Build folder + coding style guidelines

Reviewed-on: xamidev/pepperOS#12

.gitignore

@@ -10,4 +10,5 @@ iso_root
 .gdb_history
 symbols.map
 symbols.S
-*.log
+*.log
+build/

DOOM.txt

@@ -1,24 +0,0 @@
-up to doom:
-
-- Return from pedicel_main() normally (to idle)
-
-** Checkpoint: ring0 process working
-
-- VFS layer (open/read/write/...) with USTar filesystem (for initrd)
-
-** Checkpoint: files not linked to but accessible by the kernel
-
-- Ring3 memory mappings 
-- Ring3 privilege switch
-
-** Checkpoint: welcome to userland
-
-- Syscall interface
-- Implement syscalls needed for doom
-
-** Checkpoint: can run simple programs, ring 3, loaded from filesystem 
-
-- Properly handle the keyboard interrupt (keyboard buffer)
-- Port DOOMgeneric (few functions with Framebuffer/ticks/etc.)
-
-** Achievement: It runs doom!

Makefile

@@ -1,16 +1,21 @@
 SOURCES = src/debug/misc.c src/io/term/flanterm_backends/fb.c src/io/term/flanterm.c src/debug/panic.c src/debug/stacktrace.c src/boot/boot.c src/sched/scheduler.c src/sched/process.c src/mem/heap/kheap.c src/mem/paging/vmm.c src/mem/paging/paging.c src/mem/paging/pmm.c src/string/string.c src/io/kbd/ps2.c src/io/serial/serial.c src/io/term/printf.c src/io/term/term.c src/idt/idt.c src/mem/gdt/gdt.c src/mem/misc/utils.c src/time/timer.c src/kmain.c
 
-PROBLEMATIC_FLAGS=-Wno-unused-parameter -Wno-unused-variable
+CC_FLAGS=-Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-omit-frame-pointer -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel
+CC_PROBLEMATIC_FLAGS=-Wno-unused-parameter -Wno-unused-variable
+
+.PHONY: build build-iso debug debug2 run clean
 
 build:
-	rm -f *.o
-	x86_64-elf-gcc -g -c -Isrc $(SOURCES) $(PROBLEMATIC_FLAGS) -Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-omit-frame-pointer -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel
-	nasm -f elf64 src/idt/idt.S -o idt_stub.o
-	x86_64-elf-ld -o pepperk -T linker.ld *.o
+	mkdir -p build
+	rm -f *.o build/*.o
+	x86_64-elf-gcc -g -c -Isrc $(SOURCES) $(CC_PROBLEMATIC_FLAGS) $(CC_FLAGS)
+	mv *.o build/
+	nasm -f elf64 src/idt/idt.S -o build/idt_stub.o
+	x86_64-elf-ld -o pepperk -T linker.ld build/*.o
 	nm -n pepperk | awk '$$2 ~ /[TtDdBbRr]/ {print $$1, $$3}' > symbols.map
 	python3 symbols.py
-	nasm -f elf64 symbols.S -o symbols.o
-	x86_64-elf-ld -o pepperk -T linker.ld *.o
+	nasm -f elf64 symbols.S -o build/symbols.o
+	x86_64-elf-ld -o pepperk -T linker.ld build/*.o
 
 limine/limine:
 	rm -rf limine
@@ -46,4 +51,4 @@ run: build-iso
 	/usr/bin/qemu-system-x86_64 -cdrom pepper.iso -serial stdio
 
 clean:
-	rm -rf *.o symbols.map symbols.S pepperk iso_root pepper.iso limine
+	rm -rf *.o symbols.map symbols.S pepperk iso_root pepper.iso limine build/*.o

README.md

@@ -41,8 +41,10 @@ PepperOS wouldn't be possible without the following freely-licensed software:
 
 - the [Limine](https://codeberg.org/Limine/Limine) portable bootloader
 - Marco Paland's freestanding [printf implementation](https://github.com/mpaland)
-- the [ZAP](https://www.zap.org.au/projects/console-fonts-zap/) PSF console fonts
+- Mintuski's [Flanterm](https://codeberg.org/Mintsuki/Flanterm) terminal emulator
 
 ...and without these amazing resources:
 
 - the [OSDev](https://osdev.org) wiki & forums
+- Intel 64 and IA-32 Architectures Software Developer's Manual
+- Documentation for the [GNU Compiler Collection](https://gcc.gnu.org/onlinedocs/gcc/)

docs/STYLE.md

@@ -0,0 +1,83 @@
+# Pepper kernel coding style
+
+This document describes the coding style for the Pepper kernel. It is used as a guideline across all source files.
+
+## Indentation
+
+Indentations should be 4 characters long.
+
+## Line length
+
+Lines should not be more than 100 characters long.
+
+## Variables
+
+Variables should be declared at most once per line.
+
+## Braces
+
+Non-function statement blocks should have an opening brace last on the line, and a closing brace first. Exception is made for `else`, `else if` statements and the like:
+
+```c
+if (something) {
+    do_something();
+} else if (something_else) {
+    do_something_else();
+}
+```
+
+Functions should have their opening brace on a separate line, and the same goes for the closing brace:
+
+```c
+void function()
+{
+    do_something();
+}
+```
+
+## Spaces
+
+Use a space after `if, switch, case, for, do, while` keywords, but not for `sizeof, typeof, alignof, __attribute__` and the like.
+
+For pointers, the asterisk should always be placed adjacent to the type name, like `char* str;`.
+
+## Naming
+
+Functions should be named with whole words, beginning with the corresponding name of the module in the kernel (the parent folder). Words should be spaced with underscores, like so:
+
+```c
+serial_init(void* ptr, char* str, int foo);
+```
+
+Constants should be named in all caps, separated by underscores:
+
+```c
+#define MAX_HEAP_SIZE 0x1000
+```
+
+Global variables need to have descriptive names. Local variables can be kept short (especially for loop counters).
+
+## Typedefs
+
+Structures should not be `typedef`'d.
+
+## Functions
+
+Functions should be short, simple, and only do one thing.
+
+Function prototypes should include parameter names and their data types.
+
+## Commenting
+
+Comments should describe what a function does and why, not how it does it.
+
+```c
+/*
+ * This is the preferred style for multi-line
+ * comments in the Pepper kernel
+ */
+```
+
+### Resources
+
+Some of the elements here are inspired by the [Linux kernel coding style](https://www.kernel.org/doc/html/v4.10/process/coding-style.html).

src/debug/panic.c

@@ -3,6 +3,8 @@
 #include "io/serial/serial.h"
 #include "kernel.h"
 
+extern struct init_status init;
+
 void panic(struct cpu_status_t* ctx, const char* str)
 {
 	CLEAR_INTERRUPTS;
@@ -15,6 +17,13 @@ void panic(struct cpu_status_t* ctx, const char* str)
 		skputc('\r');
 		skputc('\n');
 		DEBUG("\x1b[38;5;231m\x1b[48;5;196mend Kernel panic - halting...\x1b[0m");
+
+		if (init.terminal)
+		{
+			printf("\r\n\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m Something went horribly wrong! (no cpu ctx)");
+			printf("\r\n%s\r\n\x1b[38;5;231m\x1b[48;5;196mend Kernel panic - halting...\x1b[0m", str);
+		}
+
 		hcf();
 	}
 	DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m at rip=%p\r\nSomething went horribly wrong! (%s) vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p\n\rHalting...",
@@ -22,6 +31,17 @@ void panic(struct cpu_status_t* ctx, const char* str)
 		str,
 		ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
 		ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags);
+	
+	if (init.terminal)
+	{
+		printf("\r\n\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m at rip=%p\r\nSomething went horribly wrong! (%s) vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p\n\rHalting...",
+		ctx->iret_rip,
+		str,
+		ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
+		ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags);
+	}
+	
 	debug_stack_trace(100);
+	
 	hcf();
 }

src/debug/stacktrace.c

@@ -1,9 +1,15 @@
 #include <stdint.h>
 #include "kernel.h"
 
+extern struct init_status init;
+
 void debug_stack_trace(unsigned int max_frames)
 {
     DEBUG("*** begin stack trace ***");
+    if (init.terminal)
+    {
+        printf("\r\n*** begin stack trace ***\r\n");
+    }
     // Thanks GCC :)
     uintptr_t* rbp = (uintptr_t*)__builtin_frame_address(0);
 
@@ -15,6 +21,11 @@ void debug_stack_trace(unsigned int max_frames)
         const char* name = debug_find_symbol(rip, &offset);
         DEBUG("[%u] <0x%p> (%s+0x%x)", frame, (void*)rip, name, offset);
 
+        if (init.terminal)
+        {
+            printf("[%u] <0x%p> (%s+0x%x)\r\n", frame, (void*)rip, name, offset);
+        }
+
         uintptr_t* next_rbp = (uintptr_t*)rbp[0];
 
         // invalid rbp or we're at the end
@@ -25,6 +36,10 @@ void debug_stack_trace(unsigned int max_frames)
 
         rbp = next_rbp;
     }
+    if (init.terminal)
+    {
+        printf("*** end stack trace ***");
+    }
     DEBUG("*** end stack trace ***");
 }
 

src/idt/idt.S

@@ -151,12 +151,13 @@ vector_7_handler:
 align 16
 vector_8_handler:
     ; No error code, we only push vector number
-    push qword 1
+    push qword 8
     jmp interrupt_stub
 
 ; Coprocessor Segment Overrun
 align 16
 vector_9_handler:
+    push qword 0
     push qword 9
     jmp interrupt_stub
 

src/idt/idt.c

@@ -22,7 +22,7 @@ struct idtr idt_reg;
 extern char vector_0_handler[];
 
 // Timer ticks
-extern uint64_t ticks;
+extern volatile uint64_t ticks;
 
 void idt_set_entry(uint8_t vector, void* handler, uint8_t dpl)
 {
@@ -52,9 +52,8 @@ void idt_load(void* idt_addr)
 
 void idt_init()
 {
-    // We set 256 entries, but we have only the first few stubs.
-    // Undefined behavior?
-    for (size_t i=0; i<256; i++)
+    // Hardcoded...
+    for (size_t i=0; i<=33; i++)
     {
         // Each vector handler is 16-byte aligned, so <vector_no>*16 = address of that handler
         idt_set_entry(i, vector_0_handler + (i*16), 0);
@@ -210,6 +209,7 @@ struct cpu_status_t* interrupt_dispatch(struct cpu_status_t* context)
         case 33:
             DEBUG("Keyboard Interrupt");
             keyboard_handler();
+            outb(0x20, 0x20);
             break;
 
         default:

src/io/kbd/ps2.c

@@ -17,6 +17,8 @@ uint8_t key_status = 0b00000000;
 unsigned char* keymap;
 unsigned char* keymap_shifted;
 
+extern struct init_status init;
+
 unsigned char kbdus[128] =
 {
     0,  27, '1', '2', '3', '4', '5', '6', '7', '8',	/* 9 */
@@ -176,9 +178,6 @@ void keyboard_handler()
                 key_status &= ~ALT_PRESSED_BIT;
                 break;
         }
-
-        // Send EOI
-        outb(0x20, 0x20);
         return;
     }
     else
@@ -200,20 +199,25 @@ void keyboard_handler()
 
             default:
             {
-                // Should we get a SHIFTED char or a regular one?
-                unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];
-
-                if (c)
+                // Avoiding buffer overflow from extended keys lol
+                if (scancode < 128)
                 {
-                    // Should probably have a keyboard buffer here... instead of this
-                    _putchar(c);
+                    // Should we get a SHIFTED char or a regular one?
+                    unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];
+
+                    if (c)
+                    {
+                        if (c == '\n')
+                        {
+                            _putchar('\r');
+                        }
+                        // Should probably have a keyboard buffer here... instead of this
+                        _putchar(c);
+                    }
                 }
             }
         }
     }
-
-    // End of Interrupt (to master PIC)
-    outb(0x20, 0x20);
 }
 
 void keyboard_init(unsigned char layout)
@@ -233,14 +237,21 @@ void keyboard_init(unsigned char layout)
             break;
         
         default:
-            skputs("Unsupported layout.");
+            panic(NULL, "Unsupported keyboard layout");
             return;
     }
 
+    // Flush keyboard buffer
+    while (inb(0x64) & 1)
+    {
+        inb(0x60);
+    }
+
     // Unmask IRQ1
     uint8_t mask = inb(0x21);
     mask &= ~(1 << 1);
     outb(0x21, mask);
 
     DEBUG("PS/2 Keyboard initialized");
+    init.keyboard = true;
 }

src/io/serial/serial.c

@@ -7,6 +7,8 @@
 #include <kernel.h>
 #include "serial.h"
 
+extern struct init_status init;
+
 void outb(int port, unsigned char data)
 {
     __asm__ __volatile__("outb %%al, %%dx" :: "a" (data),"d" (port));
@@ -43,6 +45,7 @@ int serial_init()
     outb(PORT + 4, 0x0F);
 
     DEBUG("*** Welcome to PepperOS! ***");
+    init.serial = true;
     return 0;
 }
 
@@ -54,6 +57,7 @@ static int is_transmit_empty()
 // Serial kernel putchar
 void skputc(char c)
 {
+    // TODO: Spinlock here (serial access)
     while (!is_transmit_empty()); // wait for free spot
     outb(PORT, c);
 }

src/io/term/term.c

@@ -16,12 +16,17 @@ because this shitty implementation will be replaced one day by Flanterm
 #include "term.h"
 #include "config.h"
 #include "flanterm.h"
+#include "flanterm_backends/fb.h"
+#include "mem/heap/kheap.h"
+#include "limine.h"
 
 extern struct flanterm_context* ft_ctx;
+extern struct init_status init;
 
 // Overhead that could be avoided, right? (for printf)
 void _putchar(char character)
 {
+	// TODO: Spinlock here (terminal access)
 	flanterm_write(ft_ctx, &character, 1);
 }
 
@@ -35,4 +40,35 @@ void kputs(const char* str)
 		i++;
 	}
 	_putchar('\r');
+}
+
+extern struct flanterm_context* ft_ctx;
+extern struct boot_context boot_ctx;
+
+void flanterm_free_wrapper(void* ptr, size_t size)
+{
+	(void)size;
+	kfree(ptr);
+}
+
+void term_init()
+{
+	uint32_t bgColor = 0x252525;
+	ft_ctx = flanterm_fb_init(
+        kmalloc,
+        flanterm_free_wrapper,
+        boot_ctx.fb->address, boot_ctx.fb->width, boot_ctx.fb->height, boot_ctx.fb->pitch,
+        boot_ctx.fb->red_mask_size, boot_ctx.fb->red_mask_shift,
+        boot_ctx.fb->green_mask_size, boot_ctx.fb->green_mask_shift,
+        boot_ctx.fb->blue_mask_size, boot_ctx.fb->blue_mask_shift,
+        NULL,
+        NULL, NULL,
+        &bgColor, NULL,
+        NULL, NULL,
+        NULL, 0, 0, 1,
+        0, 0,
+        0,
+        0
+    );
+	init.terminal = true;
 }

src/io/term/term.h

@@ -9,5 +9,6 @@
 
 void kputs(const char* str);
 void _putchar(char character);
+void term_init();
 
 #endif

src/kernel.h

@@ -19,9 +19,11 @@ enum ErrorCodes
 #include "io/serial/serial.h"
 #include "io/term/printf.h"
 #include "idt/idt.h"
+#include <stdbool.h>
 
-#define DEBUG(log, ...) fctprintf((void*)&skputc, 0, "debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__)
+extern volatile uint64_t ticks;
 
+#define DEBUG(log, ...) fctprintf((void*)&skputc, 0, "[%8u] debug: <%s>: " log "\r\n", ticks, __func__, ##__VA_ARGS__)
 
 /* #define DEBUG(log, ...) \
 	printf("debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__); \
@@ -38,6 +40,7 @@ void panic(struct cpu_status_t* ctx, const char* str);
 void hcf();
 void idle();
 
+/* debug */
 void debug_stack_trace(unsigned int max_frames);
 const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset);
 void boot_mem_display();
@@ -52,4 +55,13 @@ struct boot_context
 	struct limine_kernel_address_response* kaddr;
 };
 
+// Are these modules initialized yet?
+struct init_status
+{
+	bool terminal;
+	bool serial;
+	bool keyboard;
+	bool timer;
+};
+
 #endif

src/kmain.c

@@ -30,8 +30,6 @@
 __attribute__((used, section(".limine_requests")))
 volatile LIMINE_BASE_REVISION(3);
 
-struct flanterm_context *ft_ctx;
-
 // Halt and catch fire (makes machine stall)
 void hcf()
 {
@@ -41,9 +39,9 @@ void hcf()
 // Doing nothing (can be interrupted)
 void idle() {SET_INTERRUPTS; for(;;)asm("hlt");}
 
-// uint8_t kernel_stack[KERNEL_STACK_SIZE] __attribute__((aligned(16)));
-
+struct flanterm_context *ft_ctx;
 struct boot_context boot_ctx;
+struct init_status init = {0};
 
 extern volatile struct limine_framebuffer_request framebuffer_request;
 extern volatile struct limine_memmap_request memmap_request;
@@ -52,22 +50,25 @@ extern volatile struct limine_kernel_address_request kerneladdr_request;
 
 extern struct process_t* processes_list;
 extern struct process_t* current_process;
+struct process_t* idle_proc;
 
+bool iran = false;
+
+// Never gets executed although pedicel is scheduled?
 void pedicel_main(void* arg)
 {
+	//panic(NULL, "test");
+	bool iran = true;
 	// FROM THE NEXT LINE ONWARDS, CANNOT WRITE TO FRAMEBUFFER WITHOUT PAGE FAULT!
 	//printf("\n\nWelcome to PepperOS! Pedicel speaking.\nNothing left to do, halting the system!");
 }
 
 void idle_main(void* arg)
 {
-	for(;;)asm("hlt");
-}
-
-void flanterm_free_wrapper(void* ptr, size_t size)
-{
-	(void)size;
-	kfree(ptr);
+	for (;;)
+	{
+		asm("hlt");
+	}
 }
 
 extern uintptr_t kheap_start;
@@ -79,6 +80,7 @@ void kmain()
 	if (!LIMINE_BASE_REVISION_SUPPORTED) hcf();
 
 	serial_init();
+	timer_init();
 
 	// Populate boot context
  	boot_ctx.fb = framebuffer_request.response ? framebuffer_request.response->framebuffers[0] : NULL;
@@ -95,41 +97,19 @@ void kmain()
 
 	keyboard_init(FR);
 
-	uint32_t bgColor = 0x252525;
-	ft_ctx = flanterm_fb_init(
-        kmalloc,
-        flanterm_free_wrapper,
-        boot_ctx.fb->address, boot_ctx.fb->width, boot_ctx.fb->height, boot_ctx.fb->pitch,
-        boot_ctx.fb->red_mask_size, boot_ctx.fb->red_mask_shift,
-        boot_ctx.fb->green_mask_size, boot_ctx.fb->green_mask_shift,
-        boot_ctx.fb->blue_mask_size, boot_ctx.fb->blue_mask_shift,
-        NULL,
-        NULL, NULL,
-        &bgColor, NULL, // &bgColor
-        NULL, NULL,
-        NULL, 0, 0, 1,
-        0, 0,
-        0,
-        0
-    );
+	term_init();
 
 	gdt_init();
 	idt_init();
-
-	timer_init();
-	vmm_init();
 	
 	process_init();
-	struct process_t* idle_proc = process_create("idle", (void*)idle_main, 0);
+	idle_proc = process_create("idle", (void*)idle_main, 0);
 	struct process_t* pedicel = process_create("pedicel", (void*)pedicel_main, 0);
 
 	process_display_list(processes_list);
 
 	scheduler_init();
 
-	current_process = idle_proc; 
-    current_process->status = RUNNING;
-
 	kputs(PEPPEROS_SPLASH);
 	idle();
 }

src/sched/process.c

@@ -45,7 +45,7 @@ void process_display_list(struct process_t* processes_list)
 
 struct process_t* process_create(char* name, void(*function)(void*), void* arg)
 {
-/*     CLEAR_INTERRUPTS; */
+    CLEAR_INTERRUPTS;
     struct process_t* proc = (struct process_t*)kmalloc(sizeof(struct process_t));
     
     struct cpu_status_t* ctx = (struct cpu_status_t*)kmalloc(sizeof(struct cpu_status_t));
@@ -79,7 +79,7 @@ struct process_t* process_create(char* name, void(*function)(void*), void* arg)
 
     process_add(&processes_list, proc);
 
-/*     SET_INTERRUPTS; */
+    SET_INTERRUPTS;
     return proc;
 }
 

src/sched/scheduler.c

@@ -12,6 +12,7 @@
 
 extern struct process_t* processes_list;
 extern struct process_t* current_process;
+extern struct process_t* idle_proc;
 
 void scheduler_init()
 {
@@ -28,9 +29,8 @@ struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context)
 
     if (current_process == NULL)
     {
-        // Wtf happened
-        current_process = processes_list;
-        //panic(NULL, "Scheduler called without current process");
+        // If no more processes, then set IDLE as the current process, that's it.
+        current_process = idle_proc;
     }
 
     current_process->context = context;
@@ -49,15 +49,15 @@ struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context)
         if (current_process != NULL && current_process->status == DEAD)
         {
             process_delete(&prev_process, current_process);
+            current_process = NULL;
+            return idle_proc->context;
         } else
         {
             current_process->status = RUNNING;
             break;
         }
     }
-    
 
-    // Current_process gets wrong context?? (iret_rip points to other stuff than process function; like putpixel() for example)
     DEBUG("current_process={pid=%u, name='%s', root_page_table[virt]=%p}", current_process->pid, current_process->name, current_process->root_page_table);
 
     load_cr3(VIRT_TO_PHYS((uint64_t)current_process->root_page_table));

src/time/timer.c

@@ -18,6 +18,8 @@ interested in multi-core functionnality like SMP)
 
 volatile uint64_t ticks = 0;
 
+extern struct init_status init;
+
 void pic_remap()
 {
     uint8_t master_mask = inb(0x21);
@@ -91,4 +93,5 @@ void timer_init()
     pic_enable();
     pit_init();
     DEBUG("PIT initialized");
+    init.timer = true;
 }

test.bin

@@ -1 +0,0 @@
-ｸ�ｭﾞ�