linux.git/arch/parisc/lib, branch v4.11

parisc: fix bugs in pa_memcpy

2017-04-15T15:24:05+00:00

The patch 554bfeceb8a22d448cd986fc9efce25e833278a1 ("parisc: Fix access
fault handling in pa_memcpy()") reimplements the pa_memcpy function.
Unfortunatelly, it makes the kernel unbootable. The crash happens in the
function ide_complete_cmd where memcpy is called with the same source
and destination address.

This patch fixes a few bugs in pa_memcpy:

* When jumping to .Lcopy_loop_16 for the first time, don't skip the
  instruction "ldi 31,t0" (this bug made the kernel unbootable)
* Use the COND macro when comparing length, so that the comparison is
  64-bit (a theoretical issue, in case the length is greater than
  0xffffffff)
* Don't use the COND macro after the "extru" instruction (the PA-RISC
  specification says that the upper 32-bits of extru result are undefined,
  although they are set to zero in practice)
* Fix exception addresses in .Lcopy16_fault and .Lcopy8_fault
* Rename .Lcopy_loop_4 to .Lcopy_loop_8 (so that it is consistent with
  .Lcopy8_fault)

Cc:  # v4.9+
Fixes: 554bfeceb8a2 ("parisc: Fix access fault handling in pa_memcpy()")
Signed-off-by: Mikulas Patocka 
Signed-off-by: Helge Deller

parisc: Clean up fixup routines for get_user()/put_user()

2017-03-29T19:50:36+00:00

Al Viro noticed that userspace accesses via get_user()/put_user() can be
simplified a lot with regard to usage of the exception handling.

This patch implements a fixup routine for get_user() and put_user() in such
that the exception handler will automatically load -EFAULT into the register
%r8 (the error value) in case on a fault on userspace.  Additionally the fixup
routine will zero the target register on fault in case of a get_user() call.
The target register is extracted out of the faulting assembly instruction.

This patch brings a few benefits over the old implementation:
1. Exception handling gets much cleaner, easier and smaller in size.
2. Helper functions like fixup_get_user_skip_1 (all of fixup.S) can be dropped.
3. No need to hardcode %r9 as target register for get_user() any longer. This
   helps the compiler register allocator and thus creates less assembler
   statements.
4. No dependency on the exception_data contents any longer.
5. Nested faults will be handled cleanly.

Reported-by: Al Viro 
Cc:  # v4.9+
Signed-off-by: Helge Deller

parisc: Fix access fault handling in pa_memcpy()

2017-03-29T19:49:02+00:00

pa_memcpy() is the major memcpy implementation in the parisc kernel which is
used to do any kind of userspace/kernel memory copies.

Al Viro noticed various bugs in the implementation of pa_mempcy(), most notably
that in case of faults it may report back to have copied more bytes than it
actually did.

Fixing those bugs is quite hard in the C-implementation, because the compiler
is messing around with the registers and we are not guaranteed that specific
variables are always in the same processor registers. This makes proper fault
handling complicated.

This patch implements pa_memcpy() in assembler. That way we have correct fault
handling and adding a 64-bit copy routine was quite easy.

Runtime tested with 32- and 64bit kernels.

Reported-by: Al Viro 
Cc:  # v4.9+
Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller

Replace with globally

2016-12-24T19:46:01+00:00

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*'
  sed -i -e "s!$PATT!#include !" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro 
Signed-off-by: Linus Torvalds

parisc: Add hardened usercopy feature

2016-10-06T20:10:19+00:00

Add hardened usercopy checks to parisc architecture and clean up
indenting.

Signed-off-by: Helge Deller

parisc: Add cfi_startproc and cfi_endproc to assembly code

2016-10-05T20:54:40+00:00

Add ENTRY_CFI() and ENDPROC_CFI() macros for dwarf debug info and
convert assembly users to new macros.

Signed-off-by: Helge Deller

parisc: Change structure intialisation to C99 style in iomap.c

2016-08-02T14:44:34+00:00

Replace the in order struct initialisation style with explicit field
style.

Signed-off-by: Amitoj Kaur Chawla 
Signed-off-by: Helge Deller

parisc: Add native high-resolution sched_clock() implementation

2016-05-22T19:39:25+00:00

Add a native implementation for the sched_clock() function which utilizes the
processor-internal cycle counter (Control Register 16) as high-resolution time
source.

With this patch we now get much more fine-grained resolutions in various
in-kernel time measurements (e.g. when viewing the function tracing logs), and
probably a more accurate scheduling on SMP systems.

There are a few specific implementation details in this patch:

1. On a 32bit kernel we emulate the higher 32bits of the required 64-bit
resolution of sched_clock() by increasing a per-cpu counter at every
wrap-around of the 32bit cycle counter.

2. In a SMP system, the cycle counters of the various CPUs are not syncronized
(similiar to the TSC in a x86_64 system). To cope with this we define
HAVE_UNSTABLE_SCHED_CLOCK and let the upper layers do the adjustment work.

3. Since we need HAVE_UNSTABLE_SCHED_CLOCK, we need to provide a cmpxchg64()
function even on a 32-bit kernel.

4. A 64-bit SMP kernel which is started on a UP system will mark the
sched_clock() implementation as "stable", which means that we don't expect any
jumps in the returned counter. This is true because we then run only on one
CPU.

Signed-off-by: Helge Deller

parisc: Unbreak handling exceptions from kernel modules

2016-04-08T20:14:14+00:00

Handling exceptions from modules never worked on parisc.
It was just masked by the fact that exceptions from modules
don't happen during normal use.

When a module triggers an exception in get_user() we need to load the
main kernel dp value before accessing the exception_data structure, and
afterwards restore the original dp value of the module on exit.

Noticed-by: Mikulas Patocka 
Signed-off-by: Helge Deller 
Cc: stable@vger.kernel.org

parisc: percpu: update comments referring to __get_cpu_var

2014-12-13T20:42:53+00:00

__get_cpu_var was removed. Update comments to refer to
this_cpu_ptr() instead.

Signed-off-by: Christoph Lameter 
Cc: "James E.J. Bottomley" 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds