ACPI / TPM: replace open-coded _DSM code with helper functions

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

This patch also help to get rid of following warning messages:
[  163.509575] ACPI Error: Incorrect return type [Buffer] requested [Package]
(20130517/nsxfeval-135)

But there is still an warning left.
[  181.637366] ACPI Warning: \_SB_.IIO0.LPC0.TPM_._DSM: Argument #4 type
mismatch - Found [Buffer], ACPI requires [Package] (20130517/nsarguments-95)

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 145 insertions, 259 deletions

diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index 1e9cc11ac76a..d542ac6d0ae0 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 = {
+                .buffer.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.integer.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);
 }