When Core-0 handle SMP_ASK_C0COUNT IPI, we should make other cores to
see the result as soon as possible (especially when Store-Fill-Buffer
is enabled). Otherwise, C0_Count syncronization makes no sense.
BTW, there is a corner should be avoid: C0_Count of Core-0 is really 0.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
---
arch/mips/loongson64/loongson-3/smp.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/mips/loongson64/loongson-3/smp.c b/arch/mips/loongson64/loongson-3/smp.c
index 1a4738a..55d0f5f 100644
--- a/arch/mips/loongson64/loongson-3/smp.c
+++ b/arch/mips/loongson64/loongson-3/smp.c
@@ -275,8 +275,10 @@ void loongson3_ipi_interrupt(struct pt_regs *regs)
if (action & SMP_ASK_C0COUNT) {
BUG_ON(cpu != 0);
c0count = read_c0_count();
+ c0count = c0count ? c0count : 1;
for (i = 1; i < num_possible_cpus(); i++)
per_cpu(core0_c0count, i) = c0count;
+ __wbflush(); /* Let others see the result ASAP */
}
}
--
2.4.6
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