In preparation to bigger changes to arm64_relocate_new_kernel that would
enable this function to do MMU backed memory copy, do few clean-ups and
optimizations. These include:
1. Call raw_dcache_line_size() only when relocation is actually going to
happen. i.e. kdump type kexec, does not need it.
2. copy_page(dest, src, tmps...) increments dest and src by PAGE_SIZE, so
no need to store dest prior to calling copy_page and increment it
after. Also, src is not used after a copy, not need to copy either.
3. For consistency use comment on the same line with instruction when it
describes the instruction itself.
4. Some comment corrections
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
---
arch/arm64/kernel/relocate_kernel.S | 36 +++++++----------------------
1 file changed, 8 insertions(+), 28 deletions(-)
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 84eec95ec06c..462ffbc37071 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -17,28 +17,24 @@
/*
* arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
*
- * The memory that the old kernel occupies may be overwritten when coping the
+ * The memory that the old kernel occupies may be overwritten when copying the
* new image to its final location. To assure that the
* arm64_relocate_new_kernel routine which does that copy is not overwritten,
* all code and data needed by arm64_relocate_new_kernel must be between the
* symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end. The
* machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
- * control_code_page, a special page which has been set up to be preserved
- * during the copy operation.
+ * safe memory that has been set up to be preserved during the copy operation.
*/
SYM_CODE_START(arm64_relocate_new_kernel)
-
/* Setup the list loop variables. */
mov x18, x2 /* x18 = dtb address */
mov x17, x1 /* x17 = kimage_start */
mov x16, x0 /* x16 = kimage_head */
- raw_dcache_line_size x15, x0 /* x15 = dcache line size */
mov x14, xzr /* x14 = entry ptr */
mov x13, xzr /* x13 = copy dest */
-
/* Check if the new image needs relocation. */
tbnz x16, IND_DONE_BIT, .Ldone
-
+ raw_dcache_line_size x15, x0 /* x15 = dcache line size */
.Lloop:
and x12, x16, PAGE_MASK /* x12 = addr */
@@ -57,34 +53,18 @@ SYM_CODE_START(arm64_relocate_new_kernel)
b.lo 2b
dsb sy
- mov x20, x13
- mov x21, x12
- copy_page x20, x21, x0, x1, x2, x3, x4, x5, x6, x7
-
- /* dest += PAGE_SIZE */
- add x13, x13, PAGE_SIZE
+ copy_page x13, x12, x0, x1, x2, x3, x4, x5, x6, x7
b .Lnext
-
.Ltest_indirection:
tbz x16, IND_INDIRECTION_BIT, .Ltest_destination
-
- /* ptr = addr */
- mov x14, x12
+ mov x14, x12 /* ptr = addr */
b .Lnext
-
.Ltest_destination:
tbz x16, IND_DESTINATION_BIT, .Lnext
-
- /* dest = addr */
- mov x13, x12
-
+ mov x13, x12 /* dest = addr */
.Lnext:
- /* entry = *ptr++ */
- ldr x16, [x14], #8
-
- /* while (!(entry & DONE)) */
- tbz x16, IND_DONE_BIT, .Lloop
-
+ ldr x16, [x14], #8 /* entry = *ptr++ */
+ tbz x16, IND_DONE_BIT, .Lloop /* while (!(entry & DONE)) */
.Ldone:
/* wait for writes from copy_page to finish */
dsb nsh
--
2.25.1
