swi_exit code in exception.S instead of having its own inline expansion
of the DO_AST and PULLFRAME macros. That means that now all references
to the PUSH/PULLFRAME and DO_AST macros are localized to exception.S,
so move the macros themselves into there and remove them from asmacros.h
and eliminate vectors.S. All low-level exception handling is now
consolidated into exception.S.
Along with moving the default FIQ handler, change it to disable FIQs
before returning. An FIQ should never happen, but if it does, it's got
to be disabled as part of ignoring it.
In general, we have hand-wavy support for FIQs that probably hasn't been
used for 10 years and probably doesn't work (almost certainly doesn't
work for SMP because it only updates the vector on the current cpu). This
change doesn't really make the overall situation any better or worse.
and the functionality it provided into arm/exception.S. Rename the main
irq handling routine from arm_handler_execute() to arm_irq_handler() to
make it more congruent with how other exception handlers are named, and
also update its signature to reflect what has long been reality: it is
passed just a trapframe pointer, no interrupt number argument.
never actually ran on these chips (other than using SA1 support in an
emulator to do the early porting to FreeBSD long long ago). The clutter
and complexity of some of this code keeps getting in the way of other
maintenance, so it's time to go.
to the actual handler routine. All the pointers are static-intialized to
the only handlers available, and yet various platform-specific inits still
set those pointers (to the values they're already initialized to). Begin
to drain the swamp by removing all the redundant external declarations and
runtime setting of the pointers that's scattered around various places.
The old code used static storage to preserve a couple registers while
setting up the trapframe for the main handler. Doing so was the last
leftover crumbs from the days when a low-level debugger was hooked into
the exception entry code.
Now the exception entry sequence is essentially the same as for the
other exceptions, which still involves needlessly indirecting through
a function pointer which points to the same code on every platform.
Removing that indirection will be handled as a separate cleanup.
This work is based on an analysis by Juergen Weiss.
enabled. In vfp_discard(), if the state in the VFP hardware belongs to
the thread which is dying, NULL out pcpu fpcurthread to indicate the
state currently in the hardware belongs to nobody.
Submitted by: Juergen Weiss
Pointy hat to: me
a leftover from the days when a low-level debugger had hooks in the
undefined exception vector and needed stack space to function. These days
it effectively isn't used because we switch immediately to the svc32 mode
stack on exception entry. For that, the single undef mode stack per core
that gets set up at init time works fine.
The stack wasn't necessary but it was harmful, because the space for it
was carved out of the normal per-thread svc32 stack, in effect cutting
that 8K stack in half. If svc32 mode used more than 4k of stack space it
wandered down into the undef mode stack, and then an undef exception would
overwrite a couple words on the stack while switching to svc32 mode,
corrupting the scv32 stack. Having another stack abut the bottom of the
svc32 stack also effectively mooted the guard page below the stack.
This work is based on analysis and patches submitted by Juergen Weiss.
The old code was full of complexity that would only matter if the
kernel itself used the VFP hardware. Now that's reduced to either killing
the userland process or panicking the kernel on an illegal VFP instruction.
This removes most of the complexity from the assembler code, reducing it
to just calling the save code if the outgoing thread used the VFP.
The routine that stores the VFP state now takes a flag that indicates
whether the hardware should be disabled after saving state. Right now it
always is, but this makes the code ready to be used by get/set_mcontext()
(doing so will be addressed in a future commit).
Remove the arm-specific pc_vfpcthread from struct pcpu and use the MI
field pc_fpcurthread instead.
Reviewed by: cognet
appropriate for each of the 'foo' in the tree. This will allow us to
compile them together (although symbol conflicts prevent us from doing
that today, this just fixes the file name collision).
struct sigframe containing the struct ucontext.
The signal trampoline return code on the other hand DOES have just a
struct sigframe on the stack to work with, so have it get a pointer to
the ucontext out of there to pass along to sys_sigreturn.
In other words, make everything work right whether sys_sigreturn is
invoked from the trampoline or from userland code calling sigreturn(2).
Submitted by: Takashi Komatsu <komatsu.taka@jp.panasonic.com>
Reviewed by: cognet
It is available mostly in A10 devices like Hackberry, Marsboard,
Mele A1000, A2000, A100 HTPC, cubieboard1 and A20 device
like cubieboard2.
TX performance can be improved using both channels 0 and 1.
RX performance is poor and needs improvement with the assistance of
external DMA controller in case there is bulk TCP receiver.
Reviewed by: yongari@
Approved by: stas (mentor)
we've been using was actually just spinning due to ARM having redefined
the old 'wait for interrupt' operation via the system coprocessor as a nop
and replacing it with a WFI instruction.
code can supply a better implementation. A SoC with variable CPU frequency
is likely to use a fixed-frequency timer for DELAY() (but still use the
mpcore private timers as eventtimers).
Also remove spaces from the eventtimer and timecounter names.
implementation in arm/machdep.c. Most arm platforms either don't need to
do anything, or just need to call the standard eventtimer init routines.
A generic implementation that does that is now provided via weak linkage.
Any platform that needs to do something different can provide a its own
implementation to override the generic one.
- Don't use spaces or dots in the eventtimer or timecounter names.
They turn into sysctl node names, and it's just confusing.
- Use comparator #3 instead of #1 for one-shot events. There's an
extra 1-cycle penalty in the hardware for accessing the registers
for comparator 1, no point in paying that penalty.
- Lower the quality of the eventtimer from 1000 to 800, because the
device can't support PERCPU timers and some other device in the system
may be able to provide that.
