linux-stable.git/arch/arc/kernel, branch v4.14.331

ARC: entry: fix syscall_trace_exit argument

2022-04-27T11:15:31+00:00

commit b1c6ecfdd06907554518ec384ce8e99889d15193 upstream.

Function syscall_trace_exit expects pointer to pt_regs. However
r0 is also used to keep syscall return value. Restore pointer
to pt_regs before calling syscall_trace_exit.

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

ARC: Fix CONFIG_STACKDEPOT

2021-09-03T07:56:24+00:00

[ Upstream commit bf79167fd86f3b97390fe2e70231d383526bd9cc ]

Enabling CONFIG_STACKDEPOT results in the following build error.

arc-elf-ld: lib/stackdepot.o: in function `filter_irq_stacks':
stackdepot.c:(.text+0x456): undefined reference to `__irqentry_text_start'
arc-elf-ld: stackdepot.c:(.text+0x456): undefined reference to `__irqentry_text_start'
arc-elf-ld: stackdepot.c:(.text+0x476): undefined reference to `__irqentry_text_end'
arc-elf-ld: stackdepot.c:(.text+0x476): undefined reference to `__irqentry_text_end'
arc-elf-ld: stackdepot.c:(.text+0x484): undefined reference to `__softirqentry_text_start'
arc-elf-ld: stackdepot.c:(.text+0x484): undefined reference to `__softirqentry_text_start'
arc-elf-ld: stackdepot.c:(.text+0x48c): undefined reference to `__softirqentry_text_end'
arc-elf-ld: stackdepot.c:(.text+0x48c): undefined reference to `__softirqentry_text_end'

Other architectures address this problem by adding IRQENTRY_TEXT and
SOFTIRQENTRY_TEXT to the text segment, so do the same here.

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

ARCv2: save ABI registers across signal handling

2021-06-30T12:48:54+00:00

commit 96f1b00138cb8f04c742c82d0a7c460b2202e887 upstream.

ARCv2 has some configuration dependent registers (r30, r58, r59) which
could be targetted by the compiler. To keep the ABI stable, these were
unconditionally part of the glibc ABI
(sysdeps/unix/sysv/linux/arc/sys/ucontext.h:mcontext_t) however we
missed populating them (by saving/restoring them across signal
handling).

This patch fixes the issue by
 - adding arcv2 ABI regs to kernel struct sigcontext
 - populating them during signal handling

Change to struct sigcontext might seem like a glibc ABI change (although
it primarily uses ucontext_t:mcontext_t) but the fact is
 - it has only been extended (existing fields are not touched)
 - the old sigcontext was ABI incomplete to begin with anyways

Fixes: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/53
Cc: 
Tested-by: kernel test robot 
Reported-by: Vladimir Isaev 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: entry: fix off-by-one error in syscall number validation

2021-05-22T08:57:39+00:00

commit 3433adc8bd09fc9f29b8baddf33b4ecd1ecd2cdc upstream.

We have NR_syscall syscalls from [0 .. NR_syscall-1].
However the check for invalid syscall number is "> NR_syscall" as
opposed to >=. This off-by-one error erronesously allows "NR_syscall"
to be treated as valid syscall causeing out-of-bounds access into
syscall-call table ensuing a crash (holes within syscall table have a
invalid-entry handler but this is beyond the array implementing the
table).

This problem showed up on v5.6 kernel when testing glibc 2.33 (v5.10
kernel capable, includng faccessat2 syscall 439). The v5.6 kernel has
NR_syscalls=439 (0 to 438). Due to the bug, 439 passed by glibc was
not handled as -ENOSYS but processed leading to a crash.

Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/48
Reported-by: Shahab Vahedi 
Cc: 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

arc: kernel: Return -EFAULT if copy_to_user() fails

2021-04-28T10:08:40+00:00

[ Upstream commit 46e152186cd89d940b26726fff11eb3f4935b45a ]

The copy_to_user() function returns the number of bytes remaining to be
copied, but we want to return -EFAULT if the copy doesn't complete.

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

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

2020-12-29T12:46:43+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"

2020-11-10T09:29:07+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

2020-11-10T09:29:07+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: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE

2020-07-22T07:22:19+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: Fix ICCM & DCCM runtime size checks

2020-06-11T07:22:56+00:00

[ Upstream commit 43900edf67d7ef3ac8909854d75b8a1fba2d570c ]

As of today the ICCM and DCCM size checks are incorrectly using
mismatched units (KiB checked against bytes). The CONFIG_ARC_DCCM_SZ
and CONFIG_ARC_ICCM_SZ are in KiB, but the size calculated in
runtime and stored in cpu->dccm.sz and cpu->iccm.sz is in bytes.

Fix that.

Reported-by: Paul Greco 
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta 
Signed-off-by: Sasha Levin