ARM: 8031/2: change fixmap mapping region to support 32 CPUs

In 32-bit ARM systems, the fixmap mapping region can support no more
than 14 CPUs(total: 896k; one CPU: 64K). And we can configure NR_CPUS
up to 32. So there is a mismatch.

This patch moves fixmapping region downwards to region 0xffc00000-
0xffe00000. Then the fixmap mapping region can support up to 32 CPUs.

Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Liu Hua <sdu.liu@huawei.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

5 files changed, 29 insertions, 21 deletions

diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt
index d74e8a5901fc..256c5e067fb1 100644
--- a/Documentation/arm/memory.txt
+++ b/Documentation/arm/memory.txt
@@ -41,7 +41,7 @@ fffe8000	fffeffff	DTCM mapping area for platforms with
 fffe0000        fffe7fff        ITCM mapping area for platforms with
                                 ITCM mounted inside the CPU.
 
-fff00000        fffdffff        Fixmap mapping region.  Addresses provided
+fffc0000        ffdfffff        Fixmap mapping region.  Addresses provided
                                 by fix_to_virt() will be located here.
 
 fee00000        feffffff        Mapping of PCI I/O space. This is a static
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index be55ebc08ed4..74124b0d0d79 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -1,20 +1,8 @@
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
 
-/*
- * Nothing too fancy for now.
- *
- * On ARM we already have well known fixed virtual addresses imposed by
- * the architecture such as the vector page which is located at 0xffff0000,
- * therefore a second level page table is already allocated covering
- * 0xfff00000 upwards.
- *
- * The cache flushing code in proc-xscale.S uses the virtual area between
- * 0xfffe0000 and 0xfffeffff.
- */
-
-#define FIXADDR_START           0xfff00000UL
-#define FIXADDR_TOP             0xfffe0000UL
+#define FIXADDR_START           0xffc00000UL
+#define FIXADDR_TOP             0xffe00000UL
 #define FIXADDR_SIZE            (FIXADDR_TOP - FIXADDR_START)
 
 #define FIX_KMAP_NR_PTES        (FIXADDR_SIZE >> PAGE_SHIFT)
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
index 91b99abe7a95..535579511ed0 100644
--- a/arch/arm/include/asm/highmem.h
+++ b/arch/arm/include/asm/highmem.h
@@ -18,6 +18,7 @@
         } while (0)
 
 extern pte_t *pkmap_page_table;
+extern pte_t *fixmap_page_table;
 
 extern void *kmap_high(struct page *page);
 extern void kunmap_high(struct page *page);
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index e05e8ad26ba5..45aeaaca9052 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -18,6 +18,21 @@
 #include <asm/tlbflush.h>
 #include "mm.h"
 
+pte_t *fixmap_page_table;
+
+static inline void set_fixmap_pte(int idx, pte_t pte)
+{
+        unsigned long vaddr = __fix_to_virt(idx);
+        set_pte_ext(fixmap_page_table + idx, pte, 0);
+        local_flush_tlb_kernel_page(vaddr);
+}
+
+static inline pte_t get_fixmap_pte(unsigned long vaddr)
+{
+        unsigned long idx = __virt_to_fix(vaddr);
+        return *(fixmap_page_table + idx);
+}
+
 void *kmap(struct page *page)
 {
         might_sleep();
@@ -69,14 +84,14 @@ void *kmap_atomic(struct page *page)
          * With debugging enabled, kunmap_atomic forces that entry to 0.
          * Make sure it was indeed properly unmapped.
          */
-        BUG_ON(!pte_none(get_top_pte(vaddr)));
+        BUG_ON(!pte_none(*(fixmap_page_table + idx)));
 #endif
         /*
          * When debugging is off, kunmap_atomic leaves the previous mapping
          * in place, so the contained TLB flush ensures the TLB is updated
          * with the new mapping.
          */
-        set_top_pte(vaddr, mk_pte(page, kmap_prot));
+        set_fixmap_pte(idx, mk_pte(page, kmap_prot));
 
         return (void *)vaddr;
 }
@@ -95,7 +110,7 @@ void __kunmap_atomic(void *kvaddr)
                         __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
                 BUG_ON(vaddr != __fix_to_virt(idx));
-                set_top_pte(vaddr, __pte(0));
+                set_fixmap_pte(idx, __pte(0));
 #else
                 (void) idx;  /* to kill a warning */
 #endif
@@ -119,9 +134,9 @@ void *kmap_atomic_pfn(unsigned long pfn)
         idx = type + KM_TYPE_NR * smp_processor_id();
         vaddr = __fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
-        BUG_ON(!pte_none(get_top_pte(vaddr)));
+        BUG_ON(!pte_none(*(fixmap_page_table + idx)));
 #endif
-        set_top_pte(vaddr, pfn_pte(pfn, kmap_prot));
+        set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
 
         return (void *)vaddr;
 }
@@ -133,5 +148,5 @@ struct page *kmap_atomic_to_page(const void *ptr)
         if (vaddr < FIXADDR_START)
                 return virt_to_page(ptr);
 
-        return pte_page(get_top_pte(vaddr));
+        return pte_page(get_fixmap_pte(vaddr));
 }
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index b68c6b22e1c8..09c0a16165dc 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -35,6 +35,7 @@
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
+#include <asm/fixmap.h>
 
 #include "mm.h"
 #include "tcm.h"
@@ -1359,6 +1360,9 @@ static void __init kmap_init(void)
 #ifdef CONFIG_HIGHMEM
         pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE),
                 PKMAP_BASE, _PAGE_KERNEL_TABLE);
+
+        fixmap_page_table = early_pte_alloc(pmd_off_k(FIXADDR_START),
+                FIXADDR_START, _PAGE_KERNEL_TABLE);
 #endif
 }