scopeInfinity · scopeInfinity · Sep 5, 2021 · Aug 28, 2021 · Aug 28, 2021 · Aug 28, 2021
diff --git a/.gdbinit b/.gdbinit
@@ -1,6 +1,6 @@
-set $CS_BASE = 0x20000
-set $DS_BASE = 0x20000
-set $SS_BASE = 0x20000
+set $CS_BASE = 0x30000
+set $DS_BASE = 0x30000
+set $SS_BASE = 0x30000
 
 # config
 set architecture i386:x86-64
@@ -72,17 +72,17 @@ define view_realmode
 end
 
 define view_kernelmode
-    set $CS_BASE = 0xC000
-    set $DS_BASE = 0xC000
-    set $SS_BASE = 0xC000
+    set $CS_BASE = 0x10000
+    set $DS_BASE = 0x10000
+    set $SS_BASE = 0x10000
     symbol-file build/kernel/core.elf
     clayout
 end
 
 define view_usermode
-    set $CS_BASE = 0x20000
-    set $DS_BASE = 0x20000
-    set $SS_BASE = 0x20000
+    set $CS_BASE = 0x30000
+    set $DS_BASE = 0x30000
+    set $SS_BASE = 0x30000
     symbol-file
     clayout
 end

diff --git a/Makefile b/Makefile
@@ -61,8 +61,8 @@ SOURCE_SNAPSHOT="\"$$(git rev-parse --short HEAD)$$(git diff --quiet || echo '_u
 ## Integer is 4 bytes
 
 # Debugging controller
-DEBUG?=
-ifdef DEBUG
+NODEBUG?=
+ifndef NODEBUG
 CC_DEBUG=-g
 NASM_DEBUG=-g
 LD_DEBUG=
@@ -101,8 +101,8 @@ binaries: $(bt_stage1) $(bt_stage2) $(kernel_core) $(rm_static)
 # Note: Relying on default value doesn't guarantee bin size.
 SECTOR_COUNT_BT_STAGE1 = 1
 SECTOR_COUNT_SHARED_LIBRARY = 1
-SECTOR_COUNT_BT_STAGE2 = 11
-SECTOR_COUNT_KERNEL = 47
+SECTOR_COUNT_BT_STAGE2 = 12
+SECTOR_COUNT_KERNEL = 70
 
 SECTOR_START_BT_STAGE1 = 0
 SECTOR_START_SHARED_LIBRARY = $(shell expr $(SECTOR_START_BT_STAGE1) + $(SECTOR_COUNT_BT_STAGE1) )

diff --git a/emulator/Makefile.mk b/emulator/Makefile.mk
@@ -2,7 +2,7 @@ QEMU_SHUT_FLAGS= -no-shutdown -no-reboot
 QEMU_EXTRA_FLAGS=
 QEMU_GDB_PORT=9000
 QEMU_MONITOR_PORT=55555
-GDB_EX='echo Use GDB_EX="<command>" to execute command on connect.\n'
+GDB_EX=echo Use GDB_EX="<command>" to execute command on connect.\n
 
 qemu: $(image_vmdk)
 	qemu-system-x86_64 -smp 1 -m 128M -hda $< $(QEMU_SHUT_FLAGS) $(QEMU_EXTRA_FLAGS)
@@ -17,6 +17,5 @@ qemu_debug: $(image_vmdk)
 	qemu-system-x86_64 -S -gdb tcp::$(QEMU_GDB_PORT) -smp 1 -m 128M -hda $< $(QEMU_SHUT_FLAGS) -d  cpu,exec,in_asm
 
 qemu_debug_connect:
-	gdb -x $(ROOT_DIR)/.gdbinit -ex "target remote :$(QEMU_GDB_PORT)" -ex "$(GDB_EX)" -ex 'continue'
-
+	gdb -x $(ROOT_DIR)/.gdbinit -ex "target remote :$(QEMU_GDB_PORT)" -ex '$(GDB_EX)' -ex 'continue'
 
diff --git a/include/fuzzy/drivers/pic/pic.h b/include/fuzzy/drivers/pic/pic.h
@@ -1,15 +1,16 @@
 #pragma once
 
+#include <stddef.h>
+
 #define PIC_PIT_FREQ        1193182  // hz
 #define PIC_PIT_MAX_COUNTER 0xFFFF
 
 #define PIC_IRQ_PIT 0
 
-void interrupt_pit_enable();
+void pic_init();
+
+void pic_writemask_new(uint16_t mask);
+uint16_t pic_readmask_new();
 
 void pic_irq_enable(int irq);
 void pic_irq_disable(int irq);
-
-void pic_pit_set_counter(unsigned short counter);
-unsigned short pic_pit_get_counter();
-void pic_pit_reset();
diff --git a/include/fuzzy/drivers/pic/pit.h b/include/fuzzy/drivers/pic/pit.h
@@ -0,0 +1,13 @@
+#pragma once
+
+#include <stddef.h>
+
+static uint16_t frequency_dividor;
+
+void pit_init();
+
+void pit_set_counter(uint16_t counter);
+uint16_t pit_get_counter();
+
+void pit_reload_counter();
+void pit_reset();
diff --git a/include/fuzzy/drivers/port.h b/include/fuzzy/drivers/port.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <stddef.h>
+
+#define PORT_PIC1_CMD     0x20
+#define PORT_PIC1_DATA    0x21
+#define PORT_PIC2_CMD     0xA0
+#define PORT_PIC2_DATA    0xA1
+
+#define PORT_PIT_DATA0    0x40
+#define PORT_PIT_DATA1    0x41
+#define PORT_PIT_DATA2    0x42
+#define PORT_PIT_CMD      0x43
+
+static inline void outb(uint16_t port, uint8_t data) {
+    __asm__ volatile(
+        "outb %0, %1 \n"
+        :  /* output */
+        : "a" (data), "ir" (port)  /* input */
+        :
+    );
+}
+
+static inline uint8_t inputb(uint16_t port) {
+    uint8_t data;
+    __asm__ volatile(
+        "inb %1, %0 \n"
+        : "=a" (data) /* output */
+        : "ir" (port)  /* input */
+        :
+    );
+    return data;
+}
diff --git a/include/fuzzy/fs/ffs.h b/include/fuzzy/fs/ffs.h
@@ -50,8 +50,7 @@ int resolve_abs_lba(int parition_id, int partition_relative_lba);
 
 int partition_read_block(int block_index, void *wr_buffer);
 
-int fetch_first_block(
-    union FFSMetaData *block);
+int verify_partition(int partition_id);
 
 int fetch_file_entry(
     int partition_id,

diff --git a/include/fuzzy/kernel/panic.h b/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();
diff --git a/include/fuzzy/kernel/process/process.h b/include/fuzzy/kernel/process/process.h
@@ -2,8 +2,10 @@
 #include <process.h>
 #include<stddef.h>
 
-#define MAX_PROCESS 10
-#define GDT_TABLE_SIZE MAX_PROCESS*2+3
+#define MAX_PROCESS 127
+// each process will have CS and DS, and kernel
+// CS and DS is already included in GDT standard table.
+#define GDT_TABLE_SIZE ((MAX_PROCESS-1)*2+GDT_STD_SIZE)
 
 typedef char ARGV[PROCESS_MAX_ARGC][PROCESS_MAX_ARG_LEN];
 
@@ -13,6 +15,11 @@ enum process_state{
     STATE_READY,
     STATE_RUNNING,
     STATE_EXIT,    // should be unallocated in next scheduling cycle
+    STATE_BLOCK,    // process is waiting on IO, process_wait, etc.
+};
+
+enum process_state_block {
+    STATE_BLOCK_PROCESS_WAIT,   // waiting for another process termination.
 };
 
 struct Process {
@@ -22,6 +29,23 @@ struct Process {
     unsigned int *e;
 
     int status_code;
+
+    unsigned int ppid;  // parent pid, 0 to root under kernel_core
+
+    enum process_state_block block_type;  // valid, if state == BLOCK
+    union {
+        struct {
+            unsigned int blocked_on_pid;
+            unsigned int blocking_pid;  // TODO: make list
+        } process_wait;
+    } block_data;    // valid if state == BLOCK
+
+    // schedule for IRQ0
+    // 0  - no fork requested or last fork successful; can try fork again
+    // 1  - fork requested; should NOT try fork for now.
+    // -1 - last fork failed; can try fork again
+    signed char flagirq0_fork_ready;
+    int flagirq0_fork_newchild;  // pid
 };
 
 void process_scheduler_init();
@@ -35,11 +59,12 @@ int get_gdt_number_from_entry_id(int id);
 // allocation
 int get_idt_cs_entry(int process_id);
 int get_idt_ds_entry(int process_id);
-int get_idt_reverse_pid_lookup(int cs);
+int get_idt_reverse_pid_lookup_cs(int cs);
+int get_idt_reverse_pid_lookup_ds(int ds);
 
 // process create or kill
-int process_create(int argc, char *argv[]);
-void process_kill(int user_ds, int status);
+int process_create(unsigned int ppid, int argc, char *argv[]);
+void process_kill(unsigned int pid, int status);
 
 // scheduler
 
@@ -50,3 +75,10 @@ void process_scheduler(int *_e_ip, int *_e_cs, int *_e_sp, int *_e_ss);
 // user space <-> kernel space data transfer helper
 extern void syscall_strncpy_user_to_kernel(int user_ds, char *src_es_address, char *dest_ds_address, size_t size);
 extern void syscall_strncpy_kernel_to_user(int user_ds, char *dest_address, char *src_address, size_t size);
+extern void kernel_memncpy_absolute(int dst_ds, char *dst_address, int src_ds, char *src_address, size_t size);
+
+// operations
+int process_waitpid(unsigned int pid, unsigned int blocked_on_pid);
+
+int process_fork_mark_ready(int pid);
+int process_fork_check_ready(int pid);
diff --git a/include/fuzzy/memmgr/layout.asm b/include/fuzzy/memmgr/layout.asm
@@ -1,17 +1,17 @@
 ; constants only
 
 ; START_ENSURE_SAME_layout_h
-MEMORY_APP_SIZE EQU 0x20000
-
+MEMORY_APP_SIZE          EQU  0x20000
+MEMORY_KERNEL_SIZE       EQU  0x64000
 ; END_ENSURE_SAME_layout_h
 
 ; Kernel core is app with pid 0
 ; Kernel event is trigged via IRQ0 or syscall,
 STACKINIT_APP EQU (MEMORY_APP_SIZE-4)
-STACKINIT_KERNEL_CORE EQU (STACKINIT_APP-4)
+STACKINIT_KERNEL_CORE EQU (MEMORY_KERNEL_SIZE/2)
 
 ; Should be able to store
 ; - syscall and all internal calls
 ; - ISRs and all internal calls
-STACKINIT_KERNEL_EVENT EQU 0x18000
+STACKINIT_KERNEL_EVENT EQU (MEMORY_KERNEL_SIZE-4)
 
diff --git a/include/fuzzy/memmgr/layout.h b/include/fuzzy/memmgr/layout.h
@@ -3,16 +3,32 @@
 // START_ENSURE_SAME_layout_asm
 #define MEMORY_APP_SIZE         0x20000
 #define STACKINIT_APP           (MEMORY_APP_SIZE-4)
+#define MEMORY_REALLIBRARY_DATA_ADDRESS  0x70000
+#define MEMORY_REALLIBRARY_DATA_SIZE     0x10000
+
 // END_ENSURE_SAME_layout_asm
 
 // Most of the memory layout relies on the fact the kernel is first app
 // and kernel's pid is 0.
 #define PID_KERNEL 0
 
-#define MEMORY_APPBASE_LOCATION 0x10000
+/*
+ * Bug:
+ *  Bootloader stage 2 is not able to load kernel if
+ *  memory address need 20 address lines (0x10000) in
+ *  our case.
+ *  It works as intended in QEMU but not in others.
+ * Mitigation:
+ *  - Forcing MEMORY_KERNEL_LOCATION to be represented
+ *    by 16 address lines. For ex 0xF000.
+ * Resolution:
+ *  - I'm not sure.
+ */
+#define MEMORY_APPBASE_LOCATION 0x100000
 
-#define memmgr_app_abs_location(pid) (MEMORY_APPBASE_LOCATION + (pid)*MEMORY_APP_SIZE)
-#define memmgr_app_size(pid) (MEMORY_APP_SIZE)
+// Keep in sync with memory_layout.md
+#define memmgr_app_abs_location(pid) ((pid==PID_KERNEL)?0x0C000:(MEMORY_APPBASE_LOCATION + (pid)*MEMORY_APP_SIZE))
+#define memmgr_app_size(pid) ((pid==PID_KERNEL)?0x64000:MEMORY_APP_SIZE)
 
-#define MEMORY_KERNEL_LOCATION memmgr_app_abs_location(PID_KERNEL)
-#define MEMORY_KERNEL_SIZE memmgr_app_size(PID_KERNEL)
+#define MEMORY_KERNEL_LOCATION (memmgr_app_abs_location(PID_KERNEL))
+#define MEMORY_KERNEL_SIZE (memmgr_app_size(PID_KERNEL))
diff --git a/include/fuzzy/memmgr/tables/gdt.asm b/include/fuzzy/memmgr/tables/gdt.asm
@@ -0,0 +1,21 @@
+; constants only
+
+; START_ENSURE_SAME_gdt_h
+
+GDT_STD_SELECTOR_NULL       EQU     0
+GDT_STD_SELECTOR_KERNEL_CS  EQU     1
+GDT_STD_SELECTOR_KERNEL_DS  EQU     2
+GDT_STD_SELECTOR_ABS16_CS   EQU     3
+GDT_STD_SELECTOR_ABS16_DS   EQU     4
+GDT_STD_SELECTOR_ABS32_DS   EQU     6
+GDT_STD_SIZE                EQU     7
+
+GDT_STD_SIZEOF_ENTRY        EQU     8
+; END_ENSURE_SAME_gdt_h
+
+GDT_NULL_CS     EQU   (GDT_STD_SELECTOR_NULL*GDT_STD_SIZEOF_ENTRY)
+GDT_KERNEL_CS   EQU   (GDT_STD_SELECTOR_KERNEL_CS*GDT_STD_SIZEOF_ENTRY)
+GDT_KERNEL_DS   EQU   (GDT_STD_SELECTOR_KERNEL_DS*GDT_STD_SIZEOF_ENTRY)
+GDT_ABS16_CS    EQU   (GDT_STD_SELECTOR_ABS16_CS*GDT_STD_SIZEOF_ENTRY)
+GDT_ABS16_DS    EQU   (GDT_STD_SELECTOR_ABS16_DS*GDT_STD_SIZEOF_ENTRY)
+GDT_ABS32_DS    EQU   (GDT_STD_SELECTOR_ABS32_DS*GDT_STD_SIZEOF_ENTRY)
diff --git a/include/fuzzy/memmgr/tables/gdt.h b/include/fuzzy/memmgr/tables/gdt.h
@@ -3,6 +3,18 @@
 // Min GDT_TABLE_SIZE:    5
 // Max GDT_TABLE_SIZE: 8192
 
+// START_ENSURE_SAME_gdt_asm
+#define GDT_STD_SELECTOR_NULL      0
+#define GDT_STD_SELECTOR_KERNEL_CS 1
+#define GDT_STD_SELECTOR_KERNEL_DS 2
+#define GDT_STD_SELECTOR_ABS16_CS  3
+#define GDT_STD_SELECTOR_ABS16_DS  4
+#define GDT_STD_SELECTOR_ABS32_DS  6
+#define GDT_STD_SIZE 7
+// Entries on and after GDT_STD_SIZE are reserved for applications
+// and are in CS, DS order for each app.
+// END_ENSURE_SAME_gdt_asm
+
 #pragma pack(push, 1)
 struct GDTReference {
     unsigned short size;
@@ -18,6 +30,14 @@ struct GDTEntry {
 };
 #pragma pack(pop)
 
+#define GDT_NULL_CS      (GDT_STD_SELECTOR_NULL*sizeof(struct GDTEntry))
+#define GDT_KERNEL_CS    (GDT_STD_SELECTOR_KERNEL_CS*sizeof(struct GDTEntry))
+#define GDT_KERNEL_DS    (GDT_STD_SELECTOR_KERNEL_DS*sizeof(struct GDTEntry))
+#define GDT_ABS16_CS     (GDT_STD_SELECTOR_ABS16_CS*sizeof(struct GDTEntry))
+#define GDT_ABS16_DS     (GDT_STD_SELECTOR_ABS16_DS*sizeof(struct GDTEntry))
+#define GDT_ABS32_DS     (GDT_STD_SELECTOR_ABS32_DS*sizeof(struct GDTEntry))
+
+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,

diff --git a/memory_layout.md b/memory_layout.md
@@ -2,12 +2,18 @@
 
 | From      | To        | Size      | Usage                                         |
 |---------  |--------   |--------   |--------------------------------------------   |
-| 0x00000   | fill      | 31KB      | RESERVED                                      |
-| 0x7C00    | 0x7DFF    | 512B      | BOOTLOADER STAGE 1                            |
-| 0x7E00    | 0x7FFF    | 512B      | SHARED STATIC CODE for real_mode library      |
-| 0x8000    | 0xBFFF    | -         | BOOT LOADER STAGE 2  + own stack              |
-| 0x10000   | 0x2FFFF   | -         | KERNEL                                        |
-| 0x30000   | 0x4FFFF   | -         | Application 0                                 |
-| 0x50000   | 0x6FFFF   | -         | Application 1                                 |
-...
-| -         | 0xFFFFF   | -         | 20-bit memory limit                           |
+| 0x00000   | 0x003FF   | -         | IVT (standard)                                |
+| 0x00400   | 0x07BFF   | -         | BIOS data area + reserve                      |
+| 0x07C00   | 0x07DFF   |  512B     | Bootloader Stage 1                            |
+| 0x07E00   | 0x07FFF   |  512B     | STATIC CODE for real_mode library             |
+| 0x08000   | 0x0BFFF   |  16KB     | Bootloader Stage 2  + own stack               |
+| 0x0C000   | 0x6FFFF   | 400KB     | Kernel  + (core, isr, syscall) stack          |
+| 0x70000   | 0x7FFFF   |  64KB     | Extra space for real_mode library+client      |
+| 0x80000   | 0x9FFFF   | 128KB     | Extended BIOS Data area                       |
+| 0xA0000   | 0xBFFFF   | 128KB     | Video memory                                  |
+| 0xC0000   | 0xFFFFF   | 256KB     | BIOS stuff                                    |
+| 0x100000  | 0x1FFFFF  | 1MB       | pid 0; Kernel future location (not used)      |
+| 0x200000  | 0x2FFFFF  | 1MB       | App pid 1                                     |
+| 0x300000  | 0x3FFFFF  | 1MB       | App pid 2                                     |
+| ...       | ....      | ...       | ...                                           |
+| ...       | ....      | 1MB       | App pid 126                                   |
diff --git a/scripts/build_image.sh b/scripts/build_image.sh
@@ -25,10 +25,6 @@ function verify_subimage_and_push() {
         echo "The ${subimage} size isn't divisible by 512" >&2
         exit 2
     fi
-    if [ "$(( $fsize / 512 ))" -lt ${min_sectors:?} ]; then
-        echo "The ${subimage} uses less sectors than ${min_sectors:?}" >&2
-        exit 2
-    fi
     if [ "$(( $fsize / 512 ))" -gt ${max_sectors:?} ]; then
         echo "The ${subimage} uses more sectors than ${max_sectors:?}" >&2
         exit 2

diff --git a/src/bootloader/Makefile.mk b/src/bootloader/Makefile.mk
@@ -20,7 +20,7 @@ $(bt_stage1): $(SRC_BOOTLOADER)/stage1.asm $(SRC_BOOTLOADER)/constants.asm $(SRC
 
 $(bt_stage2).elf: $(SRC_BOOTLOADER)/stage2.asm $(SRC_BOOTLOADER)/stage2.c $(INCLUDE_DIR)/memmgr/tables/gdt.h $(SRC_MEMMGR)/tables/gdt.c $(SRC_BOOTLOADER)/io.asm $(SRC_BOOTLOADER)/constants.asm $(BUILD_LIB_UTILS)/libutils_16 $(BUILD_DRIVERS)/display/libtm_bios $(BUILD_DRIVERS)/disk/libdisk_16
 	mkdir -p $$(dirname $(bt_stage2))
-	nasm -o $(BUILD_BOOTLOADER)/stage2_asm.o -f elf32 -i $(SRC_BOOTLOADER)/ $(SRC_BOOTLOADER)/stage2.asm
+	$(NASM) -o $(BUILD_BOOTLOADER)/stage2_asm.o -i $(SRC_BOOTLOADER)/ $(SRC_BOOTLOADER)/stage2.asm
 	$(CC) -m16 -fno-pie -c -Isrc \
 	    -Iinclude \
 		-D SECTOR_START_SHARED_LIBRARY=$(SECTOR_START_SHARED_LIBRARY) \