Quelle  hsti.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * AMD Secure Processor device driver, security attributes
 *
 * Copyright (C) 2023-2024 Advanced Micro Devices, Inc.
 *
 * Author: Mario Limonciello <mario.limonciello@amd.com>
 */

#include <linux/device.h>

#include "psp-dev.h"
#include "hsti.h"

#define PSP_CAPABILITY_PSP_SECURITY_OFFSET 8

struct hsti_request {
 struct psp_req_buffer_hdr header;
 u32 hsti;
} __packed;

#define security_attribute_show(name)      \
static ssize_t name##_show(struct device *d, struct device_attribute *attr, \
      char *buf)      \
{          \
 struct sp_device *sp = dev_get_drvdata(d);    \
 struct psp_device *psp = sp->psp_data;     \
 return sysfs_emit(buf, "%d\n", psp->capability.name);  \
}

security_attribute_show(fused_part)
static DEVICE_ATTR_RO(fused_part);
security_attribute_show(debug_lock_on)
static DEVICE_ATTR_RO(debug_lock_on);
security_attribute_show(tsme_status)
static DEVICE_ATTR_RO(tsme_status);
security_attribute_show(anti_rollback_status)
static DEVICE_ATTR_RO(anti_rollback_status);
security_attribute_show(rpmc_production_enabled)
static DEVICE_ATTR_RO(rpmc_production_enabled);
security_attribute_show(rpmc_spirom_available)
static DEVICE_ATTR_RO(rpmc_spirom_available);
security_attribute_show(hsp_tpm_available)
static DEVICE_ATTR_RO(hsp_tpm_available);
security_attribute_show(rom_armor_enforced)
static DEVICE_ATTR_RO(rom_armor_enforced);

static struct attribute *psp_security_attrs[] = {
 &dev_attr_fused_part.attr,
 &dev_attr_debug_lock_on.attr,
 &dev_attr_tsme_status.attr,
 &dev_attr_anti_rollback_status.attr,
 &dev_attr_rpmc_production_enabled.attr,
 &dev_attr_rpmc_spirom_available.attr,
 &dev_attr_hsp_tpm_available.attr,
 &dev_attr_rom_armor_enforced.attr,
 NULL
};

static umode_t psp_security_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
{
 struct device *dev = kobj_to_dev(kobj);
 struct sp_device *sp = dev_get_drvdata(dev);
 struct psp_device *psp = sp->psp_data;

 if (psp && psp->capability.security_reporting)
  return 0444;

 return 0;
}

struct attribute_group psp_security_attr_group = {
 .attrs = psp_security_attrs,
 .is_visible = psp_security_is_visible,
};

static int psp_poulate_hsti(struct psp_device *psp)
{
 struct hsti_request *req;
 int ret;

 /* Are the security attributes already reported? */
 if (psp->capability.security_reporting)
  return 0;

 /* Allocate command-response buffer */
 req = kzalloc(sizeof(*req), GFP_KERNEL | __GFP_ZERO);
 if (!req)
  return -ENOMEM;

 req->header.payload_size = sizeof(*req);

 ret = psp_send_platform_access_msg(PSP_CMD_HSTI_QUERY, (struct psp_request *)req);
 if (ret)
  goto out;

 if (req->header.status != 0) {
  dev_dbg(psp->dev, "failed to populate HSTI state: %d\n", req->header.status);
  ret = -EINVAL;
  goto out;
 }

 psp->capability.security_reporting = 1;
 psp->capability.raw |= req->hsti << PSP_CAPABILITY_PSP_SECURITY_OFFSET;

out:
 kfree(req);

 return ret;
}

int psp_init_hsti(struct psp_device *psp)
{
 int ret;

 if (PSP_FEATURE(psp, HSTI)) {
  ret = psp_poulate_hsti(psp);
  if (ret)
   return ret;
 }

 /*
 * At this stage, if security information hasn't been populated by
 * either the PSP or by the driver through the platform command,
 * then there is nothing more to do.
 */
 if (!psp->capability.security_reporting)
  return 0;

 if (psp->capability.tsme_status) {
  if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
   dev_notice(psp->dev, "psp: Both TSME and SME are active, SME is unnecessary when TSME is active.\n");
  else
   dev_notice(psp->dev, "psp: TSME enabled\n");
 }

 return 0;
}