multiprocessor support:
- Implement MP-safe halt.
- Make the FPU saving code more like Bill's on the i386 MP branch.
XXX This code will no doubt be revisited again.
- Pass the cpu_info and trapframe to IPI handlers, saving some work
in the handlers themselves, and also making it possible for the
"pause" handler to reference register state for DDB.
- Add "machine cpu" to DDB, making it possible to reference other
CPUs registers (and thus get e.g. a traceback) from whichever
CPU is actually running the debugger.
- Garbage-collect "machine halt" and "machine reboot" DDB commands.
They don't have a prayer of working properly in multiprocessor
kernels, and didn't really work all that well in uniprocessor kernels.
as normal device interrupts. Because of this, we won't get IPIs while
servicing such interrupts. This can lead to the following deadlock
scenario as reported by Bill Sommerfeld:
- Process runs on cpu1, but has FP state on cpu0.
- Process executes FP-using insn, causing an FP trap, which causes
the kernel lock to be acquired.
- At roughly the same time, cpu0 receives a device interrupt, and attempts
to acquire the kernel lock, which blocks since cpu1 already has it.
- cpu1 sends cpu0 a SYNCH FPU IPI, and waits for cpu0 to release its
FP state.
- Since cpu0 cannot notice the IPI until it has processed the device
interrupt, which it cannot do because it cannot acquire the kernel
lock, we have deadlock.
Solve the problem by adding a spinlock interlock release hook which
checks for pending IPIs and processes them.
Idea from Bill Sommerfeld.
- MB_LEN_MAX is increased to 32.
- To ensure binary compatibility for old executables
under multibyte locale, versioned setlocale is added.
- __mb_len_cur definision is added in setlocale.c
and enable it in stdlib.h .
It is also important for multibyte locale stuffs,
but I just forgot.
"off_t" and the return value is a "paddr_t" to allow mappings
at offsets past 2^31 bytes. Somewhat inspired by FreeBSD, which
only changed the offset to a "vm_offset_t".
Includes updates for the i386, pc532 and sh3 mmmmap from Jason Thorpe.
"return (v0);" where v0 is an unsigned long and the function return
type is int. Stops lint warnings when this file is included.
Fix from Jason Thorpe.
macro in the MULTIPROCESSOR case (hardclock() wants it).
- Implement __GENERIC_SOFT_INTERRUPTS, and redefine the legacy
software interrupts in terms of it. Garbage-collect setsoftserial().
