sched: add kernel-mode context switching

arch/x86_64/include/arch/irq.h

@@ -36,32 +36,32 @@ struct irq_hook {
 };
 
 struct cpu_context {
-    uint64_t r15, r14, r13, r12, r11, r10, r9, r8;
-    uint64_t rdi, rsi, rbp, unused_rsp, rbx, rdx, rcx, rax;
-    uint64_t int_no, err_no;
-    uint64_t rip, cs, rflags, rsp, ss;
+	uint64_t r15, r14, r13, r12, r11, r10, r9, r8;
+	uint64_t rdi, rsi, rbp, unused_rsp, rbx, rdx, rcx, rax;
+	uint64_t int_no, err_no;
+	uint64_t rip, cs, rflags, rsp, ss;
 } __packed;
 
 struct idt_entry {
-    uint16_t base_low;
-    uint16_t selector;
-    uint8_t always0;
-    uint8_t type : 4;
-    uint8_t zero : 1;
-    uint8_t dpl : 2;
-    uint8_t present : 1;
-    uint16_t base_middle;
-    uint32_t base_high;
-    uint32_t reserved;
+	uint16_t base_low;
+	uint16_t selector;
+	uint8_t always0;
+	uint8_t type : 4;
+	uint8_t zero : 1;
+	uint8_t dpl : 2;
+	uint8_t present : 1;
+	uint16_t base_middle;
+	uint32_t base_high;
+	uint32_t reserved;
 } __packed;
 
 struct idt {
-    struct idt_entry i_entries[NR_IDT_ENTRIES];
+	struct idt_entry i_entries[NR_IDT_ENTRIES];
 };
 
 struct idt_ptr {
-    uint16_t i_limit;
-    uintptr_t i_base;
+	uint16_t i_limit;
+	uintptr_t i_base;
 } __packed;
 
 typedef void (*int_hook)(struct cpu_context *);

arch/x86_64/include/socks/machine/thread.h

@@ -0,0 +1,10 @@
+#ifndef SOCKS_X86_64_THREAD_H_
+#define SOCKS_X86_64_THREAD_H_
+
+#include <socks/sched.h>
+
+extern void switch_to(struct thread *from, struct thread *to);
+extern void prepare_stack(uintptr_t ip, uintptr_t *sp);
+extern void user_jump(uintptr_t ip, uintptr_t sp);
+
+#endif

arch/x86_64/irq.c

@@ -96,7 +96,7 @@ static void gpf_handler(struct cpu_context *regs)
 
 static void pf_handler(struct cpu_context *regs)
 {
-	printk("page fault (%016llx %016llx)", pf_faultptr(), regs->rip);
+	printk("page fault (%016llx %016llx %016llx)", pf_faultptr(), regs->rip, regs->err_no);
 	ml_halt_cpu();
 }
 
@@ -241,6 +241,10 @@ void irq_dispatch(struct cpu_context *regs)
 		hook->irq_callback();
 	}
 
+	if (need_resched()) {
+		schedule();
+	}
+
 	start_charge_period();
 }
 

arch/x86_64/thread.c

@@ -0,0 +1,20 @@
+#include <socks/machine/thread.h>
+
+struct thread_ctx {
+	uint64_t r15, r14, r13, r12, r11, r10, r9, r8;
+	uint64_t rdi, rsi, rbp, unused_rsp, rbx, rdx, rcx, rax;
+	uint64_t rfl;
+} __packed;
+
+void prepare_stack(uintptr_t ip, uintptr_t *sp)
+{
+	(*sp) -= sizeof(uintptr_t);
+	uintptr_t *dest_ip = (uintptr_t *)(*sp);
+	*dest_ip = ip;
+
+	(*sp) -= sizeof(struct thread_ctx);
+	struct thread_ctx *ctx = (struct thread_ctx *)(*sp);
+	memset(ctx, 0x0, sizeof *ctx);
+
+	ctx->rfl = 0x202;
+}

arch/x86_64/thread_switch.S

@@ -0,0 +1,54 @@
+	.code64
+
+	.extern THREAD_sp
+//TASK_threadsp:
+	//.long 32
+	
+	.global switch_to
+	.type switch_to, @function
+
+	// %rdi = (struct thread *) current thread.
+	// %rsi = (struct thread *) next thread.
+switch_to:
+	pushfq
+
+	push %rax
+	push %rcx
+	push %rdx
+	push %rbx
+	pushq $0
+	push %rbp
+	push %rsi
+	push %rdi
+	push %r8
+	push %r9
+	push %r10
+	push %r11
+	push %r12
+	push %r13
+	push %r14
+	push %r15
+	
+	movq %rsp, THREAD_sp(%rdi)
+	movq THREAD_sp(%rsi), %rsp
+
+	pop %r15
+	pop %r14
+	pop %r13
+	pop %r12
+	pop %r11
+	pop %r10
+	pop %r9
+	pop %r8
+	pop %rdi
+	pop %rsi
+	pop %rbp
+	add $8, %rsp
+	pop %rbx
+	pop %rdx
+	pop %rcx
+	pop %rax
+
+	popfq
+
+	ret