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s390/percpu: Fix MVIY_PERCPU() with older binutils

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Commit a737737cdb ("s390/percpu: Infrastructure for more efficient
this_cpu operations") introduced MVIY_PERCPU(), which stringifies
arguments that are already C string literals. This generates an
assembler macro invocation with whitespace-separated quoted arguments:

  GEN_MVIY "459712" "%r3"

GNU as versions prior to binutils 2.39 drop the separating whitespace
between quoted macro arguments during input scrubbing. They
consequently parse the invocation as a single argument and emit
repeated warnings:

  Warning: missing closing `"'

The .ifc in GEN_MVIY never matches and GNU as exits successfully
without emitting the mviy instruction. As a result, the interrupted
per-CPU sequence is not marked in lowcore and the exception return
path cannot repair the per-CPU address register after migration.

All MVIY_PERCPU() callers pass C string literals. Use them directly
and separate the assembler macro arguments with an explicit comma. The
resulting invocation is:

  GEN_MVIY 459712, %r3

This form is unambiguous for GNU as and LLVM's integrated assembler.
This behavior was fixed in GNU as from binutils 2.39, but Linux
supports binutils 2.30.

Fixes: a737737cdb ("s390/percpu: Infrastructure for more efficient this_cpu operations")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Karl Mehltretter 2026-08-12 22:30:36 +02:00 committed by Vasily Gorbik
parent 445c31ac63
commit 101782f894
1 changed files with 2 additions and 2 deletions
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4
arch/s390/include/asm/percpu.h
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@ -107,8 +107,8 @@
" .endif\n" \
".endr\n" \
".endm\n" \
ALTERNATIVE("GEN_MVIY " __stringify(disp) " " __stringify(reg) "\n", \
"GEN_MVIY " __stringify(dispalt) " " __stringify(reg) "\n", \
ALTERNATIVE("GEN_MVIY " disp ", " reg "\n", \
"GEN_MVIY " dispalt ", " reg "\n", \
ALT_FEATURE(MFEATURE_LOWCORE)) \
".purgem GEN_MVIY\n"