Improve hardware exception handler.

Author: scopeInfinity

Makefile

@@ -102,7 +102,7 @@ binaries: $(bt_stage1) $(bt_stage2) $(kernel_core) $(rm_static)
 SECTOR_COUNT_BT_STAGE1 = 1
 SECTOR_COUNT_SHARED_LIBRARY = 1
 SECTOR_COUNT_BT_STAGE2 = 12
-SECTOR_COUNT_KERNEL = 52
+SECTOR_COUNT_KERNEL = 54
 
 SECTOR_START_BT_STAGE1 = 0
 SECTOR_START_SHARED_LIBRARY = $(shell expr $(SECTOR_START_BT_STAGE1) + $(SECTOR_COUNT_BT_STAGE1) )

include/fuzzy/kernel/panic.h

@@ -9,3 +9,4 @@
 void panic_just_halt();
 int panic(int err, const char *message, const char *src_file,
     unsigned int line_number);
+int panic_screen_init();

include/fuzzy/memmgr/tables/gdt.h

@@ -18,6 +18,7 @@ struct GDTEntry {
 };
 #pragma pack(pop)
 
+int get_gdt_baseaddress(struct GDTEntry gdt_table[], unsigned int table_size, int entry_id);
 
 void populate_gdt_entry(struct GDTEntry *entry,
     unsigned int base,

src/kernel/interrupts/exceptions.asm

@@ -41,11 +41,16 @@ global _interrupt_handler_0x1F_exception
     _interrupt_handler_%1_exception:
         ; As we are HLT at end of exception there
         ; is no need to save context for now.
+        xor eax, eax
+        mov eax, ds    ; execution ds
+        push eax
+        xor eax, eax
+        mov eax, ss    ; execution ss (current also)
+        push eax
+        mov eax, 0x10  ; kernel ds
+        mov ds, eax
         mov eax, %1
         push eax
-        ; arg0: exception number
-        ; arg1: return IP
-        ; arg2: return CS
         call interrupt_handler_0x00_0x1F_exception
         HLT
 %endmacro

src/kernel/interrupts/exceptions.c

@@ -1,4 +1,8 @@
 #include <fuzzy/kernel/panic.h>
+#include <fuzzy/memmgr/tables/gdt.h>
+#include <fuzzy/kernel/process/process.h>
+
+extern struct GDTEntry gdt_table[];
 
 extern void _interrupt_handler_0x00_exception();
 extern void _interrupt_handler_0x01_exception();
@@ -33,7 +37,37 @@ extern void _interrupt_handler_0x1D_exception();
 extern void _interrupt_handler_0x1E_exception();
 extern void _interrupt_handler_0x1F_exception();
 
-void interrupt_handler_0x00_0x1F_exception(int id, int ip, int cs) {
+void interrupt_handler_0x00_0x1F_exception(int id, int err_code, int ds, int ss, int ip, int cs, int eflag) {
+    panic_screen_init();
+    unsigned int abs_address =
+    print_log("Hardware exception %d (0x%x) triggered", id, id);
+    print_log("  Error Code: %x or %x", err_code);
+    print_log("  CS    : %x (GDT entry)", cs);
+    print_log("  DS    : %x (GDT entry)", ds);
+    print_log("  SS    : %x (GDT entry)", ss);
+    print_log("  IP    : %x", ip);
+    print_log("  FLAG  : %x", eflag);
+    if(cs%sizeof(struct GDTEntry)==0) {
+        print_log("  PID   : %d", get_idt_reverse_pid_lookup_cs(cs));
+        unsigned int abs_cs = get_gdt_baseaddress(gdt_table, GDT_TABLE_SIZE, cs/sizeof(struct GDTEntry));
+        print_log("  abs IP: %x", abs_cs+ip);
+        print_log("  abs CS: %x", abs_cs);
+    } else {
+        print_log("  PID   : invalid");
+        print_log("  abs IP: invalid");
+        print_log("  abs CS: invalid");
+    }
+    if(ds%sizeof(struct GDTEntry)==0) {
+        print_log("  abs DS: %x", get_gdt_baseaddress(gdt_table, GDT_TABLE_SIZE, ds/sizeof(struct GDTEntry)));
+    } else {
+        print_log("  abs DS: invalid");
+    }
+    if(ss%sizeof(struct GDTEntry)==0) {
+        print_log("  abs SS: %x", get_gdt_baseaddress(gdt_table, GDT_TABLE_SIZE, ss/sizeof(struct GDTEntry)));
+    } else {
+        print_log("  abs SS: invalid");
+    }
+
     switch (id) {
         case 0x0D:
             PANIC(id, "[hw_exception] general_protection_fault");

src/kernel/panic.c

@@ -23,3 +23,12 @@ int panic(int err, const char *message, const char *src_file,
     print_line(message);
     panic_just_halt();
 }
+
+int panic_screen_init() {
+    set_color_bg(C_RED);
+    set_color_fg(C_WHITE);
+    // first two lines are used by panic(...)
+    move_xy(0,2);
+    // kernel can not use print_log(...) to write.
+    return 0;
+}

src/memmgr/tables/gdt.c

@@ -3,6 +3,18 @@
 
 #include <lib/utils/logging.h>
 
+int get_gdt_baseaddress(struct GDTEntry gdt_table[], unsigned int table_size, int entry_id) {
+    if(entry_id>=0 && entry_id<table_size) {
+        unsigned int base0 = gdt_table[entry_id].base0;
+        unsigned int base1 = gdt_table[entry_id].base1;
+        base1 <<= 16;
+        unsigned int base2 = gdt_table[entry_id].base2;
+        base2 <<= 24;
+        return base2|base1|base0;
+    }
+    return -1;
+}
+
 void populate_gdt_entry(struct GDTEntry *entry,
     unsigned int base,
     unsigned int limit,  // 20 bits