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ed28b16eab
tcheck() is used to check the current transaction state (active,
suspended, doomed) via the "tcheck" instruction, which writes its
result into CR field 0. The inline asm declared a GPR output operand
for this result but never actually moved the CR into it.
Every caller (tcheck_doomed(), tcheck_active(), tcheck_suspended(),
tcheck_transactional()) has effectively been testing bits of an unrelated,
arbitrary register value since this helper was introduced.
The "& 4" mask discards the TDOOMED and TS_lsb (suspended) bits before
they ever reach the callers, so tcheck_doomed() and tcheck_suspended()
can never return true, and tcheck_transactional() degrades to being
equivalent to tcheck_active().
Fix tcheck() to actually move CR into the output register with mfcr,
and widen the mask from "& 4" to "& 0xf" so the full CR0 nibble
(TDOOMED | TS_msb | TS_lsb | reserved) is preserved for the callers.
This bug has been present since tcheck() was introduced.
Link: https://bugs.launchpad.net/bugs/2107442
Fixes:
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||
|---|---|---|
| .. | ||
| crypto/chacha20-s390 | ||
| cxl | ||
| fault-injection | ||
| ktest | ||
| kunit | ||
| memblock | ||
| nvdimm | ||
| radix-tree | ||
| rbtree | ||
| scatterlist | ||
| selftests | ||
| shared | ||
| vma | ||
| vsock | ||