Commit Graph

3 Commits

Author SHA1 Message Date
Vasily Gorbik
faf79934e6 s390/alternatives: avoid using jgnop mnemonic
jgnop mnemonic is only available since binutils 2.36,
kernel minimal required version is 2.23. Stick to brcl
to avoid build errors.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: 4afeb67071 ("s390/alternatives: use instructions instead of byte patterns")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-03-28 23:27:54 +02:00
Heiko Carstens
4afeb67071 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>
2022-03-27 22:18:38 +02:00
Martin Schwidefsky
fba9eb7946 s390: add assembler macros for CPU alternatives
Add a header with macros usable in assembler files to emit alternative
code sequences. It works analog to the alternatives for inline assmeblies
in C files, with the same restrictions and capabilities.
The syntax is

     ALTERNATIVE "<default instructions sequence>", \
		 "<alternative instructions sequence>", \
		 "<features-bit>"
and

     ALTERNATIVE_2 "<default instructions sequence>", \
		   "<alternative instructions sqeuence #1>", \
		   "<feature-bit #1>",
		   "<alternative instructions sqeuence #2>", \
		   "<feature-bit #2>"

Reviewed-by: Vasily Gorbik <gor@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-03-28 08:38:27 +02:00