From ebb9d30a6a74f4ced5b7d35446ebb6362a724393 Mon Sep 17 00:00:00 2001
From: chenhui zhao <chenhui.zhao@freescale.com>
Date: Thu, 24 Dec 2015 08:39:57 +0800
Subject: [PATCH] powerpc/mm: any thread in one core can be the first to setup
TLB1
On e6500, in the case of cpu hotplug, either thread in one core
may be the first thread initilzing the TLB1. The subsequent threads
must not setup it again.
The code is derived from the comment of Scott Wood.
Signed-off-by: Chenhui Zhao <chenhui.zhao@freescale.com>
Signed-off-by: Scott Wood <oss@buserror.net>
---
arch/powerpc/include/asm/cputhreads.h | 8 ++++++++
arch/powerpc/mm/tlb_nohash.c | 4 +---
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h
index ba42e46ea58eee..ea9623147b870d 100644
--- a/arch/powerpc/include/asm/cputhreads.h
+++ b/arch/powerpc/include/asm/cputhreads.h
@@ -94,6 +94,14 @@ static inline int cpu_last_thread_sibling(int cpu)
return cpu | (threads_per_core - 1);
}
+static inline u32 get_tensr(void)
+{
+#ifdef CONFIG_BOOKE
+ if (cpu_has_feature(CPU_FTR_SMT))
+ return mfspr(SPRN_TENSR);
+#endif
+ return 1;
+}
#endif /* _ASM_POWERPC_CPUTHREADS_H */
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index bb04e4df310080..f4668488512c46 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -640,9 +640,7 @@ static void early_init_this_mmu(void)
* transient mapping would cause problems.
*/
#ifdef CONFIG_SMP
- if (cpu != boot_cpuid &&
- (cpu != cpu_first_thread_sibling(cpu) ||
- cpu == cpu_first_thread_sibling(boot_cpuid)))
+ if (hweight32(get_tensr()) > 1)
map = false;
#endif
--
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