linux-stable.git/arch/mips, branch v3.2.67

vm: add VM_FAULT_SIGSEGV handling support

2015-02-20T00:49:40+00:00

commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream.

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai 
Tested-by: Jan Engelhardt 
Acked-by: Heiko Carstens  # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2:
 - Adjust filenames, context
 - Drop arc, metag, nios2 and lustre changes
 - For sh, patch both 32-bit and 64-bit implementations to use goto bad_area
 - For s390, pass int_code and trans_exc_code as arguments to do_no_context()
   and do_sigsegv()]
Signed-off-by: Ben Hutchings

MIPS: Loongson: Make platform serial setup always built-in.

2014-12-14T16:24:00+00:00

commit 26927f76499849e095714452b8a4e09350f6a3b9 upstream.

If SERIAL_8250 is compiled as a module, the platform specific setup
for Loongson will be a module too, and it will not work very well.
At least on Loongson 3 it will trigger a build failure,
since loongson_sysconf is not exported to modules.

Fix by making the platform specific serial code always built-in.

Signed-off-by: Aaro Koskinen 
Reported-by: Ralf Baechle 
Cc: linux-mips@linux-mips.org
Cc: Huacai Chen 
Cc: Markos Chandras 
Patchwork: https://patchwork.linux-mips.org/patch/8533/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: oprofile: Fix backtrace on 64-bit kernel

2014-12-14T16:23:58+00:00

commit bbaf113a481b6ce32444c125807ad3618643ce57 upstream.

Fix incorrect cast that always results in wrong address for the new
frame on 64-bit kernels.

Signed-off-by: Aaro Koskinen 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8110/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: ftrace: Fix a microMIPS build problem

2014-12-14T16:23:51+00:00

commit aedd153f5bb5b1f1d6d9142014f521ae2ec294cc upstream.

Code before the .fixup section needs to have the .insn directive.
This has no side effects on MIPS32/64 but it affects the way microMIPS
loads the address for the return label.

Fixes the following build problem:
mips-linux-gnu-ld: arch/mips/built-in.o: .fixup+0x4a0: Unsupported jump between
ISA modes; consider recompiling with interlinking enabled.
mips-linux-gnu-ld: final link failed: Bad value
Makefile:819: recipe for target 'vmlinux' failed

The fix is similar to 1658f914ff91c3bf ("MIPS: microMIPS:
Disable LL/SC and fix linker bug.")

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8117/
Signed-off-by: Ralf Baechle 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

MIPS: Fix forgotten preempt_enable() when CPU has inclusive pcaches

2014-11-05T20:27:46+00:00

commit 5596b0b245fb9d2cefb5023b11061050351c1398 upstream.

[    1.904000] BUG: scheduling while atomic: swapper/1/0x00000002
[    1.908000] Modules linked in:
[    1.916000] CPU: 0 PID: 1 Comm: swapper Not tainted 3.12.0-rc2-lemote-los.git-5318619-dirty #1
[    1.920000] Stack : 0000000031aac000 ffffffff810d0000 0000000000000052 ffffffff802730a4
          0000000000000000 0000000000000001 ffffffff810cdf90 ffffffff810d0000
          ffffffff8068b968 ffffffff806f5537 ffffffff810cdf90 980000009f0782e8
          0000000000000001 ffffffff80720000 ffffffff806b0000 980000009f078000
          980000009f290000 ffffffff805f312c 980000009f05b5d8 ffffffff80233518
          980000009f05b5e8 ffffffff80274b7c 980000009f078000 ffffffff8068b968
          0000000000000000 0000000000000000 0000000000000000 0000000000000000
          0000000000000000 980000009f05b520 0000000000000000 ffffffff805f2f6c
          0000000000000000 ffffffff80700000 ffffffff80700000 ffffffff806fc758
          ffffffff80700000 ffffffff8020be98 ffffffff806fceb0 ffffffff805f2f6c
          ...
[    2.028000] Call Trace:
[    2.032000] [] show_stack+0x80/0x98
[    2.036000] [] __schedule_bug+0x44/0x6c
[    2.040000] [] __schedule+0x518/0x5b0
[    2.044000] [] schedule_timeout+0x128/0x1f0
[    2.048000] [] msleep+0x3c/0x60
[    2.052000] [] do_probe+0x238/0x3a8
[    2.056000] [] ide_probe_port+0x340/0x7e8
[    2.060000] [] ide_host_register+0x2d0/0x7a8
[    2.064000] [] ide_pci_init_two+0x4e4/0x790
[    2.068000] [] amd74xx_probe+0x148/0x2c8
[    2.072000] [] pci_device_probe+0xc4/0x130
[    2.076000] [] driver_probe_device+0x98/0x270
[    2.080000] [] __driver_attach+0xe0/0xe8
[    2.084000] [] bus_for_each_dev+0x78/0xe0
[    2.088000] [] bus_add_driver+0x230/0x310
[    2.092000] [] driver_register+0x84/0x158
[    2.096000] [] do_one_initcall+0x104/0x160

Signed-off-by: Yoichi Yuasa 
Reported-by: Aaro Koskinen 
Tested-by: Aaro Koskinen 
Cc: linux-mips@linux-mips.org
Cc: Linux Kernel Mailing List 
Patchwork: https://patchwork.linux-mips.org/patch/5941/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: mcount: Adjust stack pointer for static trace in MIPS32

2014-11-05T20:27:46+00:00

commit 8a574cfa2652545eb95595d38ac2a0bb501af0ae upstream.

Every mcount() call in the MIPS 32-bit kernel is done as follows:

[...]
move at, ra
jal _mcount
addiu sp, sp, -8
[...]

but upon returning from the mcount() function, the stack pointer
is not adjusted properly. This is explained in details in 58b69401c797
(MIPS: Function tracer: Fix broken function tracing).

Commit ad8c396936e3 ("MIPS: Unbreak function tracer for 64-bit kernel.)
fixed the stack manipulation for 64-bit but it didn't fix it completely
for MIPS32.

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7792/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: ZBOOT: add missing include

2014-11-05T20:27:39+00:00

commit 29593fd5a8149462ed6fad0d522234facdaee6c8 upstream.

Commit dc4d7b37 (MIPS: ZBOOT: gather string functions into string.c)
moved the string related functions into a separate file, which might
cause the following build error, depending on the configuration:

| CC      arch/mips/boot/compressed/decompress.o
| In file included from linux/arch/mips/boot/compressed/../../../../lib/decompress_unxz.c:234:0,
|                  from linux/arch/mips/boot/compressed/decompress.c:67:
| linux/arch/mips/boot/compressed/../../../../lib/xz/xz_dec_stream.c: In function 'fill_temp':
| linux/arch/mips/boot/compressed/../../../../lib/xz/xz_dec_stream.c:162:2: error: implicit declaration of function 'memcpy' [-Werror=implicit-function-declaration]
| cc1: some warnings being treated as errors
| linux/scripts/Makefile.build:308: recipe for target 'arch/mips/boot/compressed/decompress.o' failed
| make[6]: *** [arch/mips/boot/compressed/decompress.o] Error 1
| linux/arch/mips/Makefile:308: recipe for target 'vmlinuz' failed

It does not fail with the standard configuration, as when
CONFIG_DYNAMIC_DEBUG is not enabled  gets included in
include/linux/dynamic_debug.h. There might be other ways for it to
get indirectly included.

We can't add the include directly in xz_dec_stream.c as some
architectures might want to use a different version for the boot/
directory (see for example arch/x86/boot/string.h).

Signed-off-by: Aurelien Jarno 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7420/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: Fix accessing to per-cpu data when flushing the cache

2014-09-13T22:41:48+00:00

commit ff522058bd717506b2fa066fa564657f2b86477e upstream.

This fixes the following issue

BUG: using smp_processor_id() in preemptible [00000000] code: kjournald/1761
caller is blast_dcache32+0x30/0x254
Call Trace:
[<8047f02c>] dump_stack+0x8/0x34
[<802e7e40>] debug_smp_processor_id+0xe0/0xf0
[<80114d94>] blast_dcache32+0x30/0x254
[<80118484>] r4k_dma_cache_wback_inv+0x200/0x288
[<80110ff0>] mips_dma_map_sg+0x108/0x180
[<80355098>] ide_dma_prepare+0xf0/0x1b8
[<8034eaa4>] do_rw_taskfile+0x1e8/0x33c
[<8035951c>] ide_do_rw_disk+0x298/0x3e4
[<8034a3c4>] do_ide_request+0x2e0/0x704
[<802bb0dc>] __blk_run_queue+0x44/0x64
[<802be000>] queue_unplugged.isra.36+0x1c/0x54
[<802beb94>] blk_flush_plug_list+0x18c/0x24c
[<802bec6c>] blk_finish_plug+0x18/0x48
[<8026554c>] journal_commit_transaction+0x3b8/0x151c
[<80269648>] kjournald+0xec/0x238
[<8014ac00>] kthread+0xb8/0xc0
[<8010268c>] ret_from_kernel_thread+0x14/0x1c

Caches in most systems are identical - but not always, so we can't avoid
the use of smp_call_function() by just looking at the boot CPU's data,
have to fiddle with preemption instead.

Signed-off-by: Ralf Baechle 
Cc: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5835
Signed-off-by: Ben Hutchings

MIPS: perf: Fix build error caused by unused counters_per_cpu_to_total()

2014-09-13T22:41:48+00:00

commit 6c37c9580409af7dc664bb6af0a85d540d63aeea upstream.

cc1: warnings being treated as errors
arch/mips/kernel/perf_event_mipsxx.c:166: error: 'counters_per_cpu_to_total' defined but not used
make[2]: *** [arch/mips/kernel/perf_event_mipsxx.o] Error 1
make[2]: *** Waiting for unfinished jobs....

It was first introduced by 82091564cfd7ab8def42777a9c662dbf655c5d25 [MIPS:
perf: Add support for 64-bit perf counters.] in 3.2.

Signed-off-by: Florian Fainelli 
Cc: linux-mips@linux-mips.org
Cc: david.daney@cavium.com
Patchwork: https://patchwork.linux-mips.org/patch/3357/
Signed-off-by: Ralf Baechle 
Signed-off-by: Ben Hutchings

MIPS: OCTEON: make get_system_type() thread-safe

2014-09-13T22:41:46+00:00

commit 608308682addfdc7b8e2aee88f0e028331d88e4d upstream.

get_system_type() is not thread-safe on OCTEON. It uses static data,
also more dangerous issue is that it's calling cvmx_fuse_read_byte()
every time without any synchronization. Currently it's possible to get
processes stuck looping forever in kernel simply by launching multiple
readers of /proc/cpuinfo:

	(while true; do cat /proc/cpuinfo > /dev/null; done) &
	(while true; do cat /proc/cpuinfo > /dev/null; done) &
	...

Fix by initializing the system type string only once during the early
boot.

Signed-off-by: Aaro Koskinen 
Reviewed-by: Markos Chandras 
Patchwork: http://patchwork.linux-mips.org/patch/7437/
Signed-off-by: James Hogan 
Signed-off-by: Ben Hutchings