kernel: Add SMBIOS/DMI support

Signed-off-by: Ian Moffett <ian@osmora.org>

3 files changed, 322 insertions, 0 deletions

diff --git a/sys/dev/dmi/dmi.c b/sys/dev/dmi/dmi.c
new file mode 100644
index 0000000..8c7f21c
--- /dev/null
+++ b/sys/dev/dmi/dmi.c
@@ -0,0 +1,251 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/limine.h>
+#include <sys/errno.h>
+#include <sys/param.h>
+#include <sys/driver.h>
+#include <sys/cdefs.h>
+#include <sys/syslog.h>
+#include <dev/dmi/dmi.h>
+#include <dev/acpi/tables.h>
+#include <string.h>
+
+#define DMI_BIOS_INFO       0
+#define DMI_SYSTEM_INFO     1
+#define DMI_PROCESSOR_INFO  4
+#define DMI_END_OF_TABLE    127
+
+/* String offsets */
+#define BIOSINFO_VENDOR     0x01
+#define SYSINFO_PRODUCT     0x02
+#define SYSINFO_FAMILY      0x03
+#define PROCINFO_MANUFACT   0x02
+#define PROCINFO_PARTNO     0x06
+
+static struct limine_smbios_request smbios_req = {
+    .id = LIMINE_SMBIOS_REQUEST,
+    .revision = 0
+};
+
+/* DMI/SMBIOS structure header */
+struct __packed dmi_shdr {
+    uint8_t type;
+    uint8_t length;
+    uint16_t handle;
+} *hdrs[DMI_END_OF_TABLE + 1];
+
+/*
+ * Grab a structure header from a type
+ *
+ * @type: A DMI structure type to find
+ *
+ * Returns NULL if not found.
+ */
+static inline struct dmi_shdr *
+dmi_shdr(uint8_t type)
+{
+    struct dmi_shdr *hdr;
+
+    hdr = hdrs[type];
+    if (hdr == NULL) {
+        return NULL;
+    }
+
+    return hdr;
+}
+
+/*
+ * Grab a string from the DMI/SMBIOS formatted
+ * section.
+ *
+ * @hdr: DMI header to lookup string index
+ * @index: 1-based string index
+ *
+ * See section 6.1.3 of the DTMF SMBIOS Reference
+ * Specification
+ */
+static const char *
+dmi_str_index(struct dmi_shdr *hdr, uint8_t index)
+{
+    const char *strdata = PTR_OFFSET(hdr, hdr->length);
+
+    for (uint8_t i = 1; *strdata != '\0'; ++i) {
+        if (i == index) {
+            return strdata;
+        }
+
+        strdata += strlen(strdata) + 1;
+    }
+
+    return NULL;
+}
+
+/*
+ * Get the DMI/SMBIOS structure size from a
+ * header.
+ */
+static size_t
+dmi_struct_size(struct dmi_shdr *hdr)
+{
+    const char *strdata;
+    size_t i = 1;
+
+    strdata = PTR_OFFSET(hdr, hdr->length);
+    while (strdata[i - 1] != '\0' || strdata[i] != '\0') {
+        ++i;
+    }
+
+    return hdr->length + i + 1;
+}
+
+/*
+ * Get the vendor string from the DMI/SMBIOS BIOS
+ * info structure
+ *
+ * Returns NULL if not found.
+ */
+const char *
+dmi_vendor(void)
+{
+    struct dmi_shdr *hdr;
+
+    if ((hdr = dmi_shdr(DMI_BIOS_INFO)) == NULL) {
+        return NULL;
+    }
+
+    return dmi_str_index(hdr, BIOSINFO_VENDOR);
+}
+
+/*
+ * Return the product string from the DMI/SMBIOS System
+ * Info structure
+ *
+ * Returns NULL if not found.
+ */
+const char *
+dmi_product(void)
+{
+    struct dmi_shdr *hdr;
+
+    if ((hdr = dmi_shdr(DMI_SYSTEM_INFO)) == NULL) {
+        return NULL;
+    }
+
+    return dmi_str_index(hdr, SYSINFO_PRODUCT);
+}
+
+/*
+ * Return the product version from the DMI/SMBIOS
+ * System Info structure
+ *
+ * Returns NULL if not found
+ */
+const char *
+dmi_prodver(void)
+{
+    struct dmi_shdr *hdr;
+
+    if ((hdr = dmi_shdr(DMI_SYSTEM_INFO)) == NULL) {
+        return NULL;
+    }
+
+    return dmi_str_index(hdr, SYSINFO_FAMILY);
+}
+
+/*
+ * Return the CPU manufacturer string from the
+ * DMI/SMBIOS Processor Info structure
+ *
+ * Returns NULL if not found
+ */
+const char *
+dmi_cpu_manufact(void)
+{
+    struct dmi_shdr *hdr;
+
+    if ((hdr = dmi_shdr(DMI_PROCESSOR_INFO)) == NULL) {
+        return NULL;
+    }
+
+    return dmi_str_index(hdr, PROCINFO_MANUFACT);
+}
+
+static int
+dmi_init(void)
+{
+    struct dmi_entry32 *entry32 = NULL;
+    struct limine_smbios_response *resp = smbios_req.response;
+    struct dmi_entry64 *entry64 = NULL;
+    struct dmi_shdr *hdr = NULL;
+    size_t scount = 0, smax_len = 0;
+    size_t nbytes = 0, cur_nbytes = 0;
+
+    if (resp == NULL) {
+        return -ENODEV;
+    }
+    if (resp->entry_32 == 0 && resp->entry_64 == 0) {
+        return -ENODEV;
+    }
+
+    if (resp->entry_64 != 0) {
+        entry64 = (void *)resp->entry_64;
+        hdr = (void *)entry64->addr;
+        smax_len = entry64->max_size;
+    } else if (resp->entry_32 != 0) {
+        entry32 = (void *)(uint64_t)resp->entry_32;
+        hdr = (void *)(uint64_t)entry32->addr;
+        scount = entry32->nstruct;
+    } else {
+        return -ENODEV;
+    }
+
+    memset(hdrs, 0, sizeof(hdrs));
+    for (size_t i = 0; i < scount; ++i) {
+        if (hdr->type == DMI_END_OF_TABLE) {
+            break;
+        }
+
+        if (hdr->type < NELEM(hdrs)) {
+            hdrs[hdr->type] = hdr;
+        }
+        cur_nbytes = dmi_struct_size(hdr);
+        if (smax_len > 0 && (nbytes + cur_nbytes) >= smax_len) {
+            break;
+        }
+
+        nbytes += cur_nbytes;
+        hdr = PTR_OFFSET(hdr, cur_nbytes);
+    }
+
+    return 0;
+}
+
+DRIVER_EXPORT(dmi_init);
diff --git a/sys/include/dev/acpi/tables.h b/sys/include/dev/acpi/tables.h
index d190150..5340c7f 100644
--- a/sys/include/dev/acpi/tables.h
+++ b/sys/include/dev/acpi/tables.h
@@ -162,4 +162,35 @@ struct __packed acpi_mcfg {
     struct acpi_mcfg_base base[1];
 };
 
+struct __packed dmi_entry32 {
+    char signature[4];      /* _SM_ */
+    uint8_t checksum;       /* Sum of table bytes */
+    uint8_t length;         /* Length of entry table */
+    uint8_t major;          /* DMI major */
+    uint8_t minor;          /* DMI minor */
+    uint16_t max_size;      /* Max structure size */
+    uint8_t rev;            /* Entry revision */
+    char fmt_area[5];       /* Formatted area */
+    char isignature[5];     /* Intermediate signature */
+    uint8_t ichecksum;      /* Intermediate checksum */
+    uint16_t table_len;     /* Length of SMBIOS structure table */
+    uint32_t addr;          /* 32-bit physical start of SMBIOS structure table */
+    uint16_t nstruct;       /* Total number of structures */
+    uint8_t bcd_rev;
+};
+
+struct __packed dmi_entry64 {
+    char signature[5];      /* _SM_ */
+    uint8_t checksum;       /* Sum of table bytes */
+    uint8_t length;         /* Length of entry table */
+    uint8_t major;          /* DMI major */
+    uint8_t minor;          /* DMI minor */
+    uint8_t docrev;
+    uint8_t entry_rev;
+    uint8_t reserved;
+    uint16_t max_size;      /* Max structure size */
+    uint16_t padding;
+    uint64_t addr;          /* 64-bit physical address */
+};
+
 #endif  /* _ACPI_TABLES_H_ */
diff --git a/sys/include/dev/dmi/dmi.h b/sys/include/dev/dmi/dmi.h
new file mode 100644
index 0000000..d24397a
--- /dev/null
+++ b/sys/include/dev/dmi/dmi.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _DMI_DMI_H_
+#define _DMI_DMI_H_
+
+#include <sys/types.h>
+
+const char *dmi_vendor(void);
+const char *dmi_prodver(void);
+const char *dmi_product(void);
+const char *dmi_cpu_manufact(void);
+
+#endif  /* !_DMI_DMI_H_ */