[PATCH 0/8] s390: allow to build with llvm's integrated assembler

From: Heiko Carstens
Date: Wed May 11 2022 - 08:06:39 EST


A couple of patches which in result make it finally possible to build the
kernel for s390 with llvm's integrated assembler. Several configs build
without errors or warnings, and the kernel also works as expected.

Note that patch 6 ("s390/boot: workaround llvm IAS bug") reveals a
miscompile. This looks like a bug in the instruction definitions of the mvc
and clc instructions(?). I'd like to ask people to look into this, since
this silently generated broken code.

This patch series is based on linux-next, which contains two additional
required s390 specific patches to make llvm's IAS work.

Thanks,
Heiko

Heiko Carstens (8):
s390/alternatives: provide identical sized orginal/alternative sequences
s390/alternatives: remove padding generation code
s390/entry: shorten OUTSIDE macro
s390/entry: workaround llvm's IAS limitations
s390/purgatory: workaround llvm's IAS limitations
s390/boot: workaround llvm IAS bug
s390/boot: do not emit debug info for assembly with llvm's IAS
scripts/min-tool-version.sh: raise minimum clang version to 14.0.0 for s390

arch/s390/Makefile | 2 +
arch/s390/boot/head.S | 34 +++++----
arch/s390/include/asm/alternative-asm.h | 76 +++-----------------
arch/s390/include/asm/alternative.h | 93 ++++++-------------------
arch/s390/include/asm/spinlock.h | 2 +-
arch/s390/kernel/alternative.c | 61 +---------------
arch/s390/kernel/entry.S | 39 +++++++----
arch/s390/lib/spinlock.c | 4 +-
arch/s390/purgatory/head.S | 29 ++++++--
scripts/min-tool-version.sh | 3 +-
10 files changed, 104 insertions(+), 239 deletions(-)

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2.32.0