kernel from usermode. The remaining user windows are spilled
to the pcb as necessary. The user land window fault handlers
fill directly from the pcb on return.
Add system call entry points.
Submitted by: tmm
the process of exiting the kernel. The ast() function now loops as long
as the PS_ASTPENDING or PS_NEEDRESCHED flags are set. It returns with
preemption disabled so that any further AST's that arrive via an
interrupt will be delayed until the low-level MD code returns to user
mode.
- Use u_int's to store the tick counts for profiling purposes so that we
do not need sched_lock just to read p_sticks. This also closes a
problem where the call to addupc_task() could screw up the arithmetic
due to non-atomic reads of p_sticks.
- Axe need_proftick(), aston(), astoff(), astpending(), need_resched(),
clear_resched(), and resched_wanted() in favor of direct bit operations
on p_sflag.
- Fix up locking with sched_lock some. In addupc_intr(), use sched_lock
to ensure pr_addr and pr_ticks are updated atomically with setting
PS_OWEUPC. In ast() we clear pr_ticks atomically with clearing
PS_OWEUPC. We also do not grab the lock just to test a flag.
- Simplify the handling of Giant in ast() slightly.
Reviewed by: bde (mostly)
Only set sticks (and acquire sched_lock) on entry from user mode.
Add handlers for all kinds of mmu misses, and for interrupts from
user mode.
Acquire Giant before calling into the vm system so this runs with
invariants.
Try to get the restrictions for page faults on user memory from
kernel mode right.
Only set pcb_onfault and return to the alternate return code if
this is actually a fault on user memory from kernel mode.
2. Use the upcoming "tick" interface.
3. Save a call frame as well as a trap frame on proc0's initial stack.
4. Setup a pointer to the per-cpu interrupt queue.
5. Install the per-cpu pointer in interrupt and alternate globals as well.
6. Flush out setregs so exec works.
Submitted by: tmm (3, 5, 6)
2. Add spill and fill handlers for spills to the user stack on entry
to the kernel.
3. Add code to handle instruction mmu misses from user mode.
4. Add code to handle level interrupts from kernel mode and vectored
interrupt traps from either.
5. Save the pil in the trapframe on entry from kernel mode and restore
it on return.
Submitted by: tmm (1, 2)
are a really nasty interface that should have been killed long ago
when 'ptrace(PT_[SG]ETREGS' etc came along. The entity that they
operate on (struct user) will not be around much longer since it
is part-per-process and part-per-thread in a post-KSE world.
gdb does not actually use this except for the obscure 'info udot'
command which does a hexdump of as much of the child's 'struct user'
as it can get. It carries its own #defines so it doesn't break
compiles.
