linux-stable.git/arch/powerpc/kernel, branch v3.2.98

powerpc/64: Initialise thread_info for emergency stacks

2017-09-15T17:30:55+00:00

commit 34f19ff1b5a0d11e46df479623d6936460105c9f upstream.

Emergency stacks have their thread_info mostly uninitialised, which in
particular means garbage preempt_count values.

Emergency stack code runs with interrupts disabled entirely, and is
used very rarely, so this has been unnoticed so far. It was found by a
proposed new powerpc watchdog that takes a soft-NMI directly from the
masked_interrupt handler and using the emergency stack. That crashed
at BUG_ON(in_nmi()) in nmi_enter(). preempt_count()s were found to be
garbage.

To fix this, zero the entire THREAD_SIZE allocation, and initialize
the thread_info.

Reported-by: Abdul Haleem 
Signed-off-by: Nicholas Piggin 
[mpe: Move it all into setup_64.c, use a function not a macro. Fix
      crashes on Cell by setting preempt_count to 0 not HARDIRQ_OFFSET]
Signed-off-by: Michael Ellerman 
[bwh: Backported to 3.2:
 - There's only one emergency stack
 - No need to call klp_init_thread_info()
 - Add the ti variable in emergency_stack_init()]
Signed-off-by: Ben Hutchings

powerpc/kprobes: Pause function_graph tracing during jprobes handling

2017-09-15T17:30:54+00:00

commit a9f8553e935f26cb5447f67e280946b0923cd2dc upstream.

This fixes a crash when function_graph and jprobes are used together.
This is essentially commit 237d28db036e ("ftrace/jprobes/x86: Fix
conflict between jprobes and function graph tracing"), but for powerpc.

Jprobes breaks function_graph tracing since the jprobe hook needs to use
jprobe_return(), which never returns back to the hook, but instead to
the original jprobe'd function. The solution is to momentarily pause
function_graph tracing before invoking the jprobe hook and re-enable it
when returning back to the original jprobe'd function.

Fixes: 6794c78243bf ("powerpc64: port of the function graph tracer")
Signed-off-by: Naveen N. Rao 
Acked-by: Masami Hiramatsu 
Acked-by: Steven Rostedt (VMware) 
Signed-off-by: Michael Ellerman 
[bwh: Backported to 3.2: include , which apparently gets
 included indirectly upstream]
Signed-off-by: Ben Hutchings

powerpc: Don't try to fix up misaligned load-with-reservation instructions

2017-07-18T17:38:40+00:00

commit 48fe9e9488743eec9b7c1addd3c93f12f2123d54 upstream.

In the past, there was only one load-with-reservation instruction,
lwarx, and if a program attempted a lwarx on a misaligned address, it
would take an alignment interrupt and the kernel handler would emulate
it as though it was lwzx, which was not really correct, but benign since
it is loading the right amount of data, and the lwarx should be paired
with a stwcx. to the same address, which would also cause an alignment
interrupt which would result in a SIGBUS being delivered to the process.

We now have 5 different sizes of load-with-reservation instruction. Of
those, lharx and ldarx cause an immediate SIGBUS by luck since their
entries in aligninfo[] overlap instructions which were not fixed up, but
lqarx overlaps with lhz and will be emulated as such. lbarx can never
generate an alignment interrupt since it only operates on 1 byte.

To straighten this out and fix the lqarx case, this adds code to detect
the l[hwdq]arx instructions and return without fixing them up, resulting
in a SIGBUS being delivered to the process.

Signed-off-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
[bwh: Backported to 3.2: open-code get_xop()]
Signed-off-by: Ben Hutchings

powerpc/xmon: Fix data-breakpoint

2017-06-05T20:13:49+00:00

commit c21a493a2b44650707d06741601894329486f2ad upstream.

Currently xmon data-breakpoint feature is broken.

Whenever there is a watchpoint match occurs, hw_breakpoint_handler will
be called by do_break via notifier chains mechanism. If watchpoint is
registered by xmon, hw_breakpoint_handler won't find any associated
perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break
also returns without notifying to xmon.

Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not
find any perf_event associated with matched watchpoint, rather than
NOTIFY_STOP, which tells the core code to continue calling the other
breakpoint handlers including the xmon one.

Signed-off-by: Ravi Bangoria 
Signed-off-by: Michael Ellerman 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

powerpc/ptrace: Preserve previous fprs/vsrs on short regset write

2017-03-16T02:18:45+00:00

commit 99dfe80a2a246c600440a815741fd2e74a8b4977 upstream.

Ensure that if userspace supplies insufficient data to PTRACE_SETREGSET
to fill all the registers, the thread's old registers are preserved.

Fixes: c6e6771b87d4 ("powerpc: Introduce VSX thread_struct and CONFIG_VSX")
Signed-off-by: Dave Martin 
Signed-off-by: Michael Ellerman 
[bwh: Backported to 3.2:
 - fpscr and fpr are direct members of struct thread_struct
 - Use memcpy() for fpscr, like the reverse copy below, to avoid type error
 - Adjust context]
Signed-off-by: Ben Hutchings

powerpc/ibmebus: Fix further device reference leaks

2017-03-16T02:18:25+00:00

commit 815a7141c4d1b11610dccb7fcbb38633759824f2 upstream.

Make sure to drop any reference taken by bus_find_device() when creating
devices during init and driver registration.

Fixes: 55347cc9962f ("[POWERPC] ibmebus: Add device creation and bus probing based on of_device")
Signed-off-by: Johan Hovold 
Signed-off-by: Michael Ellerman 
Signed-off-by: Ben Hutchings

powerpc/ibmebus: Fix device reference leaks in sysfs interface

2017-03-16T02:18:25+00:00

commit fe0f3168169f7c34c29b0cf0c489f126a7f29643 upstream.

Make sure to drop any reference taken by bus_find_device() in the sysfs
callbacks that are used to create and destroy devices based on
device-tree entries.

Fixes: 6bccf755ff53 ("[POWERPC] ibmebus: dynamic addition/removal of adapters, some code cleanup")
Signed-off-by: Johan Hovold 
Signed-off-by: Michael Ellerman 
Signed-off-by: Ben Hutchings

powerpc: Convert cmp to cmpd in idle enter sequence

2017-02-23T03:50:54+00:00

commit 80f23935cadb1c654e81951f5a8b7ceae0acc1b4 upstream.

PowerPC's "cmp" instruction has four operands. Normally people write
"cmpw" or "cmpd" for the second cmp operand 0 or 1. But, frequently
people forget, and write "cmp" with just three operands.

With older binutils this is silently accepted as if this was "cmpw",
while often "cmpd" is wanted. With newer binutils GAS will complain
about this for 64-bit code. For 32-bit code it still silently assumes
"cmpw" is what is meant.

In this instance the code comes directly from ISA v2.07, including the
cmp, but cmpd is correct. Backport to stable so that new toolchains can
build old kernels.

Fixes: 948cf67c4726 ("powerpc: Add NAP mode support on Power7 in HV mode")
Reviewed-by: Vaidyanathan Srinivasan 
Signed-off-by: Segher Boessenkool 
Signed-off-by: Michael Ellerman 
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings

powerpc/vdso64: Use double word compare on pointers

2017-02-23T03:50:51+00:00

commit 5045ea37377ce8cca6890d32b127ad6770e6dce5 upstream.

__kernel_get_syscall_map() and __kernel_clock_getres() use cmpli to
check if the passed in pointer is non zero. cmpli maps to a 32 bit
compare on binutils, so we ignore the top 32 bits.

A simple test case can be created by passing in a bogus pointer with
the bottom 32 bits clear. Using a clk_id that is handled by the VDSO,
then one that is handled by the kernel shows the problem:

  printf("%d\n", clock_getres(CLOCK_REALTIME, (void *)0x100000000));
  printf("%d\n", clock_getres(CLOCK_BOOTTIME, (void *)0x100000000));

And we get:

  0
  -1

The bigger issue is if we pass a valid pointer with the bottom 32 bits
clear, in this case we will return success but won't write any data
to the pointer.

I stumbled across this issue because the LLVM integrated assembler
doesn't accept cmpli with 3 arguments. Fix this by converting them to
cmpldi.

Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel")
Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman 
Signed-off-by: Ben Hutchings

powerpc/nvram: Fix an incorrect partition merge

2017-02-23T03:50:50+00:00

commit 11b7e154b132232535befe51c55db048069c8461 upstream.

When we merge two contiguous partitions whose signatures are marked
NVRAM_SIG_FREE, We need update prev's length and checksum, then write it
to nvram, not cur's. So lets fix this mistake now.

Also use memset instead of strncpy to set the partition's name. It's
more readable if we want to fill up with duplicate chars .

Fixes: fa2b4e54d41f ("powerpc/nvram: Improve partition removal")
Signed-off-by: Pan Xinhui 
Signed-off-by: Michael Ellerman 
Signed-off-by: Ben Hutchings