linux/arch/x86/kernel/ksysfs.c
Daniel Kiper b3c72fc9a7 x86/boot: Introduce setup_indirect
The setup_data is a bit awkward to use for extremely large data objects,
both because the setup_data header has to be adjacent to the data object
and because it has a 32-bit length field. However, it is important that
intermediate stages of the boot process have a way to identify which
chunks of memory are occupied by kernel data. Thus introduce an uniform
way to specify such indirect data as setup_indirect struct and
SETUP_INDIRECT type.

And finally bump setup_header version in arch/x86/boot/header.S.

Suggested-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juergen Gross <jgross@suse.com>
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi <linux-efi@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-4-daniel.kiper@oracle.com
2019-11-12 16:21:15 +01:00

357 lines
7.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Architecture specific sysfs attributes in /sys/kernel
*
* Copyright (C) 2007, Intel Corp.
* Huang Ying <ying.huang@intel.com>
* Copyright (C) 2013, 2013 Red Hat, Inc.
* Dave Young <dyoung@redhat.com>
*/
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/io.h>
#include <asm/setup.h>
static ssize_t version_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "0x%04x\n", boot_params.hdr.version);
}
static struct kobj_attribute boot_params_version_attr = __ATTR_RO(version);
static ssize_t boot_params_data_read(struct file *fp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
memcpy(buf, (void *)&boot_params + off, count);
return count;
}
static struct bin_attribute boot_params_data_attr = {
.attr = {
.name = "data",
.mode = S_IRUGO,
},
.read = boot_params_data_read,
.size = sizeof(boot_params),
};
static struct attribute *boot_params_version_attrs[] = {
&boot_params_version_attr.attr,
NULL,
};
static struct bin_attribute *boot_params_data_attrs[] = {
&boot_params_data_attr,
NULL,
};
static const struct attribute_group boot_params_attr_group = {
.attrs = boot_params_version_attrs,
.bin_attrs = boot_params_data_attrs,
};
static int kobj_to_setup_data_nr(struct kobject *kobj, int *nr)
{
const char *name;
name = kobject_name(kobj);
return kstrtoint(name, 10, nr);
}
static int get_setup_data_paddr(int nr, u64 *paddr)
{
int i = 0;
struct setup_data *data;
u64 pa_data = boot_params.hdr.setup_data;
while (pa_data) {
if (nr == i) {
*paddr = pa_data;
return 0;
}
data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
if (!data)
return -ENOMEM;
pa_data = data->next;
memunmap(data);
i++;
}
return -EINVAL;
}
static int __init get_setup_data_size(int nr, size_t *size)
{
int i = 0;
struct setup_data *data;
u64 pa_data = boot_params.hdr.setup_data;
while (pa_data) {
data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
if (!data)
return -ENOMEM;
if (nr == i) {
if (data->type == SETUP_INDIRECT &&
((struct setup_indirect *)data->data)->type != SETUP_INDIRECT)
*size = ((struct setup_indirect *)data->data)->len;
else
*size = data->len;
memunmap(data);
return 0;
}
pa_data = data->next;
memunmap(data);
i++;
}
return -EINVAL;
}
static ssize_t type_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
int nr, ret;
u64 paddr;
struct setup_data *data;
ret = kobj_to_setup_data_nr(kobj, &nr);
if (ret)
return ret;
ret = get_setup_data_paddr(nr, &paddr);
if (ret)
return ret;
data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
if (!data)
return -ENOMEM;
if (data->type == SETUP_INDIRECT)
ret = sprintf(buf, "0x%x\n", ((struct setup_indirect *)data->data)->type);
else
ret = sprintf(buf, "0x%x\n", data->type);
memunmap(data);
return ret;
}
static ssize_t setup_data_data_read(struct file *fp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf,
loff_t off, size_t count)
{
int nr, ret = 0;
u64 paddr, len;
struct setup_data *data;
void *p;
ret = kobj_to_setup_data_nr(kobj, &nr);
if (ret)
return ret;
ret = get_setup_data_paddr(nr, &paddr);
if (ret)
return ret;
data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
if (!data)
return -ENOMEM;
if (data->type == SETUP_INDIRECT &&
((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
paddr = ((struct setup_indirect *)data->data)->addr;
len = ((struct setup_indirect *)data->data)->len;
} else {
paddr += sizeof(*data);
len = data->len;
}
if (off > len) {
ret = -EINVAL;
goto out;
}
if (count > len - off)
count = len - off;
if (!count)
goto out;
ret = count;
p = memremap(paddr, len, MEMREMAP_WB);
if (!p) {
ret = -ENOMEM;
goto out;
}
memcpy(buf, p + off, count);
memunmap(p);
out:
memunmap(data);
return ret;
}
static struct kobj_attribute type_attr = __ATTR_RO(type);
static struct bin_attribute data_attr __ro_after_init = {
.attr = {
.name = "data",
.mode = S_IRUGO,
},
.read = setup_data_data_read,
};
static struct attribute *setup_data_type_attrs[] = {
&type_attr.attr,
NULL,
};
static struct bin_attribute *setup_data_data_attrs[] = {
&data_attr,
NULL,
};
static const struct attribute_group setup_data_attr_group = {
.attrs = setup_data_type_attrs,
.bin_attrs = setup_data_data_attrs,
};
static int __init create_setup_data_node(struct kobject *parent,
struct kobject **kobjp, int nr)
{
int ret = 0;
size_t size;
struct kobject *kobj;
char name[16]; /* should be enough for setup_data nodes numbers */
snprintf(name, 16, "%d", nr);
kobj = kobject_create_and_add(name, parent);
if (!kobj)
return -ENOMEM;
ret = get_setup_data_size(nr, &size);
if (ret)
goto out_kobj;
data_attr.size = size;
ret = sysfs_create_group(kobj, &setup_data_attr_group);
if (ret)
goto out_kobj;
*kobjp = kobj;
return 0;
out_kobj:
kobject_put(kobj);
return ret;
}
static void __init cleanup_setup_data_node(struct kobject *kobj)
{
sysfs_remove_group(kobj, &setup_data_attr_group);
kobject_put(kobj);
}
static int __init get_setup_data_total_num(u64 pa_data, int *nr)
{
int ret = 0;
struct setup_data *data;
*nr = 0;
while (pa_data) {
*nr += 1;
data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
if (!data) {
ret = -ENOMEM;
goto out;
}
pa_data = data->next;
memunmap(data);
}
out:
return ret;
}
static int __init create_setup_data_nodes(struct kobject *parent)
{
struct kobject *setup_data_kobj, **kobjp;
u64 pa_data;
int i, j, nr, ret = 0;
pa_data = boot_params.hdr.setup_data;
if (!pa_data)
return 0;
setup_data_kobj = kobject_create_and_add("setup_data", parent);
if (!setup_data_kobj) {
ret = -ENOMEM;
goto out;
}
ret = get_setup_data_total_num(pa_data, &nr);
if (ret)
goto out_setup_data_kobj;
kobjp = kmalloc_array(nr, sizeof(*kobjp), GFP_KERNEL);
if (!kobjp) {
ret = -ENOMEM;
goto out_setup_data_kobj;
}
for (i = 0; i < nr; i++) {
ret = create_setup_data_node(setup_data_kobj, kobjp + i, i);
if (ret)
goto out_clean_nodes;
}
kfree(kobjp);
return 0;
out_clean_nodes:
for (j = i - 1; j >= 0; j--)
cleanup_setup_data_node(*(kobjp + j));
kfree(kobjp);
out_setup_data_kobj:
kobject_put(setup_data_kobj);
out:
return ret;
}
static int __init boot_params_ksysfs_init(void)
{
int ret;
struct kobject *boot_params_kobj;
boot_params_kobj = kobject_create_and_add("boot_params",
kernel_kobj);
if (!boot_params_kobj) {
ret = -ENOMEM;
goto out;
}
ret = sysfs_create_group(boot_params_kobj, &boot_params_attr_group);
if (ret)
goto out_boot_params_kobj;
ret = create_setup_data_nodes(boot_params_kobj);
if (ret)
goto out_create_group;
return 0;
out_create_group:
sysfs_remove_group(boot_params_kobj, &boot_params_attr_group);
out_boot_params_kobj:
kobject_put(boot_params_kobj);
out:
return ret;
}
arch_initcall(boot_params_ksysfs_init);