linux.git/arch/arm64/kernel/traps.c, branch v4.13

arm64: Use arch_timer_get_rate when trapping CNTFRQ_EL0

2017-08-01T11:14:06+00:00

In an ideal world, CNTFRQ_EL0 always contains the timer frequency
for the kernel to use. Sadly, we get quite a few broken systems
where the firmware authors cannot be bothered to program that
register on all CPUs, and rely on DT to provide that frequency.

So when trapping CNTFRQ_EL0, make sure to return the actual rate
(as known by the kernel), and not CNTFRQ_EL0.

Acked-by: Mark Rutland 
Signed-off-by: Marc Zyngier 
Signed-off-by: Will Deacon

arm64: traps: disable irq in die()

2017-07-20T09:21:06+00:00

In current die(), the irq is disabled for __die() handle, not
including the possible panic() handling. Since the log in __die()
can take several hundreds ms, new irq might come and interrupt
current die().

If the process calling die() holds some critical resource, and some
other process scheduled later also needs it, then it would deadlock.
The first panic will not be executed.

So here disable irq for the whole flow of die().

Signed-off-by: Qiao Zhou 
Signed-off-by: Will Deacon

arm64: fix endianness annotation in call_undef_hook()

2017-06-29T10:02:42+00:00

Here we're reading thumb or ARM instructions, which are always
stored in memory in little-endian order. These values are thus
correctly converted to native order but the intermediate value
should be annotated as for little-endian values.

Fix this by declaring the intermediate var as __le32 or __le16.

Signed-off-by: Luc Van Oostenryck 
Signed-off-by: Will Deacon

arm64: Add dump_backtrace() in show_regs

2017-05-30T10:07:42+00:00

Generic code expects show_regs() to dump the stack, but arm64's
show_regs() does not. This makes it hard to debug softlockups and
other issues that result in show_regs() being called.

This patch updates arm64's show_regs() to dump the stack, as common
code expects.

Acked-by: Mark Rutland 
Signed-off-by: Kefeng Wang 
[will: folded in bug_handler fix from mrutland]
Signed-off-by: Will Deacon

arm64: traps: fix userspace cache maintenance emulation on a tagged pointer

2017-05-09T16:26:17+00:00

When we emulate userspace cache maintenance in the kernel, we can
currently send the task a SIGSEGV even though the maintenance was done
on a valid address. This happens if the address has a non-zero address
tag, and happens to not be mapped in.

When we get the address from a user register, we don't currently remove
the address tag before performing cache maintenance on it. If the
maintenance faults, we end up in either __do_page_fault, where find_vma
can't find the VMA if the address has a tag, or in do_translation_fault,
where the tagged address will appear to be above TASK_SIZE. In both
cases, the address is not mapped in, and the task is sent a SIGSEGV.

This patch removes the tag from the address before using it. With this
patch, the fault is handled correctly, the address gets mapped in, and
the cache maintenance succeeds.

As a second bug, if cache maintenance (correctly) fails on an invalid
tagged address, the address gets passed into arm64_notify_segfault,
where find_vma fails to find the VMA due to the tag, and the wrong
si_code may be sent as part of the siginfo_t of the segfault. With this
patch, the correct si_code is sent.

Fixes: 7dd01aef0557 ("arm64: trap userspace "dc cvau" cache operation on errata-affected core")
Cc:  # 4.8.x-
Acked-by: Will Deacon 
Signed-off-by: Kristina Martsenko 
Signed-off-by: Catalin Marinas

arm64: Add CNTFRQ_EL0 trap handler

2017-04-24T11:22:25+00:00

We now trap accesses to CNTVCT_EL0 when the counter is broken
enough to require the kernel to mediate the access. But it
turns out that some existing userspace (such as OpenMPI) do
probe for the counter frequency, leading to an UNDEF exception
as CNTVCT_EL0 and CNTFRQ_EL0 share the same control bit.

The fix is to handle the exception the same way we do for CNTVCT_EL0.

Fixes: a86bd139f2ae ("arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled")
Reported-by: Hanjun Guo 
Tested-by: Hanjun Guo 
Reviewed-by: Hanjun Guo 
Signed-off-by: Marc Zyngier 
Signed-off-by: Catalin Marinas

arm64: Add CNTVCT_EL0 trap handler

2017-04-07T10:22:08+00:00

Since people seem to make a point in breaking the userspace visible
counter, we have no choice but to trap the access. Add the required
handler.

Acked-by: Thomas Gleixner 
Acked-by: Mark Rutland 
Signed-off-by: Marc Zyngier

sched/headers: Prepare to remove the dependency from

2017-03-02T07:42:37+00:00

Update code that relied on sched.h including various MM types for them.

This will allow us to remove the  include from .

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:36+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:34+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar