[RFC Patch v1 08/13] ACPI, TPM: replace open-coded _DSM specific code with helper functions

From: Jiang Liu
Date: Wed Dec 18 2013 - 01:58:08 EST


Use helper functions to simplify _DSM related code in TPM driver.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
drivers/char/tpm/tpm_ppi.c | 404 ++++++++++++++++----------------------------
1 file changed, 145 insertions(+), 259 deletions(-)

diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index 1e9cc11..ad5143f 100644
--- a/drivers/char/tpm/tpm_ppi.c
+++ b/drivers/char/tpm/tpm_ppi.c
@@ -2,15 +2,6 @@
#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
@@ -24,250 +15,185 @@ static char *tpm_device_name = "TPM";
#define PPI_VS_REQ_END 255
#define PPI_VERSION_LEN 3

+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";
+static char tpm_ppi_version[PPI_VERSION_LEN + 1];
+static acpi_handle tpm_ppi_handle;
+
static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
void **return_value)
{
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

- if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer))) {
- if (strstr(buffer.pointer, context) != NULL) {
- *return_value = handle;
- status = AE_CTRL_TERMINATE;
+ status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
+ if (ACPI_FAILURE(status))
+ return AE_OK;
+
+ if (strstr(buffer.pointer, context) != NULL) {
+ union acpi_object *obj;
+
+ /* Cache version string */
+ obj = acpi_evaluate_dsm_typed(handle, tpm_ppi_uuid,
+ TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
+ NULL, ACPI_TYPE_STRING);
+ if (obj) {
+ strlcpy(tpm_ppi_version, obj->string.pointer,
+ PPI_VERSION_LEN + 1);
+ ACPI_FREE(obj);
}
- kfree(buffer.pointer);
+
+ *return_value = handle;
+ status = AE_CTRL_TERMINATE;
}
+ kfree(buffer.pointer);

return status;
}

-static inline void ppi_assign_params(union acpi_object params[4],
- u64 function_num)
+static inline union acpi_object *
+tpm_eval_dsm(int func, acpi_object_type type, union acpi_object *argv4)
{
- 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;
+ BUG_ON(!tpm_ppi_handle);
+ return acpi_evaluate_dsm_typed(tpm_ppi_handle, tpm_ppi_uuid,
+ TPM_PPI_REVISION_ID, func, argv4, type);
}

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;
+ return scnprintf(buf, PAGE_SIZE, "%s\n", tpm_ppi_version);
}

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))
+ ssize_t size = -EINVAL;
+ union acpi_object *obj;
+
+ obj = tpm_eval_dsm(TPM_PPI_FN_GETREQ, ACPI_TYPE_PACKAGE, NULL);
+ if (!obj)
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);
+ if (obj->package.count == 2 &&
+ obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
+ obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
+ if (obj->package.elements[0].integer.value)
+ size = -EFAULT;
else
- status = -EINVAL;
- } else {
- status = -EINVAL;
+ size = scnprintf(buf, PAGE_SIZE, "%llu\n",
+ obj->package.elements[1].integer.value);
}
-cleanup:
- kfree(output.pointer);
- return status;
+
+ ACPI_FREE(obj);
+
+ return size;
}

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;
+ int func = TPM_PPI_FN_SUBREQ;
+ union acpi_object *obj, tmp;
+ union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);

- 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;
- strlcpy(version,
- ((union acpi_object *)output.pointer)->string.pointer,
- PPI_VERSION_LEN + 1);
- 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;
+ if (strcmp(tpm_ppi_version, "1.1") >= 0)
+ func = 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;
+ if (strcmp(tpm_ppi_version, "1.2") < 0) {
+ if (sscanf(buf, "%d", &req) != 1)
+ return -EINVAL;
+ argv4.type = ACPI_TYPE_BUFFER;
+ argv4.buffer.length = sizeof(req);
+ argv4.buffer.pointer = (u8 *)&req;
} else {
- params[3].package.count = 1;
- obj.type = ACPI_TYPE_INTEGER;
- sscanf(buf, "%llu", &obj.integer.value);
- params[3].package.elements = &obj;
+ tmp.type = ACPI_TYPE_INTEGER;
+ if (sscanf(buf, "%llu", &tmp.integer.value) != 1)
+ return -EINVAL;
+ }
+
+ obj = tpm_eval_dsm(func, ACPI_TYPE_INTEGER, &argv4);
+ if (!obj) {
+ return -ENXIO;
+ } else {
+ ret = obj->integer.value;
+ ACPI_FREE(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;
+ return (acpi_status)count;
+
+ return (ret == 1) ? -EPERM : -EFAULT;
}

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[] = {
+ acpi_status status;
+ union acpi_object *obj = NULL;
+ union acpi_object tmp = {
+ .type = ACPI_TYPE_BUFFER,
+ .buffer.length = 0,
+ .buffer.pointer = NULL
+ };
+
+ static 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;
- strlcpy(version,
- ((union acpi_object *)output.pointer)->string.pointer,
- PPI_VERSION_LEN + 1);
/*
* 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;
+ if (strcmp(tpm_ppi_version, "1.2") < 0)
+ obj = &tmp;
+ obj = tpm_eval_dsm(TPM_PPI_FN_GETACT, ACPI_TYPE_INTEGER, obj);
+ if (!obj) {
+ return -ENXIO;
+ } else {
+ ret = obj->integer.value;
+ ACPI_FREE(obj);
}
- 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;
}

@@ -275,27 +201,14 @@ 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))
+ acpi_status status = -EINVAL;
+ union acpi_object *obj, *ret_obj;
+ u64 req, res;
+
+ obj = tpm_eval_dsm(TPM_PPI_FN_GETRSP, ACPI_TYPE_PACKAGE, NULL);
+ if (!obj)
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
@@ -303,115 +216,81 @@ static ssize_t tpm_show_ppi_response(struct device *dev,
* 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;
+ ret_obj = obj->package.elements;
+ if (obj->package.count < 3 ||
+ ret_obj[0].type != ACPI_TYPE_INTEGER ||
+ ret_obj[1].type != ACPI_TYPE_INTEGER ||
+ ret_obj[2].type != ACPI_TYPE_INTEGER)
goto cleanup;
- }
- if (ret_obj->integer.value) {
+
+ if (ret_obj[0].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)
+
+ req = ret_obj[1].integer.value;
+ res = ret_obj[2].integer.value;
+ if (req) {
+ if (res == 0)
status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
"0: Success");
- else if (ret_obj->integer.value == 0xFFFFFFF0)
+ else if (res == 0xFFFFFFF0)
status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
"0xFFFFFFF0: User Abort");
- else if (ret_obj->integer.value == 0xFFFFFFF1)
+ else if (res == 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)
+ else if (res >= 1 && res <= 0x00000FFF)
status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
- req, ret_obj->integer.value,
- "Corresponding TPM error");
+ req, res, "Corresponding TPM error");
else
status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
- req, ret_obj->integer.value,
- "Error");
+ req, res, "Error");
} else {
status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
- ret_obj->integer.value, "No Recent Request");
+ req, "No Recent Request");
}
+
cleanup:
- kfree(output.pointer);
+ ACPI_FREE(obj);
return status;
}

static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
{
- char *str = 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];
- union acpi_object obj;
int i;
u32 ret;
- char *info[] = {
+ char *str = buf;
+ union acpi_object *obj, tmp;
+ union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);
+
+ static 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;
-
- strlcpy(version,
- ((union acpi_object *)output.pointer)->string.pointer,
- PPI_VERSION_LEN + 1);
- kfree(output.pointer);
- output.length = ACPI_ALLOCATE_BUFFER;
- output.pointer = NULL;
- if (strcmp(version, "1.2") == -1)
+ if (strcmp(tpm_ppi_version, "1.2") < 0)
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;
+ tmp.type = ACPI_TYPE_INTEGER;
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))
+ tmp.integer.value = i;
+ obj = tpm_eval_dsm(TPM_PPI_FN_GETOPR, ACPI_TYPE_INTEGER, &argv);
+ if (!obj) {
return -ENOMEM;
+ } else {
+ ret = obj->integer.value;
+ ACPI_FREE(obj);
+ }

- 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;
}

@@ -453,6 +332,13 @@ static struct attribute_group ppi_attr_grp = {

int tpm_add_ppi(struct kobject *parent)
{
+ /* Cache TPM ACPI handle and version string */
+ acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
+ ppi_callback, NULL,
+ tpm_device_name, &tpm_ppi_handle);
+ if (tpm_ppi_handle == NULL)
+ return -ENODEV;
+
return sysfs_create_group(parent, &ppi_attr_grp);
}

--
1.7.10.4

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