coreboot: add imd library

The imd (internal memory database) library provides a way to
track memory regions by assigning ids to each region. The implementation
is a direct descendant of dynamic cbmem. The intent is to replace
the existing mechanisms which do similar things: dynamic cbmem, stage
cache, etc.

Differences between dynamic cbmem and imd:
- All structures/objects are relative to one another. There
  are no absolute pointers serialized to memory.
- Allow limiting the size of the idm. i.e. provide a maximum
  memory usage.
- Allow setting the size of the root structure which allows
  control of the number of allocations to track.

Change-Id: Id7438cff80d396a594d6a7330d09b45bb4fedf2e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8621
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/include/cbmem.h

@@ -57,6 +57,7 @@
 #define CBMEM_ID_GDT		0x4c474454
 #define CBMEM_ID_HOB_POINTER	0x484f4221
 #define CBMEM_ID_IGD_OPREGION	0x4f444749
+#define CBMEM_ID_IMD_ROOT	0xff4017ff
 #define CBMEM_ID_MEMINFO	0x494D454D
 #define CBMEM_ID_MPTABLE	0x534d5054
 #define CBMEM_ID_MRCDATA	0x4d524344
@@ -103,6 +104,7 @@ struct cbmem_id_to_name {
 	{ CBMEM_ID_ELOG,		"ELOG       " }, \
 	{ CBMEM_ID_FREESPACE,		"FREE SPACE " }, \
 	{ CBMEM_ID_GDT,			"GDT        " }, \
+	{ CBMEM_ID_IMD_ROOT,		"IMD ROOT   " }, \
 	{ CBMEM_ID_MEMINFO,		"MEM INFO   " }, \
 	{ CBMEM_ID_MPTABLE,		"SMP TABLE  " }, \
 	{ CBMEM_ID_MRCDATA,		"MRC DATA   " }, \

src/include/imd.h

@@ -0,0 +1,139 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google, Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#ifndef _IMD_H_
+#define _IMD_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+/*
+ * imd is an in-memory database/directory/datastore (whatever d word you
+ * desire). It grows downwards in memory from provided upper limit and
+ * root size. Each entry has a size alignment which is also provided by
+ * the caller.
+ *
+ *             +----------------------+ <- upper_limit
+ *    |   +----|   root pointer       |
+ *    |   |    +----------------------+
+ *    |   |    |                      |--------+
+ *    |   +--->|   root block         |-----+  |
+ *    |        +----------------------+-----|--|--- root_size
+ *    |        |                      |     |  |
+ *    |        |                      |     |  |
+ *    |        |   alloc N            |<----+  |
+ *    |        +----------------------+        |
+ *    |        |                      |        |
+ *    |        |                      |        |
+ *   \|/       |   alloc N + 1        |<-------+
+ *    v        +----------------------+
+ *
+ * The root_size in imd_create_empty() encompasses the root pointer
+ * and root block. The root_size value, therefore, dictates the number
+ * of allocations maintained by the imd.
+ */
+
+/*
+ * NOTE: This API has the following calling conventions: all functions
+ * returning int supply 0 on success or < 0 on error.
+ */
+
+struct imd_entry;
+struct imd;
+
+/*
+ * Initialize handle to use for working with an imd. Upper limit is the
+ * exclusive address to start allocating down from. This function needs
+ * to be called at least once before any other imd related functions
+ * can be used.
+ */
+void imd_handle_init(struct imd *imd, void *upper_limit);
+
+/*
+ * Initialize a handle with a shallow recovery. This function doesn't
+ * verify every entry, but it does set up the root pointer. Because of
+ * this behavior it's not very safe. However, the current CBMEM constraints
+ * demand having these semantics.
+ */
+void imd_handle_init_partial_recovery(struct imd *imd);
+
+/*
+ * Create an empty imd with a specified root_size and each entry is aligned to
+ * the provided entry_align. As noted above the root size encompasses the
+ * root pointer and root block leading to the number of imd entries being a
+ * function of the root_size parameter.
+ */
+int imd_create_empty(struct imd *imd, size_t root_size, size_t entry_align);
+
+/*
+ * Recover a previously created imd.
+ */
+int imd_recover(struct imd *imd);
+
+/* Limit imd to provided max_size. */
+int imd_limit_size(struct imd *imd, size_t max_size);
+
+/* Lock down imd from further modifications. */
+int imd_lockdown(struct imd *imd);
+
+/* Fill in base address and size of region used by imd. */
+int imd_region_used(struct imd *imd, void **base, size_t *size);
+
+/* Add an entry to the imd. If id already exists NULL is returned. */
+const struct imd_entry *imd_entry_add(const struct imd *imd, uint32_t id,
+					size_t size);
+
+/* Locate an entry within the imd. NULL is returned when not found. */
+const struct imd_entry *imd_entry_find(const struct imd *imd, uint32_t id);
+
+/* Find an existing entry or add a new one. */
+const struct imd_entry *imd_entry_find_or_add(const struct imd *imd,
+						uint32_t id, size_t size);
+
+/* Returns size of entry or 0 on failure. */
+size_t imd_entry_size(const struct imd *imd, const struct imd_entry *entry);
+
+/* Returns pointer to region described by entry or NULL on failure. */
+void *imd_entry_at(const struct imd *imd, const struct imd_entry *entry);
+
+/* Attempt to remove entry from imd. */
+int imd_entry_remove(const struct imd *imd, const struct imd_entry *entry);
+
+/* Print the entry information provided by lookup with the specified size. */
+struct imd_lookup {
+	uint32_t id;
+	const char *name;
+};
+
+int imd_print_entries(const struct imd *imd, const struct imd_lookup *lookup,
+			size_t size);
+
+
+/*
+ * The struct imd is a handle for working with an in-memory directory.
+ *
+ * NOTE: Do not directly touch any fields within this structure. An imd pointer
+ * is meant to be opaque, but the fields are exposed for stack allocation.
+ */
+struct imd {
+	uintptr_t limit;
+	void *r;
+};
+
+#endif /* _IMD_H_ */

src/lib/Makefile.inc

@@ -102,6 +102,9 @@ ramstage-y += b64_decode.c
 romstage-y += cbmem_common.c dynamic_cbmem.c
 ramstage-y += cbmem_common.c dynamic_cbmem.c
 
+romstage-y += imd.c
+ramstage-y += imd.c
+
 ramstage-y += hexdump.c
 romstage-y += hexdump.c
 

src/lib/imd.c

@@ -0,0 +1,481 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google, Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#include <assert.h>
+#include <cbmem.h>
+#include <console/console.h>
+#include <imd.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* For more details on implementation and usage please see the imd.h header. */
+
+static const uint32_t IMD_ROOT_PTR_MAGIC = 0xc0389481;
+static const uint32_t IMD_ENTRY_MAGIC = ~0xc0389481;
+static const size_t LIMIT_ALIGN = 4096;
+
+/* In-memory data structures. */
+struct imd_root_pointer {
+	uint32_t magic;
+	/* Relative to upper limit/offset. */
+	int32_t root_offset;
+} __attribute__((packed));
+
+struct imd_entry {
+	uint32_t magic;
+	/* start is located relative to imd_root */
+	int32_t start_offset;
+	uint32_t size;
+	uint32_t id;
+} __attribute__((packed));
+
+struct imd_root {
+	uint32_t max_entries;
+	uint32_t num_entries;
+	uint32_t flags;
+	uint32_t entry_align;
+	/* Used for fixing the size of an imd. Relative to the root. */
+	int32_t max_offset;
+	struct imd_entry entries[0];
+} __attribute__((packed));
+
+#define IMD_FLAG_LOCKED 1
+
+static void *relative_pointer(void *base, ssize_t offset)
+{
+	intptr_t b = (intptr_t)base;
+	b += offset;
+	return (void *)b;
+}
+
+static bool imd_root_pointer_valid(const struct imd_root_pointer *rp)
+{
+	return !!(rp->magic == IMD_ROOT_PTR_MAGIC);
+}
+
+static struct imd_root *imd_root(const struct imd *imd)
+{
+	return imd->r;
+}
+
+/*
+ * The root pointer is relative to the upper limit of the imd. i.e. It sits
+ * just below the upper limit.
+ */
+static struct imd_root_pointer *imd_get_root_pointer(const struct imd *imd)
+{
+	struct imd_root_pointer *rp;
+
+	rp = relative_pointer((void *)imd->limit, -sizeof(*rp));
+
+	return rp;
+}
+
+static void imd_link_root(struct imd_root_pointer *rp, struct imd_root *r)
+{
+	rp->magic = IMD_ROOT_PTR_MAGIC;
+	rp->root_offset = (int32_t)((intptr_t)r - (intptr_t)rp);
+}
+
+static void imd_entry_assign(struct imd_entry *e, uint32_t id,
+				ssize_t offset, size_t size)
+{
+	e->magic = IMD_ENTRY_MAGIC;
+	e->start_offset = offset;
+	e->size = size;
+	e->id = id;
+}
+
+static bool root_is_locked(const struct imd_root *r)
+{
+	return !!(r->flags & IMD_FLAG_LOCKED);
+}
+
+static struct imd_entry *root_last_entry(struct imd_root *r)
+{
+	return &r->entries[r->num_entries - 1];
+}
+
+/* Initialize imd handle. */
+void imd_handle_init(struct imd *imd, void *upper_limit)
+{
+	uintptr_t limit = (uintptr_t)upper_limit;
+	/* Upper limit is aligned down to 4KiB */
+	imd->limit = ALIGN_DOWN(limit, LIMIT_ALIGN);
+	imd->r = NULL;
+}
+
+void imd_handle_init_partial_recovery(struct imd *imd)
+{
+	struct imd_root_pointer *rp;
+
+	imd_handle_init(imd, (void *)imd->limit);
+
+	rp = imd_get_root_pointer(imd);
+	imd->r = relative_pointer(rp, rp->root_offset);
+}
+
+int imd_create_empty(struct imd *imd, size_t root_size, size_t entry_align)
+{
+	struct imd_root_pointer *rp;
+	struct imd_root *r;
+	struct imd_entry *e;
+	ssize_t root_offset;
+	size_t entries_size;
+
+	if (!imd->limit)
+		return -1;
+
+	/* root_size and entry_align should be a power of 2. */
+	assert(IS_POWER_OF_2(root_size));
+	assert(IS_POWER_OF_2(entry_align));
+
+	/*
+	 * root_size needs to be large enough to accomodate root pointer and
+	 * root book keeping structure. The caller needs to ensure there's
+	 * enough room for tracking individual allocations.
+	 */
+	if (root_size < (sizeof(*rp) + sizeof(*r)))
+		return -1;
+
+	/* For simplicity don't allow sizes or alignments to exceed LIMIT_ALIGN. */
+	if (root_size > LIMIT_ALIGN || entry_align > LIMIT_ALIGN)
+		return -1;
+
+	/* Additionally, don't handle an entry alignment > root_size. */
+	if (entry_align > root_size)
+		return -1;
+
+	rp = imd_get_root_pointer(imd);
+
+	root_offset = -(ssize_t)root_size;
+	/* Set root pointer. */
+	imd->r = relative_pointer((void *)imd->limit, root_offset);
+	r = imd_root(imd);
+	imd_link_root(rp, r);
+
+	memset(r, 0, sizeof(*r));
+	r->entry_align = entry_align;
+
+	/* Calculate size left for entries. */
+	entries_size = root_size;
+	entries_size -= sizeof(*rp);
+	entries_size -= sizeof(*r);
+
+	r->max_entries = entries_size / sizeof(r->entries[0]);
+
+	/* Fill in first entry covering the root region. */
+	r->num_entries = 1;
+	e = &r->entries[0];
+	imd_entry_assign(e, CBMEM_ID_IMD_ROOT, 0, root_size);
+
+	printk(BIOS_DEBUG, "IMD: root @ %p %u entries.\n", r, r->max_entries);
+
+	return 0;
+}
+
+int imd_limit_size(struct imd *imd, size_t max_size)
+{
+	struct imd_root *r;
+	ssize_t smax_size;
+	size_t root_size;
+
+	r = imd_root(imd);
+	if (r == NULL)
+		return -1;
+
+	root_size = imd->limit - (uintptr_t)r;
+
+	if (max_size < root_size)
+		return -1;
+
+	/* Take into account the root size. */
+	smax_size = max_size - root_size;
+	smax_size = -smax_size;
+
+	r->max_offset = smax_size;
+
+	return 0;
+}
+
+int imd_recover(struct imd *imd)
+{
+	struct imd_root_pointer *rp;
+	struct imd_root *r;
+	uintptr_t low_limit;
+	size_t i;
+
+	if (!imd->limit);
+		return -1;
+
+	rp = imd_get_root_pointer(imd);
+
+	if (!imd_root_pointer_valid(rp))
+		return -1;
+
+	r = relative_pointer(rp, rp->root_offset);
+
+	/* Confirm the root and root pointer are just under the limit. */
+	if (ALIGN_UP((uintptr_t)&r->entries[r->max_entries], LIMIT_ALIGN) !=
+			imd->limit)
+		return -1;
+
+	if (r->num_entries > r->max_entries)
+		return -1;
+
+	/* Entry alignment should be power of 2. */
+	if (!IS_POWER_OF_2(r->entry_align))
+		return -1;
+
+	low_limit = (uintptr_t)relative_pointer(r, r->max_offset);
+
+	/* If no max_offset then lowest limit is 0. */
+	if (low_limit == (uintptr_t)r)
+		low_limit = 0;
+
+	for (i = 0; i < r->num_entries; i++) {
+		uintptr_t start_addr;
+		const struct imd_entry *e = &r->entries[i];
+
+		if (e->magic != IMD_ENTRY_MAGIC)
+			return -1;
+
+		start_addr = (uintptr_t)relative_pointer(r, e->start_offset);
+		if (start_addr  < low_limit)
+			return -1;
+		if (start_addr >= imd->limit ||
+				(start_addr + e->size) > imd->limit)
+			return -1;
+	}
+
+	/* Set root pointer. */
+	imd->r = r;
+
+	return 0;
+}
+
+int imd_lockdown(struct imd *imd)
+{
+	struct imd_root *r;
+
+	r = imd_root(imd);
+	if (r == NULL)
+		return -1;
+
+	r->flags |= IMD_FLAG_LOCKED;
+
+	return 0;
+}
+
+int imd_region_used(struct imd *imd, void **base, size_t *size)
+{
+	struct imd_root *r;
+	struct imd_entry *e;
+	void *low_addr;
+	size_t sz_used;
+
+	if (!imd->limit)
+		return -1;
+
+	r = imd_root(imd);
+
+	if (r == NULL)
+		return -1;
+
+	/* Use last entry to obtain lowest address. */
+	e = root_last_entry(r);
+
+	low_addr = relative_pointer(r, e->start_offset);
+
+	/* Total size used is the last entry's base up to the limit. */
+	sz_used = imd->limit - (uintptr_t)low_addr;
+
+	*base = low_addr;
+	*size = sz_used;
+
+	return 0;
+}
+
+static struct imd_entry *imd_entry_add_to_root(struct imd_root *r, uint32_t id,
+						size_t size)
+{
+	struct imd_entry *entry;
+	struct imd_entry *last_entry;
+	ssize_t e_offset;
+	size_t used_size;
+
+	if (r->num_entries == r->max_entries)
+		return NULL;
+
+	/* Determine total size taken up by entry. */
+	used_size = ALIGN_UP(size, r->entry_align);
+
+	last_entry = root_last_entry(r);
+
+	/* See if size overflows imd total size. */
+	if (r->max_offset != 0) {
+		size_t remaining = last_entry->start_offset - r->max_offset;
+
+		if (used_size > remaining)
+			return NULL;
+	}
+
+	/*
+	 * Determine if offset field overflows. All offsets should be lower
+	 * than the previous one.
+	 */
+	e_offset = last_entry->start_offset;
+	e_offset -= (ssize_t)used_size;
+	if (e_offset > last_entry->start_offset)
+		return NULL;
+
+	entry = root_last_entry(r) + 1;
+	r->num_entries++;
+
+	imd_entry_assign(entry, id, e_offset, size);
+
+	return entry;
+}
+
+const struct imd_entry *imd_entry_add(const struct imd *imd, uint32_t id,
+					size_t size)
+{
+	struct imd_root *r;
+
+	r = imd_root(imd);
+
+	if (r == NULL)
+		return NULL;
+
+	if (root_is_locked(r))
+		return NULL;
+
+	return imd_entry_add_to_root(r, id, size);
+}
+
+const struct imd_entry *imd_entry_find(const struct imd *imd, uint32_t id)
+{
+	struct imd_root *r;
+	struct imd_entry *e;
+	size_t i;
+
+	r = imd_root(imd);
+
+	if (r == NULL)
+		return NULL;
+
+	e = NULL;
+	/* Skip first entry covering the root. */
+	for (i = 1; i < r->num_entries; i++) {
+		if (id == r->entries[i].id) {
+			e = &r->entries[i];
+			break;
+		}
+	}
+
+	return e;
+}
+
+const struct imd_entry *imd_entry_find_or_add(const struct imd *imd,
+						uint32_t id, size_t size)
+{
+	const struct imd_entry *e;
+
+	e = imd_entry_find(imd, id);
+
+	if (e != NULL)
+		return e;
+
+	return imd_entry_add(imd, id, size);
+}
+
+size_t imd_entry_size(const struct imd *imd, const struct imd_entry *entry)
+{
+	return entry->size;
+}
+
+void *imd_entry_at(const struct imd *imd, const struct imd_entry *entry)
+{
+	struct imd_root *r;
+
+	r = imd_root(imd);
+
+	if (r == NULL)
+		return NULL;
+
+	return relative_pointer(r, entry->start_offset);
+}
+
+int imd_entry_remove(const struct imd *imd, const struct imd_entry *entry)
+{
+	struct imd_root *r;
+
+	r = imd_root(imd);
+
+	if (r == NULL)
+		return -1;
+
+	if (root_is_locked(r))
+		return -1;
+
+	if (entry != root_last_entry(r))
+		return -1;
+
+	r->num_entries--;
+
+	return 0;
+}
+
+int imd_print_entries(const struct imd *imd, const struct imd_lookup *lookup,
+			size_t size)
+{
+	struct imd_root *r;
+	size_t i;
+	size_t j;
+
+	if (imd == NULL)
+		return -1;
+
+	r = imd_root(imd);
+
+	if (r == NULL)
+		return -1;
+
+	for (i = 0; i < r->num_entries; i++) {
+		const char *name = NULL;
+		const struct imd_entry *e = &r->entries[i];
+
+		for (j = 0; j < size; j++) {
+			if (lookup[j].id == e->id) {
+				name = lookup[j].name;
+				break;
+			}
+		}
+
+		if (name == NULL)
+			printk(BIOS_DEBUG, "%08x   ", e->id);
+		else
+			printk(BIOS_DEBUG, "%s", name);
+		printk(BIOS_DEBUG, "%2zu. ", i);
+		printk(BIOS_DEBUG, "%p ", imd_entry_at(imd, e));
+		printk(BIOS_DEBUG, "%08zx\n", imd_entry_size(imd, e));
+	}
+
+	return 0;
+}