ARM: decompressor: factor out routine to obtain the inflated image size

Before adding another reference to the inflated image size, factor
out the slightly complicated way of loading the unaligned little-endian
constant from the end of the compressed data.

Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 8487221..d45952a 100644 (file)
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -151,6 +151,25 @@
 .L_\@:
                .endm
 
+               /*
+                * The kernel build system appends the size of the
+                * decompressed kernel at the end of the compressed data
+                * in little-endian form.
+                */
+               .macro  get_inflated_image_size, res:req, tmp1:req, tmp2:req
+               adr     \res, .Linflated_image_size_offset
+               ldr     \tmp1, [\res]
+               add     \tmp1, \tmp1, \res      @ address of inflated image size
+
+               ldrb    \res, [\tmp1]           @ get_unaligned_le32
+               ldrb    \tmp2, [\tmp1, #1]
+               orr     \res, \res, \tmp2, lsl #8
+               ldrb    \tmp2, [\tmp1, #2]
+               ldrb    \tmp1, [\tmp1, #3]
+               orr     \res, \res, \tmp2, lsl #16
+               orr     \res, \res, \tmp1, lsl #24
+               .endm
+
                .section ".start", "ax"
 /*
  * sort out different calling conventions
@@ -268,15 +287,15 @@ not_angel:
                 */
                mov     r0, pc
                cmp     r0, r4
-               ldrcc   r0, LC0+32
+               ldrcc   r0, LC0+28
                addcc   r0, r0, pc
                cmpcc   r4, r0
                orrcc   r4, r4, #1              @ remember we skipped cache_on
                blcs    cache_on
 
 restart:       adr     r0, LC0
-               ldmia   r0, {r1, r2, r3, r6, r10, r11, r12}
-               ldr     sp, [r0, #28]
+               ldmia   r0, {r1, r2, r3, r6, r11, r12}
+               ldr     sp, [r0, #24]
 
                /*
                 * We might be running at a different address.  We need
@@ -284,20 +303,8 @@ restart:   adr     r0, LC0
                 */
                sub     r0, r0, r1              @ calculate the delta offset
                add     r6, r6, r0              @ _edata
-               add     r10, r10, r0            @ inflated kernel size location
 
-               /*
-                * The kernel build system appends the size of the
-                * decompressed kernel at the end of the compressed data
-                * in little-endian form.
-                */
-               ldrb    r9, [r10, #0]
-               ldrb    lr, [r10, #1]
-               orr     r9, r9, lr, lsl #8
-               ldrb    lr, [r10, #2]
-               ldrb    r10, [r10, #3]
-               orr     r9, r9, lr, lsl #16
-               orr     r9, r9, r10, lsl #24
+               get_inflated_image_size r9, r10, lr
 
 #ifndef CONFIG_ZBOOT_ROM
                /* malloc space is above the relocated stack (64k max) */
@@ -652,13 +659,15 @@ LC0:              .word   LC0                     @ r1
                .word   __bss_start             @ r2
                .word   _end                    @ r3
                .word   _edata                  @ r6
-               .word   input_data_end - 4      @ r10 (inflated size location)
                .word   _got_start              @ r11
                .word   _got_end                @ ip
                .word   .L_user_stack_end       @ sp
                .word   _end - restart + 16384 + 1024*1024
                .size   LC0, . - LC0
 
+.Linflated_image_size_offset:
+               .long   (input_data_end - 4) - .
+
 #ifdef CONFIG_ARCH_RPC
                .globl  params
 params:                ldr     r0, =0x10000100         @ params_phys for RPC