prime objectives are:
o Implement a syscall path based on the epc inststruction (see
sys/ia64/ia64/syscall.s).
o Revisit the places were we need to save and restore registers
and define those contexts in terms of the register sets (see
sys/ia64/include/_regset.h).
Secundairy objectives:
o Remove the requirement to use contigmalloc for kernel stacks.
o Better handling of the high FP registers for SMP systems.
o Switch to the new cpu_switch() and cpu_throw() semantics.
o Add a good unwinder to reconstruct contexts for the rare
cases we need to (see sys/contrib/ia64/libuwx)
Many files are affected by this change. Functionally it boils
down to:
o The EPC syscall doesn't preserve registers it does not need
to preserve and places the arguments differently on the stack.
This affects libc and truss.
o The address of the kernel page directory (kptdir) had to
be unstaticized for use by the nested TLB fault handler.
The name has been changed to ia64_kptdir to avoid conflicts.
The renaming affects libkvm.
o The trapframe only contains the special registers and the
scratch registers. For syscalls using the EPC syscall path
no scratch registers are saved. This affects all places where
the trapframe is accessed. Most notably the unaligned access
handler, the signal delivery code and the debugger.
o Context switching only partly saves the special registers
and the preserved registers. This affects cpu_switch() and
triggered the move to the new semantics, which additionally
affects cpu_throw().
o The high FP registers are either in the PCB or on some
CPU. context switching for them is done lazily. This affects
trap().
o The mcontext has room for all registers, but not all of them
have to be defined in all cases. This mostly affects signal
delivery code now. The *context syscalls are as of yet still
unimplemented.
Many details went into the removal of the requirement to use
contigmalloc for kernel stacks. The details are mostly CPU
specific and limited to exception_save() and exception_restore().
The few places where we create, destroy or switch stacks were
mostly simplified by not having to construct physical addresses
and additionally saving the virtual addresses for later use.
Besides more efficient context saving and restoring, which of
course yields a noticable speedup, this also fixes the dreaded
SMP bootup problem as a side-effect. The details of which are
still not fully understood.
This change includes all the necessary backward compatibility
code to have it handle older userland binaries that use the
break instruction for syscalls. Support for break-based syscalls
has been pessimized in favor of a clean implementation. Due to
the overall better performance of the kernel, this will still
be notived as an improvement if it's noticed at all.
Approved by: re@ (jhb)
that crept in recently. GCC will optimize the divides and multiplies for us.
Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
MFC after: 1 day
memory while mapping a virtual address to a physical address.
This allows us to work with virtual addresses for page tables,
provided it doesn't cause infinite recursion. Currently all
page tables are direct mapped.
userland. If someone wants to implement a backup p_siglist in the kernel
for compatability and to export one could. For now, just tell KVM to hand
an empty signal set off to the userland.
after adding __FBSDID().
Garbage-collected kvm_readswap(). This was once used by kvm_uread(), but
kvm_uread() now just reads /proc/<pid>/mem and procfs hopefully handles
swapped out pages.
next step is to allow > 1 to be allocated per process. This would give
multi-processor threads. (when the rest of the infrastructure is
in place)
While doing this I noticed libkvm and sys/kern/kern_proc.c:fill_kinfo_proc
are diverging more than they should.. corrective action needed soon.
called <machine/_types.h>.
o <machine/ansi.h> will continue to live so it can define MD clock
macros, which are only MD because of gratuitous differences between
architectures.
o Change all headers to make use of this. This mainly involves
changing:
#ifdef _BSD_FOO_T_
typedef _BSD_FOO_T_ foo_t;
#undef _BSD_FOO_T_
#endif
to:
#ifndef _FOO_T_DECLARED
typedef __foo_t foo_t;
#define _FOO_T_DECLARED
#endif
Concept by: bde
Reviewed by: jake, obrien
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)
Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)
NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..
processes match the given criteria. Since revision 1.60 of malloc.c,
malloc() and friends return an invalid pointer when given a size of 0.
kvm_getprocs() uses sysctl() with a NULL oldp argument to get an
initial size, but does not check whether it's 0 before passing it to
realloc() (via _kvm_realloc()). Before the aforementioned malloc()
change, this resulted in a minimal allocation made and a valid poitner
returned, but now results in an invalid, but non-NULL, pointer being
returned. When this is passed to sysctl(), the latter returns EFAULT
(as it should).
I'll know as soon as I re-import it and compile it.. :-)
There is no longer a 'pri' strict in the proc struct.
the fields are scattered between the ksegrp and thread in question.
Make a slight change so that libkvm reaches the main thread via the
linked list, rather than assuming it is in the proc structure. Both
conditions are true in -current but only the first will be true in
the KSE M3 world.
argument to kvm_open() and kvm_openfiles() as unused.
BSD didn't read swap since kvm.c CSRG revision 5.21 (u-area is pageable
under new VM. no need to read from swap.)
The old !NEWVM code was removed in CSRG revision 5.23 (~ten years ago).
