cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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bgrt.c (2325B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * BGRT boot graphic support
      4 * Authors: Matthew Garrett, Josh Triplett <josh@joshtriplett.org>
      5 * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
      6 * Copyright 2012 Intel Corporation
      7 */
      8
      9#include <linux/kernel.h>
     10#include <linux/init.h>
     11#include <linux/device.h>
     12#include <linux/sysfs.h>
     13#include <linux/efi-bgrt.h>
     14
     15static void *bgrt_image;
     16static struct kobject *bgrt_kobj;
     17
     18#define BGRT_SHOW(_name, _member) \
     19	static ssize_t _name##_show(struct kobject *kobj,			\
     20				    struct kobj_attribute *attr, char *buf)	\
     21	{									\
     22		return sysfs_emit(buf, "%d\n", bgrt_tab._member);		\
     23	}									\
     24	static struct kobj_attribute bgrt_attr_##_name = __ATTR_RO(_name)
     25
     26BGRT_SHOW(version, version);
     27BGRT_SHOW(status, status);
     28BGRT_SHOW(type, image_type);
     29BGRT_SHOW(xoffset, image_offset_x);
     30BGRT_SHOW(yoffset, image_offset_y);
     31
     32static ssize_t image_read(struct file *file, struct kobject *kobj,
     33	       struct bin_attribute *attr, char *buf, loff_t off, size_t count)
     34{
     35	memcpy(buf, attr->private + off, count);
     36	return count;
     37}
     38
     39static BIN_ATTR_RO(image, 0);	/* size gets filled in later */
     40
     41static struct attribute *bgrt_attributes[] = {
     42	&bgrt_attr_version.attr,
     43	&bgrt_attr_status.attr,
     44	&bgrt_attr_type.attr,
     45	&bgrt_attr_xoffset.attr,
     46	&bgrt_attr_yoffset.attr,
     47	NULL,
     48};
     49
     50static struct bin_attribute *bgrt_bin_attributes[] = {
     51	&bin_attr_image,
     52	NULL,
     53};
     54
     55static const struct attribute_group bgrt_attribute_group = {
     56	.attrs = bgrt_attributes,
     57	.bin_attrs = bgrt_bin_attributes,
     58};
     59
     60int __init acpi_parse_bgrt(struct acpi_table_header *table)
     61{
     62	efi_bgrt_init(table);
     63	return 0;
     64}
     65
     66static int __init bgrt_init(void)
     67{
     68	int ret;
     69
     70	if (!bgrt_tab.image_address)
     71		return -ENODEV;
     72
     73	bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
     74			      MEMREMAP_WB);
     75	if (!bgrt_image) {
     76		pr_notice("Ignoring BGRT: failed to map image memory\n");
     77		return -ENOMEM;
     78	}
     79
     80	bin_attr_image.private = bgrt_image;
     81	bin_attr_image.size = bgrt_image_size;
     82
     83	bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
     84	if (!bgrt_kobj) {
     85		ret = -EINVAL;
     86		goto out_memmap;
     87	}
     88
     89	ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
     90	if (ret)
     91		goto out_kobject;
     92
     93	return 0;
     94
     95out_kobject:
     96	kobject_put(bgrt_kobj);
     97out_memmap:
     98	memunmap(bgrt_image);
     99	return ret;
    100}
    101device_initcall(bgrt_init);