diff options
| author | Rohan McLure <rmclure@linux.ibm.com> | 2023-05-10 06:31:12 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-06-21 08:13:57 +0300 |
| commit | b0c5b4f1ee3687c57dab65ac0729a4d61967f032 (patch) | |
| tree | 80219cd429f75e9733654e03ab54eff9dfef639b /arch/powerpc/include | |
| parent | be286b8637d417a7d7eb25dc3a509c10d0afef66 (diff) | |
| download | linux-b0c5b4f1ee3687c57dab65ac0729a4d61967f032.tar.xz | |
powerpc: powernv: Fix KCSAN datarace warnings on idle_state contention
The idle_state entry in the PACA on PowerNV features a bit which is
atomically tested and set through ldarx/stdcx. to be used as a spinlock.
This lock then guards access to other bit fields of idle_state. KCSAN
cannot differentiate between any of these bitfield accesses as they all
are implemented by 8-byte store/load instructions, thus cores contending
on the bit-lock appear to data race with modifications to idle_state.
Separate the bit-lock entry from the data guarded by the lock to avoid
the possibility of data races being detected by KCSAN.
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230510033117.1395895-7-rmclure@linux.ibm.com
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/paca.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index da0377f46597..cb325938766a 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -191,6 +191,7 @@ struct paca_struct { #ifdef CONFIG_PPC_POWERNV /* PowerNV idle fields */ /* PNV_CORE_IDLE_* bits, all siblings work on thread 0 paca */ + unsigned long idle_lock; /* A value of 1 means acquired */ unsigned long idle_state; union { /* P7/P8 specific fields */ |