- this patch fixes a deadlock which may occur if we get a
spurious interrupt while calibrating clocks during the boot
time. Since we never handle interrupts while in the kernel
(BKL locked) the interrupt code locks the lock. This is a
different situation, a corner case, boot time only. We do not
return to userspace but to the kernel, so the BKL is not
unlocked. So we need irq handler which leaves the BKL
unlocked. The clock handler does it already, this patch adds
a dummy spurious irq handler for the same reason. It is better
to handle the situation this way to keep the normal runtime
code simple.
- this is a temporary change which makes images compiled for SMP
boot in SMP mode by default.
- this change is needed until we can configure the multiboot
images from the boot loader again.
- when kernel copies from userspace, it must be sure that the TLB
entries are not stale and thus the referenced memory is correct
- everytime we change a process' address space we set p_stale_tlb
bits for all CPUs.
- Whenever a cpu finds its bit set when it wants to access the
process' memory, it refreshes the TLB
- it is more conservative than it needs to be but it has low
overhead than checking precisely
- two CPUs can issue IPI to each other now without any hazzard
- we must be able to handle synchronous scheduling IPIs from
other CPUs when we are waiting for attention from another one.
Otherwise we might livelock.
- necessary barriers to prevent reordering
Remove .ident sections, and force separations of .text and
.data sections into separate program headers, for the benefit
of the check done by MINIX boot monitor in multiboot mode.
. only use for single-page invalidations initially
. shows tiny but statistically significant performance
improvement; will be more helpful in certain VM debug
modes
. fold 2 exception-in-kernel cases (pagefault and rest)
into 1
. for exceptions that occur in kernel, don't just print
kernel stacktrace (typically that is just the exception
handler) but also the stacktrace of when the exception
happened
. remove a few asserts in the kernel and 64bi library
that are not compatible with the timing code
. change the TIME_BLOCKS code a little to work in-kernel
Before safecopies, the IO_ENDPT and DL_ENDPT message fields were needed
to know which actual process to copy data from/to, as that process may
not always be the caller. Now that we have full safecopy support, these
fields have become useless for that purpose: the owner of the grant is
*always* the caller. Allowing the caller to supply another endpoint is
in fact dangerous, because the callee may then end up using a grant
from a third party. One could call this a variant of the confused
deputy problem.
From now on, safecopy calls should always use the caller's endpoint as
grant owner. This fully obsoletes the DL_ENDPT field in the
inet/ethernet protocol. IO_ENDPT has other uses besides identifying the
grant owner though. This patch renames IO_ENDPT to USER_ENDPT, not only
because that is a more fitting name (it should never be used for I/O
after all), but also in order to intentionally break any old system
source code outside the base system. If this patch breaks your code,
fixing it is fairly simple:
- DL_ENDPT should be replaced with m_source;
- IO_ENDPT should be replaced with m_source when used for safecopies;
- IO_ENDPT should be replaced with USER_ENDPT for any other use, e.g.
when setting REP_ENDPT, matching requests in CANCEL calls, getting
DEV_SELECT flags, and retrieving of the real user process's endpoint
in DEV_OPEN.
The changes in this patch are binary backward compatible.
- kernel maintains a cpu_info array which contains various
information about each cpu as filled when each cpu boots
- the information contains idetification, features etc.
- flush TLB of processes only if the page tables has been changed and
the page tables of this process are already loaded on this cpu which
means that there might be stale entries in TLB. Until now SMP was
always flushing TLB to make sure everything is consistent.
- accidentaly this wasn't part of the SMP merge and the implementation
remained uncomplete with the timer keeping ticking periodically
- APIC timer is set for a signel shot and restarted everytime it
expires. This way we can keep the AP's trully idle
- the timer is restarted a little later before leaving to userspace
- LAPIC_TIMER_ICR is written before LAPIC_LVTTR so the newest value is
used
- fixed spurious and error interrupt handlers
- not to hog the system the warning isn't reported every time, just
once every 100 times, similarly for the spurious PIC interrupts
