Btw, I'm pushing what looks like the "final" version of sysenter/sysexit
for now. There may be bugs left, but all the known issues are resolved:
- single-stepping over the system call now works. It doesn't actually see
all of the user-mode instructions, since the fast system call interface
does not lend itself well to restoring "TF" in eflags on return, but
the trampoline code saves and restores the flags, so you will be able
to step over the important bits.
(ptrace also doesn't actually allow you to look at the instruction
contents in high memory, so gdb won't see the instructions in the
user-mode fast system call trampoline even when it can single-step
them, and I don't think I'll bother to fix it up).
- NMI at the "wrong" time (just before first instruction in kernel
space) should now be a non-issue. The per-CPU SEP stack looks like a
real (nonpreemptable) process, and follows all the conventions needed
for "current_thread_info()" and friends. This behaviour is also
triggered by the single-step debug trap, so while I've obviously not
tested NMI behaviour, I _have_ tested the very same concept at that
exact point.
- The APM problem was confirmed by Andrew to apparently be just a GDT
that was too small for the new layout.
This is in addition to the six-argument issues and the glibc address query
issues that were resolved yesterday.
Linus
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This archive was generated by hypermail 2b29 : Mon Dec 23 2002 - 22:00:21 EST