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s390/alternatives: use instructions instead of byte patterns 

Use readable nop instructions within the code which generates
the padding areas, instead of unreadable byte patterns.

The generated code is identical.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2022-03-13 22:04:10 +01:00 committed by Vasily Gorbik
parent f09354ffd8
commit 4afeb67071
2 changed files with 20 additions and 7 deletions
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12
arch/s390/include/asm/alternative-asm.h
View File

@ -37,9 +37,15 @@
* a 2-byte nop if the size of the area is not divisible by 6.
*/
.macro alt_pad_fill bytes
.fill ( \bytes ) / 6, 6, 0xc0040000
.fill ( \bytes ) % 6 / 4, 4, 0x47000000
.fill ( \bytes ) % 6 % 4 / 2, 2, 0x0700
.rept ( \bytes ) / 6
jgnop .
.endr
.rept ( \bytes ) % 6 / 4
nop
.endr
.rept ( \bytes ) % 6 % 4 / 2
nopr
.endr
.endm
/*

15
arch/s390/include/asm/alternative.h
View File

@ -71,11 +71,18 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
".if " oldinstr_pad_len(num) " > 6\n" \
"\tjg " e_oldinstr_pad_end "f\n" \
"6620:\n" \
"\t.fill (" oldinstr_pad_len(num) " - (6620b-662b)) / 2, 2, 0x0700\n" \
"\t.rept (" oldinstr_pad_len(num) " - (6620b-662b)) / 2\n" \
"\tnopr\n" \
".else\n" \
"\t.fill " oldinstr_pad_len(num) " / 6, 6, 0xc0040000\n" \
"\t.fill " oldinstr_pad_len(num) " %% 6 / 4, 4, 0x47000000\n" \
"\t.fill " oldinstr_pad_len(num) " %% 6 %% 4 / 2, 2, 0x0700\n" \
"\t.rept " oldinstr_pad_len(num) " / 6\n" \
"\t.jgnop .\n" \
"\t.endr\n" \
"\t.rept " oldinstr_pad_len(num) " %% 6 / 4\n" \
"\tnop\n" \
"\t.endr\n" \
"\t.rept " oldinstr_pad_len(num) " %% 6 %% 4 / 2\n" \
"\tnopr\n" \
".endr\n" \
".endif\n"
#define OLDINSTR(oldinstr, num) \