x86: implement atomic text_poke() via fixmap

Use fixmaps instead of vmap/vunmap in text_poke() for avoiding
page allocation and delayed unmapping.

At the result of above change, text_poke() becomes atomic and can be called
from stop_machine() etc.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
LKML-Reference: <49B14352.2040705@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 63a79c77d220..81937a5dc77c 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -111,6 +111,8 @@ enum fixed_addresses {
 #ifdef CONFIG_PARAVIRT
         FIX_PARAVIRT_BOOTMAP,
 #endif
+        FIX_TEXT_POKE0, /* reserve 2 pages for text_poke() */
+        FIX_TEXT_POKE1,
         __end_of_permanent_fixed_addresses,
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
         FIX_OHCI1394_BASE,