7918cfc46c
This patch redesigns the interface between the generic memconsole driver and its implementations to become more flexible than a flat memory buffer with unchanging bounds. This allows memconsoles like coreboot's to include lines that were added by runtime firmware after the driver was initialized. Since the console log size is thus no longer static, this means that the /sys/firmware/log file has to become unseekable. Signed-off-by: Julius Werner <jwerner@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
/*
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* memconsole.c
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*
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* Architecture-independent parts of the memory based BIOS console.
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*
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* Copyright 2017 Google Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License v2.0 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/init.h>
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#include <linux/sysfs.h>
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#include <linux/kobject.h>
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#include <linux/module.h>
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#include "memconsole.h"
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static ssize_t (*memconsole_read_func)(char *, loff_t, size_t);
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static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
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struct bin_attribute *bin_attr, char *buf,
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loff_t pos, size_t count)
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{
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if (WARN_ON_ONCE(!memconsole_read_func))
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return -EIO;
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return memconsole_read_func(buf, pos, count);
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}
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static struct bin_attribute memconsole_bin_attr = {
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.attr = {.name = "log", .mode = 0444},
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.read = memconsole_read,
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};
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void memconsole_setup(ssize_t (*read_func)(char *, loff_t, size_t))
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{
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memconsole_read_func = read_func;
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}
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EXPORT_SYMBOL(memconsole_setup);
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int memconsole_sysfs_init(void)
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{
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return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
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}
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EXPORT_SYMBOL(memconsole_sysfs_init);
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void memconsole_exit(void)
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{
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sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr);
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}
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EXPORT_SYMBOL(memconsole_exit);
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MODULE_AUTHOR("Google, Inc.");
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MODULE_LICENSE("GPL");
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