x86: fix switch_to() clobbers
commit8b6451fe5cf78909f28d3762f77df060c8603cd0
authorIngo Molnar <mingo@elte.hu>
Wed, 5 Mar 2008 09:46:38 +0000 (5 10:46 +0100)
committerIngo Molnar <mingo@elte.hu>
Thu, 17 Apr 2008 15:40:52 +0000 (17 17:40 +0200)
treea9e6a3a9f79877675a1855469ed98677db771797
parent23b55bd9f33a1812a664e548803db34c9bec56e8
x86: fix switch_to() clobbers

Liu Pingfan noticed that switch_to() clobbers more registers than its
asm constraints specify.

We get away with this due to luck mostly - schedule()
by its nature only has 'local' state which gets reloaded
automatically. Fix it nevertheless, we could hit this anytime.

it turns out that with the extra constraints gcc manages to make
schedule() even more compact:

   text    data     bss     dec     hex filename
  28626     684    2640   31950    7cce sched.o.before
  28613     684    2640   31937    7cc1 sched.o.after

Reported-by: Liu Pingfan <kernelfans@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
include/asm-x86/system.h