level to e.g. 0 to try to gain kernel privileges.

This patch prevents such modifications by always setting the two lowest bits to
one (which relates to privilege level 3 for user-space) if IAOQ0 or IAOQ1 are
modified via ptrace calls in the native and compat ptrace paths.

Link: https://bugs.gentoo.org/481768
Reported-by: Jeroen Roovers <jer@gentoo.org>
Cc: <stable@vger.kernel.org>
Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Helge Deller <deller@gmx.de>
arch: mark syscall number 435 reserved for clone3 2019-07-14T22:39:33+00:00 Christian Brauner christian@brauner.io 2019-07-14T19:22:04+00:00 1a271a68e030f3e134de12087117574a883e20f0 A while ago Arnd made it possible to give new system calls the same syscall number on all architectures (except alpha). To not break this nice new feature let's mark 435 for clone3 as reserved on all architectures that do not yet implement it. Even if an architecture does not plan to implement it this ensures that new system calls coming after clone3 will have the same number on all architectures. Signed-off-by: Christian Brauner <christian@brauner.io> Cc: linux-arch@vger.kernel.org Cc: linux-alpha@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-mips@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: sparclinux@vger.kernel.org Link: https://lore.kernel.org/r/20190714192205.27190-2-christian@brauner.io Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Christian Brauner <christian@brauner.io> 
A while ago Arnd made it possible to give new system calls the same
syscall number on all architectures (except alpha). To not break this
nice new feature let's mark 435 for clone3 as reserved on all
architectures that do not yet implement it.
Even if an architecture does not plan to implement it this ensures that
new system calls coming after clone3 will have the same number on all
architectures.

Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: linux-arch@vger.kernel.org
Cc: linux-alpha@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Link: https://lore.kernel.org/r/20190714192205.27190-2-christian@brauner.io
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <christian@brauner.io>
Merge tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping 2019-07-12T22:13:55+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-07-12T22:13:55+00:00 9e3a25dc992dd9f3170fb643bdd95da5ca9c5576 Pull dma-mapping updates from Christoph Hellwig: - move the USB special case that bounced DMA through a device bar into the USB code instead of handling it in the common DMA code (Laurentiu Tudor and Fredrik Noring) - don't dip into the global CMA pool for single page allocations (Nicolin Chen) - fix a crash when allocating memory for the atomic pool failed during boot (Florian Fainelli) - move support for MIPS-style uncached segments to the common code and use that for MIPS and nios2 (me) - make support for DMA_ATTR_NON_CONSISTENT and DMA_ATTR_NO_KERNEL_MAPPING generic (me) - convert nds32 to the generic remapping allocator (me) * tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping: (29 commits) dma-mapping: mark dma_alloc_need_uncached as __always_inline MIPS: only select ARCH_HAS_UNCACHED_SEGMENT for non-coherent platforms usb: host: Fix excessive alignment restriction for local memory allocations lib/genalloc.c: Add algorithm, align and zeroed family of DMA allocators nios2: use the generic uncached segment support in dma-direct nds32: use the generic remapping allocator for coherent DMA allocations arc: use the generic remapping allocator for coherent DMA allocations dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code dma-direct: handle DMA_ATTR_NON_CONSISTENT in common code dma-mapping: add a dma_alloc_need_uncached helper openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support arc: remove the partial DMA_ATTR_NON_CONSISTENT support arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support ARM: dma-mapping: allow larger DMA mask than supported dma-mapping: truncate dma masks to what dma_addr_t can hold iommu/dma: Apply dma_{alloc,free}_contiguous functions dma-remap: Avoid de-referencing NULL atomic_pool MIPS: use the generic uncached segment support in dma-direct dma-direct: provide generic support for uncached kernel segments au1100fb: fix DMA API abuse ... 
Pull dma-mapping updates from Christoph Hellwig:

 - move the USB special case that bounced DMA through a device bar into
   the USB code instead of handling it in the common DMA code (Laurentiu
   Tudor and Fredrik Noring)

 - don't dip into the global CMA pool for single page allocations
   (Nicolin Chen)

 - fix a crash when allocating memory for the atomic pool failed during
   boot (Florian Fainelli)

 - move support for MIPS-style uncached segments to the common code and
   use that for MIPS and nios2 (me)

 - make support for DMA_ATTR_NON_CONSISTENT and
   DMA_ATTR_NO_KERNEL_MAPPING generic (me)

 - convert nds32 to the generic remapping allocator (me)

* tag 'dma-mapping-5.3' of git://git.infradead.org/users/hch/dma-mapping: (29 commits)
  dma-mapping: mark dma_alloc_need_uncached as __always_inline
  MIPS: only select ARCH_HAS_UNCACHED_SEGMENT for non-coherent platforms
  usb: host: Fix excessive alignment restriction for local memory allocations
  lib/genalloc.c: Add algorithm, align and zeroed family of DMA allocators
  nios2: use the generic uncached segment support in dma-direct
  nds32: use the generic remapping allocator for coherent DMA allocations
  arc: use the generic remapping allocator for coherent DMA allocations
  dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code
  dma-direct: handle DMA_ATTR_NON_CONSISTENT in common code
  dma-mapping: add a dma_alloc_need_uncached helper
  openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support
  arc: remove the partial DMA_ATTR_NON_CONSISTENT support
  arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support
  ARM: dma-mapping: allow larger DMA mask than supported
  dma-mapping: truncate dma masks to what dma_addr_t can hold
  iommu/dma: Apply dma_{alloc,free}_contiguous functions
  dma-remap: Avoid de-referencing NULL atomic_pool
  MIPS: use the generic uncached segment support in dma-direct
  dma-direct: provide generic support for uncached kernel segments
  au1100fb: fix DMA API abuse
  ...
Merge tag 'pidfd-updates-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux 2019-07-11T05:17:21+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-07-11T05:17:21+00:00 5450e8a316a64cddcbc15f90733ebc78aa736545 Pull pidfd updates from Christian Brauner: "This adds two main features. - First, it adds polling support for pidfds. This allows process managers to know when a (non-parent) process dies in a race-free way. The notification mechanism used follows the same logic that is currently used when the parent of a task is notified of a child's death. With this patchset it is possible to put pidfds in an {e}poll loop and get reliable notifications for process (i.e. thread-group) exit. - The second feature compliments the first one by making it possible to retrieve pollable pidfds for processes that were not created using CLONE_PIDFD. A lot of processes get created with traditional PID-based calls such as fork() or clone() (without CLONE_PIDFD). For these processes a caller can currently not create a pollable pidfd. This is a problem for Android's low memory killer (LMK) and service managers such as systemd. Both patchsets are accompanied by selftests. It's perhaps worth noting that the work done so far and the work done in this branch for pidfd_open() and polling support do already see some adoption: - Android is in the process of backporting this work to all their LTS kernels [1] - Service managers make use of pidfd_send_signal but will need to wait until we enable waiting on pidfds for full adoption. - And projects I maintain make use of both pidfd_send_signal and CLONE_PIDFD [2] and will use polling support and pidfd_open() too" [1] https://android-review.googlesource.com/q/topic:%22pidfd+polling+support+4.9+backport%22 https://android-review.googlesource.com/q/topic:%22pidfd+polling+support+4.14+backport%22 https://android-review.googlesource.com/q/topic:%22pidfd+polling+support+4.19+backport%22 [2] https://github.com/lxc/lxc/blob/aab6e3eb73c343231cdde775db938994fc6f2803/src/lxc/start.c#L1753 * tag 'pidfd-updates-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: tests: add pidfd_open() tests arch: wire-up pidfd_open() pid: add pidfd_open() pidfd: add polling selftests pidfd: add polling support 
Pull pidfd updates from Christian Brauner:
 "This adds two main features.

   - First, it adds polling support for pidfds. This allows process
     managers to know when a (non-parent) process dies in a race-free
     way.

     The notification mechanism used follows the same logic that is
     currently used when the parent of a task is notified of a child's
     death. With this patchset it is possible to put pidfds in an
     {e}poll loop and get reliable notifications for process (i.e.
     thread-group) exit.

   - The second feature compliments the first one by making it possible
     to retrieve pollable pidfds for processes that were not created
     using CLONE_PIDFD.

     A lot of processes get created with traditional PID-based calls
     such as fork() or clone() (without CLONE_PIDFD). For these
     processes a caller can currently not create a pollable pidfd. This
     is a problem for Android's low memory killer (LMK) and service
     managers such as systemd.

  Both patchsets are accompanied by selftests.

  It's perhaps worth noting that the work done so far and the work done
  in this branch for pidfd_open() and polling support do already see
  some adoption:

   - Android is in the process of backporting this work to all their LTS
     kernels [1]

   - Service managers make use of pidfd_send_signal but will need to
     wait until we enable waiting on pidfds for full adoption.

   - And projects I maintain make use of both pidfd_send_signal and
     CLONE_PIDFD [2] and will use polling support and pidfd_open() too"

[1] https://android-review.googlesource.com/q/topic:%22pidfd+polling+support+4.9+backport%22
    https://android-review.googlesource.com/q/topic:%22pidfd+polling+support+4.14+backport%22
    https://android-review.googlesource.com/q/topic:%22pidfd+polling+support+4.19+backport%22

[2] https://github.com/lxc/lxc/blob/aab6e3eb73c343231cdde775db938994fc6f2803/src/lxc/start.c#L1753

* tag 'pidfd-updates-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  tests: add pidfd_open() tests
  arch: wire-up pidfd_open()
  pid: add pidfd_open()
  pidfd: add polling selftests
  pidfd: add polling support
Merge branch 'parisc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2019-07-09T19:08:15+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-07-09T19:08:15+00:00 593c75463ab6d6985cdc9916f3d1c28b5f6340cd Pull parisc updates from Helge Deller: "Dynamic ftrace support by Sven Schnelle and a header guard fix by Denis Efremov" * 'parisc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: asm: psw.h: missing header guard parisc: add dynamic ftrace compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY parisc: use pr_debug() in kernel/module.c parisc: add WARN_ON() to clear_fixmap parisc: add spinlock to patch function parisc: add support for patching multiple words 
Pull parisc updates from Helge Deller:
 "Dynamic ftrace support by Sven Schnelle and a header guard fix by
  Denis Efremov"

* 'parisc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: asm: psw.h: missing header guard
  parisc: add dynamic ftrace
  compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY
  parisc: use pr_debug() in kernel/module.c
  parisc: add WARN_ON() to clear_fixmap
  parisc: add spinlock to patch function
  parisc: add support for patching multiple words