linux-stable.git/arch/mips/include/asm, branch v4.4.201

MIPS: bmips: mark exception vectors as char arrays

2019-11-10T10:21:09+00:00

[ Upstream commit e4f5cb1a9b27c0f94ef4f5a0178a3fde2d3d0e9e ]

The vectors span more than one byte, so mark them as arrays.

Fixes the following build error when building when using GCC 8.3:

In file included from ./include/linux/string.h:19,
                 from ./include/linux/bitmap.h:9,
                 from ./include/linux/cpumask.h:12,
                 from ./arch/mips/include/asm/processor.h:15,
                 from ./arch/mips/include/asm/thread_info.h:16,
                 from ./include/linux/thread_info.h:38,
                 from ./include/asm-generic/preempt.h:5,
                 from ./arch/mips/include/generated/asm/preempt.h:1,
                 from ./include/linux/preempt.h:81,
                 from ./include/linux/spinlock.h:51,
                 from ./include/linux/mmzone.h:8,
                 from ./include/linux/bootmem.h:8,
                 from arch/mips/bcm63xx/prom.c:10:
arch/mips/bcm63xx/prom.c: In function 'prom_init':
./arch/mips/include/asm/string.h:162:11: error: '__builtin_memcpy' forming offset [2, 32] is out of the bounds [0, 1] of object 'bmips_smp_movevec' with type 'char' [-Werror=array-bounds]
   __ret = __builtin_memcpy((dst), (src), __len); \
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/mips/bcm63xx/prom.c:97:3: note: in expansion of macro 'memcpy'
   memcpy((void *)0xa0000200, &bmips_smp_movevec, 0x20);
   ^~~~~~
In file included from arch/mips/bcm63xx/prom.c:14:
./arch/mips/include/asm/bmips.h:80:13: note: 'bmips_smp_movevec' declared here
 extern char bmips_smp_movevec;

Fixes: 18a1eef92dcd ("MIPS: BMIPS: Introduce bmips.h")
Signed-off-by: Jonas Gorski 
Reviewed-by: Florian Fainelli 
Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Cc: Ralf Baechle 
Cc: James Hogan 
Signed-off-by: Sasha Levin

MIPS: netlogic: xlr: Remove erroneous check in nlm_fmn_send()

2019-09-21T05:12:45+00:00

commit 02eec6c9fc0cb13169cc97a6139771768791f92b upstream.

In nlm_fmn_send() we have a loop which attempts to send a message
multiple times in order to handle the transient failure condition of a
lack of available credit. When examining the status register to detect
the failure we check for a condition that can never be true, which falls
foul of gcc 8's -Wtautological-compare:

  In file included from arch/mips/netlogic/common/irq.c:65:
  ./arch/mips/include/asm/netlogic/xlr/fmn.h: In function 'nlm_fmn_send':
  ./arch/mips/include/asm/netlogic/xlr/fmn.h:304:22: error: bitwise
    comparison always evaluates to false [-Werror=tautological-compare]
     if ((status & 0x2) == 1)
                        ^~

If the path taken if this condition were true all we do is print a
message to the kernel console. Since failures seem somewhat expected
here (making the console message questionable anyway) and the condition
has clearly never evaluated true we simply remove it, rather than
attempting to fix it to check status correctly.

Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20174/
Cc: Ganesan Ramalingam 
Cc: James Hogan 
Cc: Jayachandran C 
Cc: John Crispin 
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

MIPS: VDSO: Prevent use of smp_processor_id()

2019-09-21T05:12:44+00:00

commit 351fdddd366245c0fb4636f32edfb4198c8d6b8c upstream.

VDSO code should not be using smp_processor_id(), since it is executed
in user mode.
Introduce a VDSO-specific path which will cause a compile-time
or link-time error (depending upon support for __compiletime_error) if
the VDSO ever incorrectly attempts to use smp_processor_id().

[Matt Redfearn : Move before change to
smp_processor_id in series]

Signed-off-by: Paul Burton 
Signed-off-by: Matt Redfearn 
Patchwork: https://patchwork.linux-mips.org/patch/17932/
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

MIPS: ath79: fix ar933x uart parity mode

2019-08-04T07:34:36+00:00

[ Upstream commit db13a5ba2732755cf13320f3987b77cf2a71e790 ]

While trying to get the uart with parity working I found setting even
parity enabled odd parity insted. Fix the register settings to match
the datasheet of AR9331.

A similar patch was created by 8devices, but not sent upstream.
https://github.com/8devices/openwrt-8devices/commit/77c5586ade3bb72cda010afad3f209ed0c98ea7c

Signed-off-by: Stefan Hellermann 
Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Signed-off-by: Sasha Levin

MIPS: Workaround GCC __builtin_unreachable reordering bug

2019-07-10T07:56:42+00:00

[ Upstream commit 906d441febc0de974b2a6ef848a8f058f3bfada3 ]

Some versions of GCC for the MIPS architecture suffer from a bug which
can lead to instructions from beyond an unreachable statement being
incorrectly reordered into earlier branch delay slots if the unreachable
statement is the only content of a case in a switch statement. This can
lead to seemingly random behaviour, such as invalid memory accesses from
incorrectly reordered loads or stores, and link failures on microMIPS
builds.

See this potential GCC fix for details:

    https://gcc.gnu.org/ml/gcc-patches/2015-09/msg00360.html

Runtime problems resulting from this bug were initially observed using a
maltasmvp_defconfig v4.4 kernel built using GCC 4.9.2 (from a Codescape
SDK 2015.06-05 toolchain), with the result being an address exception
taken after log messages about the L1 caches (during probe of the L2
cache):

    Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff]
    VPE topology {2,2} total 4
    Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
    Primary data cache 64kB, 4-way, PIPT, no aliases, linesize 32 bytes
    

This is early enough that the kernel exception vectors are not in use,
so any further output depends upon the bootloader. This is reproducible
in QEMU where no further output occurs - ie. the system hangs here.
Given the nature of the bug it may potentially be hit with differing
symptoms. The bug is known to affect GCC versions as recent as 7.3, and
it is unclear whether GCC 8 fixed it or just happens not to encounter
the bug in the testcase found at the link above due to differing
optimizations.

This bug can be worked around by placing a volatile asm statement, which
GCC is prevented from reordering past, prior to the
__builtin_unreachable call.

That was actually done already for other reasons by commit 173a3efd3edb
("bug.h: work around GCC PR82365 in BUG()"), but creates problems for
microMIPS builds due to the lack of a .insn directive. The microMIPS ISA
allows for interlinking with regular MIPS32 code by repurposing bit 0 of
the program counter as an ISA mode bit. To switch modes one changes the
value of this bit in the PC. However typical branch instructions encode
their offsets as multiples of 2-byte instruction halfwords, which means
they cannot change ISA mode - this must be done using either an indirect
branch (a jump-register in MIPS terminology) or a dedicated jalx
instruction. In order to ensure that regular branches don't attempt to
target code in a different ISA which they can't actually switch to, the
linker will check that branch targets are code in the same ISA as the
branch.

Unfortunately our empty asm volatile statements don't qualify as code,
and the link for microMIPS builds fails with errors such as:

    arch/mips/mm/dma-default.s:3265: Error: branch to a symbol in another ISA mode
    arch/mips/mm/dma-default.s:5027: Error: branch to a symbol in another ISA mode

Resolve this by adding a .insn directive within the asm statement which
declares that what comes next is code. This may or may not be true,
since we don't really know what comes next, but as this code is in an
unreachable path anyway that doesn't matter since we won't execute it.

We do this in asm/compiler.h & select CONFIG_HAVE_ARCH_COMPILER_H in
order to have this included by linux/compiler_types.h after
linux/compiler-gcc.h. This will result in asm/compiler.h being included
in all C compilations via the -include linux/compiler_types.h argument
in c_flags, which should be harmless.

Signed-off-by: Paul Burton 
Fixes: 173a3efd3edb ("bug.h: work around GCC PR82365 in BUG()")
Patchwork: https://patchwork.linux-mips.org/patch/20270/
Cc: James Hogan 
Cc: Ralf Baechle 
Cc: Arnd Bergmann 
Cc: linux-mips@linux-mips.org
Signed-off-by: Sasha Levin

MIPS: Fix kernel crash for R6 in jump label branch function

2019-04-03T04:23:14+00:00

commit 47c25036b60f27b86ab44b66a8861bcf81cde39b upstream.

Insert Branch instruction instead of NOP to make sure assembler don't
patch code in forbidden slot. In jump label function, it might
be possible to patch Control Transfer Instructions(CTIs) into
forbidden slot, which will generate Reserved Instruction exception
in MIPS release 6.

Signed-off-by: Archer Yan 
Reviewed-by: Paul Burton 
[paul.burton@mips.com:
  - Add MIPS prefix to subject.
  - Mark for stable from v4.0, which introduced r6 support, onwards.]
Signed-off-by: Paul Burton 
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Greg Kroah-Hartman

MIPS: Ensure pmd_present() returns false after pmd_mknotpresent()

2019-01-13T09:05:31+00:00

commit 92aa0718c9fa5160ad2f0e7b5bffb52f1ea1e51a upstream.

This patch is borrowed from ARM64 to ensure pmd_present() returns false
after pmd_mknotpresent(). This is needed for THP.

References: 5bb1cc0ff9a6 ("arm64: Ensure pmd_present() returns false after pmd_mknotpresent()")
Reviewed-by: James Hogan 
Signed-off-by: Huacai Chen 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/21135/
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: Steven J . Hill 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Cc:  # 3.8+
Signed-off-by: Greg Kroah-Hartman

mips: fix mips_get_syscall_arg o32 check

2018-12-13T08:21:30+00:00

commit c50cbd85cd7027d32ac5945bb60217936b4f7eaf upstream.

When checking for TIF_32BIT_REGS flag, mips_get_syscall_arg() should
use the task specified as its argument instead of the current task.

This potentially affects all syscall_get_arguments() users
who specify tasks different from the current.

Fixes: c0ff3c53d4f99 ("MIPS: Enable HAVE_ARCH_TRACEHOOK.")
Signed-off-by: Dmitry V. Levin 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/21185/
Cc: Elvira Khabirova 
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Greg Kroah-Hartman

MIPS: Loongson-3: Fix BRIDGE irq delivery problem

2018-11-21T08:27:41+00:00

[ Upstream commit 360fe725f8849aaddc53475fef5d4a0c439b05ae ]

After commit e509bd7da149dc349160 ("genirq: Allow migration of chained
interrupts by installing default action") Loongson-3 fails at here:

setup_irq(LOONGSON_HT1_IRQ, &cascade_irqaction);

This is because both chained_action and cascade_irqaction don't have
IRQF_SHARED flag. This will cause Loongson-3 resume fails because HPET
timer interrupt can't be delivered during S3. So we set the irqchip of
the chained irq to loongson_irq_chip which doesn't disable the chained
irq in CP0.Status.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20434/
Cc: Ralf Baechle 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Cc: Huacai Chen 
Signed-off-by: Sasha Levin

MIPS: Fix FCSR Cause bit handling for correct SIGFPE issue

2018-11-10T15:41:36+00:00

[ Upstream commit 5a1aca4469fdccd5b74ba0b4e490173b2b447895 ]

Sanitize FCSR Cause bit handling, following a trail of past attempts:

* commit 4249548454f7 ("MIPS: ptrace: Fix FP context restoration FCSR
regression"),

* commit 443c44032a54 ("MIPS: Always clear FCSR cause bits after
emulation"),

* commit 64bedffe4968 ("MIPS: Clear [MSA]FPE CSR.Cause after
notify_die()"),

* commit b1442d39fac2 ("MIPS: Prevent user from setting FCSR cause
bits"),

* commit b54d2901517d ("Properly handle branch delay slots in connection
with signals.").

Specifically do not mask these bits out in ptrace(2) processing and send
a SIGFPE signal instead whenever a matching pair of an FCSR Cause and
Enable bit is seen as execution of an affected context is about to
resume.  Only then clear Cause bits, and even then do not clear any bits
that are set but masked with the respective Enable bits.  Adjust Cause
bit clearing throughout code likewise, except within the FPU emulator
proper where they are set according to IEEE 754 exceptions raised as the
operation emulated executed.  Do so so that any IEEE 754 exceptions
subject to their default handling are recorded like with operations
executed by FPU hardware.

Signed-off-by: Maciej W. Rozycki 
Cc: Paul Burton 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14460/
Signed-off-by: Ralf Baechle 
Signed-off-by: Sasha Levin