1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * memconsole.c 4 * 5 * Architecture-independent parts of the memory based BIOS console. 6 * 7 * Copyright 2017 Google Inc. 8 */ 9 10 #include <linux/sysfs.h> 11 #include <linux/kobject.h> 12 #include <linux/module.h> 13 14 #include "memconsole.h" 15 16 static ssize_t memconsole_read(struct file *filp, struct kobject *kobp, 17 struct bin_attribute *bin_attr, char *buf, 18 loff_t pos, size_t count) 19 { 20 ssize_t (*memconsole_read_func)(char *, loff_t, size_t); 21 22 memconsole_read_func = bin_attr->private; 23 if (WARN_ON_ONCE(!memconsole_read_func)) 24 return -EIO; 25 26 return memconsole_read_func(buf, pos, count); 27 } 28 29 static struct bin_attribute memconsole_bin_attr = { 30 .attr = {.name = "log", .mode = 0444}, 31 .read = memconsole_read, 32 }; 33 34 void memconsole_setup(ssize_t (*read_func)(char *, loff_t, size_t)) 35 { 36 memconsole_bin_attr.private = read_func; 37 } 38 EXPORT_SYMBOL(memconsole_setup); 39 40 int memconsole_sysfs_init(void) 41 { 42 return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr); 43 } 44 EXPORT_SYMBOL(memconsole_sysfs_init); 45 46 void memconsole_exit(void) 47 { 48 sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr); 49 } 50 EXPORT_SYMBOL(memconsole_exit); 51 52 MODULE_AUTHOR("Google, Inc."); 53 MODULE_LICENSE("GPL"); 54