syscalls: add _syscall_sleep()

15 files changed, 150 insertions, 136 deletions

diff --git a/src/kernel/arch/amd64/32/32 b/src/kernel/arch/amd64/32/32
deleted file mode 100644
index 9bd97e6..0000000
--- a/src/kernel/arch/amd64/32/32
+++ /dev/null
@@ -1,130 +0,0 @@
-#include <kernel/arch/generic.h>
-#include <kernel/arch/amd64/gdt.h>
-#include <shared/mem.h>
-#include <stdbool.h>
-#include <stdint.h>
-
-extern char _isr_mini_stack;
-
-struct gdt_entry {
-	uint64_t limit_low  : 16;
-	uint64_t base_low   : 24;
-	uint64_t accessed   :  1; // set by the processor
-	                          // CODE        | DATA
-	uint64_t rw         :  1; // readable?   | writeable?
-	uint64_t conforming :  1; // conforming? | expands down?
-	uint64_t code       :  1; // 1           | 0
-
-	uint64_t codeordata :  1; // 1 for everything other than TSS and LDT
-	uint64_t ring       :  2;
-	uint64_t present    :  1; // always 1
-	uint64_t limit_high :  4;
-	uint64_t available  :  1; // ???
-	uint64_t long_mode  :  1;
-	uint64_t x32        :  1;
-	uint64_t gran       :  1; // 1 - 4kb, 0 - 1b
-	uint64_t base_high  :  8;
-} __attribute__((packed));
-
-struct tss_entry {
-	uint32_t _unused0;
-	uint32_t esp0; // kernel mode stack pointer
-	uint32_t ss0;  // kernel mode stack segment
-	uint8_t  _unused1[0x5c];
-} __attribute__((packed));
-
-struct lgdt_arg {
-	uint16_t limit;
-	uint32_t base;
-} __attribute__((packed));
-
-__attribute__((section(".shared")))
-static struct gdt_entry GDT[SEG_end];
-__attribute__((section(".shared")))
-static struct tss_entry TSS;
-static struct lgdt_arg lgdt_arg; // probably doesn't need to be global
-
-static void gdt_fillout(struct gdt_entry* entry, uint8_t ring, bool code);
-static void gdt_prepare(void);
-static void gdt_load(void);
-
-
-static void gdt_fillout(struct gdt_entry* entry, uint8_t ring, bool code) {
-	*entry = (struct gdt_entry) {
-		// set up the identity mapping
-		.limit_low  = 0xFFFF,
-		.limit_high = 0xF,
-		.gran       = 1, // 4KB * 0xFFFFF = (almost) 4GB
-		.base_low   = 0,
-		.base_high  = 0,
-
-		.ring       = ring,
-		.code       = code,
-
-		.accessed   = 0,
-		.rw         = 1,
-		.conforming = 0,
-		.codeordata = 1,
-		.present    = 1,
-		.long_mode  = 0, // ???
-		.available  = 1, // ???
-		.x32        = 1,
-	};
-}
-
-static void gdt_prepare(void) {
-	GDT[SEG_null].present = 0;
-
-	gdt_fillout(&GDT[SEG_r0code], 0, true);
-	gdt_fillout(&GDT[SEG_r0data], 0, false);
-	gdt_fillout(&GDT[SEG_r3code], 3, true);
-	gdt_fillout(&GDT[SEG_r3data], 3, false);
-
-	// tss
-	memset(&TSS, 0, sizeof(TSS));
-	TSS.ss0 = SEG_r0data << 3; // kernel data segment
-	TSS.esp0 = (uintptr_t) &_isr_mini_stack;
-
-	GDT[SEG_TSS] = (struct gdt_entry) {
-		.limit_low  = sizeof(TSS),
-		.limit_high = sizeof(TSS) >> 16,
-		.gran       = 0,
-		.base_low   =  (uintptr_t) &TSS,
-		.base_high  = ((uintptr_t) &TSS) >> 24,
-
-		.accessed   = 1, // 1 for TSS
-		.rw         = 0, // 1 busy / 0 not busy
-		.conforming = 0, // 0 for TSS
-		.code       = 1, // 32bit
-		.codeordata = 0, // is a system entry
-		.ring       = 3,
-		.present    = 1,
-		.available  = 0, // 0 for TSS
-		.long_mode  = 0,
-		.x32        = 0, // idk
-	};
-}
-
-static void gdt_load(void) {
-	lgdt_arg.limit = sizeof(GDT) - 1;
-	lgdt_arg.base = (uintptr_t) &GDT;
-	asm("lgdt (%0)" 
-	    : : "r" (&lgdt_arg) : "memory");
-
-	asm("ltr %%ax"
-	    : : "a" (SEG_TSS << 3 | 3) : "memory");
-
-	// update all segment registers
-	gdt_farjump(SEG_r0code << 3);
-	asm("mov %0, %%ds;"
-	    "mov %0, %%ss;"
-	    "mov %0, %%es;"
-	    "mov %0, %%fs;"
-	    "mov %0, %%gs;"
-	    : : "r" (SEG_r0data << 3) : "memory");
-}
-
-void gdt_init(void) {
-	gdt_prepare();
-	gdt_load();
-}
diff --git a/src/kernel/arch/amd64/32/boot.s b/src/kernel/arch/amd64/32/boot.s
index 0e21036..0621038 100644
--- a/src/kernel/arch/amd64/32/boot.s
+++ b/src/kernel/arch/amd64/32/boot.s
@@ -2,6 +2,7 @@
 .global _start
 .type _start, @function
 _start:
+	cli
 	mov $_stack_top, %esp
 	push %ebx // save the address of the multiboot struct
 
diff --git a/src/kernel/arch/amd64/interrupts/irq.c b/src/kernel/arch/amd64/interrupts/irq.c
index b5e9255..9872ec7 100644
--- a/src/kernel/arch/amd64/interrupts/irq.c
+++ b/src/kernel/arch/amd64/interrupts/irq.c
@@ -5,6 +5,12 @@
 static const int PIC1 = 0x20;
 static const int PIC2 = 0xA0;
 
+static void pit_init(void) {
+	uint16_t divisor = 1193;
+	port_out8(0x40, divisor & 0xFF);
+	port_out8(0x40, divisor >> 8);
+}
+
 void irq_init(void) {
 	port_out8(PIC1, 0x11); /* start init sequence */
 	port_out8(PIC2, 0x11);
@@ -18,11 +24,14 @@ void irq_init(void) {
 	port_out8(PIC2+1, 0x1);
 
 	uint8_t mask = 0xff;
+	mask &= ~(1 << IRQ_PIT);
 	mask &= ~(1 << IRQ_PS2);
 	mask &= ~(1 << IRQ_COM1);
 
 	port_out8(PIC1+1, mask);
 	port_out8(PIC2+1, 0xff);
+
+	pit_init();
 }
 
 void irq_eoi(uint8_t line) {
diff --git a/src/kernel/arch/amd64/interrupts/irq.h b/src/kernel/arch/amd64/interrupts/irq.h
index 3340101..2a4b12d 100644
--- a/src/kernel/arch/amd64/interrupts/irq.h
+++ b/src/kernel/arch/amd64/interrupts/irq.h
@@ -3,6 +3,7 @@
 #include <stdint.h>
 
 #define IRQ_IBASE 0x20
+#define IRQ_PIT 0
 #define IRQ_PS2 1
 #define IRQ_COM1 4
 
diff --git a/src/kernel/arch/amd64/interrupts/isr.c b/src/kernel/arch/amd64/interrupts/isr.c
index 71da27b..0bfd865 100644
--- a/src/kernel/arch/amd64/interrupts/isr.c
+++ b/src/kernel/arch/amd64/interrupts/isr.c
@@ -3,6 +3,7 @@
 #include <kernel/arch/amd64/interrupts/irq.h>
 #include <kernel/arch/amd64/interrupts/isr.h>
 #include <kernel/arch/amd64/port_io.h>
+#include <kernel/arch/amd64/time.h>
 #include <kernel/arch/generic.h>
 #include <kernel/panic.h>
 #include <kernel/proc.h>
@@ -28,6 +29,11 @@ void isr_stage3(int interrupt, uint64_t *stackframe) {
 			isr_test_interrupt_called = true;
 			return;
 
+		case IRQ_IBASE + IRQ_PIT:
+			pit_irq();
+			irq_eoi(IRQ_PIT);
+			return;
+
 		case IRQ_IBASE + IRQ_PS2:
 			ps2_irq();
 			irq_eoi(IRQ_PS2);
diff --git a/src/kernel/arch/amd64/time.c b/src/kernel/arch/amd64/time.c
new file mode 100644
index 0000000..d6e53dd
--- /dev/null
+++ b/src/kernel/arch/amd64/time.c
@@ -0,0 +1,50 @@
+#include <kernel/arch/amd64/time.h>
+#include <kernel/panic.h>
+#include <kernel/proc.h>
+
+static uint64_t uptime = 0, goal = ~0;
+static struct process *scheduled = NULL;
+
+uint64_t uptime_ms(void) { return uptime; }
+
+static void update_goal(void) {
+	goal = scheduled ? scheduled->waits4timer.goal : ~(uint64_t)0;
+}
+
+void pit_irq(void) {
+	// TODO inefficient - getting here executes a lot of code which could just be a few lines of asm
+	uptime++;
+	if (uptime < goal) return;
+
+	struct process *p = scheduled;
+	assert(p);
+	scheduled = p->waits4timer.next;
+	process_transition(p, PS_RUNNING);
+	update_goal();
+}
+
+void timer_schedule(struct process *p, uint64_t time) {
+	process_transition(p, PS_WAITS4TIMER);
+	p->waits4timer.goal = time;
+
+	struct process **slot = &scheduled;
+	while (*slot && (*slot)->waits4timer.goal <= time) {
+		assert((*slot)->state == PS_WAITS4TIMER);
+		slot = &(*slot)->waits4timer.next;
+	}
+	p->waits4timer.next = *slot;
+	*slot = p;
+	update_goal();
+}
+
+void timer_deschedule(struct process *p) {
+	assert(p->state == PS_WAITS4TIMER);
+
+	struct process **slot = &scheduled;
+	while (*slot && *slot != p)
+		slot = &(*slot)->waits4timer.next;
+	assert(*slot);
+	*slot = p->waits4timer.next;
+
+	update_goal();
+}
diff --git a/src/kernel/arch/amd64/time.h b/src/kernel/arch/amd64/time.h
new file mode 100644
index 0000000..04ba9b0
--- /dev/null
+++ b/src/kernel/arch/amd64/time.h
@@ -0,0 +1,4 @@
+#pragma once
+#include <kernel/arch/generic.h>
+
+void pit_irq(void);
diff --git a/src/kernel/arch/generic.h b/src/kernel/arch/generic.h
index 4a4f632..0b7b2f2 100644
--- a/src/kernel/arch/generic.h
+++ b/src/kernel/arch/generic.h
@@ -6,6 +6,8 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+struct process;
+
 // i have no idea where else to put it
 // some code assumes that it's a power of 2
 #define PAGE_SIZE 4096
@@ -22,6 +24,10 @@ void cpu_shutdown(void);
 /** on x86: waits for an IRQ */
 void cpu_pause(void);
 
+uint64_t uptime_ms(void);
+void timer_schedule(struct process *p, uint64_t time);
+void timer_deschedule(struct process *p);
+
 // src/arch/i386/sysenter.s
 _Noreturn void sysexit(struct registers);
 
diff --git a/src/kernel/proc.c b/src/kernel/proc.c
index e7a5ed6..3bf2b0d 100644
--- a/src/kernel/proc.c
+++ b/src/kernel/proc.c
@@ -132,6 +132,9 @@ void process_kill(struct process *p, int ret) {
 			*iter = p->waits4pipe.next;
 		}
 
+		if (p->state == PS_WAITS4TIMER)
+			timer_deschedule(p);
+
 		for (handle_t h = 0; h < HANDLE_MAX; h++)
 			handle_close(p->handles[h]);
 
@@ -217,14 +220,15 @@ static _Noreturn void process_switch(struct process *proc) {
 }
 
 _Noreturn void process_switch_any(void) {
-	if (process_current && process_current->state == PS_RUNNING)
-		process_switch(process_current);
+	for (;;) {
+		if (process_current && process_current->state == PS_RUNNING)
+			process_switch(process_current);
 
-	struct process *found = process_find(PS_RUNNING);
-	if (found) process_switch(found);
+		struct process *found = process_find(PS_RUNNING);
+		if (found) process_switch(found);
 
-	cpu_pause();
-	process_switch_any();
+		cpu_pause();
+	}
 }
 
 struct process *process_next(struct process *p) {
@@ -284,6 +288,7 @@ void process_transition(struct process *p, enum process_state state) {
 		case PS_WAITS4FS:
 		case PS_WAITS4REQUEST:
 		case PS_WAITS4PIPE:
+		case PS_WAITS4TIMER:
 			assert(last == PS_RUNNING);
 			break;
 
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index d6f84bd..fb14e35 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -15,6 +15,7 @@ enum process_state {
 	PS_WAITS4FS,
 	PS_WAITS4REQUEST,
 	PS_WAITS4PIPE,
+	PS_WAITS4TIMER,
 
 	PS_LAST,
 };
@@ -46,6 +47,11 @@ struct process {
 			size_t len;
 			struct process *next;
 		} waits4pipe;
+		struct {
+			/* managed by timer_schedule */
+			uint64_t goal;
+			struct process *next;
+		} waits4timer;
 	};
 	struct vfs_request *handled_req;
 
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 4537ff5..ceba528 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -363,6 +363,11 @@ long _syscall_pipe(handle_t __user user_ends[2], int flags) {
 	SYSCALL_RETURN(0);
 }
 
+void _syscall_sleep(long ms) {
+	// TODO no overflow check - can leak current uptime
+	timer_schedule(process_current, uptime_ms() + ms);
+}
+
 long _syscall_execbuf(void __user *ubuf, size_t len) {
 	if (len == 0) SYSCALL_RETURN(0);
 	if (len > sizeof(uint64_t) * 6 * 4) // TODO specify max size somewhere
@@ -434,6 +439,9 @@ long _syscall(long num, long a, long b, long c, long d, long e) {
 		case _SYSCALL_PIPE:
 			_syscall_pipe((userptr_t)a, b);
 			break;
+		case _SYSCALL_SLEEP:
+			_syscall_sleep(a);
+			break;
 		case _SYSCALL_EXECBUF:
 			_syscall_execbuf((userptr_t)a, b);
 			break;
diff --git a/src/shared/include/camellia/syscalls.h b/src/shared/include/camellia/syscalls.h
index 84af276..40cb68d 100644
--- a/src/shared/include/camellia/syscalls.h
+++ b/src/shared/include/camellia/syscalls.h
@@ -29,6 +29,8 @@ enum {
 	_SYSCALL_MEMFLAG,
 	_SYSCALL_PIPE,
 
+	_SYSCALL_SLEEP,
+
 	_SYSCALL_EXECBUF = 100,
 
 	_SYSCALL_DEBUG_KLOG,
@@ -88,6 +90,8 @@ long _syscall_fs_respond(void __user *buf, long ret, int flags);
 void __user *_syscall_memflag(void __user *addr, size_t len, int flags);
 long _syscall_pipe(handle_t __user user_ends[2], int flags);
 
+void _syscall_sleep(long ms);
+
 /* see shared/execbuf.h */
 long _syscall_execbuf(void __user *buf, size_t len);
 
diff --git a/src/user/app/shell/builtins.c b/src/user/app/shell/builtins.c
index 1a46003..d4de354 100644
--- a/src/user/app/shell/builtins.c
+++ b/src/user/app/shell/builtins.c
@@ -117,6 +117,14 @@ static void cmd_ls(int argc, char **argv) {
 	}
 }
 
+static void cmd_sleep(int argc, char **argv) {
+	if (argc < 2) {
+		eprintf("no arguments");
+		return;
+	}
+	_syscall_sleep(strtol(argv[1], NULL, 0) * 1000);
+}
+
 static void cmd_touch(int argc, char **argv) {
 	if (argc <= 1) {
 		eprintf("no arguments");
@@ -135,6 +143,7 @@ struct builtin builtins[] = {
 	{"echo", cmd_echo},
 	{"hexdump", cmd_hexdump},
 	{"ls", cmd_ls},
+	{"sleep", cmd_sleep},
 	{"touch", cmd_touch},
 	{NULL, NULL},
 };
diff --git a/src/user/app/tests/tests.c b/src/user/app/tests/tests.c
index d655ab9..5c40bcd 100644
--- a/src/user/app/tests/tests.c
+++ b/src/user/app/tests/tests.c
@@ -254,7 +254,37 @@ static void test_strtol(void) {
 	assert(!strcmp("hello", end));
 	assert(01234 == strtol("   01234hello", &end, 0));
 	assert(!strcmp("hello", end));
+}
+
+static void test_sleep(void) {
+	// TODO yet another of those fake tests that you have to verify by hand
+	if (!fork()) {
+		if (!fork()) {
+			_syscall_sleep(100);
+			printf("1\n");
+			_syscall_sleep(200);
+			printf("3\n");
+			_syscall_sleep(200);
+			printf("5\n");
+			_syscall_exit(0);
+		}
+		if (!fork()) {
+			printf("0\n");
+			_syscall_sleep(200);
+			printf("2\n");
+			_syscall_sleep(200);
+			printf("4\n");
+			/* get killed while asleep
+			* a peaceful death, i suppose. */
+			for (;;) _syscall_sleep(1000000000);
+		}
+		_syscall_await();
+		_syscall_exit(0);
+	}
 
+	/* this part checks if, after killing an asleep process, other processes can still wake up */
+	_syscall_sleep(600);
+	printf("6\n");
 }
 
 static void test_misc(void) {
@@ -276,6 +306,7 @@ int main(void) {
 	run_forked(test_execbuf);
 	run_forked(test_printf);
 	run_forked(test_strtol);
+	run_forked(test_sleep);
 	run_forked(test_misc);
 	return 1;
 }
diff --git a/src/user/lib/syscall.c b/src/user/lib/syscall.c
index 842b7b9..ffda454 100644
--- a/src/user/lib/syscall.c
+++ b/src/user/lib/syscall.c
@@ -58,6 +58,10 @@ long _syscall_pipe(handle_t __user user_ends[2], int flags) {
 	return _syscall(_SYSCALL_PIPE, (long)user_ends, (long)flags, 0, 0, 0);
 }
 
+void _syscall_sleep(long ms) {
+	return (void)_syscall(_SYSCALL_SLEEP, ms, 0, 0, 0, 0);
+}
+
 long _syscall_execbuf(void __user *buf, size_t len) {
 	return _syscall(_SYSCALL_EXECBUF, (long)buf, (long)len, 0, 0, 0);
 }