2 files changed, 128 insertions, 19 deletions

diff --git a/include/asm-powerpc/fixmap.h b/include/asm-powerpc/fixmap.h
new file mode 100644
index 000000000000..8428b38a3d30
--- /dev/null
+++ b/include/asm-powerpc/fixmap.h
@@ -0,0 +1,106 @@
+/*
+ * fixmap.h: compile-time virtual memory allocation
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998 Ingo Molnar
+ *
+ * Copyright 2008 Freescale Semiconductor Inc.
+ *   Port to powerpc added by Kumar Gala
+ */
+
+#ifndef _ASM_FIXMAP_H
+#define _ASM_FIXMAP_H
+
+extern unsigned long FIXADDR_TOP;
+
+#ifndef __ASSEMBLY__
+#include <linux/kernel.h>
+#include <asm/page.h>
+#ifdef CONFIG_HIGHMEM
+#include <linux/threads.h>
+#include <asm/kmap_types.h>
+#endif
+
+/*
+ * Here we define all the compile-time 'special' virtual
+ * addresses. The point is to have a constant address at
+ * compile time, but to set the physical address only
+ * in the boot process. We allocate these special addresses
+ * from the end of virtual memory (0xfffff000) backwards.
+ * Also this lets us do fail-safe vmalloc(), we
+ * can guarantee that these special addresses and
+ * vmalloc()-ed addresses never overlap.
+ *
+ * these 'compile-time allocated' memory buffers are
+ * fixed-size 4k pages. (or larger if used with an increment
+ * highger than 1) use fixmap_set(idx,phys) to associate
+ * physical memory with fixmap indices.
+ *
+ * TLB entries of such buffers will not be flushed across
+ * task switches.
+ */
+enum fixed_addresses {
+        FIX_HOLE,
+#ifdef CONFIG_HIGHMEM
+        FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
+        FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
+#endif
+        /* FIX_PCIE_MCFG, */
+        __end_of_fixed_addresses
+};
+
+extern void __set_fixmap (enum fixed_addresses idx,
+                                        phys_addr_t phys, pgprot_t flags);
+
+#define set_fixmap(idx, phys) \
+                __set_fixmap(idx, phys, PAGE_KERNEL)
+/*
+ * Some hardware wants to get fixmapped without caching.
+ */
+#define set_fixmap_nocache(idx, phys) \
+                __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
+
+#define clear_fixmap(idx) \
+                __set_fixmap(idx, 0, __pgprot(0))
+
+#define __FIXADDR_SIZE  (__end_of_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START           (FIXADDR_TOP - __FIXADDR_SIZE)
+
+#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
+#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
+
+extern void __this_fixmap_does_not_exist(void);
+
+/*
+ * 'index to address' translation. If anyone tries to use the idx
+ * directly without tranlation, we catch the bug with a NULL-deference
+ * kernel oops. Illegal ranges of incoming indices are caught too.
+ */
+static __always_inline unsigned long fix_to_virt(const unsigned int idx)
+{
+        /*
+         * this branch gets completely eliminated after inlining,
+         * except when someone tries to use fixaddr indices in an
+         * illegal way. (such as mixing up address types or using
+         * out-of-range indices).
+         *
+         * If it doesn't get removed, the linker will complain
+         * loudly with a reasonably clear error message..
+         */
+        if (idx >= __end_of_fixed_addresses)
+                __this_fixmap_does_not_exist();
+
+        return __fix_to_virt(idx);
+}
+
+static inline unsigned long virt_to_fix(const unsigned long vaddr)
+{
+        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
+        return __virt_to_fix(vaddr);
+}
+
+#endif /* !__ASSEMBLY__ */
+#endif
diff --git a/include/asm-powerpc/highmem.h b/include/asm-powerpc/highmem.h
index f7b21ee302b4..5d99b6489d56 100644
--- a/include/asm-powerpc/highmem.h
+++ b/include/asm-powerpc/highmem.h
@@ -27,9 +27,7 @@
 #include <asm/kmap_types.h>
 #include <asm/tlbflush.h>
 #include <asm/page.h>
-
-/* undef for production */
-#define HIGHMEM_DEBUG 1
+#include <asm/fixmap.h>
 
 extern pte_t *kmap_pte;
 extern pgprot_t kmap_prot;
@@ -40,14 +38,12 @@ extern pte_t *pkmap_page_table;
  * easily, subsequent pte tables have to be allocated in one physical
  * chunk of RAM.
  */
-#define PKMAP_BASE      CONFIG_HIGHMEM_START
 #define LAST_PKMAP      (1 << PTE_SHIFT)
 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
+#define PKMAP_BASE      ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK)
 #define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
 #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
 
-#define KMAP_FIX_BEGIN  (PKMAP_BASE + 0x00400000UL)
-
 extern void *kmap_high(struct page *page);
 extern void kunmap_high(struct page *page);
 
@@ -73,7 +69,7 @@ static inline void kunmap(struct page *page)
  * be used in IRQ contexts, so in some (very limited) cases we need
  * it.
  */
-static inline void *kmap_atomic(struct page *page, enum km_type type)
+static inline void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
 {
         unsigned int idx;
         unsigned long vaddr;
@@ -84,34 +80,39 @@ static inline void *kmap_atomic(struct page *page, enum km_type type)
                 return page_address(page);
 
         idx = type + KM_TYPE_NR*smp_processor_id();
-        vaddr = KMAP_FIX_BEGIN + idx * PAGE_SIZE;
-#ifdef HIGHMEM_DEBUG
-        BUG_ON(!pte_none(*(kmap_pte+idx)));
+        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+        BUG_ON(!pte_none(*(kmap_pte-idx)));
 #endif
-        set_pte_at(&init_mm, vaddr, kmap_pte+idx, mk_pte(page, kmap_prot));
+        set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
         flush_tlb_page(NULL, vaddr);
 
         return (void*) vaddr;
 }
 
+static inline void *kmap_atomic(struct page *page, enum km_type type)
+{
+        return kmap_atomic_prot(page, type, kmap_prot);
+}
+
 static inline void kunmap_atomic(void *kvaddr, enum km_type type)
 {
-#ifdef HIGHMEM_DEBUG
+#ifdef CONFIG_DEBUG_HIGHMEM
         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-        unsigned int idx = type + KM_TYPE_NR*smp_processor_id();
+        enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
 
-        if (vaddr < KMAP_FIX_BEGIN) { // FIXME
+        if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
                 pagefault_enable();
                 return;
         }
 
-        BUG_ON(vaddr != KMAP_FIX_BEGIN + idx * PAGE_SIZE);
+        BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
 
         /*
          * force other mappings to Oops if they'll try to access
          * this pte without first remap it
          */
-        pte_clear(&init_mm, vaddr, kmap_pte+idx);
+        pte_clear(&init_mm, vaddr, kmap_pte-idx);
         flush_tlb_page(NULL, vaddr);
 #endif
         pagefault_enable();
@@ -120,12 +121,14 @@ static inline void kunmap_atomic(void *kvaddr, enum km_type type)
 static inline struct page *kmap_atomic_to_page(void *ptr)
 {
         unsigned long idx, vaddr = (unsigned long) ptr;
+        pte_t *pte;
 
-        if (vaddr < KMAP_FIX_BEGIN)
+        if (vaddr < FIXADDR_START)
                 return virt_to_page(ptr);
 
-        idx = (vaddr - KMAP_FIX_BEGIN) >> PAGE_SHIFT;
-        return pte_page(kmap_pte[idx]);
+        idx = virt_to_fix(vaddr);
+        pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
+        return pte_page(*pte);
 }
 
 #define flush_cache_kmaps()     flush_cache_all()