linux-stable.git/arch/powerpc/kernel, branch linux-3.12.y

powerpc: Disable HFSCR[TM] if TM is not supported

2017-05-03T12:22:36+00:00

commit 7ed23e1bae8bf7e37fd555066550a00b95a3a98b upstream.

On Power8 & Power9 the early CPU inititialisation in __init_HFSCR()
turns on HFSCR[TM] (Hypervisor Facility Status and Control Register
[Transactional Memory]), but that doesn't take into account that TM
might be disabled by CPU features, or disabled by the kernel being built
with CONFIG_PPC_TRANSACTIONAL_MEM=n.

So later in boot, when we have setup the CPU features, clear HSCR[TM] if
the TM CPU feature has been disabled. We use CPU_FTR_TM_COMP to account
for the CONFIG_PPC_TRANSACTIONAL_MEM=n case.

Without this a KVM guest might try use TM, even if told not to, and
cause an oops in the host kernel. Typically the oops is seen in
__kvmppc_vcore_entry() and may or may not be fatal to the host, but is
always bad news.

In practice all shipping CPU revisions do support TM, and all host
kernels we are aware of build with TM support enabled, so no one should
actually be able to hit this in the wild.

Fixes: 2a3563b023e5 ("powerpc: Setup in HFSCR for POWER8")
Signed-off-by: Benjamin Herrenschmidt 
Tested-by: Sam Bobroff 
[mpe: Rewrite change log with input from Sam, add Fixes/stable]
Signed-off-by: Michael Ellerman 
[sb: Backported to linux-4.4.y: adjusted context]
Signed-off-by: Sam Bobroff 
Signed-off-by: Jiri Slaby

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

2017-04-27T17:34:55+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.

[js] include disassemble.h in 3.12

Signed-off-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
Signed-off-by: Jiri Slaby

powerpc/xmon: Fix data-breakpoint

2017-03-13T20:40:39+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 
Signed-off-by: Jiri Slaby

powerpc/ibmebus: Fix device reference leaks in sysfs interface

2017-01-26T16:40:49+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: Jiri Slaby

powerpc/ibmebus: Fix further device reference leaks

2017-01-26T16:40:48+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: Jiri Slaby

powerpc: Fix build warning on 32-bit PPC

2017-01-26T16:40:30+00:00

commit 8ae679c4bc2ea2d16d92620da8e3e9332fa4039f upstream.

I am getting the following warning when I build kernel 4.9-git on my
PowerBook G4 with a 32-bit PPC processor:

    AS      arch/powerpc/kernel/misc_32.o
  arch/powerpc/kernel/misc_32.S:299:7: warning: "CONFIG_FSL_BOOKE" is not defined [-Wundef]

This problem is evident after commit 989cea5c14be ("kbuild: prevent
lib-ksyms.o rebuilds"); however, this change in kbuild only exposes an
error that has been in the code since 2005 when this source file was
created.  That was with commit 9994a33865f4 ("powerpc: Introduce
entry_{32,64}.S, misc_{32,64}.S, systbl.S").

The offending line does not make a lot of sense.  This error does not
seem to cause any errors in the executable, thus I am not recommending
that it be applied to any stable versions.

Thanks to Nicholas Piggin for suggesting this solution.

Fixes: 9994a33865f4 ("powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S")
Signed-off-by: Larry Finger 
Cc: Nicholas Piggin 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby

powerpc: Convert cmp to cmpd in idle enter sequence

2017-01-26T16:39:14+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 
Signed-off-by: Joel Stanley 
Signed-off-by: Jiri Slaby

powerpc/nvram: Fix an incorrect partition merge

2016-11-08T15:38:29+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: Jiri Slaby

powerpc/eeh: Null check uses of eeh_pe_bus_get

2016-11-08T15:38:25+00:00

commit 04fec21c06e35b169a83e75a84a015ab4606bf5e upstream.

eeh_pe_bus_get() can return NULL if a PCI bus isn't found for a given PE.
Some callers don't check this, and can cause a null pointer dereference
under certain circumstances.

Fix this by checking NULL everywhere eeh_pe_bus_get() is called.

Fixes: 8a6b1bc70dbb ("powerpc/eeh: EEH core to handle special event")
Signed-off-by: Russell Currey 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Signed-off-by: Jiri Slaby

powerpc/vdso64: Use double word compare on pointers

2016-10-28T18:30:51+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: Jiri Slaby