In these instructions we load the new thread register, switch
the register window, and setup the new frame pointer.

All of these must appear atomic, and things will explode if
we take a PIL=15 NMI interrupt in the middle of this sequence.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The kernel always executes in the TSO memory model now,
so none of this stuff is necessary any more.

With helpful feedback from Nick Piggin.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This also takes care of a sparse warning as scons_pwroff's definition
point.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While doing some easy cleanups on the sparc code I noticed that the
CONFIG_SUN4 code seems to be worse than the rest - there were some
"I don't know how it should work, but the current code definitely cannot
work." places.

And while I have seen people running Linux on machines like a
SPARCstation 5 a few years ago I don't recall having seen sun4
machines, even less ones running Linux.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The majority of this patch was created by the following script:

***
ASM=arch/sparc/include/asm
mkdir -p $ASM
git mv include/asm-sparc64/ftrace.h $ASM
git rm include/asm-sparc64/*
git mv include/asm-sparc/* $ASM
sed -ie 's/asm-sparc64/asm/g' $ASM/*
sed -ie 's/asm-sparc/asm/g' $ASM/*
***

The rest was an update of the top-level Makefile to use sparc
for header files when sparc64 is being build.
And a small fixlet to pick up the correct unistd.h from
sparc64 code.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

With this commit all sparc64 header files are moved to asm-sparc.
The remaining files (71 files) were too different to be trivially
merged so divide them up in a _32.h and a _64.h file which
are both included from the file with no bit size.

The following script were used:
cd include
FILES=`wc -l asm-sparc64/*h | grep -v '^     1' | cut -b 20-`

for FILE in ${FILES}; do
  echo $FILE:
  BASE=`echo $FILE | cut -d '.' -f 1`
  FN32=${BASE}_32.h
  FN64=${BASE}_64.h
  GUARD=___ASM_SPARC_`echo $BASE | tr '-' '_' | tr [:lower:] [:upper:]`_H
  git mv asm-sparc/$FILE asm-sparc/$FN32
  git mv asm-sparc64/$FILE asm-sparc/$FN64
  echo git mv done
  printf "#ifndef %s\n" $GUARD                             >   asm-sparc/$FILE
  printf "#define %s\n" $GUARD                             >>  asm-sparc/$FILE
  printf "#if defined(__sparc__) && defined(__arch64__)\n" >>  asm-sparc/$FILE
  printf "#include <asm-sparc/%s>\n" $FN64                 >>  asm-sparc/$FILE
  printf "#else\n"                                         >>  asm-sparc/$FILE
  printf "#include <asm-sparc/%s>\n" $FN32                 >>  asm-sparc/$FILE
  printf "#endif\n"                                        >>  asm-sparc/$FILE
  printf "#endif\n"                                        >>  asm-sparc/$FILE
  git add asm-sparc/$FILE
  echo new file done
  printf "#include <asm-sparc/%s>\n" $FILE                 >  asm-sparc64/$FILE
  git add asm-sparc64/$FILE
  echo sparc64 file done
done

The guard contains three '_' to avoid conflict with existing guards.
In additing the two Kbuild files are emptied to avoid breaking
headers_* targets.
We will reintroduce the exported header files when the necessary
kbuild changes are merged.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Current limitations:

1) On SMP single stepping has some fundamental issues,
   shared with other sw single-step architectures such
   as mips and arm.

2) On 32-bit sparc we don't support SMP kgdb yet.  That
   requires some reworking of the IPI mechanisms and
   infrastructure on that platform.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Kill off some sparse warnings.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc64/kernel/process.c:467:6: warning: symbol 'fault_in_user_windows' was not declared. Should it be static?
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use cmpxchg_u32 and cmpxchg_u64 for cmpxchg_local and cmpxchg64_local. For other
type sizes, use the new generic cmpxchg_local (disables interrupt).

Change:
Since the header depends on local_irqsave/local_irqrestore, it must be
included after their declaration.

Actually, being below the
#include <linux/irqflags.h> should be enough, and on sparc64 it is
included at the beginning of system.h.

So it makes sense to move it up for sparc64.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This was found by make randconfig

If the kernel .text is very large, the .fixup section branches
are too far away to be relocated correctly.

Use "sethi %hi(label), reg; jmpl reg + %lo(label); %g0" sequence
instead of the branch to fix this.

There is another case in switch_to() involving a branch, which
is fixed similarly.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Otherwise the compiler can't see the things like the
per-cpu area base register are changing.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current scheme works on static interpretation of text names, which
is wrong.

The output-device setting, for example, must be resolved via an alias
or similar to a full path name to the console device.

Paths also contain an optional set of 'options', which starts with a
colon at the end of the path.  The option area is used to specify
which of two serial ports ('a' or 'b') the path refers to when a
device node drives multiple ports.  'a' is assumed if the option
specification is missing.

This was caught by the UltraSPARC-T1 simulator.  The 'output-device'
property was set to 'ttya' and we didn't pick upon the fact that this
is an OBP alias set to '/virtual-devices/console'.  Instead we saw it
as the first serial console device, instead of the hypervisor console.

The infrastructure is now there to take advantage of this to resolve
the console correctly even in multi-head situations in fbcon too.

Thanks to Greg Onufer for the bug report.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since Ingo's recent scheduler rewrite which was merged as commit
0437e109 sched_cacheflush is unused.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

tas() has no users, so get rid of it.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: <linux-arch@vger.kernel.org>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

set_wmb should not be used in the kernel because it just confuses the
code more and has no benefit.  Since it is not currently used in the
kernel this patch removes it so that new code does not include it.

All archs define set_wmb(var, value) to do { var = value; wmb(); }
while(0) except ia64 and sparc which use a mb() instead.  But this is
still moot since it is not used anyway.

Hasn't been tested on any archs but x86 and x86_64 (and only compiled
tested)
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

They are totally unnecessary because:

1) Interrupts are already disabled when switch_to()
   runs.

2) We don't use hard-coded alternate globals any longer.

This found a case in rtrap, which still assumed alternate
global %g6 was current_thread_info(), and that is fixed
by this changeset as well.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UltraSPARC has special sets of global registers which are switched to
for certain trap types.  There is one set for MMU related traps, one
set of Interrupt Vector processing, and another set (called the
Alternate globals) for all other trap types.

For what seems like forever we've hard coded the values in some of
these trap registers.  Some examples include:

1) Interrupt Vector global %g6 holds current processors interrupt
   work struct where received interrupts are managed for IRQ handler
   dispatch.

2) MMU global %g7 holds the base of the page tables of the currently
   active address space.

3) Alternate global %g6 held the current_thread_info() value.

Such hardcoding has resulted in some serious issues in many areas.
There are some code sequences where having another register available
would help clean up the implementation.  Taking traps such as
cross-calls from the OBP firmware requires some trick code sequences
wherein we have to save away and restore all of the special sets of
global registers when we enter/exit OBP.

We were also using the IMMU TSB register on SMP to hold the per-cpu
area base address, which doesn't work any longer now that we actually
use the TSB facility of the cpu.

The implementation is pretty straight forward.  One tricky bit is
getting the current processor ID as that is different on different cpu
variants.  We use a stub with a fancy calling convention which we
patch at boot time.  The calling convention is that the stub is
branched to and the (PC - 4) to return to is in register %g1.  The cpu
number is left in %g6.  This stub can be invoked by using the
__GET_CPUID macro.

We use an array of per-cpu trap state to store the current thread and
physical address of the current address space's page tables.  The
TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this
table, it uses __GET_CPUID and also clobbers %g1.

TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load
the current processor's IRQ software state into %g6.  It also uses
__GET_CPUID and clobbers %g1.

Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the
current address space's page tables into %g7, it clobbers %g1 and uses
__GET_CPUID.

Many refinements are possible, as well as some tuning, with this stuff
in place.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add per-arch sched_cacheflush() which is a write-back cacheflush used by
the migration-cost calibration code at bootup time.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove various things which were checking for gcc-1.x and gcc-2.x compilers.

From: Adrian Bunk <bunk@stusta.de>

    Some documentation updates and removes some code paths for gcc < 3.2.
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Since GCC has to emit a call and a delay slot to the
out-of-line "membar" routines in arch/sparc64/lib/mb.S
it is much better to just do the necessary predicted
branch inline instead as:

	ba,pt	%xcc, 1f
	 membar	#whatever
1:

instead of the current:

	call	membar_foo
	 dslot

because this way GCC is not required to allocate a stack
frame if the function can be a leaf function.

This also makes this bug fix easier to backport to 2.4.x
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It appears that a memory barrier soon after a mispredicted
branch, not just in the delay slot, can cause the hang
condition of this cpu errata.

So move them out-of-line, and explicitly put them into
a "branch always, predict taken" delay slot which should
fully kill this problem.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These two bits were accesses non-atomically from assembler
code.  So, in order to eliminate any potential races resulting
from that, move these pieces of state into two bytes elsewhere
in struct thread_info.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Instead of requiring architecture code to interact with the scheduler's
locking implementation, provide a couple of defines that can be used by the
architecture to request runqueue unlocked context switches, and ask for
interrupts to be enabled over the context switch.

Also replaces the "switch_lock" used by these architectures with an oncpu
flag (note, not a potentially slow bitflag).  This eliminates one bus
locked memory operation when context switching, and simplifies the
task_running function.
Signed-off-by: NNick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.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!