UPSTREAM: arm64: Add new asm macro copy_page

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>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Change-Id: If23a454e211b1f57f8ba1a2a00b44dabf4b82932
(cherry picked from commit 5003dbde45961dd7ab3d8a09ab9ad8bcb604db40)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 33bbb7ba7fb5c6c3bc67a7848f14ee2ec73771e7..290e13428f4a1c6b1b9425938a80dcd69460e592 100644 (file)
--- 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>
@@ -291,6 +292,24 @@ lr .req    x30             // link register
 9000:
        .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.