linux.git/arch, branch v3.13.6

ARM64: unwind: Fix PC calculation

2014-03-07T06:06:29+00:00

commit e306dfd06fcb44d21c80acb8e5a88d55f3d1cf63 upstream.

The frame PC value in the unwind code used to just take the saved LR
value and use that.  That's incorrect as a stack trace, since it shows
the return path stack, not the call path stack.

In particular, it shows faulty information in case the bl is done as
the very last instruction of one label, since the return point will be
in the next label. That can easily be seen with tail calls to panic(),
which is marked __noreturn and thus doesn't have anything useful after it.

Easiest here is to just correct the unwind code and do a -4, to get the
actual call site for the backtrace instead of the return site.

Signed-off-by: Olof Johansson 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

xtensa: introduce spill_registers_kernel macro

2014-03-07T06:06:28+00:00

commit e2fd1374c705abe4661df3fb6fadb3879c7c1846 upstream.

Most in-kernel users want registers spilled on the kernel stack and
don't require PS.EXCM to be set. That means that they don't need fixup
routine and could reuse regular window overflow mechanism for that,
which makes spill routine very simple.

Suggested-by: Chris Zankel 
Signed-off-by: Max Filippov 
Signed-off-by: Greg Kroah-Hartman

xtensa: save current register frame in fast_syscall_spill_registers_fixup

2014-03-07T06:06:28+00:00

commit 3251f1e27a5a17f0efd436cfd1e7b9896cfab0a0 upstream.

We need it saved because it contains a3 where we track which register
windows we still need to spill, and fixup handler may call C exception
handlers. Also fix comments.

Signed-off-by: Max Filippov 
Signed-off-by: Greg Kroah-Hartman

perf/x86: Fix event scheduling

2014-03-07T06:06:22+00:00

commit 26e61e8939b1fe8729572dabe9a9e97d930dd4f6 upstream.

Vince "Super Tester" Weaver reported a new round of syscall fuzzing (Trinity) failures,
with perf WARN_ON()s triggering. He also provided traces of the failures.

This is I think the relevant bit:

	>    pec_1076_warn-2804  [000] d...   147.926153: x86_pmu_disable: x86_pmu_disable
	>    pec_1076_warn-2804  [000] d...   147.926153: x86_pmu_state: Events: {
	>    pec_1076_warn-2804  [000] d...   147.926156: x86_pmu_state:   0: state: .R config: ffffffffffffffff (          (null))
	>    pec_1076_warn-2804  [000] d...   147.926158: x86_pmu_state:   33: state: AR config: 0 (ffff88011ac99800)
	>    pec_1076_warn-2804  [000] d...   147.926159: x86_pmu_state: }
	>    pec_1076_warn-2804  [000] d...   147.926160: x86_pmu_state: n_events: 1, n_added: 0, n_txn: 1
	>    pec_1076_warn-2804  [000] d...   147.926161: x86_pmu_state: Assignment: {
	>    pec_1076_warn-2804  [000] d...   147.926162: x86_pmu_state:   0->33 tag: 1 config: 0 (ffff88011ac99800)
	>    pec_1076_warn-2804  [000] d...   147.926163: x86_pmu_state: }
	>    pec_1076_warn-2804  [000] d...   147.926166: collect_events: Adding event: 1 (ffff880119ec8800)

So we add the insn:p event (fd[23]).

At this point we should have:

  n_events = 2, n_added = 1, n_txn = 1

	>    pec_1076_warn-2804  [000] d...   147.926170: collect_events: Adding event: 0 (ffff8800c9e01800)
	>    pec_1076_warn-2804  [000] d...   147.926172: collect_events: Adding event: 4 (ffff8800cbab2c00)

We try and add the {BP,cycles,br_insn} group (fd[3], fd[4], fd[15]).
These events are 0:cycles and 4:br_insn, the BP event isn't x86_pmu so
that's not visible.

	group_sched_in()
	  pmu->start_txn() /* nop - BP pmu */
	  event_sched_in()
	     event->pmu->add()

So here we should end up with:

  0: n_events = 3, n_added = 2, n_txn = 2
  4: n_events = 4, n_added = 3, n_txn = 3

But seeing the below state on x86_pmu_enable(), the must have failed,
because the 0 and 4 events aren't there anymore.

Looking at group_sched_in(), since the BP is the leader, its
event_sched_in() must have succeeded, for otherwise we would not have
seen the sibling adds.

But since neither 0 or 4 are in the below state; their event_sched_in()
must have failed; but I don't see why, the complete state: 0,0,1:p,4
fits perfectly fine on a core2.

However, since we try and schedule 4 it means the 0 event must have
succeeded!  Therefore the 4 event must have failed, its failure will
have put group_sched_in() into the fail path, which will call:

	event_sched_out()
	  event->pmu->del()

on 0 and the BP event.

Now x86_pmu_del() will reduce n_events; but it will not reduce n_added;
giving what we see below:

 n_event = 2, n_added = 2, n_txn = 2

	>    pec_1076_warn-2804  [000] d...   147.926177: x86_pmu_enable: x86_pmu_enable
	>    pec_1076_warn-2804  [000] d...   147.926177: x86_pmu_state: Events: {
	>    pec_1076_warn-2804  [000] d...   147.926179: x86_pmu_state:   0: state: .R config: ffffffffffffffff (          (null))
	>    pec_1076_warn-2804  [000] d...   147.926181: x86_pmu_state:   33: state: AR config: 0 (ffff88011ac99800)
	>    pec_1076_warn-2804  [000] d...   147.926182: x86_pmu_state: }
	>    pec_1076_warn-2804  [000] d...   147.926184: x86_pmu_state: n_events: 2, n_added: 2, n_txn: 2
	>    pec_1076_warn-2804  [000] d...   147.926184: x86_pmu_state: Assignment: {
	>    pec_1076_warn-2804  [000] d...   147.926186: x86_pmu_state:   0->33 tag: 1 config: 0 (ffff88011ac99800)
	>    pec_1076_warn-2804  [000] d...   147.926188: x86_pmu_state:   1->0 tag: 1 config: 1 (ffff880119ec8800)
	>    pec_1076_warn-2804  [000] d...   147.926188: x86_pmu_state: }
	>    pec_1076_warn-2804  [000] d...   147.926190: x86_pmu_enable: S0: hwc->idx: 33, hwc->last_cpu: 0, hwc->last_tag: 1 hwc->state: 0

So the problem is that x86_pmu_del(), when called from a
group_sched_in() that fails (for whatever reason), and without x86_pmu
TXN support (because the leader is !x86_pmu), will corrupt the n_added
state.

Reported-and-Tested-by: Vince Weaver 
Signed-off-by: Peter Zijlstra 
Cc: Paul Mackerras 
Cc: Steven Rostedt 
Cc: Stephane Eranian 
Cc: Dave Jones 
Link: http://lkml.kernel.org/r/20140221150312.GF3104@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86: dma-mapping: fix GFP_ATOMIC macro usage

2014-03-07T06:06:21+00:00

commit c091c71ad2218fc50a07b3d1dab85783f3b77efd upstream.

GFP_ATOMIC is not a single gfp flag, but a macro which expands to the other
flags, where meaningful is the LACK of __GFP_WAIT flag. To check if caller
wants to perform an atomic allocation, the code must test for a lack of the
__GFP_WAIT flag. This patch fixes the issue introduced in v3.5-rc1.

Signed-off-by: Marek Szyprowski 
Signed-off-by: Greg Kroah-Hartman

powerpc/powernv: Fix indirect XSCOM unmangling

2014-03-07T06:06:21+00:00

commit e0cf957614976896111e676e5134ac98ee227d3d upstream.

We need to unmangle the full address, not just the register
number, and we also need to support the real indirect bit
being set for in-kernel uses.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/powernv: Fix opal_xscom_{read,write} prototype

2014-03-07T06:06:21+00:00

commit 2f3f38e4d3d03dd4125cc9a1f49ab3cc91d8d670 upstream.

The OPAL firmware functions opal_xscom_read and opal_xscom_write
take a 64-bit argument for the XSCOM (PCB) address in order to
support the indirect mode on P8.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/crashdump : Fix page frame number check in copy_oldmem_page

2014-03-07T06:06:21+00:00

commit f5295bd8ea8a65dc5eac608b151386314cb978f1 upstream.

In copy_oldmem_page, the current check using max_pfn and min_low_pfn to
decide if the page is backed or not, is not valid when the memory layout is
not continuous.

This happens when running as a QEMU/KVM guest, where RTAS is mapped higher
in the memory. In that case max_pfn points to the end of RTAS, and a hole
between the end of the kdump kernel and RTAS is not backed by PTEs. As a
consequence, the kdump kernel is crashing in copy_oldmem_page when accessing
in a direct way the pages in that hole.

This fix relies on the memblock's service memblock_is_region_memory to
check if the read page is part or not of the directly accessible memory.

Signed-off-by: Laurent Dufour 
Tested-by: Mahesh Salgaonkar 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/le: Ensure that the 'stop-self' RTAS token is handled correctly

2014-03-07T06:06:21+00:00

commit 41dd03a94c7d408d2ef32530545097f7d1befe5c upstream.

Currently we're storing a host endian RTAS token in
rtas_stop_self_args.token.  We then pass that directly to rtas.  This is
fine on big endian however on little endian the token is not what we
expect.

This will typically result in hitting:
	panic("Alas, I survived.\n");

To fix this we always use the stop-self token in host order and always
convert it to be32 before passing this to rtas.

Signed-off-by: Tony Breeds 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Increase stack redzone for 64-bit userspace to 512 bytes

2014-03-07T06:06:20+00:00

commit 573ebfa6601fa58b439e7f15828762839ccd306a upstream.

The new ELFv2 little-endian ABI increases the stack redzone -- the
area below the stack pointer that can be used for storing data --
from 288 bytes to 512 bytes.  This means that we need to allow more
space on the user stack when delivering a signal to a 64-bit process.

To make the code a bit clearer, we define new USER_REDZONE_SIZE and
KERNEL_REDZONE_SIZE symbols in ptrace.h.  For now, we leave the
kernel redzone size at 288 bytes, since increasing it to 512 bytes
would increase the size of interrupt stack frames correspondingly.

Gcc currently only makes use of 288 bytes of redzone even when
compiling for the new little-endian ABI, and the kernel cannot
currently be compiled with the new ABI anyway.

In the future, hopefully gcc will provide an option to control the
amount of redzone used, and then we could reduce it even more.

This also changes the code in arch_compat_alloc_user_space() to
preserve the expanded redzone.  It is not clear why this function would
ever be used on a 64-bit process, though.

Signed-off-by: Paul Mackerras 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman