ARM: 7677/1: LPAE: Fix mapping in alloc_init_section for unaligned addresses

With LPAE enabled, alloc_init_section() does not map the entire
address space for unaligned addresses.

The issue also reproduced with CMA + LPAE. CMA tries to map 16MB
with page granularity mappings during boot. alloc_init_pte()
is called and out of 16MB, only 2MB gets mapped and rest remains
unaccessible.

Because of this OMAP5 boot is broken with CMA + LPAE enabled.
Fix the issue by ensuring that the entire addresses are
mapped.

Signed-off-by: R Sricharan <r.sricharan@ti.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoffer Dall <chris@cloudcar.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Christoffer Dall <chris@cloudcar.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 47 insertions, 26 deletions

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index e95a996ab78f..78978945492a 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -598,39 +598,60 @@ static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
         } while (pte++, addr += PAGE_SIZE, addr != end);
 }
 
-static void __init alloc_init_section(pud_t *pud, unsigned long addr,
-                                      unsigned long end, phys_addr_t phys,
-                                      const struct mem_type *type)
+static void __init map_init_section(pmd_t *pmd, unsigned long addr,
+                        unsigned long end, phys_addr_t phys,
+                        const struct mem_type *type)
 {
-        pmd_t *pmd = pmd_offset(pud, addr);
-
+#ifndef CONFIG_ARM_LPAE
         /*
-         * Try a section mapping - end, addr and phys must all be aligned
-         * to a section boundary.  Note that PMDs refer to the individual
-         * L1 entries, whereas PGDs refer to a group of L1 entries making
-         * up one logical pointer to an L2 table.
+         * In classic MMU format, puds and pmds are folded in to
+         * the pgds. pmd_offset gives the PGD entry. PGDs refer to a
+         * group of L1 entries making up one logical pointer to
+         * an L2 table (2MB), where as PMDs refer to the individual
+         * L1 entries (1MB). Hence increment to get the correct
+         * offset for odd 1MB sections.
+         * (See arch/arm/include/asm/pgtable-2level.h)
          */
-        if (type->prot_sect && ((addr | end | phys) & ~SECTION_MASK) == 0) {
-                pmd_t *p = pmd;
-
-#ifndef CONFIG_ARM_LPAE
-                if (addr & SECTION_SIZE)
-                        pmd++;
+        if (addr & SECTION_SIZE)
+                pmd++;
 #endif
+        do {
+                *pmd = __pmd(phys | type->prot_sect);
+                phys += SECTION_SIZE;
+        } while (pmd++, addr += SECTION_SIZE, addr != end);
 
-                do {
-                        *pmd = __pmd(phys | type->prot_sect);
-                        phys += SECTION_SIZE;
-                } while (pmd++, addr += SECTION_SIZE, addr != end);
+        flush_pmd_entry(pmd);
+}
 
-                flush_pmd_entry(p);
-        } else {
+static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
+                                      unsigned long end, phys_addr_t phys,
+                                      const struct mem_type *type)
+{
+        pmd_t *pmd = pmd_offset(pud, addr);
+        unsigned long next;
+
+        do {
                 /*
-                 * No need to loop; pte's aren't interested in the
-                 * individual L1 entries.
+                 * With LPAE, we must loop over to map
+                 * all the pmds for the given range.
                  */
-                alloc_init_pte(pmd, addr, end, __phys_to_pfn(phys), type);
-        }
+                next = pmd_addr_end(addr, end);
+
+                /*
+                 * Try a section mapping - addr, next and phys must all be
+                 * aligned to a section boundary.
+                 */
+                if (type->prot_sect &&
+                                ((addr | next | phys) & ~SECTION_MASK) == 0) {
+                        map_init_section(pmd, addr, next, phys, type);
+                } else {
+                        alloc_init_pte(pmd, addr, next,
+                                                __phys_to_pfn(phys), type);
+                }
+
+                phys += next - addr;
+
+        } while (pmd++, addr = next, addr != end);
 }
 
 static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
@@ -641,7 +662,7 @@ static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
 
         do {
                 next = pud_addr_end(addr, end);
-                alloc_init_section(pud, addr, next, phys, type);
+                alloc_init_pmd(pud, addr, next, phys, type);
                 phys += next - addr;
         } while (pud++, addr = next, addr != end);
 }