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authorRohan McLure <[email protected]>2023-05-10 13:31:13 +1000
committerMichael Ellerman <[email protected]>2023-06-21 15:13:57 +1000
commit8608f14b49a0a3f8644a326d32dc1bf7ed78836a (patch)
tree23039e9ef5b15191f0495689b247adad846e8b27
parentb0c5b4f1ee3687c57dab65ac0729a4d61967f032 (diff)
powerpc: Annotate accesses to ipi message flags
IPI message flags are observed and consequently consumed in the smp_ipi_demux_relaxed function, which handles these message sources until it observes none more arriving. Mark the checked loop guard with READ_ONCE, to signal to KCSAN that the read is known to be volatile, and that non-determinism is expected. Mark write for message source in smp_muxed_ipi_set_message(). Signed-off-by: Rohan McLure <[email protected]> Reviewed-by: Nicholas Piggin <[email protected]> Signed-off-by: Michael Ellerman <[email protected]> Link: https://msgid.link/[email protected]
-rw-r--r--arch/powerpc/kernel/smp.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 265801a3e94c..406e6d0ffae3 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -291,7 +291,7 @@ void smp_muxed_ipi_set_message(int cpu, int msg)
* Order previous accesses before accesses in the IPI handler.
*/
smp_mb();
- message[msg] = 1;
+ WRITE_ONCE(message[msg], 1);
}
void smp_muxed_ipi_message_pass(int cpu, int msg)
@@ -350,7 +350,7 @@ irqreturn_t smp_ipi_demux_relaxed(void)
if (all & IPI_MESSAGE(PPC_MSG_NMI_IPI))
nmi_ipi_action(0, NULL);
#endif
- } while (info->messages);
+ } while (READ_ONCE(info->messages));
return IRQ_HANDLED;
}