1 files changed, 333 insertions, 0 deletions

diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 000000000000..656004216953
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *      Marek Szyprowski <m.szyprowski@samsung.com>
+ *      Michal Nazarewicz <mina86@mina86.com>
+ *      Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *      Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+        unsigned long   base_pfn;
+        unsigned long   count;
+        unsigned long   *bitmap;
+        unsigned int order_per_bit; /* Order of pages represented by one bit */
+        struct mutex    lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+        return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+        return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+        return (1UL << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+        return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+                                                unsigned long pages)
+{
+        return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+        unsigned long bitmap_no, bitmap_count;
+
+        bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+        bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+        mutex_lock(&cma->lock);
+        bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+        mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+        int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
+        unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+        unsigned i = cma->count >> pageblock_order;
+        struct zone *zone;
+
+        cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+        if (!cma->bitmap)
+                return -ENOMEM;
+
+        WARN_ON_ONCE(!pfn_valid(pfn));
+        zone = page_zone(pfn_to_page(pfn));
+
+        do {
+                unsigned j;
+
+                base_pfn = pfn;
+                for (j = pageblock_nr_pages; j; --j, pfn++) {
+                        WARN_ON_ONCE(!pfn_valid(pfn));
+                        /*
+                         * alloc_contig_range requires the pfn range
+                         * specified to be in the same zone. Make this
+                         * simple by forcing the entire CMA resv range
+                         * to be in the same zone.
+                         */
+                        if (page_zone(pfn_to_page(pfn)) != zone)
+                                goto err;
+                }
+                init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+        } while (--i);
+
+        mutex_init(&cma->lock);
+        return 0;
+
+err:
+        kfree(cma->bitmap);
+        return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+        int i;
+
+        for (i = 0; i < cma_area_count; i++) {
+                int ret = cma_activate_area(&cma_areas[i]);
+
+                if (ret)
+                        return ret;
+        }
+
+        return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+                        phys_addr_t base, phys_addr_t limit,
+                        phys_addr_t alignment, unsigned int order_per_bit,
+                        struct cma **res_cma, bool fixed)
+{
+        struct cma *cma = &cma_areas[cma_area_count];
+        int ret = 0;
+
+        pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+                __func__, (unsigned long)size, (unsigned long)base,
+                (unsigned long)limit, (unsigned long)alignment);
+
+        if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+                pr_err("Not enough slots for CMA reserved regions!\n");
+                return -ENOSPC;
+        }
+
+        if (!size)
+                return -EINVAL;
+
+        if (alignment && !is_power_of_2(alignment))
+                return -EINVAL;
+
+        /*
+         * Sanitise input arguments.
+         * Pages both ends in CMA area could be merged into adjacent unmovable
+         * migratetype page by page allocator's buddy algorithm. In the case,
+         * you couldn't get a contiguous memory, which is not what we want.
+         */
+        alignment = max(alignment,
+                (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+        base = ALIGN(base, alignment);
+        size = ALIGN(size, alignment);
+        limit &= ~(alignment - 1);
+
+        /* size should be aligned with order_per_bit */
+        if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+                return -EINVAL;
+
+        /* Reserve memory */
+        if (base && fixed) {
+                if (memblock_is_region_reserved(base, size) ||
+                    memblock_reserve(base, size) < 0) {
+                        ret = -EBUSY;
+                        goto err;
+                }
+        } else {
+                phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+                                                        limit);
+                if (!addr) {
+                        ret = -ENOMEM;
+                        goto err;
+                } else {
+                        base = addr;
+                }
+        }
+
+        /*
+         * Each reserved area must be initialised later, when more kernel
+         * subsystems (like slab allocator) are available.
+         */
+        cma->base_pfn = PFN_DOWN(base);
+        cma->count = size >> PAGE_SHIFT;
+        cma->order_per_bit = order_per_bit;
+        *res_cma = cma;
+        cma_area_count++;
+
+        pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+                (unsigned long)base);
+        return 0;
+
+err:
+        pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+        return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+        unsigned long mask, pfn, start = 0;
+        unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+        struct page *page = NULL;
+        int ret;
+
+        if (!cma || !cma->count)
+                return NULL;
+
+        pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+                 count, align);
+
+        if (!count)
+                return NULL;
+
+        mask = cma_bitmap_aligned_mask(cma, align);
+        bitmap_maxno = cma_bitmap_maxno(cma);
+        bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+        for (;;) {
+                mutex_lock(&cma->lock);
+                bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+                                bitmap_maxno, start, bitmap_count, mask);
+                if (bitmap_no >= bitmap_maxno) {
+                        mutex_unlock(&cma->lock);
+                        break;
+                }
+                bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
+                /*
+                 * It's safe to drop the lock here. We've marked this region for
+                 * our exclusive use. If the migration fails we will take the
+                 * lock again and unmark it.
+                 */
+                mutex_unlock(&cma->lock);
+
+                pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
+                mutex_lock(&cma_mutex);
+                ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+                mutex_unlock(&cma_mutex);
+                if (ret == 0) {
+                        page = pfn_to_page(pfn);
+                        break;
+                } else if (ret != -EBUSY) {
+                        cma_clear_bitmap(cma, pfn, count);
+                        break;
+                }
+                cma_clear_bitmap(cma, pfn, count);
+                pr_debug("%s(): memory range at %p is busy, retrying\n",
+                         __func__, pfn_to_page(pfn));
+                /* try again with a bit different memory target */
+                start = bitmap_no + mask + 1;
+        }
+
+        pr_debug("%s(): returned %p\n", __func__, page);
+        return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+        unsigned long pfn;
+
+        if (!cma || !pages)
+                return false;
+
+        pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+        pfn = page_to_pfn(pages);
+
+        if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+                return false;
+
+        VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+        free_contig_range(pfn, count);
+        cma_clear_bitmap(cma, pfn, count);
+
+        return true;
+}