driver: add PPI support in tpm driver
authorXiaoyan Zhang <xiaoyan.zhang@intel.com>
Wed, 22 Aug 2012 10:47:22 +0000 (18:47 +0800)
committerKent Yoder <key@linux.vnet.ibm.com>
Wed, 22 Aug 2012 21:23:42 +0000 (16:23 -0500)
The Physical Presence Interface enables the OS and the BIOS to cooperate and
provides a simple and straightforward platform user experience for
administering the TPM without sacrificing security.

V2: separate the patch out in a separate source file,
    add #ifdef CONFIG_ACPI so it compiles out on ppc,
    use standard error instead of ACPI error as return code of show/store fns.
V3: move #ifdef CONFIG_ACPI from .c file to .h file.
V4: move tpm_ppi code from tpm module to tpm_bios module.
V5: modify sys_add_ppi() so that ppi_attr_grp doesn't need to be exported

Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@intel.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
drivers/char/tpm/Makefile
drivers/char/tpm/tpm.c
drivers/char/tpm/tpm.h
drivers/char/tpm/tpm_ppi.c [new file with mode: 0644]

index 9080cc4..5b3fc8b 100644 (file)
@@ -4,7 +4,7 @@
 obj-$(CONFIG_TCG_TPM) += tpm.o
 ifdef CONFIG_ACPI
        obj-$(CONFIG_TCG_TPM) += tpm_bios.o
-       tpm_bios-objs += tpm_eventlog.o tpm_acpi.o
+       tpm_bios-objs += tpm_eventlog.o tpm_acpi.o tpm_ppi.o
 else
 ifdef CONFIG_TCG_IBMVTPM
        obj-$(CONFIG_TCG_TPM) += tpm_bios.o
index 0a75638..39526c0 100644 (file)
@@ -1476,6 +1476,11 @@ struct tpm_chip *tpm_register_hardware(struct device *dev,
                goto put_device;
        }
 
+       if (sys_add_ppi(&dev->kobj)) {
+               misc_deregister(&chip->vendor.miscdev);
+               goto put_device;
+       }
+
        chip->bios_dir = tpm_bios_log_setup(devname);
 
        /* Make chip available */
index f1af738..02c266a 100644 (file)
@@ -327,3 +327,12 @@ extern int tpm_pm_suspend(struct device *);
 extern int tpm_pm_resume(struct device *);
 extern int wait_for_tpm_stat(struct tpm_chip *, u8, unsigned long,
                             wait_queue_head_t *);
+
+#ifdef CONFIG_ACPI
+extern ssize_t sys_add_ppi(struct kobject *parent);
+#else
+static inline ssize_t sys_add_ppi(struct kobject *parent)
+{
+       return 0;
+}
+#endif
diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
new file mode 100644 (file)
index 0000000..440fa1c
--- /dev/null
@@ -0,0 +1,460 @@
+#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;
+}
+
+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;
+}
+
+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;
+}
+
+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;
+}
+
+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;
+}
+
+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;
+}
+
+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);
+}
+
+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 = {
+       .attrs = ppi_attrs
+};
+
+ssize_t sys_add_ppi(struct kobject *parent)
+{
+       struct kobject *ppi;
+       ppi = kobject_create_and_add("ppi", parent);
+       if (sysfs_create_group(ppi, &ppi_attr_grp))
+               return -EFAULT;
+       else
+               return 0;
+}
+EXPORT_SYMBOL_GPL(sys_add_ppi);
+
+MODULE_LICENSE("GPL");