timeslicing works, also tabs->spaces in interrupts-asm.s

9 files changed, 139 insertions, 45 deletions

diff --git a/kern/Makefile b/kern/Makefile
index 846ba69..f987b2a 100644
--- a/kern/Makefile
+++ b/kern/Makefile
@@ -54,4 +54,7 @@ p-basic.o:
 p-hello.o:
 	make -C $(PIOS)/hello_os exostall
 
-.PHONY: format all install
+p-pidos.o:
+	make -C $(PIOS)/pid_os exostall
+
+.PHONY: format all install p-basic.o p-hello.o p-pidos.o
diff --git a/kern/interrupts-asm.s b/kern/interrupts-asm.s
index ee440aa..c90a24c 100644
--- a/kern/interrupts-asm.s
+++ b/kern/interrupts-asm.s
@@ -4,14 +4,14 @@
 .globl _interrupt_table_end
 .align 5
 _interrupt_table:
-	ldr pc, _reset_h
-	ldr pc, _undef_insn_h
-	ldr pc, _software_irq_h
-	ldr pc, _prefetch_abort_h
-	ldr pc, _data_abort_h
-	ldr pc, _reset_h
-	ldr pc, _irq_h
-	ldr pc, _fiq_h
+    ldr pc, _reset_h
+    ldr pc, _undef_insn_h
+    ldr pc, _software_irq_h
+    ldr pc, _prefetch_abort_h
+    ldr pc, _data_abort_h
+    ldr pc, _reset_h
+    ldr pc, _irq_h
+    ldr pc, _fiq_h
 
 _reset_h:          .word   asm_reset
 _undef_insn_h:     .word   asm_undef_insn
@@ -23,32 +23,39 @@ _fiq_h:            .word   asm_fiq
 _interrupt_table_end:
 
 asm_reset:
-	ldr sp, =kstack
-	bl reboot
+    ldr sp, =kstack
+    bl reboot
 asm_undef_insn:
-	ldr sp, =kstack
-	ldr pc, _vec_undef_insn
+    ldr sp, =kstack
+    ldr pc, _vec_undef_insn
 asm_software_irq:
-	ldr sp, =kstack
-	sub lr, lr, #4
-	push {lr}
-	stmfd sp, {r0-r14}^
-	sub sp, sp, #60
-	mov r0, sp
-	bl syscall
-	ldm sp, {r0-r15}^
+    ldr sp, =kstack
+    // sub lr, lr, #4
+    push {lr}
+    stmfd sp, {r0-r14}^
+    sub sp, sp, #60
+    mov r0, sp
+    bl syscall
+    ldm sp, {r0-r15}^
 asm_prefetch_abort:
-	ldr sp, =kstack
-	ldr pc, _vec_prefetch_abort
+    ldr sp, =kstack
+    ldr pc, _vec_prefetch_abort
 asm_data_abort:
-	ldr sp, =kstack
-	ldr pc, _vec_data_abort
+    ldr sp, =kstack
+    ldr pc, _vec_data_abort
 asm_irq:
-	ldr sp, =kstack
-	ldr pc, _vec_irq
+    ldr sp, =kstack
+    sub lr, lr, #4
+    push {lr}
+    stmfd sp, {r0-r14}^
+    sub sp, sp, #60
+    mov r0, sp
+    ldr r1, _vec_irq
+    blx r1
+    ldm sp, {r0-r15}^
 asm_fiq:
-	ldr sp, =kstack
-	ldr pc, _vec_fiq
+    ldr sp, =kstack
+    ldr pc, _vec_fiq
 
 .globl _vector_table
 _vector_table:
@@ -61,14 +68,14 @@ _vec_fiq:            .word vec_fiq
 
 .globl enable_interrupts
 enable_interrupts:
-	mrs r0, cpsr
-	bic r0, r0, #(1 << 7)
-	msr cpsr_c, r0
-	bx lr
+    mrs r0, cpsr
+    bic r0, r0, #(1 << 7)
+    msr cpsr_c, r0
+    bx lr
 
 .globl disable_interrupts
 disable_interrupts:
-	mrs r0, cpsr
-	orr r0, r0, #(1 << 7)
-	msr cpsr_c, r0
-	bx lr
+    mrs r0, cpsr
+    orr r0, r0, #(1 << 7)
+    msr cpsr_c, r0
+    bx lr
diff --git a/kern/interrupts.c b/kern/interrupts.c
index f211398..f140212 100644
--- a/kern/interrupts.c
+++ b/kern/interrupts.c
@@ -102,8 +102,17 @@ void __attribute__((interrupt("ABORT"))) vec_data_abort() {
     printf("!!!!!!! LR was: %x\n", lr);
     panic_unhandled("data_abort");
 }
-void __attribute__((interrupt("IRQ"))) vec_irq() {
-    panic_unhandled("irq");
+#include "proc.h"
+#include "timer.h"
+void vec_irq(regs_t *regs) {
+    dev_barrier();
+    if (!timer_has_irq()) return;
+
+    proc_scheduler_irq(regs);
+
+    dev_barrier();
+    timer_clear_irq();
+    dev_barrier();
 }
 void __attribute__((interrupt("FIQ"))) vec_fiq() {
     panic_unhandled("fiq");
diff --git a/kern/kern.c b/kern/kern.c
index 533fe6a..da3e77b 100644
--- a/kern/kern.c
+++ b/kern/kern.c
@@ -10,6 +10,7 @@
 #include "sys.h"
 #include "uart.h"
 #include "vm.h"
+#include "timer.h"
 
 void reboot() {
     printf("DONE!!!\n");
@@ -36,15 +37,22 @@ void kernel_start() {
 
     uart_init(115200);
     init_printf(NULL, uart_putc);
-    irq_init();
+
     kmalloc_init();
 
+    irq_init();
+    irq_enable(BASIC_TIMER_IRQ);
+    timer_irq_load(0x1000);
+
     printf("kernel booted\n");
 
-    extern unsigned char _binary_hello_bin_start;
-    extern unsigned char _binary_hello_bin_end;
-    proc_t *p_hello = proc_new(&_binary_hello_bin_start, (size_t) (&_binary_hello_bin_end - &_binary_hello_bin_start));
-    proc_run(p_hello);
+    extern unsigned char _binary_pidos_bin_start;
+    extern unsigned char _binary_pidos_bin_end;
+
+    proc_t *p_pidos_1 = proc_new(&_binary_pidos_bin_start, (size_t) (&_binary_pidos_bin_end - &_binary_pidos_bin_start));
+    proc_t *p_pidos_2 = proc_new(&_binary_pidos_bin_start, (size_t) (&_binary_pidos_bin_end - &_binary_pidos_bin_start));
+
+    proc_run(p_pidos_1);
 
     reboot();
     return;
diff --git a/kern/proc.c b/kern/proc.c
index 4df3f3a..d08fad2 100644
--- a/kern/proc.c
+++ b/kern/proc.c
@@ -42,6 +42,7 @@ void __attribute__((noreturn)) proc_run(proc_t *proc) {
     vm_set_pt(proc->pt);
     curproc = proc;
 
+    enable_interrupts(); // TODO: Set this in the SPSR
     // NOTE: To use SPSR, need to be sure we are *NOT* in user/system mode.
     // TODO(masot): add an assert like that
     set_spsr((get_cpsr() & ~0b11111) | 0b10000);
@@ -49,3 +50,23 @@ void __attribute__((noreturn)) proc_run(proc_t *proc) {
     while (1) {
     }
 }
+
+thread_id = 0;
+
+void swippityswap(regs_t *live_state, proc_t *new_thread, proc_t *old_thread) {
+    memcpy(&(old_thread->regs), live_state, sizeof(regs_t));
+    memcpy(live_state, &(new_thread->regs), sizeof(regs_t));
+}
+
+
+void proc_scheduler_irq(regs_t *regs) {
+    pid_t curr_pid = curproc->id,
+          next_pid = (curr_pid + 1) % id;
+
+    swippityswap(regs, &(procs[next_pid]), &(procs[curr_pid]));
+
+    curproc->state = PROC_RUNNABLE;
+    curproc = &(procs[next_pid]);
+    curproc->state = PROC_RUNNING;
+    vm_set_pt(curproc->pt);
+}
diff --git a/kern/proc.h b/kern/proc.h
index d908d56..592538e 100644
--- a/kern/proc.h
+++ b/kern/proc.h
@@ -48,3 +48,4 @@ extern proc_t *curproc;
 
 proc_t *proc_new(uint8_t *code, size_t codesz);
 void proc_run(proc_t *proc);
+void proc_scheduler_irq(regs_t *regs);
diff --git a/kern/syscall.c b/kern/syscall.c
index c108752..b3dab38 100644
--- a/kern/syscall.c
+++ b/kern/syscall.c
@@ -51,9 +51,11 @@ void syscall(regs_t *regs) {
     case SYSCALL_VM_MAP:
         regs->r0 = syscall_vm_map(regs->r1, regs->r2, regs->r3, regs->r4);
         break;
+    case SYSCALL_GET_PID:
+        regs->r0 = curproc->id;
+        break;
     default:
         panic("unhandled syscall %d\n", sysno);
         break;
     }
-    regs->pc += 4;
 }
diff --git a/kern/syscall_list.h b/kern/syscall_list.h
index e22d70d..9e4366a 100644
--- a/kern/syscall_list.h
+++ b/kern/syscall_list.h
@@ -4,6 +4,7 @@
 #define SYSCALL_ALLOC_PAGE   1
 #define SYSCALL_DEALLOC_PAGE 2
 #define SYSCALL_VM_MAP       3
+#define SYSCALL_GET_PID      4
 
 // NOTE: DO NOT CHANGE THESE without changing vm.h
 #define SYSCALL_ARG_ANY_PAGE 0
diff --git a/kern/timer.h b/kern/timer.h
index 95c22b7..d4e1379 100644
--- a/kern/timer.h
+++ b/kern/timer.h
@@ -1,6 +1,8 @@
 #pragma once
 
 #include "sys.h"
+#include <stdbool.h>
+#include <stdint.h>
 
 static inline void timer_init() {
     asm volatile("mcr p15, 0, %0, c15, c12, 0" ::"r"(1));
@@ -34,3 +36,43 @@ static inline void delay_us(unsigned us) {
 static inline void delay_ms(unsigned ms) {
     delay_us(ms * 1000);
 }
+
+typedef struct {
+    uint32_t load;
+    uint32_t value;
+    uint32_t ctrl;
+    uint32_t irq_clear;
+    uint32_t raw_irq;
+    uint32_t masked_irq;
+    uint32_t reload;
+    uint32_t pre_divider;
+    uint32_t free_running_counter;
+} my_timer_t;
+
+#define TIMER_CTRL_32BIT (1 << 1)
+
+#define TIMER_CTRL_PRESCALE_1   (0 << 2)
+#define TIMER_CTRL_PRESCALE_16  (1 << 2)
+#define TIMER_CTRL_PRESCALE_256 (2 << 2)
+
+#define TIMER_CTRL_INT_ENABLE  (1 << 5)
+#define TIMER_CTRL_INT_DISABLE (0 << 5)
+
+#define TIMER_CTRL_ENABLE  (1 << 7)
+#define TIMER_CTRL_DISABLE (0 << 7)
+
+static volatile my_timer_t* const timer = (my_timer_t*) pa2ka(0x2000b400);
+
+static void timer_irq_load(uint32_t load) {
+    timer->load = load;
+    timer->ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_INT_ENABLE |
+                  TIMER_CTRL_PRESCALE_256;
+}
+
+static bool timer_has_irq() {
+    return timer->masked_irq;
+}
+
+static void timer_clear_irq() {
+    timer->irq_clear = 1;
+}