ARM: Fix pfn_valid() for sparse memory

On OMAP platforms, some people want to declare to segment up the memory
between the kernel and a separate application such that there is a hole
in the middle of the memory as far as Linux is concerned.  However,
they want to be able to mmap() the hole.

This currently causes problems, because update_mmu_cache() thinks that
there are valid struct pages for the "hole".  Fix this by making
pfn_valid() slightly more expensive, by checking whether the PFN is
contained within the meminfo array.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Khasim Syed Mohammed <khasim@ti.com>

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 85763db87449f4f4c62947e30a2b6b0cf9a43e9e..b3b54c6216a4f1fea2e2145b431d2a87543e5c83 100644 (file)
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -212,7 +212,6 @@ static inline __deprecated void *bus_to_virt(unsigned long x)
  *
  *  page_to_pfn(page)  convert a struct page * to a PFN number
  *  pfn_to_page(pfn)   convert a _valid_ PFN number to struct page *
- *  pfn_valid(pfn)     indicates whether a PFN number is valid
  *
  *  virt_to_page(k)    convert a _valid_ virtual address to struct page *
  *  virt_addr_valid(k) indicates whether a virtual address is valid
@@ -221,10 +220,6 @@ static inline __deprecated void *bus_to_virt(unsigned long x)
 
 #define ARCH_PFN_OFFSET                PHYS_PFN_OFFSET
 
-#ifndef CONFIG_SPARSEMEM
-#define pfn_valid(pfn)         ((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
-#endif
-
 #define virt_to_page(kaddr)    pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define virt_addr_valid(kaddr) ((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
 
@@ -241,18 +236,6 @@ static inline __deprecated void *bus_to_virt(unsigned long x)
 #define arch_pfn_to_nid(pfn)   PFN_TO_NID(pfn)
 #define arch_local_page_offset(pfn, nid) LOCAL_MAP_NR((pfn) << PAGE_SHIFT)
 
-#define pfn_valid(pfn)                                         \
-       ({                                                      \
-               unsigned int nid = PFN_TO_NID(pfn);             \
-               int valid = nid < MAX_NUMNODES;                 \
-               if (valid) {                                    \
-                       pg_data_t *node = NODE_DATA(nid);       \
-                       valid = (pfn - node->node_start_pfn) <  \
-                               node->node_spanned_pages;       \
-               }                                               \
-               valid;                                          \
-       })
-
 #define virt_to_page(kaddr)                                    \
        (ADDR_TO_MAPBASE(kaddr) + LOCAL_MAP_NR(kaddr))
 

diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h
index 9c746af1bf6e150ae19acebe961b0a0c116b5d45..3a32af4cce30ac2ec0da9eb3089cbcf0082b193f 100644 (file)
--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -194,6 +194,10 @@ typedef unsigned long pgprot_t;
 
 typedef struct page *pgtable_t;
 
+#ifndef CONFIG_SPARSEMEM
+extern int pfn_valid(unsigned long);
+#endif
+
 #include <asm/memory.h>
 
 #endif /* !__ASSEMBLY__ */

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 3a7279c1ce5e7eb5ed857f6d7bf442920c12860c..ea36186f32c385fb50bfd4df6c3735aa82360cfb 100644 (file)
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -15,6 +15,7 @@
 #include <linux/mman.h>
 #include <linux/nodemask.h>
 #include <linux/initrd.h>
+#include <linux/sort.h>
 #include <linux/highmem.h>
 
 #include <asm/mach-types.h>
@@ -349,12 +350,43 @@ static void __init bootmem_free_node(int node, struct meminfo *mi)
        free_area_init_node(node, zone_size, min, zhole_size);
 }
 
+#ifndef CONFIG_SPARSEMEM
+int pfn_valid(unsigned long pfn)
+{
+       struct meminfo *mi = &meminfo;
+       unsigned int left = 0, right = mi->nr_banks;
+
+       do {
+               unsigned int mid = (right + left) / 2;
+               struct membank *bank = &mi->bank[mid];
+
+               if (pfn < bank_pfn_start(bank))
+                       right = mid;
+               else if (pfn >= bank_pfn_end(bank))
+                       left = mid + 1;
+               else
+                       return 1;
+       } while (left < right);
+       return 0;
+}
+EXPORT_SYMBOL(pfn_valid);
+#endif
+
+static int __init meminfo_cmp(const void *_a, const void *_b)
+{
+       const struct membank *a = _a, *b = _b;
+       long cmp = bank_pfn_start(a) - bank_pfn_start(b);
+       return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
+}
+
 void __init bootmem_init(void)
 {
        struct meminfo *mi = &meminfo;
        unsigned long min, max_low, max_high;
        int node, initrd_node;
 
+       sort(&mi->bank, mi->nr_banks, sizeof(mi->bank[0]), meminfo_cmp, NULL);
+
        /*
         * Locate which node contains the ramdisk image, if any.
         */