[PATCH v15 08/20] arm64: Add new asm macro copy_page

Geoff Levand
2016-03-14T17:48:00Z

Kexec and hibernate need to copy pages of memory, but may not have all
of the kernel mapped, and are unable to call copy_page().

Add a simplistic copy_page() macro, that can be inlined in these
situations. lib/copy_page.S provides a bigger better version, but
uses more registers.

Signed-off-by: Geoff Levand <geoff@infradead.org>
[Changed asm label to 9998, added commit message]
Signed-off-by: James Morse <james.morse@arm.com>
---
arch/arm64/include/asm/assembler.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index ec4e37c..f3854d9 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -24,6 +24,7 @@
#define __ASM_ASSEMBLER_H

#include <asm/asm-offsets.h>
+#include <asm/page.h>
#include <asm/pgtable-hwdef.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
@@ -285,6 +286,24 @@ lr .req x30 // link register
.endm

/*
+ * copy_page - copy src to dest using temp registers t1-t8
+ */
+ .macro copy_page dest:req src:req t1:req t2:req t3:req t4:req t5:req t6:req t7:req t8:req
+9998: ldp \t1, \t2, [\src]
+ ldp \t3, \t4, [\src, #16]
+ ldp \t5, \t6, [\src, #32]
+ ldp \t7, \t8, [\src, #48]
+ add \src, \src, #64
+ stnp \t1, \t2, [\dest]
+ stnp \t3, \t4, [\dest, #16]
+ stnp \t5, \t6, [\dest, #32]
+ stnp \t7, \t8, [\dest, #48]
+ add \dest, \dest, #64
+ tst \src, #(PAGE_SIZE - 1)
+ b.ne 9998b
+ .endm
+
+/*
* Annotate a function as position independent, i.e., safe to be called before
* the kernel virtual mapping is activated.
*/
--
2.5.0