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Commit 20e7e364 authored by Russell King's avatar Russell King
Browse files

ARM: ensure C page table setup code follows assembly code (part II) 



This does the same as the previous commit, but for the S bit, which also
needs to match the initial value which the assembly code used for the
same reasons.  Again, we add a check for SMP to ensure that the page
tables are correctly setup for SMP.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ca8f0b0a

arch/arm/mm/mmu.c

+19 −8
Original line number Diff line number Diff line
@@ -117,6 +117,8 @@ static struct cachepolicy cache_policies[] __initdata = { 
};



#ifdef CONFIG_CPU_CP15

static unsigned long initial_pmd_value __initdata = 0;



/*

 * Initialise the cache_policy variable with the initial state specified

 * via the "pmd" value.  This is used to ensure that on ARMv6 and later,
@@ -128,6 +130,8 @@ void __init init_default_cache_policy(unsigned long pmd) 
{

	int i;



	initial_pmd_value = pmd;



	pmd &= PMD_SECT_TEX(1) | PMD_SECT_BUFFERABLE | PMD_SECT_CACHEABLE;



	for (i = 0; i < ARRAY_SIZE(cache_policies); i++)
@@ -414,10 +418,16 @@ static void __init build_mem_type_table(void) 
		ecc_mask = 0;

	}



	if (is_smp() && cachepolicy != CPOLICY_WRITEALLOC) {

	if (is_smp()) {

		if (cachepolicy != CPOLICY_WRITEALLOC) {

			pr_warn("Forcing write-allocate cache policy for SMP\n");

			cachepolicy = CPOLICY_WRITEALLOC;

		}

		if (!(initial_pmd_value & PMD_SECT_S)) {

			pr_warn("Forcing shared mappings for SMP\n");

			initial_pmd_value |= PMD_SECT_S;

		}

	}



	/*

	 * Strip out features not present on earlier architectures.
@@ -541,11 +551,12 @@ static void __init build_mem_type_table(void) 
		mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;

#endif



		if (is_smp()) {

		/*

			 * Mark memory with the "shared" attribute

			 * for SMP systems

		 * If the initial page tables were created with the S bit

		 * set, then we need to do the same here for the same

		 * reasons given in early_cachepolicy().

		 */

		if (initial_pmd_value & PMD_SECT_S) {

			user_pgprot |= L_PTE_SHARED;

			kern_pgprot |= L_PTE_SHARED;

			vecs_pgprot |= L_PTE_SHARED;