--- /dev/null
+/*
+ * 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
+#define CREATE_TRACE_POINTS
+
+#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>
+#include <linux/highmem.h>
+#include <linux/io.h>
+#include <trace/events/cma.h>
+
+#include "cma.h"
+
+struct cma cma_areas[MAX_CMA_AREAS];
+unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(const struct cma *cma)
+{
+ return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(const struct cma *cma)
+{
+ return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
+ int align_order)
+{
+ if (align_order <= cma->order_per_bit)
+ return 0;
+ return (1UL << (align_order - cma->order_per_bit)) - 1;
+}
+
+/*
+ * Find a PFN aligned to the specified order and return an offset represented in
+ * order_per_bits.
+ */
+static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
+ int align_order)
+{
+ if (align_order <= cma->order_per_bit)
+ return 0;
+
+ return (ALIGN(cma->base_pfn, (1UL << align_order))
+ - cma->base_pfn) >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(const 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,
+ unsigned 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);
+
+#ifdef CONFIG_CMA_DEBUGFS
+ INIT_HLIST_HEAD(&cma->mem_head);
+ spin_lock_init(&cma->mem_head_lock);
+#endif
+
+ return 0;
+
+err:
+ kfree(cma->bitmap);
+ cma->count = 0;
+ 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_init_reserved_mem() - create custom contiguous area from reserved memory
+ * @base: Base address of the reserved area
+ * @size: Size of the reserved area (in bytes),
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ *
+ * This function creates custom contiguous area from already reserved memory.
+ */
+int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
+ unsigned int order_per_bit,
+ struct cma **res_cma)
+{
+ struct cma *cma;
+ phys_addr_t alignment;
+
+ /* Sanity checks */
+ if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+ pr_err("Not enough slots for CMA reserved regions!\n");
+ return -ENOSPC;
+ }
+
+ if (!size || !memblock_is_region_reserved(base, size))
+ return -EINVAL;
+
+ /* ensure minimal alignment requied by mm core */
+ alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+
+ /* alignment should be aligned with order_per_bit */
+ if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
+ return -EINVAL;
+
+ if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
+ return -EINVAL;
+
+ /*
+ * Each reserved area must be initialised later, when more kernel
+ * subsystems (like slab allocator) are available.
+ */
+ cma = &cma_areas[cma_area_count];
+ cma->base_pfn = PFN_DOWN(base);
+ cma->count = size >> PAGE_SHIFT;
+ cma->order_per_bit = order_per_bit;
+ *res_cma = cma;
+ cma_area_count++;
+ totalcma_pages += (size / PAGE_SIZE);
+
+ return 0;
+}
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @size: Size of the reserved area (in bytes),
+ * @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.
+ * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
+ *
+ * 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 base,
+ phys_addr_t size, phys_addr_t limit,
+ phys_addr_t alignment, unsigned int order_per_bit,
+ bool fixed, struct cma **res_cma)
+{
+ phys_addr_t memblock_end = memblock_end_of_DRAM();
+ phys_addr_t highmem_start;
+ int ret = 0;
+
+#ifdef CONFIG_X86
+ /*
+ * high_memory isn't direct mapped memory so retrieving its physical
+ * address isn't appropriate. But it would be useful to check the
+ * physical address of the highmem boundary so it's justfiable to get
+ * the physical address from it. On x86 there is a validation check for
+ * this case, so the following workaround is needed to avoid it.
+ */
+ highmem_start = __pa_nodebug(high_memory);
+#else
+ highmem_start = __pa(high_memory);
+#endif
+ pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
+ __func__, &size, &base, &limit, &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);
+
+ if (!base)
+ fixed = false;
+
+ /* size should be aligned with order_per_bit */
+ if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+ return -EINVAL;
+
+ /*
+ * If allocating at a fixed base the request region must not cross the
+ * low/high memory boundary.
+ */
+ if (fixed && base < highmem_start && base + size > highmem_start) {
+ ret = -EINVAL;
+ pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
+ &base, &highmem_start);
+ goto err;
+ }
+
+ /*
+ * If the limit is unspecified or above the memblock end, its effective
+ * value will be the memblock end. Set it explicitly to simplify further
+ * checks.
+ */
+ if (limit == 0 || limit > memblock_end)
+ limit = memblock_end;
+
+ /* Reserve memory */
+ if (fixed) {
+ if (memblock_is_region_reserved(base, size) ||
+ memblock_reserve(base, size) < 0) {
+ ret = -EBUSY;
+ goto err;
+ }
+ } else {
+ phys_addr_t addr = 0;
+
+ /*
+ * All pages in the reserved area must come from the same zone.
+ * If the requested region crosses the low/high memory boundary,
+ * try allocating from high memory first and fall back to low
+ * memory in case of failure.
+ */
+ if (base < highmem_start && limit > highmem_start) {
+ addr = memblock_alloc_range(size, alignment,
+ highmem_start, limit);
+ limit = highmem_start;
+ }
+
+ if (!addr) {
+ addr = memblock_alloc_range(size, alignment, base,
+ limit);
+ if (!addr) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ }
+
+ /*
+ * kmemleak scans/reads tracked objects for pointers to other
+ * objects but this address isn't mapped and accessible
+ */
+ kmemleak_ignore(phys_to_virt(addr));
+ base = addr;
+ }
+
+ ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
+ if (ret)
+ goto err;
+
+ pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
+ &base);
+ return 0;
+
+err:
+ pr_err("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, unsigned int count, unsigned int align)
+{
+ unsigned long mask, offset, 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);
+ offset = cma_bitmap_aligned_offset(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_off(cma->bitmap,
+ bitmap_maxno, start, bitmap_count, mask,
+ offset);
+ 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;
+ }
+
+ cma_clear_bitmap(cma, pfn, count);
+ if (ret != -EBUSY)
+ break;
+
+ 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;
+ }
+
+ trace_cma_alloc(page ? pfn : -1UL, page, count, align);
+
+ 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, const struct page *pages, unsigned 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);
+ trace_cma_release(pfn, pages, count);
+
+ return true;
+}
Code Review / kvmfornfv.git / blobdiff