linux/drivers/char/tpm/tpm_ppi.c

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#include <linux/acpi.h>
#include <acpi/acpi_drivers.h>
#include "tpm.h"
static const u8 tpm_ppi_uuid[] = {
0xA6, 0xFA, 0xDD, 0x3D,
0x1B, 0x36,
0xB4, 0x4E,
0xA4, 0x24,
0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
};
static char *tpm_device_name = "TPM";
#define TPM_PPI_REVISION_ID 1
#define TPM_PPI_FN_VERSION 1
#define TPM_PPI_FN_SUBREQ 2
#define TPM_PPI_FN_GETREQ 3
#define TPM_PPI_FN_GETACT 4
#define TPM_PPI_FN_GETRSP 5
#define TPM_PPI_FN_SUBREQ2 7
#define TPM_PPI_FN_GETOPR 8
#define PPI_TPM_REQ_MAX 22
#define PPI_VS_REQ_START 128
#define PPI_VS_REQ_END 255
#define PPI_VERSION_LEN 3
static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
void **return_value)
{
acpi_status status;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
if (strstr(buffer.pointer, context) != NULL) {
*return_value = handle;
kfree(buffer.pointer);
return AE_CTRL_TERMINATE;
}
return AE_OK;
}
static inline void ppi_assign_params(union acpi_object params[4],
u64 function_num)
{
params[0].type = ACPI_TYPE_BUFFER;
params[0].buffer.length = sizeof(tpm_ppi_uuid);
params[0].buffer.pointer = (char *)tpm_ppi_uuid;
params[1].type = ACPI_TYPE_INTEGER;
params[1].integer.value = TPM_PPI_REVISION_ID;
params[2].type = ACPI_TYPE_INTEGER;
params[2].integer.value = function_num;
params[3].type = ACPI_TYPE_PACKAGE;
params[3].package.count = 0;
params[3].package.elements = NULL;
}
static ssize_t tpm_show_ppi_version(struct device *dev,
struct device_attribute *attr, char *buf)
{
acpi_handle handle;
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[4];
union acpi_object *obj;
input.count = 4;
ppi_assign_params(params, TPM_PPI_FN_VERSION);
input.pointer = params;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, ppi_callback, NULL,
tpm_device_name, &handle);
if (ACPI_FAILURE(status))
return -ENXIO;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_STRING);
if (ACPI_FAILURE(status))
return -ENOMEM;
obj = (union acpi_object *)output.pointer;
status = scnprintf(buf, PAGE_SIZE, "%s\n", obj->string.pointer);
kfree(output.pointer);
return status;
}
static ssize_t tpm_show_ppi_request(struct device *dev,
struct device_attribute *attr, char *buf)
{
acpi_handle handle;
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[4];
union acpi_object *ret_obj;
input.count = 4;
ppi_assign_params(params, TPM_PPI_FN_GETREQ);
input.pointer = params;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, ppi_callback, NULL,
tpm_device_name, &handle);
if (ACPI_FAILURE(status))
return -ENXIO;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_PACKAGE);
if (ACPI_FAILURE(status))
return -ENOMEM;
/*
* output.pointer should be of package type, including two integers.
* The first is function return code, 0 means success and 1 means
* error. The second is pending TPM operation requested by the OS, 0
* means none and >0 means operation value.
*/
ret_obj = ((union acpi_object *)output.pointer)->package.elements;
if (ret_obj->type == ACPI_TYPE_INTEGER) {
if (ret_obj->integer.value) {
status = -EFAULT;
goto cleanup;
}
ret_obj++;
if (ret_obj->type == ACPI_TYPE_INTEGER)
status = scnprintf(buf, PAGE_SIZE, "%llu\n",
ret_obj->integer.value);
else
status = -EINVAL;
} else {
status = -EINVAL;
}
cleanup:
kfree(output.pointer);
return status;
}
static ssize_t tpm_store_ppi_request(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
char version[PPI_VERSION_LEN + 1];
acpi_handle handle;
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[4];
union acpi_object obj;
u32 req;
u64 ret;
input.count = 4;
ppi_assign_params(params, TPM_PPI_FN_VERSION);
input.pointer = params;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, ppi_callback, NULL,
tpm_device_name, &handle);
if (ACPI_FAILURE(status))
return -ENXIO;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_STRING);
if (ACPI_FAILURE(status))
return -ENOMEM;
strncpy(version,
((union acpi_object *)output.pointer)->string.pointer,
PPI_VERSION_LEN);
kfree(output.pointer);
output.length = ACPI_ALLOCATE_BUFFER;
output.pointer = NULL;
/*
* the function to submit TPM operation request to pre-os environment
* is updated with function index from SUBREQ to SUBREQ2 since PPI
* version 1.1
*/
if (strcmp(version, "1.1") == -1)
params[2].integer.value = TPM_PPI_FN_SUBREQ;
else
params[2].integer.value = TPM_PPI_FN_SUBREQ2;
/*
* PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
* accept buffer/string/integer type, but some BIOS accept buffer/
* string/package type. For PPI version 1.0 and 1.1, use buffer type
* for compatibility, and use package type since 1.2 according to spec.
*/
if (strcmp(version, "1.2") == -1) {
params[3].type = ACPI_TYPE_BUFFER;
params[3].buffer.length = sizeof(req);
sscanf(buf, "%d", &req);
params[3].buffer.pointer = (char *)&req;
} else {
params[3].package.count = 1;
obj.type = ACPI_TYPE_INTEGER;
sscanf(buf, "%llu", &obj.integer.value);
params[3].package.elements = &obj;
}
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_INTEGER);
if (ACPI_FAILURE(status))
return -ENOMEM;
ret = ((union acpi_object *)output.pointer)->integer.value;
if (ret == 0)
status = (acpi_status)count;
else if (ret == 1)
status = -EPERM;
else
status = -EFAULT;
kfree(output.pointer);
return status;
}
static ssize_t tpm_show_ppi_transition_action(struct device *dev,
struct device_attribute *attr,
char *buf)
{
char version[PPI_VERSION_LEN + 1];
acpi_handle handle;
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[4];
u32 ret;
char *info[] = {
"None",
"Shutdown",
"Reboot",
"OS Vendor-specific",
"Error",
};
input.count = 4;
ppi_assign_params(params, TPM_PPI_FN_VERSION);
input.pointer = params;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, ppi_callback, NULL,
tpm_device_name, &handle);
if (ACPI_FAILURE(status))
return -ENXIO;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_STRING);
if (ACPI_FAILURE(status))
return -ENOMEM;
strncpy(version,
((union acpi_object *)output.pointer)->string.pointer,
PPI_VERSION_LEN);
/*
* PPI spec defines params[3].type as empty package, but some platforms
* (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
* compatibility, define params[3].type as buffer, if PPI version < 1.2
*/
if (strcmp(version, "1.2") == -1) {
params[3].type = ACPI_TYPE_BUFFER;
params[3].buffer.length = 0;
params[3].buffer.pointer = NULL;
}
params[2].integer.value = TPM_PPI_FN_GETACT;
kfree(output.pointer);
output.length = ACPI_ALLOCATE_BUFFER;
output.pointer = NULL;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_INTEGER);
if (ACPI_FAILURE(status))
return -ENOMEM;
ret = ((union acpi_object *)output.pointer)->integer.value;
if (ret < ARRAY_SIZE(info) - 1)
status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
else
status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
info[ARRAY_SIZE(info)-1]);
kfree(output.pointer);
return status;
}
static ssize_t tpm_show_ppi_response(struct device *dev,
struct device_attribute *attr,
char *buf)
{
acpi_handle handle;
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[4];
union acpi_object *ret_obj;
u64 req;
input.count = 4;
ppi_assign_params(params, TPM_PPI_FN_GETRSP);
input.pointer = params;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, ppi_callback, NULL,
tpm_device_name, &handle);
if (ACPI_FAILURE(status))
return -ENXIO;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_PACKAGE);
if (ACPI_FAILURE(status))
return -ENOMEM;
/*
* parameter output.pointer should be of package type, including
* 3 integers. The first means function return code, the second means
* most recent TPM operation request, and the last means response to
* the most recent TPM operation request. Only if the first is 0, and
* the second integer is not 0, the response makes sense.
*/
ret_obj = ((union acpi_object *)output.pointer)->package.elements;
if (ret_obj->type != ACPI_TYPE_INTEGER) {
status = -EINVAL;
goto cleanup;
}
if (ret_obj->integer.value) {
status = -EFAULT;
goto cleanup;
}
ret_obj++;
if (ret_obj->type != ACPI_TYPE_INTEGER) {
status = -EINVAL;
goto cleanup;
}
if (ret_obj->integer.value) {
req = ret_obj->integer.value;
ret_obj++;
if (ret_obj->type != ACPI_TYPE_INTEGER) {
status = -EINVAL;
goto cleanup;
}
if (ret_obj->integer.value == 0)
status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
"0: Success");
else if (ret_obj->integer.value == 0xFFFFFFF0)
status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
"0xFFFFFFF0: User Abort");
else if (ret_obj->integer.value == 0xFFFFFFF1)
status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
"0xFFFFFFF1: BIOS Failure");
else if (ret_obj->integer.value >= 1 &&
ret_obj->integer.value <= 0x00000FFF)
status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
req, ret_obj->integer.value,
"Corresponding TPM error");
else
status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
req, ret_obj->integer.value,
"Error");
} else {
status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
ret_obj->integer.value, "No Recent Request");
}
cleanup:
kfree(output.pointer);
return status;
}
static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
{
char *str = buf;
char version[PPI_VERSION_LEN];
acpi_handle handle;
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object params[4];
union acpi_object obj;
int i;
u32 ret;
char *info[] = {
"Not implemented",
"BIOS only",
"Blocked for OS by BIOS",
"User required",
"User not required",
};
input.count = 4;
ppi_assign_params(params, TPM_PPI_FN_VERSION);
input.pointer = params;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, ppi_callback, NULL,
tpm_device_name, &handle);
if (ACPI_FAILURE(status))
return -ENXIO;
status = acpi_evaluate_object_typed(handle, "_DSM", &input, &output,
ACPI_TYPE_STRING);
if (ACPI_FAILURE(status))
return -ENOMEM;
strncpy(version,
((union acpi_object *)output.pointer)->string.pointer,
PPI_VERSION_LEN);
kfree(output.pointer);
output.length = ACPI_ALLOCATE_BUFFER;
output.pointer = NULL;
if (strcmp(version, "1.2") == -1)
return -EPERM;
params[2].integer.value = TPM_PPI_FN_GETOPR;
params[3].package.count = 1;
obj.type = ACPI_TYPE_INTEGER;
params[3].package.elements = &obj;
for (i = start; i <= end; i++) {
obj.integer.value = i;
status = acpi_evaluate_object_typed(handle, "_DSM",
&input, &output, ACPI_TYPE_INTEGER);
if (ACPI_FAILURE(status))
return -ENOMEM;
ret = ((union acpi_object *)output.pointer)->integer.value;
if (ret > 0 && ret < ARRAY_SIZE(info))
str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
i, ret, info[ret]);
kfree(output.pointer);
output.length = ACPI_ALLOCATE_BUFFER;
output.pointer = NULL;
}
return str - buf;
}
static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return show_ppi_operations(buf, 0, PPI_TPM_REQ_MAX);
}
static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return show_ppi_operations(buf, PPI_VS_REQ_START, PPI_VS_REQ_END);
}
static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
tpm_show_ppi_request, tpm_store_ppi_request);
static DEVICE_ATTR(transition_action, S_IRUGO,
tpm_show_ppi_transition_action, NULL);
static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);
static struct attribute *ppi_attrs[] = {
&dev_attr_version.attr,
&dev_attr_request.attr,
&dev_attr_transition_action.attr,
&dev_attr_response.attr,
&dev_attr_tcg_operations.attr,
&dev_attr_vs_operations.attr, NULL,
};
static struct attribute_group ppi_attr_grp = {
.name = "ppi",
.attrs = ppi_attrs
};
int tpm_add_ppi(struct kobject *parent)
{
return sysfs_create_group(parent, &ppi_attr_grp);
}
EXPORT_SYMBOL_GPL(tpm_add_ppi);
void tpm_remove_ppi(struct kobject *parent)
{
sysfs_remove_group(parent, &ppi_attr_grp);
}
EXPORT_SYMBOL_GPL(tpm_remove_ppi);
MODULE_LICENSE("GPL");