linux-stable.git/arch/arc, branch linux-3.12.y

ARC: [arcompact] brown paper bag bug in unaligned access delay slot fixup

2017-02-16T10:44:41+00:00

commit a524c218bc94c705886a0e0fedeee45d1931da32 upstream.

Reported-by: Jo-Philipp Wich 
Fixes: 9aed02feae57bf7 ("ARC: [arcompact] handle unaligned access delay slot")
Cc: linux-kernel@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby

ARC: [arcompact] handle unaligned access delay slot corner case

2017-02-15T10:56:08+00:00

commit 9aed02feae57bf7a40cb04ea0e3017cb7a998db4 upstream.

After emulating an unaligned access in delay slot of a branch, we
pretend as the delay slot never happened - so return back to actual
branch target (or next PC if branch was not taken).

Curently we did this by handling STATUS32.DE, we also need to clear the
BTA.T bit, which is disregarded when returning from original misaligned
exception, but could cause weirdness if it took the interrupt return
path (in case interrupt was acive too)

One ARC700 customer ran into this when enabling unaligned access fixup
for kernel mode accesses as well

Signed-off-by: Vineet Gupta 
Signed-off-by: Jiri Slaby

arc: don't leak bits of kernel stack into coredump

2016-11-08T15:38:12+00:00

commit 7798bf2140ebcc36eafec6a4194fffd8d585d471 upstream.

On faulting sigreturn we do get SIGSEGV, all right, but anything
we'd put into pt_regs could end up in the coredump.  And since
__copy_from_user() never zeroed on arc, we'd better bugger off
on its failure without copying random uninitialized bits of
kernel stack into pt_regs...

Signed-off-by: Al Viro 
Signed-off-by: Jiri Slaby

ARC: uaccess: get_user to zero out dest in cause of fault

2016-09-29T09:14:31+00:00

commit 05d9d0b96e53c52a113fd783c0c97c830c8dc7af upstream.

Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.

Verified using following

| {
|  	u32 bogus1 = 0xdeadbeef;
|	u64 bogus2 = 0xdead;
|	int rc1, rc2;
|
|  	pr_info("Orig values %x %llx\n", bogus1, bogus2);
|	rc1 = get_user(bogus1, (u32 __user *)0x40000000);
|	rc2 = get_user(bogus2, (u64 __user *)0x50000000);
|	pr_info("access %d %d, new values %x %llx\n",
|		rc1, rc2, bogus1, bogus2);
| }

| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0

Reported-by: Al Viro 
Cc: Linus Torvalds 
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta 
Signed-off-by: Al Viro 
Signed-off-by: Jiri Slaby

arc: unwind: warn only once if DW2_UNWIND is disabled

2016-08-19T07:50:54+00:00

commit 9bd54517ee86cb164c734f72ea95aeba4804f10b upstream.

If CONFIG_ARC_DW2_UNWIND is disabled every time arc_unwind_core()
gets called following message gets printed in debug console:
----------------->8---------------
CONFIG_ARC_DW2_UNWIND needs to be enabled
----------------->8---------------

That message makes sense if user indeed wants to see a backtrace or
get nice function call-graphs in perf but what if user disabled
unwinder for the purpose? Why pollute his debug console?

So instead we'll warn user about possibly missing feature once and
let him decide if that was what he or she really wanted.

Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
Signed-off-by: Jiri Slaby

ARC: use ASL assembler mnemonic

2016-06-15T07:32:01+00:00

commit a6416f57ce57fb390b6ee30b12c01c29032a26af upstream.

ARCompact and ARCv2 only have ASL, while binutils used to support LSL as
a alias mnemonic.

Newer binutils (upstream) don't want to do that so replace it.

Signed-off-by: Vineet Gupta 
Signed-off-by: Jiri Slaby

arc,hexagon: Delete asm/barrier.h

2015-10-28T15:37:40+00:00

commit 2ab08ee9f0a4eba27c7c4ce0b6d5118e8a18554b upstream.

Both already use asm-generic/barrier.h as per their
include/asm/Kbuild. Remove the stale files.

Signed-off-by: Peter Zijlstra 
Acked-by: Paul E. McKenney 
Link: http://lkml.kernel.org/n/tip-c7vlkshl3tblim0o8z2p70kt@git.kernel.org
Cc: Linus Torvalds 
Cc: Richard Kuo 
Cc: Vineet Gupta 
Cc: linux-hexagon@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Jiri Slaby

arch: Move smp_mb__{before,after}_atomic_{inc,dec}.h into asm/atomic.h

2015-10-28T15:37:40+00:00

commit 1de7da377bd880ff23917f78924d0e908329d978 upstream.

Move the barriers functions that depend on the atomic implementation
into the atomic implementation.

Reviewed-by: Paul E. McKenney 
Signed-off-by: Peter Zijlstra 
Acked-by: Vineet Gupta  [for arch/arc bits]
Cc: Peter Zijlstra 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Cc: Thomas Gleixner 
Cc: Paul E. McKenney 
Link: http://lkml.kernel.org/r/20131213150640.786183683@infradead.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Jiri Slaby

arch: Clean up asm/barrier.h implementations using asm-generic/barrier.h

2015-10-28T15:37:39+00:00

commit 93ea02bb84354370e51de803a9405f171f3edf88 upstream.

We're going to be adding a few new barrier primitives, and in order to
avoid endless duplication make more agressive use of
asm-generic/barrier.h.

Change the asm-generic/barrier.h such that it allows partial barrier
definitions and fills out the rest with defaults.

There are a few architectures (m32r, m68k) that could probably
do away with their barrier.h file entirely but are kept for now due to
their unconventional nop() implementation.

Suggested-by: Geert Uytterhoeven 
Reviewed-by: "Paul E. McKenney" 
Reviewed-by: Mathieu Desnoyers 
Signed-off-by: Peter Zijlstra 
Cc: Michael Ellerman 
Cc: Michael Neuling 
Cc: Russell King 
Cc: Heiko Carstens 
Cc: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Victor Kaplansky 
Cc: Tony Luck 
Cc: Oleg Nesterov 
Cc: Benjamin Herrenschmidt 
Cc: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20131213150640.846368594@infradead.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Jiri Slaby

ARC: make sure instruction_pointer() returns unsigned value

2015-08-19T06:36:33+00:00

commit f51e2f1911122879eefefa4c592dea8bf794b39c upstream.

Currently instruction_pointer() returns pt_regs->ret and so return value
is of type "long", which implicitly stands for "signed long".

While that's perfectly fine when dealing with 32-bit values if return
value of instruction_pointer() gets assigned to 64-bit variable sign
extension may happen.

And at least in one real use-case it happens already.
In perf_prepare_sample() return value of perf_instruction_pointer()
(which is an alias to instruction_pointer() in case of ARC) is assigned
to (struct perf_sample_data)->ip (which type is "u64").

And what we see if instuction pointer points to user-space application
that in case of ARC lays below 0x8000_0000 "ip" gets set properly with
leading 32 zeros. But if instruction pointer points to kernel address
space that starts from 0x8000_0000 then "ip" is set with 32 leadig
"f"-s. I.e. id instruction_pointer() returns 0x8100_0000, "ip" will be
assigned with 0xffff_ffff__8100_0000. Which is obviously wrong.

In particular that issuse broke output of perf, because perf was unable
to associate addresses like 0xffff_ffff__8100_0000 with anything from
/proc/kallsyms.

That's what we used to see:
 ----------->8----------
  6.27%  ls       [unknown]                [k] 0xffffffff8046c5cc
  2.96%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.25%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.66%  ls       [unknown]                [k] 0xffffffff80666536
  1.54%  ls       libuClibc-0.9.34-git.so  [.] 0x000224d6
  1.18%  ls       libuClibc-0.9.34-git.so  [.] 0x00022472
 ----------->8----------

With that change perf output looks much better now:
 ----------->8----------
  8.21%  ls       [kernel.kallsyms]        [k] memset
  3.52%  ls       libuClibc-0.9.34-git.so  [.] memcpy
  2.11%  ls       libuClibc-0.9.34-git.so  [.] malloc
  1.88%  ls       libuClibc-0.9.34-git.so  [.] memset
  1.64%  ls       [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
  1.41%  ls       [kernel.kallsyms]        [k] __d_lookup_rcu
 ----------->8----------

Signed-off-by: Alexey Brodkin 
Cc: arc-linux-dev@synopsys.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta 
Signed-off-by: Jiri Slaby