Fwd: [PATCH 2/4] coreboot: Add support for detecting Coreboot BIOS signatures
Philip Prindeville
philipp at redfish-solutions.com
Thu Dec 22 03:25:23 EST 2011
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recipients so I'm having to forward these to the list... Please add back the
original recipients when replying.
==== Original message follows ===
From: Philip Prindeville <philipp at redfish-solutions.com>
Date: Sun, 18 Dec 2011 12:23:53 -0700
Subject: [PATCH 2/4] coreboot: Add support for detecting Coreboot BIOS signatures
To: Ed Wildgoose <ed at wildgooses.com>,
Andrew Morton <akpm at linux-foundation.org>,
linux-geode at lists.infradead.org,
Andres Salomon <dilinger at queued.net>
Cc: Nathan Williams <nathan at traverse.com.au>,
Guy Ellis <guy at traverse.com.au>,
David Woodhouse <dwmw2 at infradead.org>,
Patrick Georgi <patrick.georgi at secunet.com>,
Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>,
linux-mm at kvack.org
Add support for Coreboot BIOS detection. This in turn can be used by
platform drivers to verify they are running on the correct hardware,
as many of the low-volume SBC's (especially in the Atom and Geode
universe) don't always identify themselves via DMI or PCI-ID.
The coreboot project lives at:
http://www.coreboot.org/
and the related project Flashrom lives here:
http://flashrom.org/
This library pulls from both, though predominantly the former.
The library locates the Coreboot tables in memory, parses them, and
provides a way to extract from the table the motherboard vendor and
model fields for use in platform drivers.
Signed-off-by: Philip Prindeville <philipp at redfish-solutions.com>
Reviewed-by: Ed Wildgoose <ed at wildgooses.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Andres Salomon <dilinger at queued.net>
Cc: Nathan Williams <nathan at traverse.com.au>
Cc: Guy Ellis <guy at traverse.com.au>
Cc: David Woodhouse <dwmw2 at infradead.org>
Cc: Patrick Georgi <patrick.georgi at secunet.com>
Cc: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
Cc: linux-geode at lists.infradead.org
Cc: linux-mm at kvack.org
---
Documentation/x86/coreboot.txt | 31 +++++
include/linux/coreboot.h | 182 +++++++++++++++++++++++++
lib/Kconfig | 8 +
lib/Makefile | 1 +
lib/coreboot.c | 290 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 512 insertions(+), 0 deletions(-)
create mode 100644 Documentation/x86/coreboot.txt
create mode 100644 include/linux/coreboot.h
create mode 100644 lib/coreboot.c
diff --git a/Documentation/x86/coreboot.txt b/Documentation/x86/coreboot.txt
new file mode 100644
index 0000000..35be360
--- /dev/null
+++ b/Documentation/x86/coreboot.txt
@@ -0,0 +1,31 @@
+Coreboot is an open source bootloader/BIOS. It currently is supported on x86, but
+has been made to run on PPC hardware as well. The project lives here:
+
+http://www.coreboot.org/
+
+It was previously known as LinuxBIOS.
+
+It has been ported to various boards, including the Geode single-board computers alix, wrap, and geos.
+
+The list is here:
+
+http://www.coreboot.org/Supported_Motherboards
+
+http://www.coreboot.org/Supported_Chipsets_and_Devices
+
+Coreboot requires gcc, binutils, and make to be built.
+
+Part of coreboot's initialization includes creating a table (called, not surprisingly, the
+coreboot table) that contains various information about the system, such as memory apertures,
+serial ports, the manufacturer and model number of the system, etc.
+
+A bootable utility called FlashROM is available for programming flash chips. It lives here:
+
+http://flashrom.org/Documentation
+
+it includes a library for reading coreboot tables. Source for flashrom is here:
+
+svn://flashrom.org/flashrom/trunk
+
+The lib/coreboot.c module borrows heavily from flashrom's cbtable.c and coreboot_tables.h
+
diff --git a/include/linux/coreboot.h b/include/linux/coreboot.h
new file mode 100644
index 0000000..0ed6118
--- /dev/null
+++ b/include/linux/coreboot.h
@@ -0,0 +1,182 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2002 Linux Networx
+ * (Written by Eric Biederman <ebiederman at lnxi.com> for Linux Networx)
+ * Copyright (C) 2005-2007 coresystems GmbH
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#ifndef COREBOOT_H
+#define COREBOOT_H
+
+#include <linux/types.h>
+
+/* The coreboot table information is for conveying information
+ * from the firmware to the loaded OS image. Primarily this
+ * is expected to be information that cannot be discovered by
+ * other means, such as querying the hardware directly.
+ *
+ * All of the information should be Position Independent Data.
+ * That is it should be safe to relocated any of the information
+ * without it's meaning/correctness changing. For table that
+ * can reasonably be used on multiple architectures the data
+ * size should be fixed. This should ease the transition between
+ * 32 bit and 64 bit architectures etc.
+ *
+ * The completeness test for the information in this table is:
+ * - Can all of the hardware be detected?
+ * - Are the per motherboard constants available?
+ * - Is there enough to allow a kernel to run that was written before
+ * a particular motherboard is constructed? (Assuming the kernel
+ * has drivers for all of the hardware but it does not have
+ * assumptions on how the hardware is connected together).
+ *
+ * With this test it should be straight forward to determine if a
+ * table entry is required or not. This should remove much of the
+ * long term compatibility burden as table entries which are
+ * irrelevant or have been replaced by better alternatives may be
+ * dropped. Of course it is polite and expedite to include extra
+ * table entries and be backwards compatible, but it is not required.
+ */
+
+/* Since coreboot is usually compiled 32bit, gcc will align 64bit
+ * types to 32bit boundaries. If the coreboot table is dumped on a
+ * 64bit system, a uint64_t would be aligned to 64bit boundaries,
+ * breaking the table format.
+ *
+ * lb_uint64 will keep 64bit coreboot table values aligned to 32bit
+ * to ensure compatibility. They can be accessed with the two functions
+ * below: unpack_lb64() and pack_lb64()
+ *
+ * See also: util/lbtdump/lbtdump.c
+ */
+
+struct lb_uint64 {
+ uint32_t lo;
+ uint32_t hi;
+};
+
+static inline uint64_t unpack_lb64(struct lb_uint64 value)
+{
+ uint64_t result;
+ result = value.hi;
+ result = (result << 32) + value.lo;
+ return result;
+}
+
+static inline struct lb_uint64 pack_lb64(uint64_t value)
+{
+ struct lb_uint64 result;
+ result.lo = (value >> 0) & 0xffffffff;
+ result.hi = (value >> 32) & 0xffffffff;
+ return result;
+}
+
+struct lb_header {
+ uint8_t signature[4]; /* LBIO */
+ uint32_t header_bytes;
+ uint32_t header_checksum;
+ uint32_t table_bytes;
+ uint32_t table_checksum;
+ uint32_t table_entries;
+};
+
+/* Every entry in the boot environment list will correspond to a boot
+ * info record. Encoding both type and size. The type is obviously
+ * so you can tell what it is. The size allows you to skip that
+ * boot environment record if you don't know what it easy. This allows
+ * forward compatibility with records not yet defined.
+ */
+struct lb_record {
+ uint32_t tag; /* tag ID */
+ uint32_t size; /* size of record (in bytes) */
+};
+
+#define LB_TAG_UNUSED 0x0000
+
+#define LB_TAG_MEMORY 0x0001
+
+struct lb_memory_range {
+ struct lb_uint64 start;
+ struct lb_uint64 size;
+ uint32_t type;
+#define LB_MEM_RAM 1 /* Memory anyone can use */
+#define LB_MEM_RESERVED 2 /* Don't use this memory region */
+#define LB_MEM_TABLE 16 /* Ram configuration tables are kept in */
+};
+
+struct lb_memory {
+ uint32_t tag;
+ uint32_t size;
+ struct lb_memory_range map[0];
+};
+
+#define LB_TAG_HWRPB 0x0002
+struct lb_hwrpb {
+ uint32_t tag;
+ uint32_t size;
+ uint64_t hwrpb;
+};
+
+#define LB_TAG_MAINBOARD 0x0003
+struct lb_mainboard {
+ uint32_t tag;
+ uint32_t size;
+ uint8_t vendor_idx;
+ uint8_t part_number_idx;
+ uint8_t strings[0];
+};
+
+#define LB_TAG_VERSION 0x0004
+#define LB_TAG_EXTRA_VERSION 0x0005
+#define LB_TAG_BUILD 0x0006
+#define LB_TAG_COMPILE_TIME 0x0007
+#define LB_TAG_COMPILE_BY 0x0008
+#define LB_TAG_COMPILE_HOST 0x0009
+#define LB_TAG_COMPILE_DOMAIN 0x000a
+#define LB_TAG_COMPILER 0x000b
+#define LB_TAG_LINKER 0x000c
+#define LB_TAG_ASSEMBLER 0x000d
+struct lb_string {
+ uint32_t tag;
+ uint32_t size;
+ uint8_t string[0];
+};
+
+#define LB_TAG_FORWARD 0x0011
+struct lb_forward {
+ uint32_t tag;
+ uint32_t size;
+ uint64_t forward;
+};
+
+/*
+ * vendor string, taken from mainboard record.
+ */
+extern const char *coreboot_vendor(void);
+
+/*
+ * part # string, taken from mainboard record.
+ */
+extern const char *coreboot_part(void);
+
+/*
+ * search for Coreboot tables. if found, search entries for
+ * mainboard record and parse it. return address of first record.
+ */
+extern struct lb_record *coreboot_init(void);
+
+#endif /* COREBOOT_TABLES_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 201e1b3..d880af8 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -98,6 +98,14 @@ config AUDIT_GENERIC
depends on AUDIT && !AUDIT_ARCH
default y
+config COREBOOT
+ bool "Coreboot location/parsing support"
+ depends on X86
+ help
+ Support for boards running coreboot. It allows platform drivers to
+ detect their manufacturer and part number by interrogating the BIOS
+ populated tables.
+
#
# compression support is select'ed if needed
#
diff --git a/lib/Makefile b/lib/Makefile
index dace162..9dd493d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_CRC7) += crc7.o
obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
obj-$(CONFIG_CRC8) += crc8.o
obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
+obj-$(CONFIG_COREBOOT) += coreboot.o
obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
diff --git a/lib/coreboot.c b/lib/coreboot.c
new file mode 100644
index 0000000..f3dd191
--- /dev/null
+++ b/lib/coreboot.c
@@ -0,0 +1,290 @@
+/*
+ * This file was extracted from parts of the flashrom project.
+ *
+ * Copyright (C) 2002 Steven James <pyro at linuxlabs.com>
+ * Copyright (C) 2002 Linux Networx
+ * (Written by Eric Biederman <ebiederman at lnxi.com> for Linux Networx)
+ * Copyright (C) 2006-2009 coresystems GmbH
+ * (Written by Stefan Reinauer <stepan at coresystems.de> for coresystems GmbH)
+ * Copyright (C) 2010 Carl-Daniel Hailfinger
+ * Copyright (C) 2011 Philip Prindeville
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/types.h>
+#include <linux/unistd.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/io.h>
+
+#include <linux/ioport.h>
+
+#include <asm/checksum.h>
+#include <asm/page.h>
+
+#include <linux/coreboot.h>
+
+#define for_each_lbrec(head, rec) \
+ for(rec = (struct lb_record *)(((caddr_t)head) + sizeof(*head)); \
+ (((caddr_t)rec) < (((caddr_t)head) + sizeof(*head) + head->table_bytes)) && \
+ (rec->size >= 1) && \
+ ((((caddr_t)rec) + rec->size) <= (((caddr_t)head) + sizeof(*head) + head->table_bytes)); \
+ rec = (struct lb_record *)(((caddr_t)rec) + rec->size))
+
+static char lb_part[32], lb_vendor[32];
+
+static inline __sum16 compute_checksum(void *addr, unsigned long length)
+{
+ return ip_compute_csum(addr, length);
+}
+
+static inline uintptr_t vpage_offset(void *addr)
+{
+ return ((uintptr_t)addr & ~PAGE_MASK);
+}
+
+static inline void *vpage_base(void *addr)
+{
+ return (void *)((uintptr_t)addr & PAGE_MASK);
+}
+
+static inline void *__v_offset(void *addr, unsigned offset)
+{
+ return (void *)((caddr_t)addr + offset);
+}
+
+static inline uintptr_t ppage_offset(phys_addr_t addr)
+{
+ return (addr & ~PAGE_MASK);
+}
+
+static inline phys_addr_t ppage_base(phys_addr_t addr)
+{
+ return (phys_addr_t)(addr & PAGE_MASK);
+}
+
+static unsigned count_lb_records(const struct lb_header *head)
+{
+ struct lb_record *rec;
+ unsigned count;
+
+ count = 0;
+ for_each_lbrec(head, rec) {
+ count++;
+ }
+
+ return count;
+}
+
+#ifdef DEBUG
+static void dump_lb_header(const struct lb_header *lh)
+{
+ printk(KERN_DEBUG "header 0x%p\n"
+ " sig: %.4s, bytes %u, chksum %#04x,"
+ " bytes %u, chksum %#04x, entries %u\n",
+ lh, lh->signature, lh->header_bytes, lh->header_checksum,
+ lh->table_bytes, lh->table_checksum, lh->table_entries);
+}
+
+static void dump_lb_forward(const struct lb_forward *lf)
+{
+ printk(KERN_DEBUG "forward 0x%p\n tag %04x, size %u, forward %#llx\n",
+ lf, lf->tag, lf->size, lf->forward);
+}
+
+static void dump_lb_mainboard(struct lb_mainboard *lm)
+{
+ printk(KERN_DEBUG "mainboard: 0x%p\n tag %04x, size %u, vendor %s, part %s\n",
+ lm, lm->tag, lm->size, &lm->strings[lm->vendor_idx],
+ &lm->strings[lm->part_number_idx]);
+}
+#endif
+
+static struct lb_header *find_lb_table(void *base, void *end)
+{
+ void *addr;
+
+ printk(KERN_DEBUG "Starting search at 0x%p\n", base);
+ /* For now be stupid.... */
+ for (addr = base; addr < end; addr += 16) {
+ struct lb_header *head = (struct lb_header *)addr;
+ struct lb_record *recs;
+
+ if (memcmp(head->signature, "LBIO", 4) != 0)
+ continue;
+ printk(KERN_DEBUG "Found candidate at: 0x%p-%p\n",
+ addr, addr + head->table_bytes);
+#ifdef DEBUG
+ dump_lb_header(head);
+#endif
+ if (head->header_bytes != sizeof(*head)) {
+ printk(KERN_DEBUG "Header bytes of %u are incorrect.\n",
+ head->header_bytes);
+ continue;
+ }
+ if (count_lb_records(head) != head->table_entries) {
+ printk(KERN_DEBUG "Bad record count: %u.\n",
+ head->table_entries);
+ continue;
+ }
+ if (compute_checksum(head, sizeof(*head)) != 0) {
+ printk(KERN_DEBUG "Bad header checksum.\n");
+ continue;
+ }
+ recs = (struct lb_record *)__v_offset(addr, sizeof(*head));
+ if (compute_checksum(recs, head->table_bytes)
+ != head->table_checksum) {
+ printk(KERN_DEBUG "Bad table checksum: %#04x.\n",
+ head->table_checksum);
+ continue;
+ }
+ printk(KERN_DEBUG "Found coreboot table at 0x%p.\n", addr);
+ return head;
+
+ };
+
+ return 0;
+}
+
+static void find_mainboard(struct lb_record *ptr)
+{
+ struct lb_mainboard *rec = (struct lb_mainboard *)ptr;
+
+#ifdef DEBUG
+ dump_lb_mainboard(rec);
+#endif
+
+ strlcpy(lb_vendor, &rec->strings[rec->vendor_idx], sizeof(lb_vendor));
+ strlcpy(lb_part, &rec->strings[rec->part_number_idx], sizeof(lb_part));
+}
+
+static struct lb_record *next_record(struct lb_record *rec)
+{
+ return (struct lb_record *)__v_offset(rec, rec->size);
+}
+
+static void search_lb_records(struct lb_record *rec, struct lb_record *last)
+{
+ struct lb_record *next;
+
+ for (next = next_record(rec); (rec < last) && (next <= last); rec = next) {
+ next = next_record(rec);
+ if (rec->tag == LB_TAG_MAINBOARD) {
+ find_mainboard(rec);
+ break;
+ }
+ }
+}
+
+
+#define BYTES_TO_MAP (1024*1024)
+struct lb_record *coreboot_init(void)
+{
+ phys_addr_t start;
+ void *addr, *remap;
+ struct lb_header *lb_table;
+ struct lb_record *rec, *last;
+
+ remap = NULL;
+
+ start = 0x0;
+ addr = phys_to_virt(start);
+
+ lb_table = find_lb_table(addr, addr + 0x1000);
+ if (!lb_table) {
+ start = 0xf0000;
+ addr = phys_to_virt(start);
+ lb_table = find_lb_table(addr, addr + BYTES_TO_MAP);
+ }
+ if (lb_table) {
+ struct lb_forward *forward = (struct lb_forward *)
+ __v_offset(lb_table, lb_table->header_bytes);
+
+ if (forward->tag == LB_TAG_FORWARD) {
+ int mapped = 0;
+ phys_addr_t forward_phys = forward->forward;
+ phys_addr_t upper = iomem_map_find_boundary(forward_phys, &mapped);
+ unsigned extent = BYTES_TO_MAP;
+
+#ifdef DEBUG
+ dump_lb_forward(forward);
+#endif
+
+ if (!upper)
+ goto no_region; /* not a valid address */
+
+ if (mapped) {
+ addr = phys_to_virt(forward_phys);
+ } else {
+ phys_addr_t base = ppage_base(forward_phys);
+
+ upper += 1;
+ if (base + extent > upper)
+ extent = upper - base;
+
+ remap = ioremap(base, extent);
+ if (!remap) {
+ printk(KERN_DEBUG "Couldn't map %x, %u.\n",
+ base, extent);
+ return NULL;
+ }
+
+ addr = remap + ppage_offset(forward_phys);
+ }
+
+ lb_table = find_lb_table(addr, __v_offset(vpage_base(addr), extent));
+ }
+ }
+
+ if (!lb_table) {
+no_region:
+ printk(KERN_DEBUG "No coreboot table found.\n");
+ return NULL;
+ }
+
+ printk(KERN_DEBUG "coreboot table found at 0x%x.\n", virt_to_phys(lb_table));
+
+ rec = (struct lb_record *)__v_offset(lb_table, lb_table->header_bytes);
+ last = (struct lb_record *)__v_offset(rec, lb_table->table_bytes);
+
+#ifdef DEBUG
+ dump_lb_header(lb_table);
+#endif
+ search_lb_records(rec, last);
+
+ if (remap) {
+ iounmap(remap);
+ }
+
+ return rec;
+}
+EXPORT_SYMBOL(coreboot_init);
+
+const char *coreboot_vendor(void)
+{
+ return lb_vendor;
+}
+EXPORT_SYMBOL(coreboot_vendor);
+
+const char *coreboot_part(void)
+{
+ return lb_part;
+}
+EXPORT_SYMBOL(coreboot_part);
+
--
1.7.7.4
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