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>

diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h
index ba42e46ea58eeed448d3d7abb5c67f5570e96bca..ea9623147b870d222aa880a0ab9de9f6db28d1a5 100644 (file)
--- 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 bb04e4df31008089e5390619dc52a7c6c26d5f7b..f4668488512c46d278cc1742672e741a9016639b 100644 (file)
--- 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