s390/kernel/relocate_kernel.S

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  * Copyright IBM Corp. 2005
0004  *
0005  * Author(s): Rolf Adelsberger
0006  *
0007  */
0008
0009 #include <linux/linkage.h>
0010 #include <asm/page.h>
0011 #include <asm/sigp.h>
0012
0013 /*
0014  * moves the new kernel to its destination...
0015  * %r2 = pointer to first kimage_entry_t
0016  * %r3 = start address - where to jump to after the job is done...
0017  * %r4 = subcode
0018  *
0019  * %r5 will be used as temp. storage
0020  * %r6 holds the destination address
0021  * %r7 = PAGE_SIZE
0022  * %r8 holds the source address
0023  * %r9 = PAGE_SIZE
0024  *
0025  * 0xf000 is a page_mask
0026  */
0027
0028     .text
0029 ENTRY(relocate_kernel)
0030         basr    %r13,0      # base address
0031     .base:
0032         lghi    %r7,PAGE_SIZE   # load PAGE_SIZE in r7
0033         lghi    %r9,PAGE_SIZE   # load PAGE_SIZE in r9
0034         lg  %r5,0(%r2)  # read another word for indirection page
0035         aghi    %r2,8       # increment pointer
0036         tml %r5,0x1     # is it a destination page?
0037         je  .indir_check    # NO, goto "indir_check"
0038         lgr %r6,%r5     # r6 = r5
0039         nill    %r6,0xf000  # mask it out and...
0040         j   .base       # ...next iteration
0041     .indir_check:
0042         tml %r5,0x2     # is it a indirection page?
0043         je  .done_test  # NO, goto "done_test"
0044         nill    %r5,0xf000  # YES, mask out,
0045         lgr %r2,%r5     # move it into the right register,
0046         j   .base       # and read next...
0047     .done_test:
0048         tml %r5,0x4     # is it the done indicator?
0049         je  .source_test    # NO! Well, then it should be the source indicator...
0050         j   .done       # ok, lets finish it here...
0051     .source_test:
0052         tml %r5,0x8     # it should be a source indicator...
0053         je  .base       # NO, ignore it...
0054         lgr %r8,%r5     # r8 = r5
0055         nill    %r8,0xf000  # masking
0056     0:  mvcle   %r6,%r8,0x0 # copy PAGE_SIZE bytes from r8 to r6 - pad with 0
0057         jo  0b
0058         j   .base
0059     .done:
0060         lgr %r0,%r4     # subcode
0061         cghi    %r3,0
0062         je  .diag
0063         la  %r4,load_psw-.base(%r13)    # load psw-address into the register
0064         o   %r3,4(%r4)  # or load address into psw
0065         st  %r3,4(%r4)
0066         mvc 0(8,%r0),0(%r4) # copy psw to absolute address 0
0067     .diag:
0068         diag    %r0,%r0,0x308
0069 ENDPROC(relocate_kernel)
0070
0071         .align  8
0072     load_psw:
0073         .long   0x00080000,0x80000000
0074     relocate_kernel_end:
0075     .align 8
0076     .globl  relocate_kernel_len
0077     relocate_kernel_len:
0078         .quad   relocate_kernel_end - relocate_kernel