x86: expand irq-off region in text_poke()

Expand irq-off region to cover fixmap using code and cache synchronizing.
Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <49B54688.8090403@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/alternative.c

@@ -526,13 +526,12 @@ void *__kprobes text_poke(void *addr, const void *opcode, size_t len)
 		pages[1] = virt_to_page(addr + PAGE_SIZE);
 	}
 	BUG_ON(!pages[0]);
+	local_irq_save(flags);
 	set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0]));
 	if (pages[1])
 		set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1]));
 	vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0);
-	local_irq_save(flags);
 	memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
-	local_irq_restore(flags);
 	clear_fixmap(FIX_TEXT_POKE0);
 	if (pages[1])
 		clear_fixmap(FIX_TEXT_POKE1);
@@ -542,5 +541,6 @@ void *__kprobes text_poke(void *addr, const void *opcode, size_t len)
 	   that causes hangs on some VIA CPUs. */
 	for (i = 0; i < len; i++)
 		BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]);
+	local_irq_restore(flags);
 	return addr;
 }