--- /dev/null
+/*
+ * arch/s390/mm/vmem.c
+ *
+ * Copyright IBM Corp. 2006
+ * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/bootmem.h>
+#include <linux/pfn.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/setup.h>
+#include <asm/tlbflush.h>
+
+unsigned long vmalloc_end;
+EXPORT_SYMBOL(vmalloc_end);
+
+static struct page *vmem_map;
+static DEFINE_MUTEX(vmem_mutex);
+
+struct memory_segment {
+ struct list_head list;
+ unsigned long start;
+ unsigned long size;
+};
+
+static LIST_HEAD(mem_segs);
+
+void memmap_init(unsigned long size, int nid, unsigned long zone,
+ unsigned long start_pfn)
+{
+ struct page *start, *end;
+ struct page *map_start, *map_end;
+ int i;
+
+ start = pfn_to_page(start_pfn);
+ end = start + size;
+
+ for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
+ unsigned long cstart, cend;
+
+ cstart = PFN_DOWN(memory_chunk[i].addr);
+ cend = cstart + PFN_DOWN(memory_chunk[i].size);
+
+ map_start = mem_map + cstart;
+ map_end = mem_map + cend;
+
+ if (map_start < start)
+ map_start = start;
+ if (map_end > end)
+ map_end = end;
+
+ map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1))
+ / sizeof(struct page);
+ map_end += ((PFN_ALIGN((unsigned long) map_end)
+ - (unsigned long) map_end)
+ / sizeof(struct page));
+
+ if (map_start < map_end)
+ memmap_init_zone((unsigned long)(map_end - map_start),
+ nid, zone, page_to_pfn(map_start),
+ MEMMAP_EARLY);
+ }
+}
+
+static inline void *vmem_alloc_pages(unsigned int order)
+{
+ if (slab_is_available())
+ return (void *)__get_free_pages(GFP_KERNEL, order);
+ return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
+}
+
+static inline pmd_t *vmem_pmd_alloc(void)
+{
+ pmd_t *pmd;
+ int i;
+
+ pmd = vmem_alloc_pages(PMD_ALLOC_ORDER);
+ if (!pmd)
+ return NULL;
+ for (i = 0; i < PTRS_PER_PMD; i++)
+ pmd_clear(pmd + i);
+ return pmd;
+}
+
+static inline pte_t *vmem_pte_alloc(void)
+{
+ pte_t *pte;
+ pte_t empty_pte;
+ int i;
+
+ pte = vmem_alloc_pages(PTE_ALLOC_ORDER);
+ if (!pte)
+ return NULL;
+ pte_val(empty_pte) = _PAGE_TYPE_EMPTY;
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ set_pte(pte + i, empty_pte);
+ return pte;
+}
+
+/*
+ * Add a physical memory range to the 1:1 mapping.
+ */
+static int vmem_add_range(unsigned long start, unsigned long size)
+{
+ unsigned long address;
+ pgd_t *pg_dir;
+ pmd_t *pm_dir;
+ pte_t *pt_dir;
+ pte_t pte;
+ int ret = -ENOMEM;
+
+ for (address = start; address < start + size; address += PAGE_SIZE) {
+ pg_dir = pgd_offset_k(address);
+ if (pgd_none(*pg_dir)) {
+ pm_dir = vmem_pmd_alloc();
+ if (!pm_dir)
+ goto out;
+ pgd_populate(&init_mm, pg_dir, pm_dir);
+ }
+
+ pm_dir = pmd_offset(pg_dir, address);
+ if (pmd_none(*pm_dir)) {
+ pt_dir = vmem_pte_alloc();
+ if (!pt_dir)
+ goto out;
+ pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
+ }
+
+ pt_dir = pte_offset_kernel(pm_dir, address);
+ pte = pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL);
+ set_pte(pt_dir, pte);
+ }
+ ret = 0;
+out:
+ flush_tlb_kernel_range(start, start + size);
+ return ret;
+}
+
+/*
+ * Remove a physical memory range from the 1:1 mapping.
+ * Currently only invalidates page table entries.
+ */
+static void vmem_remove_range(unsigned long start, unsigned long size)
+{
+ unsigned long address;
+ pgd_t *pg_dir;
+ pmd_t *pm_dir;
+ pte_t *pt_dir;
+ pte_t pte;
+
+ pte_val(pte) = _PAGE_TYPE_EMPTY;
+ for (address = start; address < start + size; address += PAGE_SIZE) {
+ pg_dir = pgd_offset_k(address);
+ if (pgd_none(*pg_dir))
+ continue;
+ pm_dir = pmd_offset(pg_dir, address);
+ if (pmd_none(*pm_dir))
+ continue;
+ pt_dir = pte_offset_kernel(pm_dir, address);
+ set_pte(pt_dir, pte);
+ }
+ flush_tlb_kernel_range(start, start + size);
+}
+
+/*
+ * Add a backed mem_map array to the virtual mem_map array.
+ */
+static int vmem_add_mem_map(unsigned long start, unsigned long size)
+{
+ unsigned long address, start_addr, end_addr;
+ struct page *map_start, *map_end;
+ pgd_t *pg_dir;
+ pmd_t *pm_dir;
+ pte_t *pt_dir;
+ pte_t pte;
+ int ret = -ENOMEM;
+
+ map_start = vmem_map + PFN_DOWN(start);
+ map_end = vmem_map + PFN_DOWN(start + size);
+
+ start_addr = (unsigned long) map_start & PAGE_MASK;
+ end_addr = PFN_ALIGN((unsigned long) map_end);
+
+ for (address = start_addr; address < end_addr; address += PAGE_SIZE) {
+ pg_dir = pgd_offset_k(address);
+ if (pgd_none(*pg_dir)) {
+ pm_dir = vmem_pmd_alloc();
+ if (!pm_dir)
+ goto out;
+ pgd_populate(&init_mm, pg_dir, pm_dir);
+ }
+
+ pm_dir = pmd_offset(pg_dir, address);
+ if (pmd_none(*pm_dir)) {
+ pt_dir = vmem_pte_alloc();
+ if (!pt_dir)
+ goto out;
+ pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
+ }
+
+ pt_dir = pte_offset_kernel(pm_dir, address);
+ if (pte_none(*pt_dir)) {
+ unsigned long new_page;
+
+ new_page =__pa(vmem_alloc_pages(0));
+ if (!new_page)
+ goto out;
+ pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
+ set_pte(pt_dir, pte);
+ }
+ }
+ ret = 0;
+out:
+ flush_tlb_kernel_range(start_addr, end_addr);
+ return ret;
+}
+
+static int vmem_add_mem(unsigned long start, unsigned long size)
+{
+ int ret;
+
+ ret = vmem_add_range(start, size);
+ if (ret)
+ return ret;
+ return vmem_add_mem_map(start, size);
+}
+
+/*
+ * Add memory segment to the segment list if it doesn't overlap with
+ * an already present segment.
+ */
+static int insert_memory_segment(struct memory_segment *seg)
+{
+ struct memory_segment *tmp;
+
+ if (PFN_DOWN(seg->start + seg->size) > max_pfn ||
+ seg->start + seg->size < seg->start)
+ return -ERANGE;
+
+ list_for_each_entry(tmp, &mem_segs, list) {
+ if (seg->start >= tmp->start + tmp->size)
+ continue;
+ if (seg->start + seg->size <= tmp->start)
+ continue;
+ return -ENOSPC;
+ }
+ list_add(&seg->list, &mem_segs);
+ return 0;
+}
+
+/*
+ * Remove memory segment from the segment list.
+ */
+static void remove_memory_segment(struct memory_segment *seg)
+{
+ list_del(&seg->list);
+}
+
+static void __remove_shared_memory(struct memory_segment *seg)
+{
+ remove_memory_segment(seg);
+ vmem_remove_range(seg->start, seg->size);
+}
+
+int remove_shared_memory(unsigned long start, unsigned long size)
+{
+ struct memory_segment *seg;
+ int ret;
+
+ mutex_lock(&vmem_mutex);
+
+ ret = -ENOENT;
+ list_for_each_entry(seg, &mem_segs, list) {
+ if (seg->start == start && seg->size == size)
+ break;
+ }
+
+ if (seg->start != start || seg->size != size)
+ goto out;
+
+ ret = 0;
+ __remove_shared_memory(seg);
+ kfree(seg);
+out:
+ mutex_unlock(&vmem_mutex);
+ return ret;
+}
+
+int add_shared_memory(unsigned long start, unsigned long size)
+{
+ struct memory_segment *seg;
+ struct page *page;
+ unsigned long pfn, num_pfn, end_pfn;
+ int ret;
+
+ mutex_lock(&vmem_mutex);
+ ret = -ENOMEM;
+ seg = kzalloc(sizeof(*seg), GFP_KERNEL);
+ if (!seg)
+ goto out;
+ seg->start = start;
+ seg->size = size;
+
+ ret = insert_memory_segment(seg);
+ if (ret)
+ goto out_free;
+
+ ret = vmem_add_mem(start, size);
+ if (ret)
+ goto out_remove;
+
+ pfn = PFN_DOWN(start);
+ num_pfn = PFN_DOWN(size);
+ end_pfn = pfn + num_pfn;
+
+ page = pfn_to_page(pfn);
+ memset(page, 0, num_pfn * sizeof(struct page));
+
+ for (; pfn < end_pfn; pfn++) {
+ page = pfn_to_page(pfn);
+ init_page_count(page);
+ reset_page_mapcount(page);
+ SetPageReserved(page);
+ INIT_LIST_HEAD(&page->lru);
+ }
+ goto out;
+
+out_remove:
+ __remove_shared_memory(seg);
+out_free:
+ kfree(seg);
+out:
+ mutex_unlock(&vmem_mutex);
+ return ret;
+}
+
+/*
+ * map whole physical memory to virtual memory (identity mapping)
+ */
+void __init vmem_map_init(void)
+{
+ unsigned long map_size;
+ int i;
+
+ map_size = ALIGN(max_low_pfn, MAX_ORDER_NR_PAGES) * sizeof(struct page);
+ vmalloc_end = PFN_ALIGN(VMALLOC_END_INIT) - PFN_ALIGN(map_size);
+ vmem_map = (struct page *) vmalloc_end;
+ NODE_DATA(0)->node_mem_map = vmem_map;
+
+ for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++)
+ vmem_add_mem(memory_chunk[i].addr, memory_chunk[i].size);
+}
+
+/*
+ * Convert memory chunk array to a memory segment list so there is a single
+ * list that contains both r/w memory and shared memory segments.
+ */
+static int __init vmem_convert_memory_chunk(void)
+{
+ struct memory_segment *seg;
+ int i;
+
+ mutex_lock(&vmem_mutex);
+ for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
+ if (!memory_chunk[i].size)
+ continue;
+ seg = kzalloc(sizeof(*seg), GFP_KERNEL);
+ if (!seg)
+ panic("Out of memory...\n");
+ seg->start = memory_chunk[i].addr;
+ seg->size = memory_chunk[i].size;
+ insert_memory_segment(seg);
+ }
+ mutex_unlock(&vmem_mutex);
+ return 0;
+}
+
+core_initcall(vmem_convert_memory_chunk);
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