Merge branch 'main' of https://github.com/kenshineto/kern into fat32

Merging main into here

6 files changed, 283 insertions, 62 deletions

diff --git a/kernel/cpu/cpu.c b/kernel/cpu/cpu.c
index 136a1d8..f607b36 100644
--- a/kernel/cpu/cpu.c
+++ b/kernel/cpu/cpu.c
@@ -1,8 +1,10 @@
 #include <lib.h>
 #include <comus/cpu.h>
+#include <comus/asm.h>
 
 #include "pic.h"
 #include "idt.h"
+#include "tss.h"
 
 static inline void fpu_init(void)
 {
@@ -60,8 +62,10 @@ void cpu_init(void)
 	struct cpu_feat feats;
 	cpu_feats(&feats);
 
-	pic_remap();
+	cli();
 	idt_init();
+	tss_init();
+	pic_remap();
 	if (feats.fpu)
 		fpu_init();
 	if (feats.sse) {
@@ -178,25 +182,26 @@ void cpu_feats(struct cpu_feat *feats)
 
 void cpu_print_regs(struct cpu_regs *regs)
 {
-	kprintf("rax: %#016lx (%lu)\n", regs->rax, regs->rax);
-	kprintf("rbx: %#016lx (%lu)\n", regs->rbx, regs->rbx);
-	kprintf("rcx: %#016lx (%lu)\n", regs->rcx, regs->rcx);
-	kprintf("rdx: %#016lx (%lu)\n", regs->rdx, regs->rdx);
-	kprintf("rsi: %#016lx (%lu)\n", regs->rsi, regs->rsi);
-	kprintf("rdi: %#016lx (%lu)\n", regs->rdi, regs->rdi);
-	kprintf("rsp: %#016lx (%lu)\n", regs->rsp, regs->rsp);
-	kprintf("rbp: %#016lx (%lu)\n", regs->rbp, regs->rbp);
-	kprintf("r8 : %#016lx (%lu)\n", regs->r8, regs->r8);
-	kprintf("r9 : %#016lx (%lu)\n", regs->r9, regs->r9);
-	kprintf("r10: %#016lx (%lu)\n", regs->r10, regs->r10);
-	kprintf("r11: %#016lx (%lu)\n", regs->r11, regs->r11);
-	kprintf("r12: %#016lx (%lu)\n", regs->r12, regs->r12);
-	kprintf("r13: %#016lx (%lu)\n", regs->r13, regs->r13);
-	kprintf("r14: %#016lx (%lu)\n", regs->r14, regs->r14);
-	kprintf("r15: %#016lx (%lu)\n", regs->r15, regs->r15);
-	kprintf("rip: %#016lx (%lu)\n", regs->rip, regs->rip);
-	kprintf("rflags: %#016lx (%lu)\n", regs->rflags, regs->rflags);
-	kputs("rflags: ");
+	kprintf("rax:\t%#016lx (%lu)\n", regs->rax, regs->rax);
+	kprintf("rbx:\t%#016lx (%lu)\n", regs->rbx, regs->rbx);
+	kprintf("rcx:\t%#016lx (%lu)\n", regs->rcx, regs->rcx);
+	kprintf("rdx:\t%#016lx (%lu)\n", regs->rdx, regs->rdx);
+	kprintf("rsi:\t%#016lx (%lu)\n", regs->rsi, regs->rsi);
+	kprintf("rdi:\t%#016lx (%lu)\n", regs->rdi, regs->rdi);
+	kprintf("rsp:\t%#016lx (%lu)\n", regs->rsp, regs->rsp);
+	kprintf("rbp:\t%#016lx (%lu)\n", regs->rbp, regs->rbp);
+	kprintf("r8:\t%#016lx (%lu)\n", regs->r8, regs->r8);
+	kprintf("r9:\t%#016lx (%lu)\n", regs->r9, regs->r9);
+	kprintf("r10:\t%#016lx (%lu)\n", regs->r10, regs->r10);
+	kprintf("r11:\t%#016lx (%lu)\n", regs->r11, regs->r11);
+	kprintf("r12:\t%#016lx (%lu)\n", regs->r12, regs->r12);
+	kprintf("r13:\t%#016lx (%lu)\n", regs->r13, regs->r13);
+	kprintf("r14:\t%#016lx (%lu)\n", regs->r14, regs->r14);
+	kprintf("r15:\t%#016lx (%lu)\n", regs->r15, regs->r15);
+	kprintf("rip:\t%#016lx (%lu)\n", regs->rip, regs->rip);
+	kprintf("rflags: %#016lx (%lu) [ ", regs->rflags, regs->rflags);
+	if (regs->rflags & (3 << 12))
+		kprintf("IOPL=%lu ", (regs->rflags >> 12) & 0x3);
 	if (regs->rflags & (1 << 0))
 		kputs("CF ");
 	if (regs->rflags & (1 << 2))
@@ -215,8 +220,6 @@ void cpu_print_regs(struct cpu_regs *regs)
 		kputs("DF ");
 	if (regs->rflags & (1 << 11))
 		kputs("OF ");
-	if (regs->rflags & (3 << 12))
-		kputs("IOPL ");
 	if (regs->rflags & (1 << 14))
 		kputs("NT ");
 	if (regs->rflags & (1 << 15))
@@ -233,5 +236,19 @@ void cpu_print_regs(struct cpu_regs *regs)
 		kputs("VIP ");
 	if (regs->rflags & (1 << 21))
 		kputs("ID ");
+	kputs("]\n");
+	kprintf("cs:\t%#04lx (%lu) [ DPL=%lu ]\n", regs->cs, regs->cs,
+			regs->cs & 0x3);
+	kprintf("ss:\t%#04lx (%lu) [ DPL=%lu ]\n", regs->ss, regs->ss,
+			regs->ss & 0x3);
+	kprintf("ds:\t%#04hx (%hu) [ DPL=%hu ]\n", regs->ds, regs->ds,
+			regs->ds & 0x3);
+	kprintf("es:\t%#04hx (%hu) [ DPL=%hu ]\n", regs->es, regs->es,
+			regs->es & 0x3);
+	kprintf("fs:\t%#04hx (%hu) [ DPL=%hu ]\n", regs->fs, regs->fs,
+			regs->fs & 0x3);
+	kprintf("gs:\t%#04hx (%hu) [ DPL=%hu ]\n", regs->gs, regs->gs,
+			regs->gs & 0x3);
+	kprintf("cr3:\t%#016lx (%lu)\n", regs->cr3, regs->cr3);
 	kputs("\n");
 }
diff --git a/kernel/cpu/idt.S b/kernel/cpu/idt.S
index 0ba35f8..b3a8454 100644
--- a/kernel/cpu/idt.S
+++ b/kernel/cpu/idt.S
@@ -1,12 +1,17 @@
 	.global isr_stub_table
+	.global syscall_return
 
 	.extern idt_exception_handler
 	.extern idt_pic_timer
 	.extern idt_pic_keyboard
 	.extern idt_pic_mouse
 	.extern idt_pic_eoi
+	.extern syscall_handler
+	.extern current_pcb
+	.extern isr_save
 
 .macro PUSHALL
+	# regs
 	pushq	%rax
 	pushq 	%rbx
 	pushq 	%rcx
@@ -22,9 +27,38 @@
 	pushq 	%r13
 	pushq 	%r14
 	pushq 	%r15
+
+	# segments
+	movw 	%ds, %ax
+	pushw	%ax
+	movw 	%es, %ax
+	pushw	%ax
+	movw 	%fs, %ax
+	pushw	%ax
+	movw 	%gs, %ax
+	pushw	%ax
+
+	# pgdir
+	movq	%cr3, %rax
+	pushq	%rax
 .endm
 
 .macro POPALL
+	# pgdir
+	popq	%rax
+	movq	%rax, %cr3
+
+	# segments
+	popw	%ax
+	movw 	%ax, %gs
+	popw	%ax
+	movw 	%ax, %fs
+	popw	%ax
+	movw 	%ax, %es
+	popw	%ax
+	movw 	%ax, %ds
+
+	# regs
 	popq	%r15
 	popq 	%r14
 	popq 	%r13
@@ -42,19 +76,29 @@
 	popq 	%rax
 .endm
 
+.macro ISRSave
+	PUSHALL
+	cld
+
+	movq	%rsp, %rdi
+	callq	isr_save
+.endm
+
+.macro ISRRestore
+	POPALL
+	iretq
+.endm
+
 # call the exception handler with the interrupt number
 # args: interrupt number
 .macro ISRException num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
-	movq	$\num, %rdi			# exception number
+	ISRSave
+	movq	$\num, %rdi				# exception number
 	movq	$0, %rsi                # placeholder error code
-	movq	%rsp, %rdx				# top of stack
 	callq	idt_exception_handler
-	POPALL
-	iretq
+	ISRRestore
 .endm
 
 # call the exception handler with the interrupt number
@@ -64,65 +108,64 @@ isr_stub_\num:
 	.align 8
 isr_stub_\num:
 	# retrieve the error code without corrupting registers
-	mov 	%eax, isr_tmp
+	movq	%rax, isr_tmp
 	popq	%rax
-	mov 	%eax, isr_err_code
+	movq	%rax, isr_err_code
 	movq	isr_tmp, %rax
-	PUSHALL
-	cld
+	ISRSave
 	movq	$\num, %rdi             # exception number
 	movq	isr_err_code, %rsi      # error code
-	movq	%rsp, %rdx              # top of stack
 	callq	idt_exception_handler
-	POPALL
-	iretq
+	ISRRestore
+.endm
+
+.macro SYSCALL num
+	.align 8
+isr_stub_\num:
+	ISRSave
+	callq	syscall_handler
+	jmp		syscall_return
 .endm
 
 .macro PICGeneric num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
+	ISRSave
 	movq	$\num, %rdi
 	callq	idt_pic_eoi
-	POPALL
-	iretq
+	ISRRestore
 .endm
 
+# we have to send eoi first since
+# idt_pic_timer may not return
 .macro PICTimer num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
-	callq	idt_pic_timer
-	movq	$\num, %rdi
+	ISRSave
 	callq	idt_pic_eoi
-	POPALL
-	iretq
+	movq	$\num, %rdi
+	callq	idt_pic_timer
+	ISRRestore
 .endm
 
 .macro PICKeyboard num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
+	ISRSave
 	callq	idt_pic_keyboard
 	movq	$\num, %rdi
 	callq	idt_pic_eoi
-	POPALL
-	iretq
+	ISRRestore
 .endm
 
 .macro PICMouse num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
+	ISRSave
 	callq	idt_pic_mouse
 	movq	$\num, %rdi
 	callq	idt_pic_eoi
-	POPALL
-	iretq
+	ISRRestore
 .endm
 
 # do nothing
@@ -402,10 +445,22 @@ isr_stub_table:
 	.quad isr_stub_254
 	.quad isr_stub_255
 
-# isr stubs
 	.section .text
 	.code64
 
+# isr restore
+syscall_return:
+	// get current pcb address
+	movq	current_pcb, %rbx
+
+	// load user stack
+	leaq	8(%rbx), %rsp
+
+	// return
+	POPALL
+	iretq
+
+# isr stubs
 ISRException 0
 ISRException 1
 ISRException 2
@@ -536,7 +591,7 @@ ISRIgnore 124
 ISRIgnore 125
 ISRIgnore 126
 ISRIgnore 127
-ISRIgnore 128
+SYSCALL 128
 ISRIgnore 129
 ISRIgnore 130
 ISRIgnore 131
diff --git a/kernel/cpu/idt.c b/kernel/cpu/idt.c
index bf4b499..2eab7ec 100644
--- a/kernel/cpu/idt.c
+++ b/kernel/cpu/idt.c
@@ -2,7 +2,10 @@
 #include <comus/memory.h>
 #include <comus/asm.h>
 #include <comus/cpu.h>
+#include <comus/drivers/ps2.h>
 #include <comus/drivers/pit.h>
+#include <comus/procs.h>
+#include <comus/memory.h>
 
 #include "idt.h"
 #include "pic.h"
@@ -41,8 +44,12 @@ struct idtr {
 __attribute__((aligned(0x10))) static struct idt_entry idt[256];
 
 static struct idtr idtr;
-// from idt.S
 extern void *isr_stub_table[];
+extern char kern_stack_start[];
+extern char kern_stack_end[];
+
+// current register state on interrupt
+static struct cpu_regs *state;
 
 // initialize and load the IDT
 void idt_init(void)
@@ -57,15 +64,17 @@ void idt_init(void)
 
 		uint64_t isr = (uint64_t)isr_stub_table[vector];
 		// interrupts before 0x20 are for cpu exceptions
-		uint8_t gate_type = (vector < 0x20) ? GATE_64BIT_TRAP : GATE_64BIT_INT;
 
 		entry->kernel_cs = 0x08; // offset of 1 into GDT
 		entry->ist = 0;
-		entry->flags = PRESENT | RING0 | gate_type;
+		entry->flags = PRESENT | RING0 | GATE_64BIT_INT;
 		entry->isr_low = isr & 0xffff;
 		entry->isr_mid = (isr >> 16) & 0xffff;
 		entry->isr_high = (isr >> 32) & 0xffffffff;
 		entry->reserved = 0;
+
+		if (vector == 0x80)
+			entry->flags |= RING3;
 	}
 
 	__asm__ volatile("lidt %0" : : "m"(idtr));
@@ -111,8 +120,8 @@ char *EXCEPTIONS[] = {
 	"Reserved",
 };
 
-void idt_exception_handler(uint64_t exception, uint64_t code,
-						   struct cpu_regs *state)
+__attribute__((noreturn)) void idt_exception_handler(uint64_t exception,
+													 uint64_t code)
 {
 	uint64_t cr2;
 
@@ -144,22 +153,43 @@ void idt_exception_handler(uint64_t exception, uint64_t code,
 	}
 }
 
+void isr_save(struct cpu_regs *regs)
+{
+	// make sure were in the kernel memory context
+	mem_ctx_switch(kernel_mem_ctx);
+
+	// save pointer to registers
+	state = regs;
+
+	// if we have a kernel stack pointer
+	// we should return to not save kernel context
+	// data to userspace
+	if (regs->rsp >= (size_t)kern_stack_start &&
+		regs->rsp <= (size_t)kern_stack_end)
+		return;
+
+	// save registers in current_pcb
+	if (current_pcb != NULL)
+		current_pcb->regs = *regs;
+}
+
 void idt_pic_eoi(uint8_t exception)
 {
 	pic_eoi(exception - PIC_REMAP_OFFSET);
 }
 
-int counter = 0;
-
 void idt_pic_timer(void)
 {
 	ticks++;
+	pcb_on_tick();
 }
 
 void idt_pic_keyboard(void)
 {
+	ps2kb_recv();
 }
 
 void idt_pic_mouse(void)
 {
+	ps2mouse_recv();
 }
diff --git a/kernel/cpu/tss.S b/kernel/cpu/tss.S
new file mode 100644
index 0000000..27f2955
--- /dev/null
+++ b/kernel/cpu/tss.S
@@ -0,0 +1,6 @@
+	.globl tss_flush
+
+tss_flush:
+	movw	$0x28, %ax
+	ltr		%ax
+	ret
diff --git a/kernel/cpu/tss.c b/kernel/cpu/tss.c
new file mode 100644
index 0000000..bca979d
--- /dev/null
+++ b/kernel/cpu/tss.c
@@ -0,0 +1,82 @@
+#include <comus/memory.h>
+#include <lib.h>
+
+#include "tss.h"
+
+struct sys_seg_descriptor {
+	uint64_t limit0_15 : 16;
+	uint64_t base0_15 : 16;
+	uint64_t base16_23 : 8;
+	uint64_t type : 4;
+	uint64_t : 1;
+	uint64_t DPL : 2;
+	uint64_t present : 1;
+	uint64_t limit16_19 : 4;
+	uint64_t available : 1;
+	uint64_t : 1;
+	uint64_t : 1;
+	uint64_t gran : 1;
+	uint64_t base24_31 : 8;
+	uint64_t base32_63 : 32;
+	uint64_t : 32;
+} __attribute__((packed));
+
+struct tss {
+	uint64_t : 32;
+	uint64_t rsp0 : 64;
+	uint64_t rsp1 : 64;
+	uint64_t rsp2 : 64;
+	uint64_t : 64;
+	uint64_t ist1 : 64;
+	uint64_t ist2 : 64;
+	uint64_t ist3 : 64;
+	uint64_t ist4 : 64;
+	uint64_t ist5 : 64;
+	uint64_t ist6 : 64;
+	uint64_t ist7 : 64;
+	uint64_t : 64;
+	uint64_t : 16;
+	uint64_t iopb : 16;
+} __attribute__((packed));
+
+// tss entry
+static volatile struct tss tss;
+
+// gdt entries
+extern volatile uint8_t GDT[];
+static volatile struct sys_seg_descriptor *GDT_TSS;
+
+// kernel stack pointer
+static char interrupt_stack[PAGE_SIZE * 2];
+
+void tss_init(void)
+{
+	uint64_t base = (uint64_t)&tss;
+	uint64_t limit = sizeof tss - 1;
+
+	// setup tss entry
+	memsetv(&tss, 0, sizeof(struct tss));
+	tss.rsp0 = (uint64_t)interrupt_stack + sizeof(interrupt_stack);
+
+	// map tss into gdt
+	GDT_TSS = (volatile struct sys_seg_descriptor *)(GDT + 0x28);
+	memsetv(GDT_TSS, 0, sizeof(struct sys_seg_descriptor));
+	GDT_TSS->limit0_15 = limit & 0xFFFF;
+	GDT_TSS->base0_15 = base & 0xFFFF;
+	GDT_TSS->base16_23 = (base >> 16) & 0xFF;
+	GDT_TSS->type = 0x9;
+	GDT_TSS->DPL = 0;
+	GDT_TSS->present = 1;
+	GDT_TSS->limit16_19 = (limit >> 16) & 0xF;
+	GDT_TSS->available = 0;
+	GDT_TSS->gran = 0;
+	GDT_TSS->base24_31 = (base >> 24) & 0xFF;
+	GDT_TSS->base32_63 = (base >> 32) & 0xFFFFFFFF;
+
+	tss_flush();
+}
+
+void tss_set_stack(uint64_t stack)
+{
+	tss.rsp0 = stack;
+}
diff --git a/kernel/cpu/tss.h b/kernel/cpu/tss.h
new file mode 100644
index 0000000..f17b619
--- /dev/null
+++ b/kernel/cpu/tss.h
@@ -0,0 +1,31 @@
+/**
+ * @file tss.h
+ *
+ * @author Freya Murphy <freya@freyacat.org>
+ *
+ * TSS functions
+ */
+
+#ifndef TSS_H_
+#define TSS_H_
+
+#define TSS_REMAP_OFFSET 0x20
+
+#include <stdint.h>
+
+/**
+ * Load the TSS selector
+ */
+void tss_init(void);
+
+/**
+ * Flush the tss
+ */
+void tss_flush(void);
+
+/**
+ * Set the kernel stack pointer in the tss
+ */
+void tss_set_stack(uint64_t stack);
+
+#endif /* tss.h */