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)
Fixes a problem where directory entries could show up twice: once
on the top layer of the union stack, and once on the bottom layer.
Approved by: re (rwatson)
Those who really need this information can find it in the include file.
* Include a succinct description of the st_birthtime field.
Approved by: re (bmah)
- strip out the nasty PIC_PROLOGUE/EPILOGUE stuff, since we dont have
to lose a register in PIC mode anymore (we use %rip-relative addressing).
- update for C register argument passing conventions.
- convert 32 bit to 64 bit register sizes etc.
Note that the syscall instruction clobbers %rcx, which is inconvenient
because it is the fourth syscall argument, so we use %r10 (another scratch
register) for the 4th syscall arg instead (I picked %r10 to be the same as
NetBSD). int 0x80 is still possible though, and it uses %rcx as usual.
Note that the syscall style syscall does *NOT* preserve all the registers,
unlike int 0x80. We do not preserve the scratch registers except for
%rdi and %rsi. int 0x80 does preserve everything but the return values.
technique) so that we don't wind up calling into an application's
version if the application defines them.
Inspired by: qpopper's interfering and buggy version of strlcpy
setgrent, and endgrent also. (The previous NSS implementation used to
simply twiddle the internal data of the various modules directly.)
A symptom (group list set incorrectly in sshd) was
Reported by: Glenn Johnson <gjohnson@srrc.ars.usda.gov>
Sponsored by: DARPA, Network Associates Laboratories
idea to re-initialize `struct passwd', because e.g. pw_class might
get set by one module, but not by another. Add another call to the
internal pwd_init function to accomplish this.
Sponsored by: DARPA, Network Associates Laboratories
Correct a bug that should have wreaked havoc everywhere, but for
some reason only bit unlucky people who use `-march' optimizations.
The compiler cannot assist one in distinguishing between the two
function calls below.
int nsdispatch(void *, ...);
void *discard;
nsdispatch(&discard, ...); /* correct .. no, really! */
nsdispatch(discard, ...); /* Boom */
Robin provided me with a debugging environment in which I could see
what was going on.
Badness when using CPUTYPE was
Reported by: "Robin P. Blanchard" <Robin.Blanchard@gactr.uga.edu>
Reported by: nork
Sponsored by: DARPA, Network Associates Laboratories
An incorrectly-sized allocation was being made due to an incorrect
argument to the `sizeof' operator. Obvious, because it violated the
`foo = malloc(sizeof(*foo))' idiom. Hard-to-see, because it was a
missing `*' (`*p' versus `**p').
Resulting failure was
Reported by: ache
Sponsored by: DARPA, Network Associates Laboratories
