linux-stable.git/arch/mips/kernel/cpu-probe.c, branch v3.18.76

MIPS: HTW: Prevent accidental HTW start due to nested htw_{start, stop}

2015-03-06T22:53:01+00:00

commit ed4cbc81addbc076b016c5b979fd1a02f0897f0a upstream.

activate_mm() and switch_mm() call get_new_mmu_context() which in turn
can enable the HTW before the entryhi is changed with the new ASID.
Since the latter will enable the HTW in local_flush_tlb_all(),
then there is a small timing window where the HTW is running with the
new ASID but with an old pgd since the TLBMISS_HANDLER_SETUP_PGD
hasn't assigned a new one yet. In order to prevent that, we introduce a
simple htw counter to avoid starting HTW accidentally due to nested
htw_{start,stop}() sequences. Moreover, since various IPI calls can
enforce TLB flushing operations on a different core, such an operation
may interrupt another htw_{stop,start} in progress leading inconsistent
updates of the htw_seq variable. In order to avoid that, we disable the
interrupts whenever we update that variable.

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9118/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

MIPS: cpu-probe: Set the FTLB probability bit on supported cores

2014-11-24T06:44:05+00:00

Make use of the Config6/FLTBP bit to set the probability of a TLBWR
instruction to hit the FTLB or the VTLB. A value of 0 (which may be
the default value on certain cores, such as proAptiv or P5600)
means that a TLBWR instruction will never hit the VTLB which
leads to performance limitations since it effectively decreases
the number of available TLB slots.

Signed-off-by: Markos Chandras 
Reviewed-by: James Hogan 
Cc:  # v3.15+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8368/
Signed-off-by: Ralf Baechle

MIPS: Loongson: Set Loongson-3's ISA level to MIPS64R1

2014-11-19T17:22:07+00:00

In CPU manual Loongson-3 is MIPS64R2 compatible, but during tests we
found that its EI/DI instructions have problems. So we just set the ISA
level to MIPS64R1.

Signed-off-by: Huacai Chen 
Cc: John Crispin 
Cc: Steven J. Hill 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Patchwork: https://patchwork.linux-mips.org/patch/8320/
Signed-off-by: Ralf Baechle

MIPS: Loongson: Fix the write-combine CCA value setting

2014-11-19T17:22:07+00:00

All Loongson-2/3 processors support _CACHE_UNCACHED_ACCELERATED, not
only Loongson-3A.

Signed-off-by: Huacai Chen 
Cc: John Crispin 
Cc: Steven J. Hill 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Patchwork: https://patchwork.linux-mips.org/patch/8319/
Signed-off-by: Ralf Baechle

MIPS: cpu-probe: Set the write-combine CCA value on per core basis

2014-09-22T11:35:53+00:00

Different cores use different CCA values to achieve write-combine
memory writes. For cores that do not support write-combine we
set the default value to CCA:2 (uncached, non-coherent) which is the
default value as set by the kernel.

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7402/
Signed-off-by: Ralf Baechle

MIPS: detect presence of MAARs

2014-08-01T22:06:45+00:00

Detect the presence of MAAR using the MRP bit in Config5, and record
that presence using a CPU option bit. A cpu_has_maar macro will then
allow code to conditionalise upon the presence of MAARs.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7330/
Signed-off-by: Ralf Baechle

MIPS: ensure MSA gets disabled during boot

2014-08-01T22:06:44+00:00

The kernel relies upon MSA being disabled when a task begins running,
so that it can initialise or restore context in response to the
resulting MSA disabled exception. Previously the state of MSA following
boot was left as it was before the kernel ran, where MSA could
potentially have been enabled. Explicitly disable it during boot to
prevent any problems.

As a nice side effect the code reads a little better too.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7306/
Signed-off-by: Ralf Baechle

MIPS: kernel: cpu-probe: Detect unique RI/XI exceptions

2014-08-01T22:06:40+00:00

Detect if the core supports unique exception codes for the
Read-Inhibit and Execute-Inhibit exceptions and set the
option accordingly. The RI/XI exception support is detected
by setting the 27th bit (IEC) of the PageGrain C0 register
and reading back the value of that register to verify the
bit is enabled.

Signed-off-by: Leonid Yegoshin 
Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7340/
Signed-off-by: Ralf Baechle

MIPS: kernel: cpu-probe: Add support for the HardWare Table Walker

2014-08-01T22:06:39+00:00

Detect if the core implements the HTW and set the option accordingly.
Also, add a new kernel parameter called 'nohtw' allowing
the user to disable the htw support and fallback to the software
refill handler.

Signed-off-by: Markos Chandras 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7335/
Signed-off-by: Ralf Baechle

MIPS: Add Loongson-3B support

2014-07-30T19:47:00+00:00

Loongson-3B is a 8-cores processor. In general it looks like there are
two Loongson-3A integrated in one chip: 8 cores are separated into two
groups (two NUMA node), each node has its own local memory.

Of course there are some differences between one Loongson-3B and two
Loongson-3A. E.g., the base addresses of IPI registers of each node are
not the same; Loongson-3A use ChipConfig register to enable/disable
clock, but Loongson-3B use FreqControl register instead.

There are two revision of Loongson-3B, the first revision is called as
Loongson-3B1000, whose frequency is 1GHz and has a PRid 0x6306, the
second revision is called as Loongson-3B1500, whose frequency is 1.5GHz
and has a PRid 0x6307. Both revisions has a bug that clock cannot be
disabled at runtime, but this will be fixed in future.

Signed-off-by: Huacai Chen 
Cc: John Crispin 
Cc: Steven J. Hill 
Cc: Aurelien Jarno 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Patchwork: https://patchwork.linux-mips.org/patch/7188/
Signed-off-by: Ralf Baechle