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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/platform/x86/dell/dell-smbios-smm.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/platform/x86/dell/dell-smbios-smm.c')
-rw-r--r--drivers/platform/x86/dell/dell-smbios-smm.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell/dell-smbios-smm.c b/drivers/platform/x86/dell/dell-smbios-smm.c
new file mode 100644
index 000000000..4d375985c
--- /dev/null
+++ b/drivers/platform/x86/dell/dell-smbios-smm.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SMI methods for use with dell-smbios
+ *
+ * Copyright (c) Red Hat <mjg@redhat.com>
+ * Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
+ * Copyright (c) 2014 Pali Rohár <pali@kernel.org>
+ * Copyright (c) 2017 Dell Inc.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/dmi.h>
+#include <linux/gfp.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include "dcdbas.h"
+#include "dell-smbios.h"
+
+static int da_command_address;
+static int da_command_code;
+static struct smi_buffer smi_buf;
+static struct calling_interface_buffer *buffer;
+static struct platform_device *platform_device;
+static DEFINE_MUTEX(smm_mutex);
+
+static void parse_da_table(const struct dmi_header *dm)
+{
+ struct calling_interface_structure *table =
+ container_of(dm, struct calling_interface_structure, header);
+
+ /* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
+ * 6 bytes of entry
+ */
+ if (dm->length < 17)
+ return;
+
+ da_command_address = table->cmdIOAddress;
+ da_command_code = table->cmdIOCode;
+}
+
+static void find_cmd_address(const struct dmi_header *dm, void *dummy)
+{
+ switch (dm->type) {
+ case 0xda: /* Calling interface */
+ parse_da_table(dm);
+ break;
+ }
+}
+
+static int dell_smbios_smm_call(struct calling_interface_buffer *input)
+{
+ struct smi_cmd command;
+ size_t size;
+
+ size = sizeof(struct calling_interface_buffer);
+ command.magic = SMI_CMD_MAGIC;
+ command.command_address = da_command_address;
+ command.command_code = da_command_code;
+ command.ebx = smi_buf.dma;
+ command.ecx = 0x42534931;
+
+ mutex_lock(&smm_mutex);
+ memcpy(buffer, input, size);
+ dcdbas_smi_request(&command);
+ memcpy(input, buffer, size);
+ mutex_unlock(&smm_mutex);
+ return 0;
+}
+
+/* When enabled this indicates that SMM won't work */
+static bool test_wsmt_enabled(void)
+{
+ struct calling_interface_token *wsmt;
+
+ /* if token doesn't exist, SMM will work */
+ wsmt = dell_smbios_find_token(WSMT_EN_TOKEN);
+ if (!wsmt)
+ return false;
+
+ /* If token exists, try to access over SMM but set a dummy return.
+ * - If WSMT disabled it will be overwritten by SMM
+ * - If WSMT enabled then dummy value will remain
+ */
+ buffer->cmd_class = CLASS_TOKEN_READ;
+ buffer->cmd_select = SELECT_TOKEN_STD;
+ memset(buffer, 0, sizeof(struct calling_interface_buffer));
+ buffer->input[0] = wsmt->location;
+ buffer->output[0] = 99;
+ dell_smbios_smm_call(buffer);
+ if (buffer->output[0] == 99)
+ return true;
+
+ return false;
+}
+
+int init_dell_smbios_smm(void)
+{
+ int ret;
+ /*
+ * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
+ * is passed to SMI handler.
+ */
+ ret = dcdbas_smi_alloc(&smi_buf, PAGE_SIZE);
+ if (ret)
+ return ret;
+ buffer = (void *)smi_buf.virt;
+
+ dmi_walk(find_cmd_address, NULL);
+
+ if (test_wsmt_enabled()) {
+ pr_debug("Disabling due to WSMT enabled\n");
+ ret = -ENODEV;
+ goto fail_wsmt;
+ }
+
+ platform_device = platform_device_alloc("dell-smbios", 1);
+ if (!platform_device) {
+ ret = -ENOMEM;
+ goto fail_platform_device_alloc;
+ }
+
+ ret = platform_device_add(platform_device);
+ if (ret)
+ goto fail_platform_device_add;
+
+ ret = dell_smbios_register_device(&platform_device->dev,
+ &dell_smbios_smm_call);
+ if (ret)
+ goto fail_register;
+
+ return 0;
+
+fail_register:
+ platform_device_del(platform_device);
+
+fail_platform_device_add:
+ platform_device_put(platform_device);
+
+fail_wsmt:
+fail_platform_device_alloc:
+ dcdbas_smi_free(&smi_buf);
+ return ret;
+}
+
+void exit_dell_smbios_smm(void)
+{
+ if (platform_device) {
+ dell_smbios_unregister_device(&platform_device->dev);
+ platform_device_unregister(platform_device);
+ dcdbas_smi_free(&smi_buf);
+ }
+}