[PATCH 1/6] ARM: Add inline function smp_cpu() for early init testing

Shilimkar, Santosh santosh.shilimkar at ti.com
Fri Sep 3 08:12:22 EDT 2010


> > BTW, so far looks like we should only need this during init to set up
> things.
> 
> Here's this one updated to replace smp_cpu() instead of smp_on_up().
> 


diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h
index 8db3512..82bc488 100644
--- a/arch/arm/include/asm/smp_plat.h
+++ b/arch/arm/include/asm/smp_plat.h
@@ -39,4 +39,11 @@ static inline int cache_ops_need_broadcast(void)
 #define UP(instr...)	_str(instr)
 #endif
 
+static inline int smp_cpu(void)
+{
+        u32 mpidr;
+        asm volatile("mrc p15, 0, %0, c0, c0, 5" : "=r" (mpidr));
+        return (mpidr >> 31) ? !(mpidr >> 30) : 0;
+}
+
Will this be called on UP machines ?? if yes, then mpidr register is not
available on those
 #endif
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 6e1c4f6..2bfaefd 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -430,15 +430,17 @@ static void __init build_mem_type_table(void)
 		/*
 		 * Mark memory with the "shared" attribute for SMP systems
 		 */
-		user_pgprot |= L_PTE_SHARED;
-		kern_pgprot |= L_PTE_SHARED;
-		vecs_pgprot |= L_PTE_SHARED;
-		mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
-		mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
-		mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
-		mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
-		mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
-		mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
+		if (smp_cpu()) {
+			user_pgprot |= L_PTE_SHARED;
+			kern_pgprot |= L_PTE_SHARED;
+			vecs_pgprot |= L_PTE_SHARED;
+			mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
+			mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
+			mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
+			mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
+			mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
+			mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
+		}
 #endif
 	}




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