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linux-next/arch/sh/kernel/relocate_kernel.S
Paul Mundt 510c72ad2d sh: Fixup various PAGE_SIZE == 4096 assumptions.
There were a number of places that made evil PAGE_SIZE == 4k
assumptions that ended up breaking when trying to play with
8k and 64k page sizes, this fixes those up.

The most significant change is the way we load THREAD_SIZE,
previously this was done via:

	mov	#(THREAD_SIZE >> 8), reg
	shll8	reg

to avoid a memory access and allow the immediate load. With
a 64k PAGE_SIZE, we're out of range for the immediate load
size without resorting to special instructions available in
later ISAs (movi20s and so on). The "workaround" for this is
to bump up the shift to 10 and insert a shll2, which gives a
bit more flexibility while still being much cheaper than a
memory access.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-12-06 10:45:39 +09:00

100 lines
1.7 KiB
ArmAsm

/*
* relocate_kernel.S - put the kernel image in place to boot
* 2005.9.17 kogiidena@eggplant.ddo.jp
*
* LANDISK/sh4 is supported. Maybe, SH archtecture works well.
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/linkage.h>
#include <asm/addrspace.h>
#include <asm/page.h>
.globl relocate_new_kernel
relocate_new_kernel:
/* r4 = indirection_page */
/* r5 = reboot_code_buffer */
/* r6 = start_address */
/* r7 = vbr_reg */
mov.l 10f,r8 /* PAGE_SIZE */
mov.l 11f,r9 /* P2SEG */
/* stack setting */
add r8,r5
mov r5,r15
bra 1f
mov r4,r0 /* cmd = indirection_page */
0:
mov.l @r4+,r0 /* cmd = *ind++ */
1: /* addr = (cmd | P2SEG) & 0xfffffff0 */
mov r0,r2
or r9,r2
mov #-16,r1
and r1,r2
/* if(cmd & IND_DESTINATION) dst = addr */
tst #1,r0
bt 2f
bra 0b
mov r2,r5
2: /* else if(cmd & IND_INDIRECTION) ind = addr */
tst #2,r0
bt 3f
bra 0b
mov r2,r4
3: /* else if(cmd & IND_DONE) goto 6 */
tst #4,r0
bt 4f
bra 6f
nop
4: /* else if(cmd & IND_SOURCE) memcpy(dst,addr,PAGE_SIZE) */
tst #8,r0
bt 0b
mov r8,r3
shlr2 r3
shlr2 r3
5:
dt r3
mov.l @r2+,r1 /* 16n+0 */
mov.l r1,@r5
add #4,r5
mov.l @r2+,r1 /* 16n+4 */
mov.l r1,@r5
add #4,r5
mov.l @r2+,r1 /* 16n+8 */
mov.l r1,@r5
add #4,r5
mov.l @r2+,r1 /* 16n+12 */
mov.l r1,@r5
add #4,r5
bf 5b
bra 0b
nop
6:
#ifdef CONFIG_SH_STANDARD_BIOS
ldc r7, vbr
#endif
jmp @r6
nop
.align 2
10:
.long PAGE_SIZE
11:
.long P2SEG
relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.long relocate_new_kernel_end - relocate_new_kernel