Commit Graph

16 Commits

Author SHA1 Message Date
Paul Mundt
43f8f9b95b sh: Simplify kernel_thread_helper() for sh32.
This can use the same implementation as sh64, the generated assembly is
the same between the new and old version, so there is not much point in
leaving it open coded in inline assembly.

This is preparatory work for future consolidation of the _32/_64
variants.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:44:44 +09:00
Paul Mundt
1da1180c6e sh: Split out the idle loop for reuse between _32/_64 variants.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:43:50 +09:00
Paul Mundt
f74c034d52 sh: do not latency trace idle.
Description snipped from Steven Rostedt's PPC patch:

    When idle is called, interrupts are blocked, but the idle
    function will still wake up on an interrupt. The problem is
    that the interrupt disabled latency tracer will take this call
    to idle as a latency.

    This patch disables the latency tracing when going into idle.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:43:49 +09:00
Paul Mundt
75fd24c107 sh: Tidy up backtrace formatting with kallsyms disabled.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:43:49 +09:00
Paul Mundt
9cfc9a9b6f sh: Add a simple code dumper for SUPERH32 show_regs().
This implements a simple show_code() that is in turn plugged in to
show_regs() to provide minimal code dumping at the end of the trace.

Built on top of a simple instruction disassembler derived from the
binutils opcode table.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:43:49 +09:00
Paul Mundt
e7ab3cd251 sh: Add FPU registers to regset interface.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-09-21 19:04:55 +09:00
Paul Mundt
3d58695edb sh: Trivial trace_mark() instrumentation for core events.
This implements a few trace points across events that are deemed
interesting. This implements a number of trace points:

	- The page fault handler / TLB miss
	- IPC calls
	- Kernel thread creation

The original LTTng patch had the slow-path instrumented, which
fails to account for the vast majority of events. In general
placing this in the fast-path is not a huge performance hit, as
we don't take page faults for kernel addresses.

The other bits of interest are some of the other trap handlers, as
well as the syscall entry/exit (which is better off being handled
through the tracehook API). Most of the other trap handlers are corner
cases where alternate means of notification exist, so there is little
value in placing extra trace points in these locations.

Based on top of the points provided both by the LTTng instrumentation
patch as well as the patch shipping in the ST-Linux tree, albeit in a
stripped down form.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-09-21 13:56:39 +09:00
Paul Mundt
fa43972fab sh: fixup many sparse errors.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-09-08 10:35:04 +09:00
Paul Mundt
7d96169cb7 sh: Display CPU information in show_regs().
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-09-08 10:35:03 +09:00
Adrian Bunk
4c1cfab1e0 sh/kernel/ cleanups
This patch contains the following cleanups:
- make the following needlessly global code static:
  - cf-enabler.c: cf_init()
  - cpu/clock.c: __clk_enable()
  - cpu/clock.c: __clk_disable()
  - process_32.c: default_idle()
  - time_32.c: struct clocksource_sh
  - timers/timer-tmu.c: struct tmu_timer_ops
- remove the following unused functions (no CONFIG_BLK_DEV_FD on sh):
  - process_{32,64}.c: disable_hlt()
  - process_{32,64}.c: enable_hlt()

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-07-28 18:10:30 +09:00
Thomas Gleixner
b8f8c3cf0a nohz: prevent tick stop outside of the idle loop
Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:

	scheduler switch to idle task
	enable interrupts

Window starts here

	----> interrupt happens (does not set NEED_RESCHED)
	      	irq_exit() stops the tick

	----> interrupt happens (does set NEED_RESCHED)

	return from schedule()
	
	cpu_idle(): preempt_disable();

Window ends here

The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.

The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.

Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.

cpu_idle()
{
	preempt_disable();

	while(1) {
		 tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
		 			          are in the idle loop

		 while (!need_resched())
		       halt();

		 tick_nohz_restart_sched_tick(); <- disables NOHZ mode
		 preempt_enable_no_resched();
		 schedule();
		 preempt_disable();
	}
}

In hindsight we should have done this forever, but ... 

/me grabs a large brown paperbag.

Debugged-by: Jack Ren <jack.ren@marvell.com>, 
Debugged-by: eric miao <eric.y.miao@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-07-18 18:10:28 +02:00
Paul Mundt
9bbafce2ee sh: Fix occasional FPU register corruption under preempt.
Presently with preempt enabled there's the possibility to be preempted
after the TIF_USEDFPU test and the register save, leading to bogus
state post-__switch_to(). Use an explicit preempt_disable()/enable()
pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86
change.

Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-03-26 19:02:47 +09:00
Stuart Menefy
1efe4ce3ca sh: GUSA atomic rollback support.
This implements kernel-level atomic rollback built on top of gUSA,
as an alternative non-IRQ based atomicity method. This is generally
a faster method for platforms that are lacking the LL/SC pairs that
SH-4A and later use, and is only supportable on legacy cores.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-01-28 13:18:58 +09:00
Paul Mundt
5a4f7c66be sh: Share bug/debug traps across _32 and _64.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-01-28 13:18:50 +09:00
Paul Mundt
e7e0a4b54a sh: Share the ELF dump_task interfaces.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-01-28 13:18:49 +09:00
Paul Mundt
fe51bc9eaf sh: Split out arch/sh/kernel/process.c for _32 and _64 variants.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-01-28 13:18:42 +09:00