linux-stable.git/arch/arc, branch v4.19.166

ARC: stack unwinding: don't assume non-current task is sleeping

2020-12-30T10:25:38+00:00

[ Upstream commit e42404fa10fd11fe72d0a0e149a321d10e577715 ]

To start stack unwinding (SP, PC and BLINK) are needed. When the
explicit execution context (pt_regs etc) is not available, unwinder
assumes the task is sleeping (in __switch_to()) and fetches SP and BLINK
from kernel mode stack.

But this assumption is not true, specially in a SMP system, when top
runs on 1 core, there may be active running processes on all cores.

So when unwinding non courrent tasks, ensure they are NOT running.

And while at it, handle the self unwinding case explicitly.

This came out of investigation of a customer reported hang with
rcutorture+top

Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/31
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

Revert "ARC: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE"

2020-11-10T11:36:01+00:00

This reverts commit 00fdec98d9881bf5173af09aebd353ab3b9ac729.
(but only from 5.2 and prior kernels)

The original commit was a preventive fix based on code-review and was
auto-picked for stable back-port (for better or worse).
It was OK for v5.3+ kernels, but turned up needing an implicit change
68e5c6f073bcf70 "(ARC: entry: EV_Trap expects r10 (vs. r9) to have
 exception cause)" merged in v5.3 which itself was not backported.
So to summarize the stable backport of this patch for v5.2 and prior
kernels is busted and it won't boot.

The obvious solution is backport 68e5c6f073bcf70 but that is a pain as
it doesn't revert cleanly and each of affected kernels (so far v4.19,
v4.14, v4.9, v4.4) needs a slightly different massaged varaint.
So the easier fix is to simply revert the backport from 5.2 and prior.
The issue was not a big deal as it would cause strace to sporadically
not work correctly.

Waldemar Brodkorb first reported this when running ARC uClibc regressions
on latest stable kernels (with offending backport). Once he bisected it,
the analysis was trivial, so thx to him for this.

Reported-by: Waldemar Brodkorb 
Bisected-by: Waldemar Brodkorb 
Cc: stable  # 5.2 and prior
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: stack unwinding: avoid indefinite looping

2020-11-10T11:36:01+00:00

commit 328d2168ca524d501fc4b133d6be076142bd305c upstream.

Currently stack unwinder is a while(1) loop which relies on the dwarf
unwinder to signal termination, which in turn relies on dwarf info to do
so. This in theory could cause an infinite loop if the dwarf info was
somehow messed up or the register contents were etc.

This fix thus detects the excessive looping and breaks the loop.

| Mem: 26184K used, 1009136K free, 0K shrd, 0K buff, 14416K cached
| CPU:  0.0% usr 72.8% sys  0.0% nic 27.1% idle  0.0% io  0.0% irq  0.0% sirq
| Load average: 4.33 2.60 1.11 2/74 139
|   PID  PPID USER     STAT   VSZ %VSZ CPU %CPU COMMAND
|   133     2 root     SWN      0  0.0   3 22.9 [rcu_torture_rea]
|   132     2 root     SWN      0  0.0   0 22.0 [rcu_torture_rea]
|   131     2 root     SWN      0  0.0   3 21.5 [rcu_torture_rea]
|   126     2 root     RW       0  0.0   2  5.4 [rcu_torture_wri]
|   129     2 root     SWN      0  0.0   0  0.2 [rcu_torture_fak]
|   137     2 root     SW       0  0.0   0  0.2 [rcu_torture_cbf]
|   127     2 root     SWN      0  0.0   0  0.1 [rcu_torture_fak]
|   138   115 root     R     1464  0.1   2  0.1 top
|   130     2 root     SWN      0  0.0   0  0.1 [rcu_torture_fak]
|   128     2 root     SWN      0  0.0   0  0.1 [rcu_torture_fak]
|   115     1 root     S     1472  0.1   1  0.0 -/bin/sh
|   104     1 root     S     1464  0.1   0  0.0 inetd
|     1     0 root     S     1456  0.1   2  0.0 init
|    78     1 root     S     1456  0.1   0  0.0 syslogd -O /var/log/messages
|   134     2 root     SW       0  0.0   2  0.0 [rcu_torture_sta]
|    10     2 root     IW       0  0.0   1  0.0 [rcu_preempt]
|    88     2 root     IW       0  0.0   1  0.0 [kworker/1:1-eve]
|    66     2 root     IW       0  0.0   2  0.0 [kworker/2:2-eve]
|    39     2 root     IW       0  0.0   2  0.0 [kworker/2:1-eve]
| unwinder looping too long, aborting !

Cc: 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

arc: plat-hsdk: fix kconfig dependency warning when !RESET_CONTROLLER

2020-10-29T08:55:17+00:00

[ Upstream commit 63bcf87cb1c57956e1179f1a78dde625c7e3cba7 ]

When ARC_SOC_HSDK is enabled and RESET_CONTROLLER is disabled, it results
in the following Kbuild warning:

WARNING: unmet direct dependencies detected for RESET_HSDK
  Depends on [n]: RESET_CONTROLLER [=n] && HAS_IOMEM [=y] && (ARC_SOC_HSDK [=y] || COMPILE_TEST [=n])
  Selected by [y]:
  - ARC_SOC_HSDK [=y] && ISA_ARCV2 [=y]

The reason is that ARC_SOC_HSDK selects RESET_HSDK without depending on or
selecting RESET_CONTROLLER while RESET_HSDK is subordinate to
RESET_CONTROLLER.

Honor the kconfig menu hierarchy to remove kconfig dependency warnings.

Fixes: a528629dfd3b ("ARC: [plat-hsdk] select CONFIG_RESET_HSDK from Kconfig")
Signed-off-by: Necip Fazil Yildiran 
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

ARC: [plat-hsdk]: Switch ethernet phy-mode to rgmii-id

2020-09-17T11:45:25+00:00

[ Upstream commit 26907eb605fbc3ba9dbf888f21d9d8d04471271d ]

HSDK board has Micrel KSZ9031, recent commit
bcf3440c6dd ("net: phy: micrel: add phy-mode support for the KSZ9031 PHY")
caused a breakdown of Ethernet.
Using 'phy-mode = "rgmii"' is not correct because accodring RGMII
specification it is necessary to have delay on RX (PHY to MAX)
which is not generated in case of "rgmii".
Using "rgmii-id" adds necessary delay and solves the issue.

Also adding name of PHY placed on HSDK board.

Signed-off-by: Evgeniy Didin 
Cc: Eugeniy Paltsev 
Cc: Alexey Brodkin 
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

irqchip/eznps: Fix build error for !ARC700 builds

2020-09-17T11:45:25+00:00

[ Upstream commit 89d29997f103d08264b0685796b420d911658b96 ]

eznps driver is supposed to be platform independent however it ends up
including stuff from inside arch/arc headers leading to rand config
build errors.

The quick hack to fix this (proper fix is too much chrun for non active
user-base) is to add following to nps platform agnostic header.
 - copy AUX_IENABLE from arch/arc header
 - move CTOP_AUX_IACK from arch/arc/plat-eznps/*/**

Reported-by: kernel test robot 
Reported-by: Sebastian Andrzej Siewior 
Link: https://lkml.kernel.org/r/20200824095831.5lpkmkafelnvlpi2@linutronix.de
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin

ARC: HSDK: wireup perf irq

2020-09-17T11:45:23+00:00

[ Upstream commit fe81d927b78c4f0557836661d32e41ebc957b024 ]

Newer version of HSDK aka HSDK-4xD (with dual issue HS48x4 CPU) wired up
the perf interrupt, so enable that in DT.
This is OK for old HSDK where this irq is ignored because pct irq is not
wired up in hardware.

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

ARC: elf: use right ELF_ARCH

2020-07-16T06:17:27+00:00

commit b7faf971081a4e56147f082234bfff55135305cb upstream.

Cc: 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE

2020-07-16T06:17:27+00:00

commit 00fdec98d9881bf5173af09aebd353ab3b9ac729 upstream.

Trap handler for syscall tracing reads EFA (Exception Fault Address),
in case strace wants PC of trap instruction (EFA is not part of pt_regs
as of current code).

However this EFA read is racy as it happens after dropping to pure
kernel mode (re-enabling interrupts). A taken interrupt could
context-switch, trigger a different task's trap, clobbering EFA for this
execution context.

Fix this by reading EFA early, before re-enabling interrupts. A slight
side benefit is de-duplication of FAKE_RET_FROM_EXCPN in trap handler.
The trap handler is common to both ARCompact and ARCv2 builds too.

This just came out of code rework/review and no real problem was reported
but is clearly a potential problem specially for strace.

Cc: 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: [plat-eznps]: Restrict to CONFIG_ISA_ARCOMPACT

2020-06-07T11:17:55+00:00

[ Upstream commit 799587d5731db9dcdafaac4002463aa7d9cd6cf7 ]

Elide invalid configuration EZNPS + ARCv2, triggered by a
make allyesconfig build.

Granted the root cause is in source code (asm/barrier.h) where we check
for ARCv2 before PLAT_EZNPS, but it is better to avoid such combinations
at onset rather then baking subtle nuances into code.

Reported-by: kbuild test robot 
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin