fix/kernel: Started fixing bootstrap acpi parser

kernel/src/emk.c

@@ -171,5 +171,13 @@ void emk_entry(void)
     acpi_init();
     log_early("Initialized ACPI");
 
+    void *madt = acpi_find_table("MADT");
+    if (!madt)
+    {
+        kpanic(NULL, "Failed to find MADT table");
+    }
+
+    log_early("Found MADT at %p", madt);
+
     hlt();
 }

kernel/src/sys/acpi.c

@@ -8,31 +8,6 @@
 static int acpi_uses_xsdt = 0;
 static void *acpi_rsdt_ptr = NULL;
 
-static uint8_t acpi_checksum(void *ptr, size_t len)
-{
-    uint8_t sum = 0;
-    uint8_t *data = (uint8_t *)ptr;
-    for (size_t i = 0; i < len; i++)
-    {
-        sum += data[i];
-    }
-    return sum;
-}
-
-static int acpi_validate_rsdp(acpi_rsdp_t *rsdp)
-{
-    return acpi_checksum(rsdp, sizeof(acpi_rsdp_t)) == 0;
-}
-
-static int acpi_validate_xsdp(acpi_xsdp_t *xsdp)
-{
-    if (acpi_checksum(xsdp, sizeof(acpi_rsdp_t)) != 0)
-        return 0;
-    if (acpi_checksum(xsdp, xsdp->length) != 0)
-        return 0;
-    return 1;
-}
-
 void acpi_init(void)
 {
     if (!rsdp_response || !rsdp_response->address)
@@ -40,81 +15,47 @@ void acpi_init(void)
         kpanic(NULL, "No RSDP provided");
     }
 
-    acpi_rsdp_t *rsdp = (acpi_rsdp_t *)rsdp_response->address;
+    acpi_rsdp_t *rsdp = (acpi_rsdp_t *)HIGHER_HALF(rsdp_response->address);
-    log_early("RSDP found at %p", rsdp);
+    if (memcmp(rsdp->signature, "RSD PTR", 7))
-    if (strncmp(rsdp->signature, "RSD PTR ", 8) != 0)
+        kpanic(NULL, "Invalid RSDP signature!");
-    {
-        kpanic(NULL, "Invalid RSDP signature");
-    }
 
-    if (rsdp->revision >= 2)
+    if (rsdp->revision != 0)
     {
-        acpi_xsdp_t *xsdp = (acpi_xsdp_t *)rsdp;
-        if (!acpi_validate_xsdp(xsdp))
-        {
-            kpanic(NULL, "XSDP checksum validation failed");
-        }
         acpi_uses_xsdt = 1;
-        acpi_rsdt_ptr = (void *)(uintptr_t)xsdp->xsdt_address;
+        acpi_xsdp_t *xsdp = (acpi_xsdp_t *)rsdp;
-    }
+        acpi_rsdt_ptr = (acpi_xsdt_t *)HIGHER_HALF(xsdp->xsdt_address);
-    else
+        log_early("XSDT found at %p", acpi_rsdt_ptr);
-    {
+        return;
-        if (!acpi_validate_rsdp(rsdp))
-        {
-            kpanic(NULL, "RSDP checksum validation failed");
-        }
-        acpi_uses_xsdt = 0;
-        acpi_rsdt_ptr = (void *)(uintptr_t)rsdp->rsdt_address;
     }
 
-    /* Validate RSDT/XSDT header */
+    acpi_rsdt_ptr = (acpi_rsdt_t *)HIGHER_HALF(rsdp->rsdt_address);
-    acpi_sdt_header_t *sdt = (acpi_sdt_header_t *)acpi_rsdt_ptr;
+    log_early("RSDT found at %p", acpi_rsdt_ptr);
-    if (acpi_checksum(sdt, sdt->length) != 0)
-    {
-        kpanic(NULL, "RSDT/XSDT checksum validation failed");
-    }
-
-    log_early("ACPI initialized, using %s at %p",
-              acpi_uses_xsdt ? "XSDT" : "RSDT", acpi_rsdt_ptr);
 }
 
 void *acpi_find_table(const char *name)
 {
-    if (!acpi_rsdt_ptr || !name)
+    if (!acpi_uses_xsdt)
+    {
+        acpi_rsdt_t *rsdt = (acpi_rsdt_t *)acpi_rsdt_ptr;
+        uint32_t entries = (rsdt->sdt.length - sizeof(rsdt->sdt)) / 4;
+        for (uint32_t i = 0; i < entries; i++)
+        {
+            acpi_sdt_header_t *sdt = (acpi_sdt_header_t *)HIGHER_HALF(*((uint32_t *)rsdt->table + i));
+            if (!memcmp(sdt->signature, name, 4))
+                return (void *)sdt;
+        }
         return NULL;
-
-    acpi_sdt_header_t *sdt = (acpi_sdt_header_t *)acpi_rsdt_ptr;
-    uint32_t entries;
-
-    if (acpi_uses_xsdt)
-    {
-        entries = (sdt->length - sizeof(acpi_sdt_header_t)) / sizeof(uint64_t);
-    }
-    else
-    {
-        entries = (sdt->length - sizeof(acpi_sdt_header_t)) / sizeof(uint32_t);
     }
+    acpi_xsdt_t *xsdt = (acpi_xsdt_t *)acpi_rsdt_ptr;
+    log_early("XSDT address: %p", xsdt);
+    uint32_t entries = (xsdt->sdt.length - sizeof(xsdt->sdt)) / 8;
 
     for (uint32_t i = 0; i < entries; i++)
     {
-        acpi_sdt_header_t *table;
+        acpi_sdt_header_t *sdt = (acpi_sdt_header_t *)HIGHER_HALF(*((uint64_t *)xsdt->table + i));
-        if (acpi_uses_xsdt)
+        if (!memcmp(sdt->signature, name, 4))
         {
-            uint64_t *xsdt_entries = (uint64_t *)(sdt + 1);
+            return (void *)sdt;
-            table = (acpi_sdt_header_t *)(uintptr_t)xsdt_entries[i];
-        }
-        else
-        {
-            uint32_t *rsdt_entries = (uint32_t *)(sdt + 1);
-            table = (acpi_sdt_header_t *)(uintptr_t)rsdt_entries[i];
-        }
-
-        if (strncmp(table->signature, name, 4) == 0)
-        {
-            if (acpi_checksum(table, table->length) == 0)
-            {
-                return table;
-            }
         }
     }
 

kernel/src/sys/acpi.h

@@ -22,9 +22,10 @@ typedef struct acpi_xsdp
     char oem_id[6];
     uint8_t revision;
     uint32_t rsdt_address;
+    uint32_t resv;
     uint32_t length;
     uint64_t xsdt_address;
-    uint8_t full_checksum;
+    uint8_t extended_checksum;
     uint8_t reserved[3];
 } __attribute__((packed)) acpi_xsdp_t;
 
@@ -41,6 +42,18 @@ typedef struct acpi_sdt_header
     uint32_t creator_revision;
 } __attribute__((packed)) acpi_sdt_header_t;
 
+typedef struct acpi_rsdt
+{
+    acpi_sdt_header_t sdt;
+    char table[];
+} __attribute__((packed)) acpi_rsdt_t;
+
+typedef struct acpi_xsdt
+{
+    acpi_sdt_header_t sdt;
+    char table[];
+} __attribute__((packed)) acpi_xsdt_t;
+
 void *acpi_find_table(const char *name);
 void acpi_init(void);