i386: prepare shared mm/pgtable.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 373 insertions, 0 deletions

diff --git a/arch/i386/mm/pgtable_32.c b/arch/i386/mm/pgtable_32.c
new file mode 100644
index 000000000000..01437c46baae
--- /dev/null
+++ b/arch/i386/mm/pgtable_32.c
@@ -0,0 +1,373 @@
+/*
+ *  linux/arch/i386/mm/pgtable.c
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/quicklist.h>
+
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/fixmap.h>
+#include <asm/e820.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+void show_mem(void)
+{
+        int total = 0, reserved = 0;
+        int shared = 0, cached = 0;
+        int highmem = 0;
+        struct page *page;
+        pg_data_t *pgdat;
+        unsigned long i;
+        unsigned long flags;
+
+        printk(KERN_INFO "Mem-info:\n");
+        show_free_areas();
+        printk(KERN_INFO "Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
+        for_each_online_pgdat(pgdat) {
+                pgdat_resize_lock(pgdat, &flags);
+                for (i = 0; i < pgdat->node_spanned_pages; ++i) {
+                        page = pgdat_page_nr(pgdat, i);
+                        total++;
+                        if (PageHighMem(page))
+                                highmem++;
+                        if (PageReserved(page))
+                                reserved++;
+                        else if (PageSwapCache(page))
+                                cached++;
+                        else if (page_count(page))
+                                shared += page_count(page) - 1;
+                }
+                pgdat_resize_unlock(pgdat, &flags);
+        }
+        printk(KERN_INFO "%d pages of RAM\n", total);
+        printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
+        printk(KERN_INFO "%d reserved pages\n", reserved);
+        printk(KERN_INFO "%d pages shared\n", shared);
+        printk(KERN_INFO "%d pages swap cached\n", cached);
+
+        printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
+        printk(KERN_INFO "%lu pages writeback\n",
+                                        global_page_state(NR_WRITEBACK));
+        printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
+        printk(KERN_INFO "%lu pages slab\n",
+                global_page_state(NR_SLAB_RECLAIMABLE) +
+                global_page_state(NR_SLAB_UNRECLAIMABLE));
+        printk(KERN_INFO "%lu pages pagetables\n",
+                                        global_page_state(NR_PAGETABLE));
+}
+
+/*
+ * Associate a virtual page frame with a given physical page frame 
+ * and protection flags for that frame.
+ */ 
+static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pgd = swapper_pg_dir + pgd_index(vaddr);
+        if (pgd_none(*pgd)) {
+                BUG();
+                return;
+        }
+        pud = pud_offset(pgd, vaddr);
+        if (pud_none(*pud)) {
+                BUG();
+                return;
+        }
+        pmd = pmd_offset(pud, vaddr);
+        if (pmd_none(*pmd)) {
+                BUG();
+                return;
+        }
+        pte = pte_offset_kernel(pmd, vaddr);
+        if (pgprot_val(flags))
+                /* <pfn,flags> stored as-is, to permit clearing entries */
+                set_pte(pte, pfn_pte(pfn, flags));
+        else
+                pte_clear(&init_mm, vaddr, pte);
+
+        /*
+         * It's enough to flush this one mapping.
+         * (PGE mappings get flushed as well)
+         */
+        __flush_tlb_one(vaddr);
+}
+
+/*
+ * Associate a large virtual page frame with a given physical page frame 
+ * and protection flags for that frame. pfn is for the base of the page,
+ * vaddr is what the page gets mapped to - both must be properly aligned. 
+ * The pmd must already be instantiated. Assumes PAE mode.
+ */ 
+void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+
+        if (vaddr & (PMD_SIZE-1)) {             /* vaddr is misaligned */
+                printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
+                return; /* BUG(); */
+        }
+        if (pfn & (PTRS_PER_PTE-1)) {           /* pfn is misaligned */
+                printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
+                return; /* BUG(); */
+        }
+        pgd = swapper_pg_dir + pgd_index(vaddr);
+        if (pgd_none(*pgd)) {
+                printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
+                return; /* BUG(); */
+        }
+        pud = pud_offset(pgd, vaddr);
+        pmd = pmd_offset(pud, vaddr);
+        set_pmd(pmd, pfn_pmd(pfn, flags));
+        /*
+         * It's enough to flush this one mapping.
+         * (PGE mappings get flushed as well)
+         */
+        __flush_tlb_one(vaddr);
+}
+
+static int fixmaps;
+unsigned long __FIXADDR_TOP = 0xfffff000;
+EXPORT_SYMBOL(__FIXADDR_TOP);
+
+void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
+{
+        unsigned long address = __fix_to_virt(idx);
+
+        if (idx >= __end_of_fixed_addresses) {
+                BUG();
+                return;
+        }
+        set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
+        fixmaps++;
+}
+
+/**
+ * reserve_top_address - reserves a hole in the top of kernel address space
+ * @reserve - size of hole to reserve
+ *
+ * Can be used to relocate the fixmap area and poke a hole in the top
+ * of kernel address space to make room for a hypervisor.
+ */
+void reserve_top_address(unsigned long reserve)
+{
+        BUG_ON(fixmaps > 0);
+        printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
+               (int)-reserve);
+        __FIXADDR_TOP = -reserve - PAGE_SIZE;
+        __VMALLOC_RESERVE += reserve;
+}
+
+pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
+{
+        return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
+}
+
+struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+        struct page *pte;
+
+#ifdef CONFIG_HIGHPTE
+        pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
+#else
+        pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
+#endif
+        return pte;
+}
+
+void pmd_ctor(void *pmd, struct kmem_cache *cache, unsigned long flags)
+{
+        memset(pmd, 0, PTRS_PER_PMD*sizeof(pmd_t));
+}
+
+/*
+ * List of all pgd's needed for non-PAE so it can invalidate entries
+ * in both cached and uncached pgd's; not needed for PAE since the
+ * kernel pmd is shared. If PAE were not to share the pmd a similar
+ * tactic would be needed. This is essentially codepath-based locking
+ * against pageattr.c; it is the unique case in which a valid change
+ * of kernel pagetables can't be lazily synchronized by vmalloc faults.
+ * vmalloc faults work because attached pagetables are never freed.
+ * -- wli
+ */
+DEFINE_SPINLOCK(pgd_lock);
+struct page *pgd_list;
+
+static inline void pgd_list_add(pgd_t *pgd)
+{
+        struct page *page = virt_to_page(pgd);
+        page->index = (unsigned long)pgd_list;
+        if (pgd_list)
+                set_page_private(pgd_list, (unsigned long)&page->index);
+        pgd_list = page;
+        set_page_private(page, (unsigned long)&pgd_list);
+}
+
+static inline void pgd_list_del(pgd_t *pgd)
+{
+        struct page *next, **pprev, *page = virt_to_page(pgd);
+        next = (struct page *)page->index;
+        pprev = (struct page **)page_private(page);
+        *pprev = next;
+        if (next)
+                set_page_private(next, (unsigned long)pprev);
+}
+
+
+
+#if (PTRS_PER_PMD == 1)
+/* Non-PAE pgd constructor */
+static void pgd_ctor(void *pgd)
+{
+        unsigned long flags;
+
+        /* !PAE, no pagetable sharing */
+        memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
+
+        spin_lock_irqsave(&pgd_lock, flags);
+
+        /* must happen under lock */
+        clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
+                        swapper_pg_dir + USER_PTRS_PER_PGD,
+                        KERNEL_PGD_PTRS);
+        paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
+                                __pa(swapper_pg_dir) >> PAGE_SHIFT,
+                                USER_PTRS_PER_PGD,
+                                KERNEL_PGD_PTRS);
+        pgd_list_add(pgd);
+        spin_unlock_irqrestore(&pgd_lock, flags);
+}
+#else  /* PTRS_PER_PMD > 1 */
+/* PAE pgd constructor */
+static void pgd_ctor(void *pgd)
+{
+        /* PAE, kernel PMD may be shared */
+
+        if (SHARED_KERNEL_PMD) {
+                clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
+                                swapper_pg_dir + USER_PTRS_PER_PGD,
+                                KERNEL_PGD_PTRS);
+        } else {
+                unsigned long flags;
+
+                memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
+                spin_lock_irqsave(&pgd_lock, flags);
+                pgd_list_add(pgd);
+                spin_unlock_irqrestore(&pgd_lock, flags);
+        }
+}
+#endif  /* PTRS_PER_PMD */
+
+static void pgd_dtor(void *pgd)
+{
+        unsigned long flags; /* can be called from interrupt context */
+
+        if (SHARED_KERNEL_PMD)
+                return;
+
+        paravirt_release_pd(__pa(pgd) >> PAGE_SHIFT);
+        spin_lock_irqsave(&pgd_lock, flags);
+        pgd_list_del(pgd);
+        spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
+#define UNSHARED_PTRS_PER_PGD                           \
+        (SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
+
+/* If we allocate a pmd for part of the kernel address space, then
+   make sure its initialized with the appropriate kernel mappings.
+   Otherwise use a cached zeroed pmd.  */
+static pmd_t *pmd_cache_alloc(int idx)
+{
+        pmd_t *pmd;
+
+        if (idx >= USER_PTRS_PER_PGD) {
+                pmd = (pmd_t *)__get_free_page(GFP_KERNEL);
+
+                if (pmd)
+                        memcpy(pmd,
+                               (void *)pgd_page_vaddr(swapper_pg_dir[idx]),
+                               sizeof(pmd_t) * PTRS_PER_PMD);
+        } else
+                pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
+
+        return pmd;
+}
+
+static void pmd_cache_free(pmd_t *pmd, int idx)
+{
+        if (idx >= USER_PTRS_PER_PGD)
+                free_page((unsigned long)pmd);
+        else
+                kmem_cache_free(pmd_cache, pmd);
+}
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+        int i;
+        pgd_t *pgd = quicklist_alloc(0, GFP_KERNEL, pgd_ctor);
+
+        if (PTRS_PER_PMD == 1 || !pgd)
+                return pgd;
+
+        for (i = 0; i < UNSHARED_PTRS_PER_PGD; ++i) {
+                pmd_t *pmd = pmd_cache_alloc(i);
+
+                if (!pmd)
+                        goto out_oom;
+
+                paravirt_alloc_pd(__pa(pmd) >> PAGE_SHIFT);
+                set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
+        }
+        return pgd;
+
+out_oom:
+        for (i--; i >= 0; i--) {
+                pgd_t pgdent = pgd[i];
+                void* pmd = (void *)__va(pgd_val(pgdent)-1);
+                paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
+                pmd_cache_free(pmd, i);
+        }
+        quicklist_free(0, pgd_dtor, pgd);
+        return NULL;
+}
+
+void pgd_free(pgd_t *pgd)
+{
+        int i;
+
+        /* in the PAE case user pgd entries are overwritten before usage */
+        if (PTRS_PER_PMD > 1)
+                for (i = 0; i < UNSHARED_PTRS_PER_PGD; ++i) {
+                        pgd_t pgdent = pgd[i];
+                        void* pmd = (void *)__va(pgd_val(pgdent)-1);
+                        paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
+                        pmd_cache_free(pmd, i);
+                }
+        /* in the non-PAE case, free_pgtables() clears user pgd entries */
+        quicklist_free(0, pgd_dtor, pgd);
+}
+
+void check_pgt_cache(void)
+{
+        quicklist_trim(0, pgd_dtor, 25, 16);
+}
+