1 files changed, 202 insertions, 0 deletions

diff --git a/arch/arm26/mm/memc.c b/arch/arm26/mm/memc.c
new file mode 100644
index 000000000000..8e8a2bb2487d
--- /dev/null
+++ b/arch/arm26/mm/memc.c
@@ -0,0 +1,202 @@
+/*
+ *  linux/arch/arm26/mm/memc.c
+ *
+ *  Copyright (C) 1998-2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  Page table sludge for older ARM processor architectures.
+ */
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/page.h>
+#include <asm/memory.h>
+#include <asm/hardware.h>
+
+#include <asm/map.h>
+
+#define MEMC_TABLE_SIZE (256*sizeof(unsigned long))
+
+kmem_cache_t *pte_cache, *pgd_cache;
+int page_nr;
+
+/*
+ * Allocate space for a page table and a MEMC table.
+ * Note that we place the MEMC
+ * table before the page directory.  This means we can
+ * easily get to both tightly-associated data structures
+ * with a single pointer.
+ */
+static inline pgd_t *alloc_pgd_table(void)
+{
+        void *pg2k = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
+
+        if (pg2k)
+                pg2k += MEMC_TABLE_SIZE;
+
+        return (pgd_t *)pg2k;
+}
+
+/*
+ * Free a page table. this function is the counterpart to get_pgd_slow
+ * below, not alloc_pgd_table above.
+ */
+void free_pgd_slow(pgd_t *pgd)
+{
+        unsigned long tbl = (unsigned long)pgd;
+
+        tbl -= MEMC_TABLE_SIZE;
+
+        kmem_cache_free(pgd_cache, (void *)tbl);
+}
+
+/*
+ * Allocate a new pgd and fill it in ready for use
+ *
+ * A new tasks pgd is completely empty (all pages !present) except for:
+ *
+ * o The machine vectors at virtual address 0x0
+ * o The vmalloc region at the top of address space
+ *
+ */
+#define FIRST_KERNEL_PGD_NR     (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
+
+pgd_t *get_pgd_slow(struct mm_struct *mm)
+{
+        pgd_t *new_pgd, *init_pgd;
+        pmd_t *new_pmd, *init_pmd;
+        pte_t *new_pte, *init_pte;
+
+        new_pgd = alloc_pgd_table();
+        if (!new_pgd)
+                goto no_pgd;
+
+        /*
+         * This lock is here just to satisfy pmd_alloc and pte_lock
+         * FIXME: I bet we could avoid taking it pretty much altogether
+         */
+        spin_lock(&mm->page_table_lock);
+
+        /*
+         * On ARM, first page must always be allocated since it contains
+         * the machine vectors.
+         */
+        new_pmd = pmd_alloc(mm, new_pgd, 0);
+        if (!new_pmd)
+                goto no_pmd;
+
+        new_pte = pte_alloc_kernel(mm, new_pmd, 0);
+        if (!new_pte)
+                goto no_pte;
+
+        init_pgd = pgd_offset(&init_mm, 0);
+        init_pmd = pmd_offset(init_pgd, 0);
+        init_pte = pte_offset(init_pmd, 0);
+
+        set_pte(new_pte, *init_pte);
+
+        /*
+         * the page table entries are zeroed
+         * when the table is created. (see the cache_ctor functions below)
+         * Now we need to plonk the kernel (vmalloc) area at the end of
+         * the address space. We copy this from the init thread, just like
+         * the init_pte we copied above...
+         */
+        memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
+                (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
+
+        spin_unlock(&mm->page_table_lock);
+
+        /* update MEMC tables */
+        cpu_memc_update_all(new_pgd);
+        return new_pgd;
+
+no_pte:
+        spin_unlock(&mm->page_table_lock);
+        pmd_free(new_pmd);
+        free_pgd_slow(new_pgd);
+        return NULL;
+
+no_pmd:
+        spin_unlock(&mm->page_table_lock);
+        free_pgd_slow(new_pgd);
+        return NULL;
+
+no_pgd:
+        return NULL;
+}
+
+/*
+ * No special code is required here.
+ */
+void setup_mm_for_reboot(char mode)
+{
+}
+
+/*
+ * This contains the code to setup the memory map on an ARM2/ARM250/ARM3
+ *  o swapper_pg_dir = 0x0207d000
+ *  o kernel proper starts at 0x0208000
+ *  o create (allocate) a pte to contain the machine vectors
+ *  o populate the pte (points to 0x02078000) (FIXME - is it zeroed?)
+ *  o populate the init tasks page directory (pgd) with the new pte
+ *  o zero the rest of the init tasks pgdir (FIXME - what about vmalloc?!)
+ */
+void __init memtable_init(struct meminfo *mi)
+{
+        pte_t *pte;
+        int i;
+
+        page_nr = max_low_pfn;
+
+        pte = alloc_bootmem_low_pages(PTRS_PER_PTE * sizeof(pte_t));
+        pte[0] = mk_pte_phys(PAGE_OFFSET + SCREEN_SIZE, PAGE_READONLY);
+        pmd_populate(&init_mm, pmd_offset(swapper_pg_dir, 0), pte);
+
+        for (i = 1; i < PTRS_PER_PGD; i++)
+                pgd_val(swapper_pg_dir[i]) = 0;
+}
+
+void __init iotable_init(struct map_desc *io_desc)
+{
+        /* nothing to do */
+}
+
+/*
+ * We never have holes in the memmap
+ */
+void __init create_memmap_holes(struct meminfo *mi)
+{
+}
+
+static void pte_cache_ctor(void *pte, kmem_cache_t *cache, unsigned long flags)
+{
+        memzero(pte, sizeof(pte_t) * PTRS_PER_PTE);
+}
+
+static void pgd_cache_ctor(void *pgd, kmem_cache_t *cache, unsigned long flags)
+{
+        memzero(pgd + MEMC_TABLE_SIZE, USER_PTRS_PER_PGD * sizeof(pgd_t));
+}
+
+void __init pgtable_cache_init(void)
+{
+        pte_cache = kmem_cache_create("pte-cache",
+                                sizeof(pte_t) * PTRS_PER_PTE,
+                                0, 0, pte_cache_ctor, NULL);
+        if (!pte_cache)
+                BUG();
+
+        pgd_cache = kmem_cache_create("pgd-cache", MEMC_TABLE_SIZE +
+                                sizeof(pgd_t) * PTRS_PER_PGD,
+                                0, 0, pgd_cache_ctor, NULL);
+        if (!pgd_cache)
+                BUG();
+}