From: Mark Salter <[email protected]>

ARM is different from other architectures in that fixmap pages are indexed
with a positive offset from FIXADDR_START.  Other architectures index with
a negative offset from FIXADDR_TOP.  In order to use the generic fixmap.h
definitions, this patch redefines FIXADDR_TOP to be inclusive of the
useable range.  That is, FIXADDR_TOP is the virtual address of the topmost
fixed page.  The newly defined FIXADDR_END is the first virtual address
past the fixed mappings.

Signed-off-by: Mark Salter <[email protected]>
Reviewed-by: Doug Anderson <[email protected]>
[kees: update for a05e54c103b0b8 "ARM: 8031/2: change fixmap ..."]
[kees: fixed highmem usage, thanks to Laura Abbott and Rob Herring]
Signed-off-by: Kees Cook <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Rob Herring <[email protected]>
---
 arch/arm/include/asm/fixmap.h  | 27 +++++++++------------------
 arch/arm/include/asm/highmem.h |  1 -
 arch/arm/mm/highmem.c          | 15 ++++++++-------
 arch/arm/mm/init.c             |  2 +-
 arch/arm/mm/mmu.c              |  6 +++---
 5 files changed, 21 insertions(+), 30 deletions(-)

diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index 74124b0d0d79..a7add6f9315d 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -2,27 +2,18 @@
 #define _ASM_FIXMAP_H
 
 #define FIXADDR_START          0xffc00000UL
-#define FIXADDR_TOP            0xffe00000UL
-#define FIXADDR_SIZE           (FIXADDR_TOP - FIXADDR_START)
+#define FIXADDR_END            0xffe00000UL
+#define FIXADDR_TOP            (FIXADDR_END - PAGE_SIZE)
 
-#define FIX_KMAP_NR_PTES       (FIXADDR_SIZE >> PAGE_SHIFT)
+#include <asm/kmap_types.h>
 
-#define __fix_to_virt(x)       (FIXADDR_START + ((x) << PAGE_SHIFT))
-#define __virt_to_fix(x)       (((x) - FIXADDR_START) >> PAGE_SHIFT)
+enum fixed_addresses {
+       FIX_KMAP_BEGIN,
+       FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
 
-extern void __this_fixmap_does_not_exist(void);
+       __end_of_fixed_addresses
+};
 
-static inline unsigned long fix_to_virt(const unsigned int idx)
-{
-       if (idx >= FIX_KMAP_NR_PTES)
-               __this_fixmap_does_not_exist();
-       return __fix_to_virt(idx);
-}
-
-static inline unsigned int virt_to_fix(const unsigned long vaddr)
-{
-       BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
-       return __virt_to_fix(vaddr);
-}
+#include <asm-generic/fixmap.h>
 
 #endif
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
index 535579511ed0..91b99abe7a95 100644
--- a/arch/arm/include/asm/highmem.h
+++ b/arch/arm/include/asm/highmem.h
@@ -18,7 +18,6 @@
        } 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 45aeaaca9052..f87e0b89b738 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -18,19 +18,20 @@
 #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);
+       pte_t *ppte = pte_offset_kernel(pmd_off_k(FIXADDR_START), vaddr);
+
+       set_pte_ext(ppte, 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);
+       pte_t *ppte = pte_offset_kernel(pmd_off_k(FIXADDR_START), vaddr);
+
+       return *ppte;
 }
 
 void *kmap(struct page *page)
@@ -84,7 +85,7 @@ 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(*(fixmap_page_table + idx)));
+       BUG_ON(!pte_none(*get_fixmap_pte(vaddr)));
 #endif
        /*
         * When debugging is off, kunmap_atomic leaves the previous mapping
@@ -134,7 +135,7 @@ 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(*(fixmap_page_table + idx)));
+       BUG_ON(!pte_none(*get_fixmap_pte(vaddr)));
 #endif
        set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
 
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 659c75d808dc..ad82c05bfc3a 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -570,7 +570,7 @@ void __init mem_init(void)
                        MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
                        MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 #endif
-                       MLK(FIXADDR_START, FIXADDR_TOP),
+                       MLK(FIXADDR_START, FIXADDR_END),
                        MLM(VMALLOC_START, VMALLOC_END),
                        MLM(PAGE_OFFSET, (unsigned long)high_memory),
 #ifdef CONFIG_HIGHMEM
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 8348ed6b2efe..7fa0966cd15f 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1326,10 +1326,10 @@ 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
+
+       early_pte_alloc(pmd_off_k(FIXADDR_START), FIXADDR_START,
+                       _PAGE_KERNEL_TABLE);
 }
 
 static void __init map_lowmem(void)
-- 
1.9.1

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