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firmware: google memconsole: Move specific EBDA parts
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This patch splits memconsole.c in 2 parts. One containing the
architecture-independent part and the other one containing the EBDA
specific part. This prepares the integration of coreboot support for the
memconsole.

The memconsole driver is now named as memconsole-x86-legacy.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Thierry Escande authored and Greg Kroah-Hartman committed Apr 8, 2017
1 parent f952a40 commit afe9dba
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Showing 5 changed files with 229 additions and 135 deletions.
9 changes: 7 additions & 2 deletions drivers/firmware/google/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,13 @@ config GOOGLE_SMI
variables.

config GOOGLE_MEMCONSOLE
tristate "Firmware Memory Console"
depends on DMI
tristate
depends on GOOGLE_MEMCONSOLE_X86_LEGACY

config GOOGLE_MEMCONSOLE_X86_LEGACY
tristate "Firmware Memory Console - X86 Legacy support"
depends on X86 && ACPI && DMI
select GOOGLE_MEMCONSOLE
help
This option enables the kernel to search for a firmware log in
the EBDA on Google servers. If found, this log is exported to
Expand Down
3 changes: 2 additions & 1 deletion drivers/firmware/google/Makefile
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@

obj-$(CONFIG_GOOGLE_SMI) += gsmi.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE) += memconsole.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE) += memconsole.o
obj-$(CONFIG_GOOGLE_MEMCONSOLE_X86_LEGACY) += memconsole-x86-legacy.o
154 changes: 154 additions & 0 deletions drivers/firmware/google/memconsole-x86-legacy.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,154 @@
/*
* memconsole-x86-legacy.c
*
* EBDA specific parts of the memory based BIOS console.
*
* Copyright 2017 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* 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.
*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/dmi.h>
#include <linux/mm.h>
#include <asm/bios_ebda.h>
#include <asm/e820.h>
#include <linux/acpi.h>

#include "memconsole.h"

#define BIOS_MEMCONSOLE_V1_MAGIC 0xDEADBABE
#define BIOS_MEMCONSOLE_V2_MAGIC (('M')|('C'<<8)|('O'<<16)|('N'<<24))

struct biosmemcon_ebda {
u32 signature;
union {
struct {
u8 enabled;
u32 buffer_addr;
u16 start;
u16 end;
u16 num_chars;
u8 wrapped;
} __packed v1;
struct {
u32 buffer_addr;
/* Misdocumented as number of pages! */
u16 num_bytes;
u16 start;
u16 end;
} __packed v2;
};
} __packed;

static void found_v1_header(struct biosmemcon_ebda *hdr)
{
pr_info("memconsole: BIOS console v1 EBDA structure found at %p\n",
hdr);
pr_info("memconsole: BIOS console buffer at 0x%.8x, start = %d, end = %d, num = %d\n",
hdr->v1.buffer_addr, hdr->v1.start,
hdr->v1.end, hdr->v1.num_chars);

memconsole_setup(phys_to_virt(hdr->v1.buffer_addr), hdr->v1.num_chars);
}

static void found_v2_header(struct biosmemcon_ebda *hdr)
{
pr_info("memconsole: BIOS console v2 EBDA structure found at %p\n",
hdr);
pr_info("memconsole: BIOS console buffer at 0x%.8x, start = %d, end = %d, num_bytes = %d\n",
hdr->v2.buffer_addr, hdr->v2.start,
hdr->v2.end, hdr->v2.num_bytes);

memconsole_setup(phys_to_virt(hdr->v2.buffer_addr + hdr->v2.start),
hdr->v2.end - hdr->v2.start);
}

/*
* Search through the EBDA for the BIOS Memory Console, and
* set the global variables to point to it. Return true if found.
*/
static bool memconsole_ebda_init(void)
{
unsigned int address;
size_t length, cur;

address = get_bios_ebda();
if (!address) {
pr_info("memconsole: BIOS EBDA non-existent.\n");
return false;
}

/* EBDA length is byte 0 of EBDA (in KB) */
length = *(u8 *)phys_to_virt(address);
length <<= 10; /* convert to bytes */

/*
* Search through EBDA for BIOS memory console structure
* note: signature is not necessarily dword-aligned
*/
for (cur = 0; cur < length; cur++) {
struct biosmemcon_ebda *hdr = phys_to_virt(address + cur);

/* memconsole v1 */
if (hdr->signature == BIOS_MEMCONSOLE_V1_MAGIC) {
found_v1_header(hdr);
return true;
}

/* memconsole v2 */
if (hdr->signature == BIOS_MEMCONSOLE_V2_MAGIC) {
found_v2_header(hdr);
return true;
}
}

pr_info("memconsole: BIOS console EBDA structure not found!\n");
return false;
}

static struct dmi_system_id memconsole_dmi_table[] __initdata = {
{
.ident = "Google Board",
.matches = {
DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."),
},
},
{}
};
MODULE_DEVICE_TABLE(dmi, memconsole_dmi_table);

static bool __init memconsole_find(void)
{
if (!dmi_check_system(memconsole_dmi_table))
return false;

return memconsole_ebda_init();
}

static int __init memconsole_x86_init(void)
{
if (!memconsole_find())
return -ENODEV;

return memconsole_sysfs_init();
}

static void __exit memconsole_x86_exit(void)
{
memconsole_exit();
}

module_init(memconsole_x86_init);
module_exit(memconsole_x86_exit);

MODULE_AUTHOR("Google, Inc.");
MODULE_LICENSE("GPL");
155 changes: 23 additions & 132 deletions drivers/firmware/google/memconsole.c
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Original file line number Diff line number Diff line change
@@ -1,171 +1,62 @@
/*
* memconsole.c
*
* Infrastructure for importing the BIOS memory based console
* into the kernel log ringbuffer.
* Architecture-independent parts of the memory based BIOS console.
*
* Copyright 2010 Google Inc. All rights reserved.
* Copyright 2017 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* 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.
*/

#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/dmi.h>
#include <linux/io.h>
#include <asm/bios_ebda.h>

#define BIOS_MEMCONSOLE_V1_MAGIC 0xDEADBABE
#define BIOS_MEMCONSOLE_V2_MAGIC (('M')|('C'<<8)|('O'<<16)|('N'<<24))
#include "memconsole.h"

struct biosmemcon_ebda {
u32 signature;
union {
struct {
u8 enabled;
u32 buffer_addr;
u16 start;
u16 end;
u16 num_chars;
u8 wrapped;
} __packed v1;
struct {
u32 buffer_addr;
/* Misdocumented as number of pages! */
u16 num_bytes;
u16 start;
u16 end;
} __packed v2;
};
} __packed;

static u32 memconsole_baseaddr;
static char *memconsole_baseaddr;
static size_t memconsole_length;

static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
struct bin_attribute *bin_attr, char *buf,
loff_t pos, size_t count)
{
char *memconsole;
ssize_t ret;

memconsole = ioremap_cache(memconsole_baseaddr, memconsole_length);
if (!memconsole) {
pr_err("memconsole: ioremap_cache failed\n");
return -ENOMEM;
}
ret = memory_read_from_buffer(buf, count, &pos, memconsole,
memconsole_length);
iounmap(memconsole);
return ret;
return memory_read_from_buffer(buf, count, &pos, memconsole_baseaddr,
memconsole_length);
}

static struct bin_attribute memconsole_bin_attr = {
.attr = {.name = "log", .mode = 0444},
.read = memconsole_read,
};


static void __init found_v1_header(struct biosmemcon_ebda *hdr)
{
pr_info("BIOS console v1 EBDA structure found at %p\n", hdr);
pr_info("BIOS console buffer at 0x%.8x, "
"start = %d, end = %d, num = %d\n",
hdr->v1.buffer_addr, hdr->v1.start,
hdr->v1.end, hdr->v1.num_chars);

memconsole_length = hdr->v1.num_chars;
memconsole_baseaddr = hdr->v1.buffer_addr;
}

static void __init found_v2_header(struct biosmemcon_ebda *hdr)
{
pr_info("BIOS console v2 EBDA structure found at %p\n", hdr);
pr_info("BIOS console buffer at 0x%.8x, "
"start = %d, end = %d, num_bytes = %d\n",
hdr->v2.buffer_addr, hdr->v2.start,
hdr->v2.end, hdr->v2.num_bytes);

memconsole_length = hdr->v2.end - hdr->v2.start;
memconsole_baseaddr = hdr->v2.buffer_addr + hdr->v2.start;
}

/*
* Search through the EBDA for the BIOS Memory Console, and
* set the global variables to point to it. Return true if found.
*/
static bool __init found_memconsole(void)
void memconsole_setup(void *baseaddr, size_t length)
{
unsigned int address;
size_t length, cur;

address = get_bios_ebda();
if (!address) {
pr_info("BIOS EBDA non-existent.\n");
return false;
}

/* EBDA length is byte 0 of EBDA (in KB) */
length = *(u8 *)phys_to_virt(address);
length <<= 10; /* convert to bytes */

/*
* Search through EBDA for BIOS memory console structure
* note: signature is not necessarily dword-aligned
*/
for (cur = 0; cur < length; cur++) {
struct biosmemcon_ebda *hdr = phys_to_virt(address + cur);

/* memconsole v1 */
if (hdr->signature == BIOS_MEMCONSOLE_V1_MAGIC) {
found_v1_header(hdr);
return true;
}

/* memconsole v2 */
if (hdr->signature == BIOS_MEMCONSOLE_V2_MAGIC) {
found_v2_header(hdr);
return true;
}
}

pr_info("BIOS console EBDA structure not found!\n");
return false;
memconsole_baseaddr = baseaddr;
memconsole_length = length;
}
EXPORT_SYMBOL(memconsole_setup);

static struct dmi_system_id memconsole_dmi_table[] __initdata = {
{
.ident = "Google Board",
.matches = {
DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."),
},
},
{}
};
MODULE_DEVICE_TABLE(dmi, memconsole_dmi_table);

static int __init memconsole_init(void)
int memconsole_sysfs_init(void)
{
if (!dmi_check_system(memconsole_dmi_table))
return -ENODEV;

if (!found_memconsole())
return -ENODEV;

memconsole_bin_attr.size = memconsole_length;
return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
}
EXPORT_SYMBOL(memconsole_sysfs_init);

static void __exit memconsole_exit(void)
void memconsole_exit(void)
{
sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr);
}

module_init(memconsole_init);
module_exit(memconsole_exit);
EXPORT_SYMBOL(memconsole_exit);

MODULE_AUTHOR("Google, Inc.");
MODULE_LICENSE("GPL");
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