From 2d0bb16fad4c70f5adcee3af133aae29bf5e6b49 Mon Sep 17 00:00:00 2001
From: Nigel <nigelbarink@hotmail.com>
Date: Mon, 27 Feb 2023 00:32:16 +0100
Subject: [PATCH] Fixed up ACPI Version 1.0 checksum validation code

---
 CoreLib/Memory.cpp   | 12 +++++-------
 kernel/acpi/acpi.cpp | 34 +++++++++++++++++++++++++---------
 kernel/acpi/acpi.h   |  7 ++++---
 kernel/acpi/rsdp.cpp |  9 +--------
 kernel/acpi/rsdp.h   | 25 ++++++++++++++++++-------
 5 files changed, 53 insertions(+), 34 deletions(-)

diff --git a/CoreLib/Memory.cpp b/CoreLib/Memory.cpp
index 491ed38..155dba1 100644
--- a/CoreLib/Memory.cpp
+++ b/CoreLib/Memory.cpp
@@ -16,16 +16,14 @@ void* memset (void* ptr, int value, size_t num)
 
 int memcmp( const void* ptr1, const void* ptr2, size_t num)
 {
-    const unsigned char * cs = (const unsigned char*) ptr1;
-    const unsigned char * ct = (const unsigned char*) ptr2;
+    auto* cs = (const unsigned char*) ptr1;
+    auto* ct = (const unsigned char*) ptr2;
 
 
     for (int i = 0 ; i < num ; i++, cs++, ct++ ){
-        if( *cs < *ct){
-            return -1;
-        } else if( *cs > *ct){
-            return 1;
-        }
+        if( *cs != *ct)
+            return *cs - *ct;
+
     }
 
     return 0;
diff --git a/kernel/acpi/acpi.cpp b/kernel/acpi/acpi.cpp
index e904ae6..bc83d08 100644
--- a/kernel/acpi/acpi.cpp
+++ b/kernel/acpi/acpi.cpp
@@ -1,5 +1,6 @@
 #include "acpi.h"
 RSDPDescriptor* ACPI::rsd_ptr;
+RSCPDescriptor20* ACPI::rsd2_ptr;
 RSDT* ACPI::rsd_table;
 
 
@@ -8,19 +9,34 @@ void ACPI::initialize(){
 
     // Find the Root System Description Pointer
     ACPI::rsd_ptr = FindRSD();
+    printf("RSD address: 0x%x\n", ACPI::rsd_ptr);
+    //printRSD(rsd_ptr);
 
-    // is it valid
-    int sum = 0;
-    for (int i =0; i < 20 ; i++) {
-        sum += ((char*)rsd_ptr)[i];
+
+    if( rsd_ptr->Revision == 0 ){
+        // Using veriosn 1.0 of the ACPI specifiction
+        int sum = rsd_ptr->Checksum;
+        for (int i =0; i < sizeof(RSDPDescriptor) ; i++) {
+            sum += ((char*)rsd_ptr)[i];
+        }
+
+        printf(" 0x%x sum\n", sum);
+        if(sum & 0xfff0)
+            printf("valid rsd!\n");
+        else
+            printf("invalid rsd\n");
+
+
+        //  Get the Root System Description Table NOTE: might need memory mapping
+        //RSDT* rootSystemDescriptionTable = (RSDT*) (rsd_ptr->RsdtAddress + 0xC0000000);
+    } else{
+        // parse it as of version2.0
+        ACPI::rsd2_ptr = (RSCPDescriptor20*)rsd_ptr;
     }
 
-    printf(" 0x%x sum\n", sum);
-    return;
 
-    //  Get the Root System Description Table
-    RSDT* rootSystemDescriptionTable =  getRSDT((RSDPDescriptor *) rsd_ptr);
 
+/*
     auto tableHeader = &rootSystemDescriptionTable->h;
 
     // do checksum
@@ -31,5 +47,5 @@ void ACPI::initialize(){
     }
 
     if( sum != 0)
-        printf("Table invalid!");
+        printf("Table invalid!");*/
 }
\ No newline at end of file
diff --git a/kernel/acpi/acpi.h b/kernel/acpi/acpi.h
index c2293d0..97ca223 100644
--- a/kernel/acpi/acpi.h
+++ b/kernel/acpi/acpi.h
@@ -6,8 +6,9 @@ class ACPI {
         
         // In the future ACPI might start
         // doing more systems initialization
-        
+
+    static RSDPDescriptor* rsd_ptr;
+    static RSCPDescriptor20* rsd2_ptr;
+    static RSDT* rsd_table;
     private:
-       static RSDPDescriptor* rsd_ptr;
-       static RSDT* rsd_table;
 };
\ No newline at end of file
diff --git a/kernel/acpi/rsdp.cpp b/kernel/acpi/rsdp.cpp
index f4408c2..3ed66e9 100644
--- a/kernel/acpi/rsdp.cpp
+++ b/kernel/acpi/rsdp.cpp
@@ -1,5 +1,6 @@
 #include "rsdp.h"
 #include "../memory/VirtualMemoryManager.h"
+#include "../../CoreLib/Memory.h"
 
 
 void printRSD(RSDPDescriptor* rsd){
@@ -16,7 +17,6 @@ void printRSD(RSDPDescriptor* rsd){
     kterm_put('\n');
 
     printf("Revision: %d\n", rsd->Revision);
-    printf("RSDT Address: 0x%x\n", rsd->RsdtAddress );
 }
 
 RSDPDescriptor* FindRSD(){
@@ -31,10 +31,3 @@ RSDPDescriptor* FindRSD(){
     }
     return (RSDPDescriptor*) memory_byte;
 }
-
-
-RSDT* getRSDT(RSDPDescriptor* rsd){
-    printf("rsdt Address: 0x%x\n", rsd->RsdtAddress);
-    return (RSDT*)rsd->RsdtAddress ;
-
-}
\ No newline at end of file
diff --git a/kernel/acpi/rsdp.h b/kernel/acpi/rsdp.h
index 4ae6899..aef9445 100644
--- a/kernel/acpi/rsdp.h
+++ b/kernel/acpi/rsdp.h
@@ -3,13 +3,6 @@
 #include <CoreLib/Memory.h>
 #include <stdint-gcc.h>
 
-struct RSDPDescriptor {
-    char signature[8];
-    uint8_t Checksum ;
-    char OEMID [6];
-    uint8_t Revision;
-    uint32_t RsdtAddress;
-}__attribute__((packed));
 
 struct ACPISDTHeader{
     char Signature[4];
@@ -28,6 +21,24 @@ struct RSDT{
     struct ACPISDTHeader h;
     uint32_t PointerToSDT[]; // Length of array : (header.Length - sizeof(header))/ 4
 }__attribute__((packed));
+
+
+struct RSDPDescriptor {
+    char signature[8];
+    uint8_t Checksum ;
+    char OEMID [6];
+    uint8_t Revision;
+    RSDT* RsdtAddress;
+}__attribute__((packed));
+
+struct RSCPDescriptor20{
+   RSDPDescriptor base;
+   uint32_t Length;
+   uint64_t XsdtAddress;
+   uint8_t ExtendedChecksum;
+   uint8_t reserved[3];
+}__attribute__((packed));
+
 RSDPDescriptor* FindRSD();
 
 void printRSD(RSDPDescriptor* rsd);