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s390/purgatory: workaround llvm's IAS limitations

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llvm's integrated assembler cannot handle immediate values which are
calculated with two local labels:

arch/s390/purgatory/head.S:139:11: error: invalid operand for instruction
 aghi %r8,-(.base_crash-purgatory_start)

Workaround this by partially rewriting the code.

Link: https://lore.kernel.org/r/20220511120532.2228616-6-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2022-05-11 14:05:29 +02:00
parent 4c25f0ff63
commit adda746629
1 changed files with 23 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

30
arch/s390/purgatory/head.S
View file

@ -44,11 +44,14 @@
.endm
.macro MEMSWAP dst,src,buf,len
10: cghi \len,bufsz
10: larl %r0,purgatory_end
larl %r1,stack
slgr %r0,%r1
cgr \len,%r0
jh 11f
lgr %r4,\len
j 12f
11: lghi %r4,bufsz
11: lgr %r4,%r0
12: MEMCPY \buf,\dst,%r4
MEMCPY \dst,\src,%r4
@ -135,12 +138,18 @@ ENTRY(purgatory_start)
.start_crash_kernel:
/* Location of purgatory_start in crash memory */
larl %r0,.base_crash
larl %r1,purgatory_start
slgr %r0,%r1
lgr %r8,%r13
aghi %r8,-(.base_crash-purgatory_start)
sgr %r8,%r0
/* Destination for this code i.e. end of memory to be swapped. */
larl %r0,purgatory_end
larl %r1,purgatory_start
slgr %r0,%r1
lg %r9,crash_size-.base_crash(%r13)
aghi %r9,-(purgatory_end-purgatory_start)
sgr %r9,%r0
/* Destination in crash memory, i.e. same as r9 but in crash memory. */
lg %r10,crash_start-.base_crash(%r13)
@ -149,15 +158,19 @@ ENTRY(purgatory_start)
/* Buffer location (in crash memory) and size. As the purgatory is
* behind the point of no return it can re-use the stack as buffer.
*/
lghi %r11,bufsz
larl %r11,purgatory_end
larl %r12,stack
slgr %r11,%r12
MEMCPY %r12,%r9,%r11 /* dst -> (crash) buf */
MEMCPY %r9,%r8,%r11 /* self -> dst */
/* Jump to new location. */
lgr %r7,%r9
aghi %r7,.jump_to_dst-purgatory_start
larl %r0,.jump_to_dst
larl %r1,purgatory_start
slgr %r0,%r1
agr %r7,%r0
br %r7
.jump_to_dst:
@ -169,7 +182,10 @@ ENTRY(purgatory_start)
/* Load new buffer location after jump */
larl %r7,stack
aghi %r10,stack-purgatory_start
lgr %r0,%r7
larl %r1,purgatory_start
slgr %r0,%r1
agr %r10,%r0
MEMCPY %r10,%r7,%r11 /* (new) buf -> (crash) buf */
/* Now the code is set up to run from its designated location. Start