Another issue with 20Kc's WAIT, waiting for more details. With the
2.6.23 release immindent simply disable the use of WAIT instead of a
more fancy workaround.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patch to add mips common support for the PMC-Sierra MSP71xx devices.
Signed-off-by: Marc St-Jean <Marc_St-Jean@pmc-sierra.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Which will cut down the cost of RDHWR $29 which is used to obtain the
TLS pointer and so far being emulated in software down to a single cycle
operation.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The idle loop goes to sleep using the WAIT instruction if !need_resched().
This has is suffering from from a race condition that if if just after
need_resched has returned 0 an interrupt might set TIF_NEED_RESCHED but
we've just completed the test so go to sleep anyway. This would be
trivial to fix by just disabling interrupts during that sequence as in:
local_irq_disable();
if (!need_resched())
__asm__("wait");
local_irq_enable();
but the processor architecture leaves it undefined if a processor calling
WAIT with interrupts disabled will ever restart its pipeline and indeed
some processors have made use of the freedom provided by the architecture
definition. This has been resolved and the Config7.WII bit indicates that
the use of WAIT is safe on 24K, 24KE and 34K cores. It also is safe on
74K starting revision 2.1.0 so enable the use of WAIT with interrupts
disabled for 74K based on a c0_prid of at least that.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
We used to avoid the WAIT entirely on the 20K but really only need to do
this on early revs of the 20K. Without this a 20K was a bit of a
power hog. Well, in the lower power power hog category ;-)
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This fixes some sparse warnings. ("warning: symbol 'foo' was not
declared. Should it be static?")
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Only revisions < 4.0 don't have a functional wait instruction.
From Thomas Koeller (Thomas.Koeller@baslerweb.com).
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
If a thread became runnable between need_resched() and the WAIT
instruction, switching to the thread will delay until a next interrupt.
Some CPUs can execute the WAIT instruction with interrupt disabled, so
we can get rid of this race on them (at least UP case).
Original Patch by Atsushi with fixing up for MIPS Technology's cores by
Ralf based on feedback from the RTL designers.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The appended patch drops the inline for decode_configs, this saves about
2k of text size.
Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The wrong revision number in the check was forcing a fallback to FPU
emulation for all SB1 cores in 2.6.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Nothing exciting; Linux just didn't know it yet so this is most adding
a value to a case statement.
Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
So for now we just unconditionally set the option - Linux wouldn't
work without a TLB anyway.
Setting MIPS_CPU_4KTLB was missing for Alchemy and Sandcraft, add that
back.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Ralf Baechle