linux/arch/um/kernel/tt
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
..
include [PATCH] uml: move headers to arch/um/include 2006-01-18 19:20:19 -08:00
ptproxy [PATCH] uml: move libc-dependent utility procedures 2006-01-18 19:20:19 -08:00
Makefile [PATCH] uml: time initialization tidying 2005-06-25 16:24:35 -07:00
exec_kern.c [PATCH] uml: move libc-dependent time code 2006-01-18 19:20:19 -08:00
exec_user.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
gdb.c [PATCH] uml: move libc-dependent utility procedures 2006-01-18 19:20:19 -08:00
gdb_kern.c [PATCH] uml: hot-unplug code cleanup 2005-06-25 16:24:36 -07:00
ksyms.c [PATCH] uml: Export clear_user_* 2005-05-20 15:48:18 -07:00
mem.c [PATCH] uml: Use CONFIG variable for address space size 2005-05-06 22:09:30 -07:00
mem_user.c [PATCH] uml: move libc code out of mem_user.c and tempfile.c 2005-09-17 11:50:00 -07:00
process_kern.c [PATCH] uml: clean arch_switch usage 2006-03-31 12:18:52 -08:00
syscall_kern.c [PATCH] uml: TT - SYSCALL_DEBUG - fix buglet introduced in cleanup 2006-02-01 08:53:22 -08:00
syscall_user.c [PATCH] uml: system call path cleanup 2005-09-05 00:06:23 -07:00
tlb.c [PATCH] mm: uml kill unused 2005-10-29 21:40:42 -07:00
tracer.c [PATCH] uml: move libc-dependent code from signal_user.c 2006-01-08 20:13:39 -08:00
trap_user.c [PATCH] uml: TT mode softint fixes 2006-01-18 19:20:20 -08:00
uaccess.c [PATCH] uml: fix access_ok 2005-11-13 18:14:15 -08:00
uaccess_user.c [PATCH] uml: separate libc-dependent uaccess code 2005-11-07 07:53:31 -08:00