move context save area to pcb not in stack

4 files changed, 135 insertions, 81 deletions

diff --git a/kernel/cpu/cpu.c b/kernel/cpu/cpu.c
index 6ef5ef5..f607b36 100644
--- a/kernel/cpu/cpu.c
+++ b/kernel/cpu/cpu.c
@@ -1,5 +1,6 @@
 #include <lib.h>
 #include <comus/cpu.h>
+#include <comus/asm.h>
 
 #include "pic.h"
 #include "idt.h"
@@ -61,8 +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) {
@@ -74,8 +77,6 @@ void cpu_init(void)
 		if (feats.avx)
 			avx_init();
 	}
-
-	tss_init();
 }
 
 void cpu_report(void)
@@ -181,25 +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))
@@ -218,8 +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))
@@ -236,5 +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 06c70a0..05c34f5 100644
--- a/kernel/cpu/idt.S
+++ b/kernel/cpu/idt.S
@@ -1,6 +1,5 @@
 	.global isr_stub_table
 	.global syscall_return
-	.global awd
 
 	.extern idt_exception_handler
 	.extern idt_pic_timer
@@ -9,8 +8,10 @@
 	.extern idt_pic_eoi
 	.extern syscall_handler
 	.extern current_pcb
+	.extern isr_save
 
 .macro PUSHALL
+	# regs
 	pushq	%rax
 	pushq 	%rbx
 	pushq 	%rcx
@@ -26,9 +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
+	movw 	%ax, %fs
+	popw	%ax
+	movw 	%ax, %es
+	popw	%ax
+	movw 	%ax, %ds
+	popw	%ax
+
+	# regs
 	popq	%r15
 	popq 	%r14
 	popq 	%r13
@@ -46,19 +76,28 @@
 	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
@@ -68,26 +107,21 @@ 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:
-	PUSHALL
-	cld
-	movq	%rsp, %rdi				# top of stack
+	ISRSave
 	callq	syscall_handler
 	jmp		syscall_return
 .endm
@@ -95,48 +129,40 @@ isr_stub_\num:
 .macro PICGeneric num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
+	ISRSave
 	movq	$\num, %rdi
 	callq	idt_pic_eoi
-	POPALL
-	iretq
+	ISRRestore
 .endm
 
 .macro PICTimer num
 	.align 8
 isr_stub_\num:
-	PUSHALL
-	cld
+	ISRSave
 	callq	idt_pic_timer
 	movq	$\num, %rdi
 	callq	idt_pic_eoi
-	POPALL
-	iretq
+	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
@@ -421,18 +447,13 @@ isr_stub_table:
 
 # isr restore
 syscall_return:
-	movq	current_pcb, %rbx // return user stack
-	movq	0(%rbx), %rsp // esp
-	movq	8(%rbx), %rcx // pml4
-	movq	(%rcx), %rcx
-	movq	%rcx, %cr3
+	// get current pcb address
+	movq	current_pcb, %rbx
 
-	movw	$(0x20 | 3), %ax
-	movw 	%ax, %ds
-	movw 	%ax, %es
-	movw 	%ax, %fs
-	movw 	%ax, %gs
+	// load user stack
+	leaq	8(%rbx), %rsp
 
+	// return
 	POPALL
 	iretq
 
diff --git a/kernel/cpu/idt.c b/kernel/cpu/idt.c
index 8bddc21..d071d29 100644
--- a/kernel/cpu/idt.c
+++ b/kernel/cpu/idt.c
@@ -3,6 +3,7 @@
 #include <comus/asm.h>
 #include <comus/cpu.h>
 #include <comus/drivers/pit.h>
+#include <comus/procs.h>
 #include <comus/memory.h>
 
 #include "idt.h"
@@ -42,8 +43,12 @@ 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)
@@ -58,11 +63,10 @@ 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;
@@ -115,14 +119,11 @@ 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;
 
-	// make sure were in the kernel memory context
-	mem_ctx_switch(kernel_mem_ctx);
-
 	switch (exception) {
 	case EX_PAGE_FAULT:
 		// page faults store the offending address in cr2
@@ -151,16 +152,35 @@ 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)
diff --git a/kernel/cpu/tss.c b/kernel/cpu/tss.c
index 184b884..bca979d 100644
--- a/kernel/cpu/tss.c
+++ b/kernel/cpu/tss.c
@@ -1,6 +1,5 @@
-#include "comus/memory.h"
-#include "lib/kstring.h"
-#include <stdint.h>
+#include <comus/memory.h>
+#include <lib.h>
 
 #include "tss.h"
 
@@ -48,7 +47,7 @@ extern volatile uint8_t GDT[];
 static volatile struct sys_seg_descriptor *GDT_TSS;
 
 // kernel stack pointer
-static char interrupt_stack[PAGE_SIZE*2];
+static char interrupt_stack[PAGE_SIZE * 2];
 
 void tss_init(void)
 {