feat: add initial process, thread and scheduler

.gitignore

@@ -30,6 +30,7 @@ build/
 /.idea/
 !/.idea/runConfigurations
 /.vscode/
+!/.idea/settings.json
 *~
 *.swp
 [._]*.s[a-w][a-z]
@@ -60,4 +61,4 @@ compile_commands.json
 # Misc
 NOTES
 /server.PID
-
+compile_commands.json

.vscode/launch.json

@@ -12,6 +12,6 @@
             "cwd": "${workspaceRoot}",
             // "preLaunchTask": "run_debug",
             "valuesFormatting": "prettyPrinters"
-        },
+        }
     ]
-}
+}

kernel/src/common/include/interrupt.h

@@ -36,30 +36,6 @@
 
 #define BRANCH_INSTRUCTION 0xe59ff018  // ldr pc, pc+offset (where offset is 0x20 bytes)
 
-// System Call Types
-// TODO: maybe make enum?
-#define SYSCALL_CREATE        0
-#define SYSCALL_SWITCH        1
-#define SYSCALL_DELETE        2
-#define SYSCALL_OPEN          3
-#define SYSCALL_READ          4
-#define SYSCALL_WRITE         5
-#define SYSCALL_CLOSE         6
-#define SYSCALL_SET_PERM      7
-#define SYSCALL_MEM_MAP       8
-#define SYSCALL_SEEK          9
-#define SYSCALL_MKDIR         10
-#define SYSCALL_COPY          11
-#define SYSCALL_LS            12
-#define SYSCALL_MALLOC        13
-#define SYSCALL_ALIGNED_ALLOC 14
-#define SYSCALL_FREE          15
-#define SYSCALL_PRINTF        16
-#define SYSCALL_DUMMY         99
-#define SYSCALL_EXIT          100
-#define SYSCALL_WRITEV        101
-#define SYSCALL_PAUSE         102
-
 void init_vector_table(void);
 
 // vector table handlers, should be loaded at 0x00 in this order!

kernel/src/common/include/kernel_programs.h

@@ -0,0 +1,2 @@
+void kernel_one();
+void kernel_two();

kernel/src/common/interrupt.c

@@ -2,6 +2,7 @@
 #include <interrupt.h>
 #include <mmio.h>
 #include <stdio.h>
+#include <syscallhandler.h>
 #include <vm2.h>
 
 /* copy vector table from wherever QEMU loads the kernel to 0x00 */
@@ -77,15 +78,16 @@ void __attribute__((interrupt("UNDEF"))) undef_instruction_handler() {
 }
 
 long __attribute__((interrupt("SWI"))) software_interrupt_handler(void) {
-    int callNumber = 0, r0 = 0, r1 = 0, r2 = 0, r3 = 0;
+    size_t callNumber = 0, r0 = 0, r1 = 0, r2 = 0, r3 = 0;
 
     asm volatile("MOV %0, r7" : "=r"(callNumber)::);
     asm volatile("MOV %0, r0" : "=r"(r0)::);
     asm volatile("MOV %0, r1" : "=r"(r1)::);
     asm volatile("MOV %0, r2" : "=r"(r2)::);
     asm volatile("MOV %0, r3" : "=r"(r3)::);
 
-    kprintf("SOFTWARE INTERRUPT HANDLER\n");
+    DEBUG("SYSCALL");
+
 
     // Print out syscall # for debug purposes
     kprintf("Syscall #: ");
@@ -96,85 +98,9 @@ long __attribute__((interrupt("SWI"))) software_interrupt_handler(void) {
     kprintf("arg3=%d\n", r3);
     kprintf("\n");
 
-    // System Call Handler
-    switch (callNumber) {
-        case SYSCALL_EXIT:
-            // TODO: remove current process from scheduler
-            for (;;)
-                ;
-            break;
-        case SYSCALL_DUMMY:
-            return 0L;
-            break;
+    handle_syscall(callNumber, r0, r1, r2, r3);
 
-        // NOTE: All FS syscalls have been *DISABLED* until the filesystem works again.
-        case SYSCALL_CREATE:
-            kprintf("Create system call called!\n");
-            return -1;
-
-            //		return (long) kcreate((char*) r0, r1, 0);
-        case SYSCALL_DELETE:
-            kprintf("Delete system call called!\n");
-            return -1;
-
-            //		return (long) kdelete((char*) r0, 1);
-        case SYSCALL_OPEN:
-            kprintf("Open system call called!\n");
-            return -1;
-
-            //		return (long) kopen((char*) r0, r1);
-        case SYSCALL_MKDIR:
-            kprintf("Mkdir system call called!\n");
-            return -1;
-
-            //		return (long) kcreate((char*) r0, 'w', 1);
-        case SYSCALL_READ:
-            kprintf("Read system call called!\n");
-            return -1;
-
-            //		return (long) kread(r0, (void*) r1, r2);
-        case SYSCALL_WRITE:
-            kprintf("Write system call called!\n");
-            return -1;
-
-            //		return (long) kwrite(r0, (void*) r1, r2);
-        case SYSCALL_CLOSE:
-            kprintf("Close system call called!\n");
-            return -1;
-
-            //		return (long) kclose(r0);
-        case SYSCALL_SEEK:
-            kprintf("Seek system call called!\n");
-            return -1;
-
-            //		return (long) kseek(r0, r1);
-        case SYSCALL_COPY:
-            kprintf("Copy system call called!\n");
-            return -1;
-
-            //		return (long) kcopy((char*) r0, (char*) r1, r2);
-        case SYSCALL_LS:
-            kprintf("Ls system call called!\n");
-            return -1;
-            //		return (long) kls((char*) r0);
-        case SYSCALL_SET_PERM:
-            kprintf("Set permission system call called!\n");
-            kprintf("Yet to be implemented\n");
-            return -1;
-        case SYSCALL_MEM_MAP:
-            kprintf("Memory map system call called!\n");
-            kprintf("Yet to be implemented\n");
-            return -1;
-
-        case SYSCALL_PRINTF:
-            kprintf("Printf system call called!\n");
-
-            kprintf((const char *)r0);
-            return 0L;
-        default:
-            kprintf("That wasn't a syscall you knob!\n");
-            return -1L;
-    }
+    return 0;
 }
 
 void __attribute__((interrupt("ABORT"))) prefetch_abort_handler(void) {

kernel/src/common/kernel_programs.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+
+void kernel_one() {
+    /** asm volatile(
+        "mov %r7, $4 \n" \
+        "swi $0 \n"
+    ); */
+    kprintf("Starting kernel program one.\n");
+
+    for (size_t i = 0; i < 100; i++) {
+        kprintf("Hello #%i from program one.\n", i);
+    }
+
+    kprintf("Goodbye from program one.\n");
+}
+
+void kernel_two() {
+    asm volatile(
+        "mov %r7, $4 \n" \
+        "swi $0 \n"
+    );
+    kprintf("Starting kernel program two.\n");
+
+    for (size_t i = 0; i < 100; i++) {
+        kprintf("Hello #%i from program two.\n", i);
+    }
+
+    kprintf("Goodbye from program two.\n");
+}

kernel/src/common/start.c

@@ -2,10 +2,12 @@
 #include <hardwareinfo.h>
 #include <interrupt.h>
 #include <klibc.h>
+#include <kernel_programs.h>
 #include <mem_alloc.h>
 #include <stdint.h>
-#include <test.h>
 #include <vm2.h>
+#include <test.h>
+#include <scheduler.h>
 
 /// Entrypoint for the C part of the kernel.
 /// This function is called by the assembly located in [startup.s].
@@ -50,6 +52,7 @@ void start(uint32_t * p_bootargs) {
     // Call the chipset again to do any initialization after enabling interrupts and the heap.
     chipset.late_init();
 
+    Scheduler *scheduler = create_scheduler();
 
 #ifndef ENABLE_TESTS
 //    argparse_process(p_bootargs);
@@ -62,6 +65,14 @@ void start(uint32_t * p_bootargs) {
 #endif
 
 
+    Process *process1 = create_process(kernel_one, NULL);
+    Process *process2 = create_process(kernel_two, NULL);
+    add_process_to_scheduler(scheduler, process1);
+    add_process_to_scheduler(scheduler, process2);
+
+    enable_scheduler(scheduler);
+    free_scheduler(scheduler);
+
     // TODO:
     //  * Mount vfs
     //  * Load initramfs into tmpfs

kernel/src/drivers/chipset/bcm2836/uart.c

@@ -2,6 +2,7 @@
 #include <chipset.h>
 #include <interrupt.h>
 #include <limits.h>
+#include <klibc.h>
 
 /*
 // raspberry pi zero, 1, b+ etc
@@ -106,7 +107,7 @@ void bcm2836_uart_putc(char c, int uartchannel) {
         case 3:
             return uart_write_byte(BCM2836_UART3_ADDRESS, c);
         default:
-            __unreachable();
+            panic();
     }
 }
 

kernel/src/process/asm_helper.s

@@ -0,0 +1,50 @@
+.text
+    .global switch_context
+
+switch_context:
+    ; Set the CPSR register.
+    ldr r1, [r0, #16]
+    msr cpsr, r1
+    ; Load the stack pointer.
+    ldr sp, [r0, #52]
+    ; Push all other registers on the stack.
+    ldr r1, [r0, #60]
+    push {r1}
+    ldr r1, [r0, #56]
+    push {r1}
+    ldr r1, [r0, #48]
+    push {r1}
+    ldr r1, [r0, #44]
+    push {r1}
+    ldr r1, [r0, #40]
+    push {r1}
+    ldr r1, [r0, #36]
+    push {r1}
+    ldr r1, [r0, #32]
+    push {r1}
+    ldr r1, [r0, #28]
+    push {r1}
+    ldr r1, [r0, #24]
+    push {r1}
+    ldr r1, [r0, #20]
+    push {r1}
+    ldr r1, [r0, #16]
+    push {r1}
+    ldr r1, [r0, #12]
+    push {r1}
+    ldr r1, [r0, #8]
+    push {r1}
+    ldr r1, [r0, #4]
+    push {r1}
+    ldr r1, [r0, #0]
+    push {r1}
+
+    ; TODO: Enter user space
+    ; cps #16
+    ; Or:
+    ; msr CPSR_c, #0x10
+
+    ; Load all register states.
+    ; Loading the PC register effectively jumps into the user program
+    pop {r0-r12}
+    pop {r14-pc}

kernel/src/process/include/asm_helper.h

@@ -0,0 +1,8 @@
+#ifndef COURSE_OS_ASM_HELPER_H
+#define COURSE_OS_ASM_HELPER_H
+
+#include "./registers.h"
+
+void switch_context(Registers *registers);
+
+#endif //COURSE_OS_ASM_HELPER_H

kernel/src/process/include/process.h

@@ -0,0 +1,22 @@
+#ifndef COURSE_OS_PROCESS_H
+#define COURSE_OS_PROCESS_H
+
+#include <vp_array_list.h>
+#include <vas2.h>
+
+#define MAX_PROCESS_PRIORITY 20
+#define DEFAULT_PROCESS_PRIORITY 10
+
+typedef struct Process {
+    uint8_t priority;
+    size_t pid;
+    uint8_t exit_code;
+    struct vas2* vas;
+    VPArrayList *threads;
+    struct Process *parent;
+} Process;
+
+Process *create_process(void *entry, Process *parent);
+void free_process(Process *process);
+
+#endif //COURSE_OS_PROCESS_H

kernel/src/process/include/registers.h

@@ -0,0 +1,50 @@
+#ifndef COURSE_OS_REGISTERS_H
+#define COURSE_OS_REGISTERS_H
+
+#include <stdint.h>
+
+typedef struct Registers {
+    size_t R0;
+    size_t R1;
+    size_t R2;
+    size_t R3;
+    size_t R4;
+    size_t R5;
+    size_t R6;
+    union {
+        size_t R7;
+        size_t WR;
+    };
+    size_t R8;
+    union {
+        size_t R9;
+        size_t SB;
+    };
+    union {
+        size_t R10;
+        size_t SL;
+    };
+    union {
+        size_t R11;
+        size_t FP;
+    };
+    union {
+        size_t R12;
+        size_t IP;
+    };
+    union {
+        size_t R13;
+        size_t SP;
+    };
+    union {
+        size_t R14;
+        size_t LR;
+    };
+    union {
+        size_t R15;
+        size_t PC;
+    };
+    size_t CPSR;
+} Registers;
+
+#endif //COURSE_OS_REGISTERS_H