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: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 92df149..df875c4 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -117,6 +117,8 @@
};
#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 @@
{
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++)
@@ -414,9 +418,15 @@
ecc_mask = 0;
}
- if (is_smp() && cachepolicy != CPOLICY_WRITEALLOC) {
- pr_warn("Forcing write-allocate cache policy for SMP\n");
- 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;
+ }
}
/*
@@ -541,11 +551,12 @@
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;