Merge branches 'audit', 'delay', 'fixes', 'misc' and 'sta2x11' into for-linus

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / arm / mm / mmu.c

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index e5dad60b558b468315294b2c8b95c70193b6f74d..4c2d0451e84af1c2a0347a6fe462dd2e3306db3e 100644 (file)
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -16,13 +16,13 @@
 #include <linux/memblock.h>
 #include <linux/fs.h>
 #include <linux/vmalloc.h>
+#include <linux/sizes.h>
 
 #include <asm/cp15.h>
 #include <asm/cputype.h>
 #include <asm/sections.h>
 #include <asm/cachetype.h>
 #include <asm/setup.h>
-#include <asm/sizes.h>
 #include <asm/smp_plat.h>
 #include <asm/tlb.h>
 #include <asm/highmem.h>
@@ -421,12 +421,6 @@ static void __init build_mem_type_table(void)
        cp = &cache_policies[cachepolicy];
        vecs_pgprot = kern_pgprot = user_pgprot = cp->pte;
 
-       /*
-        * Only use write-through for non-SMP systems
-        */
-       if (!is_smp() && cpu_arch >= CPU_ARCH_ARMv5 && cachepolicy > CPOLICY_WRITETHROUGH)
-               vecs_pgprot = cache_policies[CPOLICY_WRITETHROUGH].pte;
-
        /*
         * Enable CPU-specific coherency if supported.
         * (Only available on XSC3 at the moment.)
@@ -791,6 +785,79 @@ void __init iotable_init(struct map_desc *io_desc, int nr)
        }
 }
 
+#ifndef CONFIG_ARM_LPAE
+
+/*
+ * The Linux PMD is made of two consecutive section entries covering 2MB
+ * (see definition in include/asm/pgtable-2level.h).  However a call to
+ * create_mapping() may optimize static mappings by using individual
+ * 1MB section mappings.  This leaves the actual PMD potentially half
+ * initialized if the top or bottom section entry isn't used, leaving it
+ * open to problems if a subsequent ioremap() or vmalloc() tries to use
+ * the virtual space left free by that unused section entry.
+ *
+ * Let's avoid the issue by inserting dummy vm entries covering the unused
+ * PMD halves once the static mappings are in place.
+ */
+
+static void __init pmd_empty_section_gap(unsigned long addr)
+{
+       struct vm_struct *vm;
+
+       vm = early_alloc_aligned(sizeof(*vm), __alignof__(*vm));
+       vm->addr = (void *)addr;
+       vm->size = SECTION_SIZE;
+       vm->flags = VM_IOREMAP | VM_ARM_STATIC_MAPPING;
+       vm->caller = pmd_empty_section_gap;
+       vm_area_add_early(vm);
+}
+
+static void __init fill_pmd_gaps(void)
+{
+       struct vm_struct *vm;
+       unsigned long addr, next = 0;
+       pmd_t *pmd;
+
+       /* we're still single threaded hence no lock needed here */
+       for (vm = vmlist; vm; vm = vm->next) {
+               if (!(vm->flags & VM_ARM_STATIC_MAPPING))
+                       continue;
+               addr = (unsigned long)vm->addr;
+               if (addr < next)
+                       continue;
+
+               /*
+                * Check if this vm starts on an odd section boundary.
+                * If so and the first section entry for this PMD is free
+                * then we block the corresponding virtual address.
+                */
+               if ((addr & ~PMD_MASK) == SECTION_SIZE) {
+                       pmd = pmd_off_k(addr);
+                       if (pmd_none(*pmd))
+                               pmd_empty_section_gap(addr & PMD_MASK);
+               }
+
+               /*
+                * Then check if this vm ends on an odd section boundary.
+                * If so and the second section entry for this PMD is empty
+                * then we block the corresponding virtual address.
+                */
+               addr += vm->size;
+               if ((addr & ~PMD_MASK) == SECTION_SIZE) {
+                       pmd = pmd_off_k(addr) + 1;
+                       if (pmd_none(*pmd))
+                               pmd_empty_section_gap(addr);
+               }
+
+               /* no need to look at any vm entry until we hit the next PMD */
+               next = (addr + PMD_SIZE - 1) & PMD_MASK;
+       }
+}
+
+#else
+#define fill_pmd_gaps() do { } while (0)
+#endif
+
 static void * __initdata vmalloc_min =
        (void *)(VMALLOC_END - (240 << 20) - VMALLOC_OFFSET);
 
@@ -1072,6 +1139,7 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
         */
        if (mdesc->map_io)
                mdesc->map_io();
+       fill_pmd_gaps();
 
        /*
         * Finally flush the caches and tlb to ensure that we're in a