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@@ -0,0 +1,31 @@
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+From: James Hogan <[email protected]>
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+Date: Fri, 4 Mar 2016 10:10:51 +0000
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+Subject: [PATCH] MIPS: smp.c: Fix uninitialised temp_foreign_map
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+
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+When calculate_cpu_foreign_map() recalculates the cpu_foreign_map
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+cpumask it uses the local variable temp_foreign_map without initialising
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+it to zero. Since the calculation only ever sets bits in this cpumask
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+any existing bits at that memory location will remain set and find their
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+way into cpu_foreign_map too. This could potentially lead to cache
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+operations suboptimally doing smp calls to multiple VPEs in the same
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+core, even though the VPEs share primary caches.
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+
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+Therefore initialise temp_foreign_map using cpumask_clear() before use.
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+
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+Fixes: cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores")
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+Signed-off-by: James Hogan <[email protected]>
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+Cc: Ralf Baechle <[email protected]>
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+Cc: Paul Burton <[email protected]>
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+Cc: [email protected]
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+---
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+
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+--- a/arch/mips/kernel/smp.c
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++++ b/arch/mips/kernel/smp.c
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+@@ -121,6 +121,7 @@ static inline void calculate_cpu_foreign
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+ cpumask_t temp_foreign_map;
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+
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+ /* Re-calculate the mask */
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++ cpumask_clear(&temp_foreign_map);
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+ for_each_online_cpu(i) {
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+ core_present = 0;
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+ for_each_cpu(k, &temp_foreign_map)
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Felix Fietkau