From: Rohan McLure Date: Wed, 10 May 2023 03:31:13 +0000 (+1000) Subject: powerpc: Annotate accesses to ipi message flags X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8608f14b49a0a3f8644a326d32dc1bf7ed78836a;p=linux.git 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 Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230510033117.1395895-8-rmclure@linux.ibm.com --- diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 265801a3e94cf..406e6d0ffae36 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; }