forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
150 lines
3.3 KiB
150 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Export Runtime Configuration Interface Table Version 2 (RCI2) |
|
* to sysfs |
|
* |
|
* Copyright (C) 2019 Dell Inc |
|
* by Narendra K <[email protected]> |
|
* |
|
* System firmware advertises the address of the RCI2 Table via |
|
* an EFI Configuration Table entry. This code retrieves the RCI2 |
|
* table from the address and exports it to sysfs as a binary |
|
* attribute 'rci2' under /sys/firmware/efi/tables directory. |
|
*/ |
|
|
|
#include <linux/kobject.h> |
|
#include <linux/device.h> |
|
#include <linux/sysfs.h> |
|
#include <linux/efi.h> |
|
#include <linux/types.h> |
|
#include <linux/io.h> |
|
|
|
#define RCI_SIGNATURE "_RC_" |
|
|
|
struct rci2_table_global_hdr { |
|
u16 type; |
|
u16 resvd0; |
|
u16 hdr_len; |
|
u8 rci2_sig[4]; |
|
u16 resvd1; |
|
u32 resvd2; |
|
u32 resvd3; |
|
u8 major_rev; |
|
u8 minor_rev; |
|
u16 num_of_structs; |
|
u32 rci2_len; |
|
u16 rci2_chksum; |
|
} __packed; |
|
|
|
static u8 *rci2_base; |
|
static u32 rci2_table_len; |
|
unsigned long rci2_table_phys __ro_after_init = EFI_INVALID_TABLE_ADDR; |
|
|
|
static ssize_t raw_table_read(struct file *file, struct kobject *kobj, |
|
struct bin_attribute *attr, char *buf, |
|
loff_t pos, size_t count) |
|
{ |
|
memcpy(buf, attr->private + pos, count); |
|
return count; |
|
} |
|
|
|
static BIN_ATTR(rci2, S_IRUSR, raw_table_read, NULL, 0); |
|
|
|
static u16 checksum(void) |
|
{ |
|
u8 len_is_odd = rci2_table_len % 2; |
|
u32 chksum_len = rci2_table_len; |
|
u16 *base = (u16 *)rci2_base; |
|
u8 buf[2] = {0}; |
|
u32 offset = 0; |
|
u16 chksum = 0; |
|
|
|
if (len_is_odd) |
|
chksum_len -= 1; |
|
|
|
while (offset < chksum_len) { |
|
chksum += *base; |
|
offset += 2; |
|
base++; |
|
} |
|
|
|
if (len_is_odd) { |
|
buf[0] = *(u8 *)base; |
|
chksum += *(u16 *)(buf); |
|
} |
|
|
|
return chksum; |
|
} |
|
|
|
static int __init efi_rci2_sysfs_init(void) |
|
{ |
|
struct kobject *tables_kobj; |
|
int ret = -ENOMEM; |
|
|
|
if (rci2_table_phys == EFI_INVALID_TABLE_ADDR) |
|
return 0; |
|
|
|
rci2_base = memremap(rci2_table_phys, |
|
sizeof(struct rci2_table_global_hdr), |
|
MEMREMAP_WB); |
|
if (!rci2_base) { |
|
pr_debug("RCI2 table init failed - could not map RCI2 table\n"); |
|
goto err; |
|
} |
|
|
|
if (strncmp(rci2_base + |
|
offsetof(struct rci2_table_global_hdr, rci2_sig), |
|
RCI_SIGNATURE, 4)) { |
|
pr_debug("RCI2 table init failed - incorrect signature\n"); |
|
ret = -ENODEV; |
|
goto err_unmap; |
|
} |
|
|
|
rci2_table_len = *(u32 *)(rci2_base + |
|
offsetof(struct rci2_table_global_hdr, |
|
rci2_len)); |
|
|
|
memunmap(rci2_base); |
|
|
|
if (!rci2_table_len) { |
|
pr_debug("RCI2 table init failed - incorrect table length\n"); |
|
goto err; |
|
} |
|
|
|
rci2_base = memremap(rci2_table_phys, rci2_table_len, MEMREMAP_WB); |
|
if (!rci2_base) { |
|
pr_debug("RCI2 table - could not map RCI2 table\n"); |
|
goto err; |
|
} |
|
|
|
if (checksum() != 0) { |
|
pr_debug("RCI2 table - incorrect checksum\n"); |
|
ret = -ENODEV; |
|
goto err_unmap; |
|
} |
|
|
|
tables_kobj = kobject_create_and_add("tables", efi_kobj); |
|
if (!tables_kobj) { |
|
pr_debug("RCI2 table - tables_kobj creation failed\n"); |
|
goto err_unmap; |
|
} |
|
|
|
bin_attr_rci2.size = rci2_table_len; |
|
bin_attr_rci2.private = rci2_base; |
|
ret = sysfs_create_bin_file(tables_kobj, &bin_attr_rci2); |
|
if (ret != 0) { |
|
pr_debug("RCI2 table - rci2 sysfs bin file creation failed\n"); |
|
kobject_del(tables_kobj); |
|
kobject_put(tables_kobj); |
|
goto err_unmap; |
|
} |
|
|
|
return 0; |
|
|
|
err_unmap: |
|
memunmap(rci2_base); |
|
err: |
|
pr_debug("RCI2 table - sysfs initialization failed\n"); |
|
return ret; |
|
} |
|
late_initcall(efi_rci2_sysfs_init);
|
|
|