efi_loader: Implement memory allocation and map

The EFI loader needs to maintain views of memory - general system memory
windows as well as used locations inside those and potential runtime service
MMIO windows.

To manage all of these, add a few helpers that maintain an internal
representation of the map the similar to how the EFI API later on reports
it to the application.

For allocations, the scheme is very simple. We basically allow allocations
to replace chunks of previously done maps, so that a new LOADER_DATA
allocation for example can remove a piece of the RAM map. When no specific
address is given, we just take the highest possible address in the lowest
RAM map that fits the allocation size.

Signed-off-by: Alexander Graf <agraf@suse.de>
Tested-by: Simon Glass <sjg@chromium.org>

1 files changed, 319 insertions, 0 deletions

diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
new file mode 100644
index 0000000..c82b53f
--- /dev/null
+++ b/lib/efi_loader/efi_memory.c
@@ -0,0 +1,319 @@
+/*
+ *  EFI application memory management
+ *
+ *  Copyright (c) 2016 Alexander Graf
+ *
+ *  SPDX-License-Identifier:     GPL-2.0+
+ */
+
+/* #define DEBUG_EFI */
+
+#include <common.h>
+#include <efi_loader.h>
+#include <malloc.h>
+#include <asm/global_data.h>
+#include <libfdt_env.h>
+#include <inttypes.h>
+#include <watchdog.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct efi_mem_list {
+	struct list_head link;
+	struct efi_mem_desc desc;
+};
+
+/* This list contains all memory map items */
+LIST_HEAD(efi_mem);
+
+/*
+ * Unmaps all memory occupied by the carve_desc region from the
+ * list entry pointed to by map.
+ *
+ * Returns 1 if carving was performed or 0 if the regions don't overlap.
+ * Returns -1 if it would affect non-RAM regions but overlap_only_ram is set.
+ * Carving is only guaranteed to complete when all regions return 0.
+ */
+static int efi_mem_carve_out(struct efi_mem_list *map,
+			     struct efi_mem_desc *carve_desc,
+			     bool overlap_only_ram)
+{
+	struct efi_mem_list *newmap;
+	struct efi_mem_desc *map_desc = &map->desc;
+	uint64_t map_start = map_desc->physical_start;
+	uint64_t map_end = map_start + (map_desc->num_pages << EFI_PAGE_SHIFT);
+	uint64_t carve_start = carve_desc->physical_start;
+	uint64_t carve_end = carve_start +
+			     (carve_desc->num_pages << EFI_PAGE_SHIFT);
+
+	/* check whether we're overlapping */
+	if ((carve_end <= map_start) || (carve_start >= map_end))
+		return 0;
+
+	/* We're overlapping with non-RAM, warn the caller if desired */
+	if (overlap_only_ram && (map_desc->type != EFI_CONVENTIONAL_MEMORY))
+		return -1;
+
+	/* Sanitize carve_start and carve_end to lie within our bounds */
+	carve_start = max(carve_start, map_start);
+	carve_end = min(carve_end, map_end);
+
+	/* Carving at the beginning of our map? Just move it! */
+	if (carve_start == map_start) {
+		if (map_end == carve_end) {
+			/* Full overlap, just remove map */
+			list_del(&map->link);
+		}
+
+		map_desc->physical_start = carve_end;
+		map_desc->num_pages = (map_end - carve_end) >> EFI_PAGE_SHIFT;
+		return 1;
+	}
+
+	/*
+	 * Overlapping maps, just split the list map at carve_start,
+	 * it will get moved or removed in the next iteration.
+	 *
+	 * [ map_desc |__carve_start__| newmap ]
+	 */
+
+	/* Create a new map from [ carve_start ... map_end ] */
+	newmap = calloc(1, sizeof(*newmap));
+	newmap->desc = map->desc;
+	newmap->desc.physical_start = carve_start;
+	newmap->desc.num_pages = (map_end - carve_start) >> EFI_PAGE_SHIFT;
+        list_add_tail(&newmap->link, &efi_mem);
+
+	/* Shrink the map to [ map_start ... carve_start ] */
+	map_desc->num_pages = (carve_start - map_start) >> EFI_PAGE_SHIFT;
+
+	return 1;
+}
+
+uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
+			    bool overlap_only_ram)
+{
+	struct list_head *lhandle;
+	struct efi_mem_list *newlist;
+	bool do_carving;
+
+	if (!pages)
+		return start;
+
+	newlist = calloc(1, sizeof(*newlist));
+	newlist->desc.type = memory_type;
+	newlist->desc.physical_start = start;
+	newlist->desc.virtual_start = start;
+	newlist->desc.num_pages = pages;
+
+	switch (memory_type) {
+	case EFI_RUNTIME_SERVICES_CODE:
+	case EFI_RUNTIME_SERVICES_DATA:
+		newlist->desc.attribute = (1 << EFI_MEMORY_WB_SHIFT) |
+					  (1ULL << EFI_MEMORY_RUNTIME_SHIFT);
+		break;
+	case EFI_MMAP_IO:
+		newlist->desc.attribute = 1ULL << EFI_MEMORY_RUNTIME_SHIFT;
+		break;
+	default:
+		newlist->desc.attribute = 1 << EFI_MEMORY_WB_SHIFT;
+		break;
+	}
+
+	/* Add our new map */
+	do {
+		do_carving = false;
+		list_for_each(lhandle, &efi_mem) {
+			struct efi_mem_list *lmem;
+			int r;
+
+			lmem = list_entry(lhandle, struct efi_mem_list, link);
+			r = efi_mem_carve_out(lmem, &newlist->desc,
+					      overlap_only_ram);
+			if (r < 0) {
+				return 0;
+			} else if (r) {
+				do_carving = true;
+				break;
+			}
+		}
+	} while (do_carving);
+
+	/* Add our new map */
+        list_add_tail(&newlist->link, &efi_mem);
+
+	return start;
+}
+
+static uint64_t efi_find_free_memory(uint64_t len, uint64_t max_addr)
+{
+	struct list_head *lhandle;
+
+	list_for_each(lhandle, &efi_mem) {
+		struct efi_mem_list *lmem = list_entry(lhandle,
+			struct efi_mem_list, link);
+		struct efi_mem_desc *desc = &lmem->desc;
+		uint64_t desc_len = desc->num_pages << EFI_PAGE_SHIFT;
+		uint64_t desc_end = desc->physical_start + desc_len;
+		uint64_t curmax = min(max_addr, desc_end);
+		uint64_t ret = curmax - len;
+
+		/* We only take memory from free RAM */
+		if (desc->type != EFI_CONVENTIONAL_MEMORY)
+			continue;
+
+		/* Out of bounds for max_addr */
+		if ((ret + len) > max_addr)
+			continue;
+
+		/* Out of bounds for upper map limit */
+		if ((ret + len) > desc_end)
+			continue;
+
+		/* Out of bounds for lower map limit */
+		if (ret < desc->physical_start)
+			continue;
+
+		/* Return the highest address in this map within bounds */
+		return ret;
+	}
+
+	return 0;
+}
+
+efi_status_t efi_allocate_pages(int type, int memory_type,
+				unsigned long pages, uint64_t *memory)
+{
+	u64 len = pages << EFI_PAGE_SHIFT;
+	efi_status_t r = EFI_SUCCESS;
+	uint64_t addr;
+
+	switch (type) {
+	case 0:
+		/* Any page */
+		addr = efi_find_free_memory(len, gd->ram_top);
+		if (!addr) {
+			r = EFI_NOT_FOUND;
+			break;
+		}
+		break;
+	case 1:
+		/* Max address */
+		addr = efi_find_free_memory(len, *memory);
+		if (!addr) {
+			r = EFI_NOT_FOUND;
+			break;
+		}
+		break;
+	case 2:
+		/* Exact address, reserve it. The addr is already in *memory. */
+		addr = *memory;
+		break;
+	default:
+		/* UEFI doesn't specify other allocation types */
+		r = EFI_INVALID_PARAMETER;
+		break;
+	}
+
+	if (r == EFI_SUCCESS) {
+		uint64_t ret;
+
+		/* Reserve that map in our memory maps */
+		ret = efi_add_memory_map(addr, pages, memory_type, true);
+		if (ret == addr) {
+			*memory = addr;
+		} else {
+			/* Map would overlap, bail out */
+			r = EFI_OUT_OF_RESOURCES;
+		}
+	}
+
+	return r;
+}
+
+void *efi_alloc(uint64_t len, int memory_type)
+{
+	uint64_t ret = 0;
+	uint64_t pages = (len + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
+	efi_status_t r;
+
+	r = efi_allocate_pages(0, memory_type, pages, &ret);
+	if (r == EFI_SUCCESS)
+		return (void*)(uintptr_t)ret;
+
+	return NULL;
+}
+
+efi_status_t efi_free_pages(uint64_t memory, unsigned long pages)
+{
+	/* We don't free, let's cross our fingers we have plenty RAM */
+	return EFI_SUCCESS;
+}
+
+efi_status_t efi_get_memory_map(unsigned long *memory_map_size,
+			       struct efi_mem_desc *memory_map,
+			       unsigned long *map_key,
+			       unsigned long *descriptor_size,
+			       uint32_t *descriptor_version)
+{
+	ulong map_size = 0;
+	struct list_head *lhandle;
+
+	list_for_each(lhandle, &efi_mem)
+		map_size += sizeof(struct efi_mem_desc);
+
+	*memory_map_size = map_size;
+
+	if (descriptor_size)
+		*descriptor_size = sizeof(struct efi_mem_desc);
+
+	if (*memory_map_size < map_size)
+		return EFI_BUFFER_TOO_SMALL;
+
+	/* Copy list into array */
+	if (memory_map) {
+		list_for_each(lhandle, &efi_mem) {
+			struct efi_mem_list *lmem;
+
+			lmem = list_entry(lhandle, struct efi_mem_list, link);
+			*memory_map = lmem->desc;
+			memory_map++;
+		}
+	}
+
+	return EFI_SUCCESS;
+}
+
+int efi_memory_init(void)
+{
+	uint64_t runtime_start, runtime_end, runtime_pages;
+	uint64_t uboot_start, uboot_pages;
+	uint64_t uboot_stack_size = 16 * 1024 * 1024;
+	int i;
+
+	/* Add RAM */
+	for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+		u64 ram_start = gd->bd->bi_dram[i].start;
+		u64 ram_size = gd->bd->bi_dram[i].size;
+		u64 start = (ram_start + EFI_PAGE_MASK) & ~EFI_PAGE_MASK;
+		u64 pages = (ram_size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
+
+		efi_add_memory_map(start, pages, EFI_CONVENTIONAL_MEMORY,
+				   false);
+	}
+
+	/* Add U-Boot */
+	uboot_start = (gd->start_addr_sp - uboot_stack_size) & ~EFI_PAGE_MASK;
+	uboot_pages = (gd->ram_top - uboot_start) >> EFI_PAGE_SHIFT;
+	efi_add_memory_map(uboot_start, uboot_pages, EFI_LOADER_DATA, false);
+
+	/* Add Runtime Services */
+	runtime_start = (ulong)&__efi_runtime_start & ~EFI_PAGE_MASK;
+	runtime_end = (ulong)&__efi_runtime_stop;
+	runtime_end = (runtime_end + EFI_PAGE_MASK) & ~EFI_PAGE_MASK;
+	runtime_pages = (runtime_end - runtime_start) >> EFI_PAGE_SHIFT;
+	efi_add_memory_map(runtime_start, runtime_pages,
+			   EFI_RUNTIME_SERVICES_CODE, false);
+
+	return 0;
+}