/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright IBM Corp. 2005
 *
 * Author(s): Rolf Adelsberger
 *
 */

#include <linux/linkage.h>
#include <asm/page.h>
#include <asm/sigp.h>

/*
 * moves the new kernel to its destination...
 * %r2 = pointer to first kimage_entry_t
 * %r3 = start address - where to jump to after the job is done...
 * %r4 = subcode
 *
 * %r5 will be used as temp. storage
 * %r6 holds the destination address
 * %r7 = PAGE_SIZE
 * %r8 holds the source address
 * %r9 = PAGE_SIZE
 *
 * 0xf000 is a page_mask
 */

        .text
SYM_CODE_START(relocate_kernel)
        basr    %r13,0          # base address
.base:
        lghi    %r7,PAGE_SIZE   # load PAGE_SIZE in r7
        lghi    %r9,PAGE_SIZE   # load PAGE_SIZE in r9
        lg      %r5,0(%r2)      # read another word for indirection page
        aghi    %r2,8           # increment pointer
        tml     %r5,0x1         # is it a destination page?
        je      .indir_check    # NO, goto "indir_check"
        lgr     %r6,%r5         # r6 = r5
        nill    %r6,0xf000      # mask it out and...
        j       .base           # ...next iteration
.indir_check:
        tml     %r5,0x2         # is it a indirection page?
        je      .done_test      # NO, goto "done_test"
        nill    %r5,0xf000      # YES, mask out,
        lgr     %r2,%r5         # move it into the right register,
        j       .base           # and read next...
.done_test:
        tml     %r5,0x4         # is it the done indicator?
        je      .source_test    # NO! Well, then it should be the source indicator...
        j       .done           # ok, lets finish it here...
.source_test:
        tml     %r5,0x8         # it should be a source indicator...
        je      .base           # NO, ignore it...
        lgr     %r8,%r5         # r8 = r5
        nill    %r8,0xf000      # masking
0:      mvcle   %r6,%r8,0x0     # copy PAGE_SIZE bytes from r8 to r6 - pad with 0
        jo      0b
        j       .base
.done:
        lgr     %r0,%r4         # subcode
        cghi    %r3,0
        je      .diag
        la      %r4,load_psw-.base(%r13)        # load psw-address into the register
        o       %r3,4(%r4)      # or load address into psw
        st      %r3,4(%r4)
        mvc     0(8,%r0),0(%r4) # copy psw to absolute address 0
.diag:
        diag    %r0,%r0,0x308
SYM_CODE_END(relocate_kernel)

        .balign 8
SYM_DATA_START_LOCAL(load_psw)
        .long   0x00080000,0x80000000
SYM_DATA_END_LABEL(load_psw, SYM_L_LOCAL, relocate_kernel_end)
        .balign 8
SYM_DATA(relocate_kernel_len, .quad relocate_kernel_end - relocate_kernel)