linux-stable.git/arch/arc/kernel, branch v4.4.210

ARC: perf: Accommodate big-endian CPU

2019-11-28T17:26:16+00:00

commit 5effc09c4907901f0e71e68e5f2e14211d9a203f upstream.

8-letter strings representing ARC perf events are stores in two
32-bit registers as ASCII characters like that: "IJMP", "IALL", "IJMPTAK" etc.

And the same order of bytes in the word is used regardless CPU endianness.

Which means in case of big-endian CPU core we need to swap bytes to get
the same order as if it was on little-endian CPU.

Otherwise we're seeing the following error message on boot:
------------------------->8----------------------
ARC perf        : 8 counters (32 bits), 40 conditions, [overflow IRQ support]
sysfs: cannot create duplicate filename '/devices/arc_pct/events/pmji'
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.18 #3
Stack Trace:
  arc_unwind_core+0xd4/0xfc
  dump_stack+0x64/0x80
  sysfs_warn_dup+0x46/0x58
  sysfs_add_file_mode_ns+0xb2/0x168
  create_files+0x70/0x2a0
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/events/core.c:12144 perf_event_sysfs_init+0x70/0xa0
Failed to register pmu: arc_pct, reason -17
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.18 #3
Stack Trace:
  arc_unwind_core+0xd4/0xfc
  dump_stack+0x64/0x80
  __warn+0x9c/0xd4
  warn_slowpath_fmt+0x22/0x2c
  perf_event_sysfs_init+0x70/0xa0
---[ end trace a75fb9a9837bd1ec ]---
------------------------->8----------------------

What happens here we're trying to register more than one raw perf event
with the same name "PMJI". Why? Because ARC perf events are 4 to 8 letters
and encoded into two 32-bit words. In this particular case we deal with 2
events:
 * "IJMP____" which counts all jump & branch instructions
 * "IJMPC___" which counts only conditional jumps & branches

Those strings are split in two 32-bit words this way "IJMP" + "____" &
"IJMP" + "C___" correspondingly. Now if we read them swapped due to CPU core
being big-endian then we read "PMJI" + "____" & "PMJI" + "___C".

And since we interpret read array of ASCII letters as a null-terminated string
on big-endian CPU we end up with 2 events of the same name "PMJI".

Signed-off-by: Alexey Brodkin 
Cc: stable@vger.kernel.org
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: export "abort" for modules

2019-09-21T05:12:54+00:00

This is a custom patch (no mainline equivalent) for stable backport only
to address 0-Day kernel test infra ARC 4.x.y builds errors.

The reason for this custom patch as that it is a single patch, touches
only ARC, vs. atleast two 7c2c11b208be09c1, dc8635b78cd8669 which touch
atleast 3 other arches (one long removed) and could potentially have a
fallout.

Reported-by: kbuild test robot 
CC: stable@vger.kernel.org	# 4.4, 4.9
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: hide unused function unw_hdr_alloc

2019-07-21T07:07:14+00:00

commit fd5de2721ea7d16e2b16c4049ac49f229551b290 upstream.

As kernelci.org reports, this function is not used in
vdk_hs38_defconfig:

arch/arc/kernel/unwind.c:188:14: warning: 'unw_hdr_alloc' defined but not used [-Wunused-function]

Fixes: bc79c9a72165 ("ARC: dw2 unwind: Reinstante unwinding out of modules")
Link: https://kernelci.org/build/id/5d1cae3f59b514300340c132/logs/
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: handle gcc generated __builtin_trap for older compiler

2019-07-10T07:56:44+00:00

commit af1be2e21203867cb958aaceed5366e2e24b88e8 upstream.

ARC gcc prior to GNU 2018.03 release didn't have a target specific
__builtin_trap() implementation, generating default abort() call.

Implement the abort() call - emulating what newer gcc does for the same,
as suggested by Arnd.

Acked-by: Arnd Bergmann 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: Assume multiplier is always present

2019-07-10T07:56:41+00:00

[ Upstream commit 0eca6fdb3193410fbe66b6f064431cc394513e82 ]

It is unlikely that designs running Linux will not have multiplier.
Further the current support is not complete as tool don't generate a
multilib w/o multiplier.

Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

ARCv2: Enable unaligned access in early ASM code

2019-03-23T07:44:18+00:00

commit 252f6e8eae909bc075a1b1e3b9efb095ae4c0b56 upstream.

It is currently done in arc_init_IRQ() which might be too late
considering gcc 7.3.1 onwards (GNU 2018.03) generates unaligned
memory accesses by default

Cc: stable@vger.kernel.org #4.4+
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta 
[vgupta: rewrote changelog]
Signed-off-by: Greg Kroah-Hartman

ARC: clone syscall to setp r25 as thread pointer

2018-10-13T07:11:34+00:00

commit c58a584f05e35d1d4342923cd7aac07d9c3d3d16 upstream.

Per ARC TLS ABI, r25 is designated TP (thread pointer register).
However so far kernel didn't do any special treatment, like setting up
usermode r25, even for CLONE_SETTLS. We instead relied on libc runtime
to do this, in say clone libc wrapper [1]. This was deliberate to keep
kernel ABI agnostic (userspace could potentially change TP, specially
for different ARC ISA say ARCompact vs. ARCv2 with different spare
registers etc)

However userspace setting up r25, after clone syscall opens a race, if
child is not scheduled and gets a signal instead. It starts off in
userspace not in clone but in a signal handler and anything TP sepcific
there such as pthread_self() fails which showed up with uClibc
testsuite nptl/tst-kill6 [2]

Fix this by having kernel populate r25 to TP value. So this locks in
ABI, but it was not going to change anyways, and fwiw is same for both
ARCompact (arc700 core) and ARCvs (HS3x cores)

[1] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/arc/clone.S
[2] https://github.com/wbx-github/uclibc-ng-test/blob/master/test/nptl/tst-kill6.c

Fixes: ARC STAR 9001378481
Cc: stable@vger.kernel.org
Reported-by: Nikita Sobolev 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: Enable machine_desc->init_per_cpu for !CONFIG_SMP

2018-08-24T11:26:55+00:00

[ Upstream commit 2f24ef7413a4d91657ef04e77c27ce0b313e6c95 ]

machine_desc->init_per_cpu() hook is supposed to be per cpu
initialization and would seem to apply  equally to UP and/or SMP.
Infact the comment in header file seems to suggest it works for
UP too, which was not the case and this patch.

This enables !CONFIG_SMP build for platforms such as hsdk.

Signed-off-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
[vgupta: trimmeed changelog]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: Re-enable MMU upon Machine Check exception

2017-09-27T09:00:16+00:00

commit 1ee55a8f7f6b7ca4c0c59e0b4b4e3584a085c2d3 upstream.

I recently came upon a scenario where I would get a double fault
machine check exception tiriggered by a kernel module.
However the ensuing crash stacktrace (ksym lookup) was not working
correctly.

Turns out that machine check auto-disables MMU while modules are allocated
in kernel vaddr spapce.

This patch re-enables the MMU before start printing the stacktrace
making stacktracing of modules work upon a fatal exception.

Signed-off-by: Jose Abreu 
Reviewed-by: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
[vgupta: moved code into low level handler to avoid in 2 places]
Signed-off-by: Greg Kroah-Hartman

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

2017-02-14T23:22:50+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: Greg Kroah-Hartman