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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm26/mm/memc.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm26/mm/memc.c')
-rw-r--r--arch/arm26/mm/memc.c202
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 00000000000..8e8a2bb2487
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+++ b/arch/arm26/mm/memc.c
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+/*
+ * 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();
+}