linux/arch/um/sys-i386
Paolo 'Blaisorblade' Giarrusso 972410b023 [PATCH] uml: clean arch_switch usage
Call arch_switch also in switch_to_skas, even if it's, for now, a no-op for
that case (and mark this in the comment); this will change soon.

Also, arch_switch for TT mode is actually useless when the PT proxy (a
complicate debugging instrumentation for TT mode) is not enabled.  In fact, it
only calls update_debugregs, which checks debugregs_seq against seq (to check
if the registers are up-to-date - seq here means a "version number" of the
registers).

If the ptrace proxy is not enabled, debugregs_seq always stays 0 and
update_debugregs will be a no-op.  So, optimize this out (the compiler can't
do it).

Also, I've been disappointed by the fact that it would make a lot of sense if,
after calling a successful
update_debugregs(current->thread.arch.debugregs_seq),
current->thread.arch.debugregs_seq were updated with the new debugregs_seq.
But this is not done.  Is this a bug or a feature?  For all purposes, it seems
a bug (otherwise the whole mechanism does not make sense, which is also a
possibility to check), which causes some performance only problems (not
correctness), since we write_debugregs when not needed.

Also, as suggested by Jeff, remove a redundant enabling of SIGVTALRM,
comprised in the subsequent local_irq_enable().  I'm just a bit dubious if
ordering matters there...

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:18:52 -08:00
..
bugs.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
checksum.S [PATCH] uml: s390 preparation, checksumming done in arch code 2005-05-05 16:36:38 -07:00
delay.c [PATCH] uml: Delay loop cleanups 2005-05-20 15:48:17 -07:00
fault.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ksyms.c [PATCH] uml: s390 preparation, delay moved to arch 2005-05-05 16:36:38 -07:00
ldt.c [PATCH] uml: fix usage of kernel_errno in place of errno 2006-02-24 14:31:37 -08:00
Makefile [PATCH] uml: clean up remapping code build magic 2006-03-31 12:18:51 -08:00
ptrace_user.c [PATCH] uml: clean arch_switch usage 2006-03-31 12:18:52 -08:00
ptrace.c [PATCH] uml: clean arch_switch usage 2006-03-31 12:18:52 -08:00
sigcontext.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.c [PATCH] uml: sparse cleanups 2006-03-31 12:18:51 -08:00
stub_segv.c [PATCH] uml: properly invoke x86_64 system calls 2005-11-22 09:13:41 -08:00
stub.S [PATCH] uml: skas0 stubs now check system call return values 2005-09-05 00:06:24 -07:00
sys_call_table.S [PATCH] uml: fix syscall table by including $(SUBARCH)'s one, for i386 2005-05-01 08:58:55 -07:00
syscalls.c [PATCH] uml: sparse cleanups 2006-03-31 12:18:51 -08:00
sysrq.c [PATCH] uml: Fix sysrq-r support for skas mode 2005-10-04 13:22:01 -07:00
unmap.c [PATCH] uml: workaround host bug in "TT mode vs. NPTL link fix" 2005-07-14 09:00:24 -07:00
user-offsets.c [PATCH] uml: move libc-dependent irq code to os-Linux 2006-03-27 08:44:37 -08:00