linux-toradex.git/arch/frv/kernel, branch v2.6.16

[PATCH] FRV: Use virtual interrupt disablement

2006-02-15T00:09:35+00:00

Make the FRV arch use virtual interrupt disablement because accesses to the
processor status register (PSR) are relatively slow and because we will
soon have the need to deal with multiple interrupt controls at the same
time (separate h/w and inter-core interrupts).

The way this is done is to dedicate one of the four integer condition code
registers (ICC2) to maintaining a virtual interrupt disablement state
whilst inside the kernel.  This uses the ICC2.Z flag (Zero) to indicate
whether the interrupts are virtually disabled and the ICC2.C flag (Carry)
to indicate whether the interrupts are physically disabled.

ICC2.Z is set to indicate interrupts are virtually disabled.  ICC2.C is set
to indicate interrupts are physically enabled.  Under normal running
conditions Z==0 and C==1.

Disabling interrupts with local_irq_disable() doesn't then actually
physically disable interrupts - it merely sets ICC2.Z to 1.  Should an
interrupt then happen, the exception prologue will note ICC2.Z is set and
branch out of line using one instruction (an unlikely BEQ).  Here it will
physically disable interrupts and clear ICC2.C.

When it comes time to enable interrupts (local_irq_enable()), this simply
clears the ICC2.Z flag and invokes a trap #2 if both Z and C flags are
clear (the HI integer condition).  This can be done with the TIHI
conditional trap instruction.

The trap then physically reenables interrupts and sets ICC2.C again.  Upon
returning the interrupt will be taken as interrupts will then be enabled.
Note that whilst processing the trap, the whole exceptions system is
disabled, and so an interrupt can't happen till it returns.

If no pending interrupt had happened, ICC2.C would still be set, the HI
condition would not be fulfilled, and no trap will happen.

Saving interrupts (local_irq_save) is simply a matter of pulling the ICC2.Z
flag out of the CCR register, shifting it down and masking it off.  This
gives a result of 0 if interrupts were enabled and 1 if they weren't.

Restoring interrupts (local_irq_restore) is then a matter of taking the
saved value mentioned previously and XOR'ing it against 1.  If it was one,
the result will be zero, and if it was zero the result will be non-zero.
This result is then used to affect the ICC2.Z flag directly (it is a
condition code flag after all).  An XOR instruction does not affect the
Carry flag, and so that bit of state is unchanged.  The two flags can then
be sampled to see if they're both zero using the trap (TIHI) as for the
unconditional reenablement (local_irq_enable).

This patch also:

 (1) Modifies the debugging stub (break.S) to handle single-stepping crossing
     into the trap #2 handler and into virtually disabled interrupts.

 (2) Removes superseded fixup pointers from the second instructions in the trap
     tables (there's no a separate fixup table for this).

 (3) Declares the trap #3 vector for use in .org directives in the trap table.

 (4) Moves irq_enter() and irq_exit() in do_IRQ() to avoid problems with
     virtual interrupt handling, and removes the duplicate code that has now
     been folded into irq_exit() (softirq and preemption handling).

 (5) Tells the compiler in the arch Makefile that ICC2 is now reserved.

 (6) Documents the in-kernel ABI, including the virtual interrupts.

 (7) Renames the old irq management functions to different names.

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] FRV: Miscellaneous fixes

2006-02-15T00:09:35+00:00

Make various alterations and fixes to the FRV arch:

 (1) Resyncs the FRV system call collection with the i386 arch.

 (2) Discards __iounmap() as it's not used.

 (3) Fixes the use of the SWAP/SWAPI instruction to get the arguments the right
     way around in atomic.h, and also to get the asm constraints correct.

 (4) Moves copy_to/from_user_page() to asm/cacheflush.h to be consistent with
     other archs.

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Handle TIF_RESTORE_SIGMASK for FRV

2006-01-19T03:20:29+00:00

Handle TIF_RESTORE_SIGMASK as added by David Woodhouse's patch entitled:

        [PATCH] 2/3 Add TIF_RESTORE_SIGMASK support for arch/powerpc
        [PATCH] 3/3 Generic sys_rt_sigsuspend

It does the following:

 (1) Declares TIF_RESTORE_SIGMASK for FRV.

 (2) Invokes it over to do_signal() when TIF_RESTORE_SIGMASK is set.

 (3) Makes do_signal() support TIF_RESTORE_SIGMASK, using the signal mask saved
     in current->saved_sigmask.

 (4) Discards sys_rt_sigsuspend() from the arch, using the generic one instead.

 (5) Makes sys_sigsuspend() save the signal mask and set TIF_RESTORE_SIGMASK
     rather than attempting to fudge the return registers.

 (6) Makes sys_sigsuspend() return -ERESTARTNOHAND rather than looping
     intrinsically.

 (7) Makes setup_frame(), setup_rt_frame() and handle_signal() return 0 or
     -EFAULT rather than true/false to be consistent with the rest of the
      kernel.

Due to the fact do_signal() is then only called from one place:

 (8) Make do_signal() no longer have a return value is it was just being
     ignored; force_sig() takes care of this.

 (9) Discards the old sigmask argument to do_signal() as it's no longer
     necessary.

This patch depends on the FRV signalling patches as well as the
sys_rt_sigsuspend patch.

Signed-off-by: David Howells 
Signed-off-by: David Woodhouse 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] frv: task_thread_info(), task_stack_page()

2006-01-12T17:08:54+00:00

Signed-off-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] dump_thread() cleanup

2006-01-10T16:01:25+00:00


)

From: Adrian Bunk 

- create one common dump_thread() prototype in kernel.h

- dump_thread() is only used in fs/binfmt_aout.c and can therefore be
  removed on all architectures where CONFIG_BINFMT_AOUT is not
  available

Signed-off-by: Adrian Bunk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] frv: miscellaneous changes

2006-01-09T04:13:38+00:00

Fix a number of miscellanous items:

 (1) Declare lock sections in the linker script.

 (2) Recurse in the correct manner in the arch makefile.

 (3) asm/bug.h requires asm/linkage.h to be included first. One C file puts
     asm/bug.h first.

 (4) Add an empty RTC header file to avoid missing header file errors.

 (5) sg_dma_address() should use the dma_address member of a scatter list.

 (6) Add trivial pci_unmap support.

 (7) Add pgprot_noncached()

 (8) Discard u_quad_t.

 (9) Use ~0UL rather than ULONG_MAX in unistd.h in case the latter isn't
     declared.

(10) Add an empty VGA header file to avoid missing header file errors.

(11) Add an XOR header file to use the generic XOR stuff.

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] frv: force serial driver inclusion

2006-01-09T04:13:38+00:00

Force the 8230 serial driver to be built in if the on-CPU UARTs are to be
used.  It can't be used as a module because the arch setup needs to call into
it.

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] frv: add module support stubs

2006-01-09T04:13:37+00:00

Add stubs for FRV module support.

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] frv: implement and export various things required by modules

2006-01-09T04:13:36+00:00

Export a number of features required to build all the modules.  It also
implements the following simple features:

 (*) csum_partial_copy_from_user() for MMU as well as no-MMU.

 (*) __ucmpdi2().

so that they can be exported too.

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] frv: improve signal handling

2006-01-06T16:33:33+00:00

The attached patch improves the signal handling:

 (1) It makes do_signal() static as it isn't called from anywhere outside of
     the arch code.

 (2) It removes the regs argument to all the static functions within that file,
     using __frame instead (which is the same thing held in a global register).

Signed-off-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds