From 48d47dea94cc1c5c11d2ad8836d4f1365dd7d2ca Mon Sep 17 00:00:00 2001
From: Mark <alnyan@airmail.cc>
Date: Fri, 11 Oct 2019 21:16:58 +0300
Subject: [PATCH] Now with userspace

---
 include/sys/amd64/cpu.h    |  2 ++
 include/sys/amd64/hw/gdt.h |  1 +
 sys/amd64/hw/ap_code.nasm  |  2 ++
 sys/amd64/hw/gdt.c         | 24 ++++++++++++++++--------
 sys/amd64/hw/gdt_s.S       |  2 ++
 sys/amd64/hw/irq0.S        |  6 ++++++
 sys/amd64/smp/smp.c        |  2 ++
 sys/amd64/sys/sched.c      | 15 +++++++++------
 8 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/include/sys/amd64/cpu.h b/include/sys/amd64/cpu.h
index 99db323..c28a2c5 100644
--- a/include/sys/amd64/cpu.h
+++ b/include/sys/amd64/cpu.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "sys/amd64/asm/asm_irq.h"
+#include "sys/amd64/hw/gdt.h"
 #include "sys/types.h"
 #include "sys/thread.h"
 
@@ -9,6 +10,7 @@ struct cpu {
 
     struct thread *thread;      // 0x08
     uint64_t ticks;             // 0x10
+    amd64_tss_t *tss;           // 0x18
 
     // No need to define offsets for these: ther're not accessed
     // from assembly
diff --git a/include/sys/amd64/hw/gdt.h b/include/sys/amd64/hw/gdt.h
index 57451c4..7ff6db6 100644
--- a/include/sys/amd64/hw/gdt.h
+++ b/include/sys/amd64/hw/gdt.h
@@ -35,5 +35,6 @@ typedef struct {
 } __attribute__((packed)) amd64_gdt_ptr_t;
 
 amd64_gdt_ptr_t *amd64_gdtr_get(int cpu);
+amd64_tss_t *amd64_tss_get(int cpu);
 
 void amd64_gdt_init(void);
diff --git a/sys/amd64/hw/ap_code.nasm b/sys/amd64/hw/ap_code.nasm
index 7d3f719..9441709 100644
--- a/sys/amd64/hw/ap_code.nasm
+++ b/sys/amd64/hw/ap_code.nasm
@@ -76,6 +76,8 @@ ap_startup_long:
     add rax, rcx
 
     lgdt [rax]
+    mov ax, 0x28
+    ltr ax
 
     mov rax, 0x10
     mov ds, rax
diff --git a/sys/amd64/hw/gdt.c b/sys/amd64/hw/gdt.c
index 1b129aa..f122047 100644
--- a/sys/amd64/hw/gdt.c
+++ b/sys/amd64/hw/gdt.c
@@ -1,5 +1,5 @@
 #include "sys/amd64/hw/gdt.h"
-#define GDT_SIZE    3
+#define GDT_SIZE    7
 
 extern void amd64_gdt_load(void *p);
 
@@ -35,6 +35,10 @@ amd64_gdt_ptr_t *amd64_gdtr_get(int cpu) {
     return &amd64_gdtr[cpu];
 }
 
+amd64_tss_t *amd64_tss_get(int cpu) {
+    return &amd64_tss[cpu];
+}
+
 void amd64_gdt_init(void) {
     for (size_t i = 0; i < AMD64_MAX_SMP; ++i) {
         amd64_gdt_set(i, 0, 0, 0, 0, 0);
@@ -44,14 +48,18 @@ void amd64_gdt_init(void) {
         amd64_gdt_set(i, 2, 0, 0,
                       0,
                       GDT_ACC_PR | GDT_ACC_S | GDT_ACC_RW);
-        //amd64_gdt_set(i, 3, 0, 0,
-        //              0,
-        //              GDT_ACC_PR | GDT_ACC_R3 | GDT_ACC_S | GDT_ACC_RW);
-        //amd64_gdt_set(i, 4, 0, 0,
-        //              GDT_FLG_LONG,
-        //              GDT_ACC_PR | GDT_ACC_R3 | GDT_ACC_S | GDT_ACC_EX);
+        amd64_gdt_set(i, 3, 0, 0,
+                      0,
+                      GDT_ACC_PR | GDT_ACC_R3 | GDT_ACC_S | GDT_ACC_RW);
+        amd64_gdt_set(i, 4, 0, 0,
+                      GDT_FLG_LONG,
+                      GDT_ACC_PR | GDT_ACC_R3 | GDT_ACC_S | GDT_ACC_EX);
+        amd64_gdt_set(i, 5, ((uintptr_t) &amd64_tss[i]) & 0xFFFFFFFF, sizeof(amd64_tss_t) - 1,
+                      GDT_FLG_LONG,
+                      GDT_ACC_PR | GDT_ACC_AC | GDT_ACC_EX);
+        *(uint64_t *) &gdt[i * GDT_SIZE + 6] = ((uintptr_t) &amd64_tss[i]) >> 32;
 
-        amd64_gdtr[i].size = sizeof(GDT_SIZE) * sizeof(amd64_gdt_entry_t) - 1;
+        amd64_gdtr[i].size = GDT_SIZE * sizeof(amd64_gdt_entry_t) - 1;
         amd64_gdtr[i].offset = (uintptr_t) &gdt[GDT_SIZE * i];
     }
 
diff --git a/sys/amd64/hw/gdt_s.S b/sys/amd64/hw/gdt_s.S
index 7cec8c2..e8c030d 100644
--- a/sys/amd64/hw/gdt_s.S
+++ b/sys/amd64/hw/gdt_s.S
@@ -3,4 +3,6 @@
 amd64_gdt_load:
     lgdt (%rdi)
     // Not sure if CS reload is needed
+    movw $0x28, %ax
+    ltr %ax
     retq
diff --git a/sys/amd64/hw/irq0.S b/sys/amd64/hw/irq0.S
index d046e82..a3ed25f 100644
--- a/sys/amd64/hw/irq0.S
+++ b/sys/amd64/hw/irq0.S
@@ -31,6 +31,12 @@ amd64_irq0:
     // rsi = thread structure pointer
     movq get_cpu(0x08), %rsi
     movq 0(%rsi), %rsp
+
+    // Write TSS entry
+    movq get_cpu(0x18), %rdi
+    movq %rsp, %rax
+    addq $(25 * 8), %rax
+    movq %rax, 4(%rdi)
 1:
     // Assume we're now on TASK2's stack
 
diff --git a/sys/amd64/smp/smp.c b/sys/amd64/smp/smp.c
index e10efee..37a8546 100644
--- a/sys/amd64/smp/smp.c
+++ b/sys/amd64/smp/smp.c
@@ -141,6 +141,7 @@ void amd64_smp_add(uint8_t apic_id) {
     cpus[i].self = &cpus[i];
     cpus[i].apic_id = (uint64_t) apic_id;
     cpus[i].processor_id = i;
+    cpus[i].tss = amd64_tss_get(i);
 }
 
 static void amd64_smp_bsp_configure(void) {
@@ -149,6 +150,7 @@ static void amd64_smp_bsp_configure(void) {
     cpus[0].self = &cpus[0];
     cpus[0].processor_id = 0;
     cpus[0].apic_id = 0 /* TODO: apic_id may be different from 0 for BSP */;
+    cpus[0].tss = amd64_tss_get(0);
     set_cpu((uintptr_t) &cpus[0]);
 }
 
diff --git a/sys/amd64/sys/sched.c b/sys/amd64/sys/sched.c
index 04f5d39..9b26629 100644
--- a/sys/amd64/sys/sched.c
+++ b/sys/amd64/sys/sched.c
@@ -16,9 +16,12 @@ static char t_stack3[TEST_STACK * AMD64_MAX_SMP] = {0};
 static struct thread t_idle[AMD64_MAX_SMP] = {0};
 
 void idle_func(uintptr_t id) {
+    int v = 0;
     while (1) {
-        //kdebug("%d\n", id);
-        //asm volatile ("sti; hlt");
+        // Cannot call kernel functions directly - they use privileged insns.
+        *((uint16_t *) 0xFFFFFF00000B8000 + id) = v * 0x700 | ('A' + id);
+        v = !v;
+        for (size_t i = 0; i < 100000000; ++i);
     }
 }
 
@@ -40,8 +43,8 @@ static void make_idle_task(int cpu) {
 
     ctx->rip = (uintptr_t) idle_func;
     ctx->rsp = t->data.stack3_base + t->data.stack3_size;
-    ctx->cs = 0x08;
-    ctx->ss = 0x10;
+    ctx->cs = 0x23;
+    ctx->ss = 0x1B;
     ctx->rflags = 0x248;
 
     ctx->rax = 0;
@@ -65,8 +68,8 @@ static void make_idle_task(int cpu) {
     ctx->r14 = 0;
     ctx->r15 = 0;
 
-    ctx->ds = 0x10;
-    ctx->es = 0x10;
+    ctx->ds = 0x1B;
+    ctx->es = 0x1B;
     ctx->fs = 0;
 
     ctx->__canary = AMD64_STACK_CTX_CANARY;