android_kernel_samsung_msm8976/arch/um/kernel/skas
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
..
clone.c [PATCH] uml skas0: stop gcc's insanity 2005-12-18 11:19:44 -08:00
exec_kern.c [PATCH] uml: skas0 - separate kernel address space on stock hosts 2005-07-07 18:23:44 -07:00
Makefile [PATCH] uml: move libc-dependent skas process handling 2006-01-18 19:20:19 -08:00
mem.c [PATCH] uml: maintain own LDT entries 2005-11-07 07:53:31 -08:00
mmu.c [PATCH] uml: move LDT creation 2006-01-18 19:20:18 -08:00
process_kern.c [PATCH] uml: clean arch_switch usage 2006-03-31 12:18:52 -08:00
syscall.c [PATCH] uml: system call path cleanup 2005-09-05 00:06:23 -07:00
tlb.c [PATCH] uml: skas0 stubs now check system call return values 2005-09-05 00:06:24 -07:00
uaccess.c [PATCH] uml: move libc-dependent utility procedures 2006-01-18 19:20:19 -08:00