we're bringing kjarna back and not doing the crazy stuff with trying to have task management during efi. that was a bit extra.kjarna

6 files changed, 154 insertions, 58 deletions

diff --git a/kc/core/cpu/arch_thread.c b/kc/core/cpu/arch_thread.c
new file mode 100644
index 0000000..c0d707a
--- /dev/null
+++ b/kc/core/cpu/arch_thread.c
@@ -0,0 +1,81 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdnoreturn.h>
+
+#include <libc/stdio.h>
+
+#include "task.h"
+
+struct arch_register_context
+{
+	uint64_t
+		r15,
+		r14,
+		r13,
+		r12,
+		r11,
+		r10,
+		r9,
+		r8,
+		rsi,
+		rdi,
+		rdx,
+		rcx,
+		rbx,
+		rax,
+		rbp,
+		rsp;
+};
+
+extern uint64_t *get_tss_rsp0(void);
+
+struct arch_thread_context
+{
+	struct arch_register_context register_context;
+	void *return_address;
+};
+
+extern void arch_swap_thread_stack(
+		void * volatile *outgoing_stack,
+		void *incoming_stack);
+
+extern void arch_begin_thread(
+		void *(func)(void *),
+		void *params);
+
+void arch_create_thread(
+		struct kc_thread *thread,
+		void *(*func)(void *),
+		void *params)
+{
+	uintptr_t stack_pointer = (uintptr_t)thread->kernel_stack_pointer;
+	struct arch_thread_context *context = (struct arch_thread_context *)
+		(stack_pointer -= sizeof(*context));
+	thread->kernel_stack_pointer = (void *)stack_pointer;
+
+	context->return_address = (void *)arch_begin_thread;
+	context->register_context.rdi = (uint64_t)func;
+	context->register_context.rsi = (uint64_t)params;
+	context->register_context.rdx = (uint64_t)thread;
+	context->register_context.rsp = (uint64_t)&context->return_address;
+}
+
+void arch_swap_thread(
+		struct kc_thread *outgoing,
+		struct kc_thread *incoming)
+{
+	arch_swap_thread_stack(&outgoing->kernel_stack_pointer, incoming->kernel_stack_pointer);
+}
+
+void *arch_idle_loop(void *)
+{
+	for (;;) __asm__ ("hlt");
+	return nullptr;
+}
+
+noreturn void arch_terminate_thread(union kc_thread_result result, struct kc_thread *)
+{
+	kct_terminate(result);
+	for (;;) __asm__ ("hlt");
+}
+
diff --git a/kc/core/cpu/arch_thread.h b/kc/core/cpu/arch_thread.h
new file mode 100644
index 0000000..2b8d0fb
--- /dev/null
+++ b/kc/core/cpu/arch_thread.h
@@ -0,0 +1,12 @@
+#pragma once
+
+void * arch_idle_loop(void *);
+
+void arch_create_thread(
+		struct kc_thread *thread,
+		void *(kc_thread_func)(void *),
+		void *params);
+
+void arch_swap_thread(
+		struct kc_thread *outgoing,
+		struct kc_thread *incoming);
diff --git a/kc/core/cpu/cpu.c b/kc/core/cpu/cpu.c
index da55d38..226c9cf 100644
--- a/kc/core/cpu/cpu.c
+++ b/kc/core/cpu/cpu.c
@@ -10,7 +10,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#include <lib/kstdio.h>
+#include <libc/stdio.h>
 
 #define GDT_ENTRIES 16
 #define IDT_ENTRIES 256
@@ -53,7 +53,7 @@ uint64_t *get_tss_rsp0(void)
 
 static void syscall_entry(void)
 {
-    kprintf("system call\n");
+    printf("system call\n");
     halt();
 }
 
diff --git a/kc/core/cpu/cpu_task.S b/kc/core/cpu/cpu_task.S
deleted file mode 100644
index a411028..0000000
--- a/kc/core/cpu/cpu_task.S
+++ /dev/null
@@ -1,54 +0,0 @@
-/* thread switching routines for x86_64
-* adapted from:
-* https://wiki.osdev.org/Brendan%27s_Multi-tasking_Tutorial
-* 
-* 
-*/
-
-.hidden cpu_set_thread
-.global cpu_set_thread
-.type cpu_set_thread, @function
-cpu_set_thread:
-    /* x86_64 SysV ABI
-    *  must save the following registers to the stack:
-    *   rbx, rsp, rbp, r12, r13, r14, r15
-    *  the following are the parameters for switching tasks
-    *   rdi: pointer to control block of thread being switched to 
-    *   rsi: pointer to control block of the current thread
-    *   rdx: pointer to this cpu's task state segment rsp0 field
-    */
-    // test for attempt to switch to same thread
-    cmp %rdi,%rsi
-    je .Lnothing
-    // test for a NULL origin thread
-    test %rsi,%rsi
-    // skip saving the state for a NULL origin thread
-    jz .Lnull_thread
-    push %rbx
-    push %r12
-    push %r13
-    push %r14
-    push %r15
-    push %rbp
-    /* the current task will be in rsi */
-    mov %rsp, 0(%rsi) // save the stack pointer for the current task
-.Lnull_thread:
-    mov 0(%rdi),%rsp // new stack is the next's task's stack
-    mov 8(%rdi),%rbx // top of the next task's kernel stack
-    mov %rbx,0(%rdx) // save the esp0 to the tss
-    mov 16(%rdi),%rax // page map for the next task
-    mov %cr3, %rcx // in case we need to change the page map
-    cmp %rax,%rcx
-    je .Lfinish
-    mov %rax,%cr3 // if the page maps are not the same, reload
-.Lfinish:
-    pop %rbp // get all the registers off the new task's stack
-    pop %r15
-    pop %r14
-    pop %r13
-    pop %r12
-    pop %rbx
-.Lnothing: // do nothing if the threads are the same
-    ret // leave into the new task
-.size cpu_set_thread, . - cpu_set_thread
-
diff --git a/kc/core/cpu/cpu_thread.S b/kc/core/cpu/cpu_thread.S
new file mode 100644
index 0000000..c4d04e1
--- /dev/null
+++ b/kc/core/cpu/cpu_thread.S
@@ -0,0 +1,57 @@
+.section .text
+
+.extern arch_terminate_thread
+
+.global arch_begin_thread
+arch_begin_thread:
+	movq %rdi, %rax
+	movq %rsi, %rdi
+	pushq %rdx
+	pushq %rbp
+	movq %rsp, %rbp
+	andq $-16, %rsp
+	callq *%rax
+	movq %rax, %rdi
+	movq 8(%rbp), %rsi
+	callq arch_terminate_thread
+
+.global arch_swap_thread_stack
+arch_swap_thread_stack:
+	pushq %rsp
+	pushq %rbp
+	pushq %rax
+	pushq %rbx
+	pushq %rcx
+	pushq %rdx
+	pushq %rdi
+	pushq %rsi
+	pushq %r8
+	pushq %r9
+	pushq %r10
+	pushq %r11
+	pushq %r12
+	pushq %r13
+	pushq %r14
+	pushq %r15
+	movq %rsp, (%rdi)
+	.Lenter_thread:
+	movq %rsi, %rsp
+	popq %r15
+	popq %r14
+	popq %r13
+	popq %r12
+	popq %r11
+	popq %r10
+	popq %r9
+	popq %r8
+	popq %rsi
+	popq %rdi
+	popq %rdx
+	popq %rcx
+	popq %rbx
+	popq %rax
+	popq %rbp
+	popq %rsp
+	retq
+
+
diff --git a/kc/core/cpu/exceptions.h b/kc/core/cpu/exceptions.h
index 7babb65..14a2088 100644
--- a/kc/core/cpu/exceptions.h
+++ b/kc/core/cpu/exceptions.h
@@ -21,7 +21,7 @@
 
 #ifndef __ASSEMBLER__
 
-#include <lib/kstdio.h>
+#include <libc/stdio.h>
 
 struct isr_context_param_regs
 {
@@ -53,7 +53,7 @@ struct isr_context
 
 static inline void print_exception_context(struct isr_context *context)
 {
-    kprintf(
+    printf(
             "exception %#hhx:%x context:\n"
             "interrupt entry state:\n"
             "rip: %#hx:%p rflags: %#0.16lx\n"