The new code maintains two variables 'current_spl_level' and
'hardware_spl_level'. Variable hardware_spl_level reflects actual
priority level at the hardware's point of view. hardware_spl_level is
always synchronized to hardware.
splraise() just increases current_spl_level. splx() sets
current_spl_level. If (and only if) hardware_spl_level and
current_spl_level is not same, splx() synchronizes interrupt mask
register and hardware_spl_level to current_spl_level.
In most case, splraise() raises current_spl_level and splx() restores
only current_spl_level.
When an interrupt occurs, hardware_spl_level and interrupt mask
register are synchronized to current_spl_level.
In this implementation, during a higher priority interrupt handler is
running, lower priority interrupts never cause intr_dispatch() to run.
It will avoid some race condition.
config write with the device number specified in AD[15:11]. If
we don't set this field when issuing a Type 0 cycle, each device
could end of thinking it is at device 0, which can cause a number
of problems. Doing this unconditionally should be OK when only
PCI devices are present.
be inserted into ktrace records. The general change has been to replace
"struct proc *" with "struct lwp *" in various function prototypes, pass
the lwp through and use l_proc to get the process pointer when needed.
Bump the kernel rev up to 1.6V
the test as spl0 is actually a macro for splx(0). The code now calls
splx(0)
(note building with the #ifdef fixed, caused the build to fail on a
GENERIC acorn32 kernel.)
enabled on amd64). Add a dmat64 field to various PCI attach structures,
and pass it down where needed. Implement a simple new function called
pci_dma64_available(pa) to test if 64bit DMA addresses may be used.
This returns 1 iff _PCI_HAVE_DMA64 is defined in <machine/pci_machdep.h>,
and there is more than 4G of memory.
with a more generic "devmap" structure that can also handle mappings
made with large and small pages. Add new pmap routines to enter these
mappings during bootstrap (and "remember" the devmap), and routines to
look up the static mappings once the kernel is running.
bsh