linux/drivers/char/tpm/tpm_acpi.c
Lv Zheng a238317ce8 ACPI: Clean up acpi_os_map/unmap_memory() to eliminate __iomem.
ACPICA doesn't include protections around address space checking, Linux
build tests always complain increased sparse warnings around ACPICA
internal acpi_os_map/unmap_memory() invocations.  This patch tries to fix
this issue permanently.

There are 2 choices left for us to solve this issue:
 1. Add __iomem address space awareness into ACPICA.
 2. Remove sparse checker of __iomem from ACPICA source code.

This patch chooses solution 2, because:
 1.  Most of the acpi_os_map/unmap_memory() invocations are used for ACPICA.
     table mappings, which in fact are not IO addresses.
 2.  The only IO addresses usage is for "system memory space" mapping code in:
      drivers/acpi/acpica/exregion.c
      drivers/acpi/acpica/evrgnini.c
      drivers/acpi/acpica/exregion.c
    The mapped address is accessed in the handler of "system memory space"
    - acpi_ex_system_memory_space_handler().  This function in fact can be
    changed to invoke acpi_os_read/write_memory() so that __iomem can
    always be type-casted in the OSL layer.

According to the above investigation, we drew the following conclusion:
It is not a good idea to introduce __iomem address space awareness into
ACPICA mostly in order to protect non-IO addresses.

We can simply remove __iomem for acpi_os_map/unmap_memory() to remove
__iomem checker for ACPICA code. Then we need to enforce external usages
to invoke other APIs that are aware of __iomem address space.
The external usages are:
 drivers/acpi/apei/einj.c
 drivers/acpi/acpi_extlog.c
 drivers/char/tpm/tpm_acpi.c
 drivers/acpi/nvs.c

This patch thus performs cleanups in this way:
 1. Add acpi_os_map/unmap_iomem() to be invoked by non-ACPICA code.
 2. Remove __iomem from acpi_os_map/unmap_memory().

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-27 18:13:08 +02:00

110 lines
2.5 KiB
C

/*
* Copyright (C) 2005 IBM Corporation
*
* Authors:
* Seiji Munetoh <munetoh@jp.ibm.com>
* Stefan Berger <stefanb@us.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* Access to the eventlog extended by the TCG BIOS of PC platform
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include "tpm.h"
#include "tpm_eventlog.h"
struct acpi_tcpa {
struct acpi_table_header hdr;
u16 platform_class;
union {
struct client_hdr {
u32 log_max_len __packed;
u64 log_start_addr __packed;
} client;
struct server_hdr {
u16 reserved;
u64 log_max_len __packed;
u64 log_start_addr __packed;
} server;
};
};
/* read binary bios log */
int read_log(struct tpm_bios_log *log)
{
struct acpi_tcpa *buff;
acpi_status status;
void __iomem *virt;
u64 len, start;
if (log->bios_event_log != NULL) {
printk(KERN_ERR
"%s: ERROR - Eventlog already initialized\n",
__func__);
return -EFAULT;
}
/* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
status = acpi_get_table(ACPI_SIG_TCPA, 1,
(struct acpi_table_header **)&buff);
if (ACPI_FAILURE(status)) {
printk(KERN_ERR "%s: ERROR - Could not get TCPA table\n",
__func__);
return -EIO;
}
switch(buff->platform_class) {
case BIOS_SERVER:
len = buff->server.log_max_len;
start = buff->server.log_start_addr;
break;
case BIOS_CLIENT:
default:
len = buff->client.log_max_len;
start = buff->client.log_start_addr;
break;
}
if (!len) {
printk(KERN_ERR "%s: ERROR - TCPA log area empty\n", __func__);
return -EIO;
}
/* malloc EventLog space */
log->bios_event_log = kmalloc(len, GFP_KERNEL);
if (!log->bios_event_log) {
printk("%s: ERROR - Not enough Memory for BIOS measurements\n",
__func__);
return -ENOMEM;
}
log->bios_event_log_end = log->bios_event_log + len;
virt = acpi_os_map_iomem(start, len);
if (!virt) {
kfree(log->bios_event_log);
printk("%s: ERROR - Unable to map memory\n", __func__);
return -EIO;
}
memcpy_fromio(log->bios_event_log, virt, len);
acpi_os_unmap_iomem(virt, len);
return 0;
}