kernel/arch/s390/include/asm/alternative-asm.h, branch linux-6.2.y

s390/alternatives: remove padding generation code

2022-05-17T13:16:28Z

clang fails to handle ".if" statements in inline assembly which are heavily used in the alternatives code. To work around this remove this code, and enforce that users of alternatives must specify original and alternative instruction sequences which have identical sizes. Add a compile time check with two ".org" statements similar to arm64. In result not only clang can handle this, but also quite a lot of code can be removed. Acked-by: Vasily Gorbik Tested-by: Nathan Chancellor Tested-by: Nick Desaulniers Link: https://github.com/ClangBuiltLinux/linux/issues/1356 Link: https://lore.kernel.org/r/20220511120532.2228616-3-hca@linux.ibm.com Signed-off-by: Heiko Carstens

s390/alternatives: avoid using jgnop mnemonic

2022-03-28T21:27:54Z

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 Fixes: 4afeb670710e ("s390/alternatives: use instructions instead of byte patterns") Signed-off-by: Vasily Gorbik

s390/alternatives: use instructions instead of byte patterns

2022-03-27T20:18:38Z

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 Signed-off-by: Vasily Gorbik

s390: add assembler macros for CPU alternatives

2018-03-28T06:38:27Z

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 "", \ "", \ "" and ALTERNATIVE_2 "", \ "", \ "", "", \ "" Reviewed-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky