Accordingly to the documentation
---cut---
The GCR_ERROR_CAUSE.ERR_TYPE field and the GCR_ERROR_MULT.ERR_TYPE
fields can be cleared by either a reset or by writing the current
value of GCR_ERROR_CAUSE.ERR_TYPE to the
GCR_ERROR_CAUSE.ERR_TYPE register.
---cut---
Do exactly this. Original value of cm_error may be safely written back;
it clears error cause and keeps other bits untouched.

Fixes: 3885c2b463f6 ("MIPS: CM: Add support for reporting CM cache errors")
Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev@linux.intel.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # v4.3+

On my Yeeloong 8089, I noticed the machine fails to shutdown
properly, and often, the function mach_prepare_reboot() is
unexpectedly executed, thus the machine reboots instead. A
wait loop is needed to ensure the system is in a well-defined
state before going down.

In commit 997e93d4df16 ("MIPS: Hang more efficiently on
halt/powerdown/restart"), a general superset of the wait loop for all
platforms is already provided, so we don't need to implement our own.

This commit simply removes the unreachable() compiler marco after
mach_prepare_reboot(), thus allowing the execution of machine_hang().
My test shows that the machine is now able to shutdown successfully.

Please note that there are two different bugs preventing the machine
from shutting down, another work-in-progress commit is needed to
fix a lockup in cpufreq / i8259 driver, please read Reference, this
commit does not fix that bug.

Reference: https://lkml.org/lkml/2019/2/5/908
Signed-off-by: Yifeng Li <tomli@tomli.me>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: stable@vger.kernel.org # v4.17+

Patch (b6c7a324df37b "MIPS: Fix get_frame_info() handling of
microMIPS function size.") introduces additional function size
check for microMIPS by only checking insn between ip and ip + func_size.
However, func_size in get_frame_info() is always 0 if KALLSYMS is not
enabled. This causes get_frame_info() to return immediately without
calculating correct frame_size, which in turn causes "Can't analyze
schedule() prologue" warning messages at boot time.

This patch removes func_size check, and let the frame_size check run
up to 128 insns for both MIPS and microMIPS.

Signed-off-by: Jun-Ru Chang <jrjang@realtek.com>
Signed-off-by: Tony Wu <tonywu@realtek.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: b6c7a324df37b ("MIPS: Fix get_frame_info() handling of microMIPS function size.")
Cc: <ralf@linux-mips.org>
Cc: <jhogan@kernel.org>
Cc: <macro@mips.com>
Cc: <yamada.masahiro@socionext.com>
Cc: <peterz@infradead.org>
Cc: <mingo@kernel.org>
Cc: <linux-mips@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>

DTC introduced an i2c_bus_reg check in v1.4.7, used since Linux v4.20,
which complains about upper case addresses used in the unit name.

nexys4ddr.dts names an I2C device node "ad7420@4B", leading to:

arch/mips/boot/dts/xilfpga/nexys4ddr.dts:109.16-112.8: Warning
(i2c_bus_reg): /i2c@10A00000/ad7420@4B: I2C bus unit address format
error, expected "4b"

Fix this by switching to lower case addresses throughout the file, as is
*mostly* the case in the file already & fairly standard throughout the
tree.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: stable@vger.kernel.org # v4.20+
Cc: linux-mips@vger.kernel.org

On the Loongson-2G/2H/3A/3B there is a hardware flaw that ll/sc and
lld/scd is very weak ordering. We should add sync instructions "before
each ll/lld" and "at the branch-target between ll/sc" to workaround.
Otherwise, this flaw will cause deadlock occasionally (e.g. when doing
heavy load test with LTP).

Below is the explaination of CPU designer:

"For Loongson 3 family, when a memory access instruction (load, store,
or prefetch)'s executing occurs between the execution of LL and SC, the
success or failure of SC is not predictable. Although programmer would
not insert memory access instructions between LL and SC, the memory
instructions before LL in program-order, may dynamically executed
between the execution of LL/SC, so a memory fence (SYNC) is needed
before LL/LLD to avoid this situation.

Since Loongson-3A R2 (3A2000), we have improved our hardware design to
handle this case. But we later deduce a rarely circumstance that some
speculatively executed memory instructions due to branch misprediction
between LL/SC still fall into the above case, so a memory fence (SYNC)
at branch-target (if its target is not between LL/SC) is needed for
Loongson 3A1000, 3B1500, 3A2000 and 3A3000.

Our processor is continually evolving and we aim to to remove all these
workaround-SYNCs around LL/SC for new-come processor."

Here is an example:

Both cpu1 and cpu2 simutaneously run atomic_add by 1 on same atomic var,
this bug cause both 'sc' run by two cpus (in atomic_add) succeed at same
time('sc' return 1), and the variable is only *added by 1*, sometimes,
which is wrong and unacceptable(it should be added by 2).

Why disable fix-loongson3-llsc in compiler?
Because compiler fix will cause problems in kernel's __ex_table section.

This patch fix all the cases in kernel, but:

+. the fix at the end of futex_atomic_cmpxchg_inatomic is for branch-target
of 'bne', there other cases which smp_mb__before_llsc() and smp_llsc_mb() fix
the ll and branch-target coincidently such as atomic_sub_if_positive/
cmpxchg/xchg, just like this one.

+. Loongson 3 does support CONFIG_EDAC_ATOMIC_SCRUB, so no need to touch
edac.h

+. local_ops and cmpxchg_local should not be affected by this bug since
only the owner can write.

+. mips_atomic_set for syscall.c is deprecated and rarely used, just let
it go

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Huang Pei <huangpei@loongson.cn>
[paul.burton@mips.com:
- Simplify the addition of -mno-fix-loongson3-llsc to cflags, and add
a comment describing why it's there.
- Make loongson_llsc_mb() a no-op when
CONFIG_CPU_LOONGSON3_WORKAROUNDS=n, rather than a compiler memory
barrier.
- Add a comment describing the bug & how loongson_llsc_mb() helps
in asm/barrier.h.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: ambrosehua@gmail.com
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: Li Xuefeng <lixuefeng@loongson.cn>
Cc: Xu Chenghua <xuchenghua@loongson.cn>

When generating vdso-o32.lds & vdso-n32.lds for use with programs
running as compat ABIs under 64b kernels, we previously haven't included
the compiler flags that are supposedly common to all ABIs - ie. those in
the ccflags-vdso variable.

This is problematic in cases where we need to provide the -m%-float flag
in order to ensure that we don't attempt to use a floating point ABI
that's incompatible with the target CPU & ABI. For example a toolchain
using current gcc trunk configured --with-fp-32=xx fails to build a
64r6el_defconfig kernel with the following error:

cc1: error: '-march=mips1' requires '-mfp32'
make[2]: *** [arch/mips/vdso/Makefile:135: arch/mips/vdso/vdso-o32.lds] Error 1

Include $(ccflags-vdso) for the compat VDSO .lds builds, just as it is
included for the native VDSO .lds & when compiling objects for the
compat VDSOs. This ensures we consistently provide the -msoft-float flag
amongst others, avoiding the problem by ensuring we're agnostic to the
toolchain defaults.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Cc: linux-mips@vger.kernel.org
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Maciej W . Rozycki <macro@linux-mips.org>
Cc: stable@vger.kernel.org # v4.4+

The MIPS VDSO build currently doesn't provide the -msoft-float flag to
the compiler as the kernel proper does. This results in an attempt to
use the compiler's default floating point configuration, which can be
problematic in cases where this is incompatible with the target CPU's
-march= flag. For example decstation_defconfig fails to build using
toolchains in which gcc was configured --with-fp-32=xx with the
following error:

LDS arch/mips/vdso/vdso.lds
cc1: error: '-march=r3000' requires '-mfp32'
make[2]: *** [scripts/Makefile.build:379: arch/mips/vdso/vdso.lds] Error 1

The kernel proper avoids this error because we build with the
-msoft-float compiler flag, rather than using the compiler's default.
Pass this flag through to the VDSO build so that it too becomes agnostic
to the toolchain's floating point configuration.

Note that this is filtered out from KBUILD_CFLAGS rather than simply
always using -msoft-float such that if we switch the kernel to use
-mno-float in the future the VDSO will automatically inherit the change.

The VDSO doesn't actually include any floating point code, and its
.MIPS.abiflags section is already manually generated to specify that
it's compatible with any floating point ABI. As such this change should
have no effect on the resulting VDSO, apart from fixing the build
failure for affected toolchains.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Reported-by: Kevin Hilman <khilman@baylibre.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Kevin Hilman <khilman@baylibre.com>
References: https://lore.kernel.org/linux-mips/1477843551-21813-1-git-send-email-linux@roeck-us.net/
References: https://kernelci.org/build/id/5c4e4ae059b5142a249ad004/logs/
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.4+

Don't set octeon_dma_bar_type if PCI is disabled. This avoids creation
of the MSI irqchip later on, and saves a bit of memory.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: a214720cbf50 ("Disable MSI also when pcie-octeon.pcie_disable on")
Cc: stable@vger.kernel.org # v3.3+
Cc: linux-mips@vger.kernel.org

According to the Schematic, the hardware of ci20 leads to uart3,
but not to uart2. Uart2 is miswritten in the original code.

Signed-off-by: Zhou Yanjie <zhouyanjie@cduestc.edu.cn>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips <linux-mips@vger.kernel.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Cc: devicetree@vger.kernel.org
Cc: robh+dt@kernel.org
Cc: ralf@linux-mips.org
Cc: jhogan@kernel.org
Cc: mark.rutland@arm.com
Cc: malat@debian.org
Cc: ezequiel@collabora.co.uk
Cc: ulf.hansson@linaro.org
Cc: syq <syq@debian.org>
Cc: jiaxun.yang <jiaxun.yang@flygoat.com>

The interrupt number set in the devicetree node of the DMA driver was
wrong.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Pull pstore fixes from Kees Cook:

- Fix console ramoops to show the previous boot logs (Sai Prakash
Ranjan)

- Avoid allocation and leak of platform data

* tag 'pstore-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore/ram: Avoid allocation and leak of platform data
pstore/ram: Fix console ramoops to show the previous boot logs

Pull gcc-plugins fixes from Kees Cook:
"Fix ARM per-task stack protector plugin under GCC 9 (Ard Biesheuvel)"

* tag 'gcc-plugins-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: arm_ssp_per_task_plugin: fix for GCC 9+
gcc-plugins: arm_ssp_per_task_plugin: sign extend the SP mask

Yue Hu noticed that when parsing device tree the allocated platform data
was never freed. Since it's not used beyond the function scope, this
switches to using a stack variable instead.

Reported-by: Yue Hu <huyue2@yulong.com>
Fixes: 35da60941e44 ("pstore/ram: add Device Tree bindings")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>