Merge branch 'feat_inital_context_switching' into 'develop_ba'

Implement Context Switching

See merge request teachos/kernel!6

10 files changed, 291 insertions, 1 deletions

diff --git a/arch/x86_64/src/kernel/cpu/call.cpp b/arch/x86_64/src/kernel/cpu/call.cpp
new file mode 100644
index 0000000..98fa248
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/call.cpp
@@ -0,0 +1,9 @@
+#include "arch/kernel/cpu/call.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto call(far_pointer pointer) -> void
+  {
+    asm volatile("rex64 lcall *%[input]" : /* no output from call */ : [input] "m"(pointer));
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/control_register.cpp b/arch/x86_64/src/kernel/cpu/control_register.cpp
new file mode 100644
index 0000000..41b8cd7
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/control_register.cpp
@@ -0,0 +1,66 @@
+#include "arch/kernel/cpu/control_register.hpp"
+
+#include "arch/exception_handling/panic.hpp"
+
+#include <type_traits>
+
+namespace teachos::arch::kernel::cpu
+{
+  auto read_control_register(control_register cr) -> uint64_t
+  {
+    uint64_t current_value;
+    switch (cr)
+    {
+      case control_register::CR0:
+        asm volatile("mov %%cr0, %[output]" : [output] "=r"(current_value));
+        break;
+      case control_register::CR2:
+        asm volatile("mov %%cr2, %[output]" : [output] "=r"(current_value));
+        break;
+      case control_register::CR3:
+        asm volatile("mov %%cr3, %[output]" : [output] "=r"(current_value));
+        break;
+      case control_register::CR4:
+        asm volatile("mov %%cr4, %[output]" : [output] "=r"(current_value));
+        break;
+    }
+    return current_value;
+  }
+
+  auto write_control_register(control_register cr, uint64_t new_value) -> void
+  {
+    switch (cr)
+    {
+      case control_register::CR0:
+        asm volatile("mov %[input], %%cr0"
+                     : /* no output from call */
+                     : [input] "r"(new_value)
+                     : "memory");
+        break;
+      case control_register::CR2:
+        asm volatile("mov %[input], %%cr2"
+                     : /* no output from call */
+                     : [input] "r"(new_value)
+                     : "memory");
+        break;
+      case control_register::CR3:
+        asm volatile("mov %[input], %%cr3"
+                     : /* no output from call */
+                     : [input] "r"(new_value)
+                     : "memory");
+        break;
+      case control_register::CR4:
+        asm volatile("mov %[input], %%cr4"
+                     : /* no output from call */
+                     : [input] "r"(new_value)
+                     : "memory");
+        break;
+    }
+  }
+
+  auto set_cr0_bit(cr0_flags flag) -> void
+  {
+    auto const cr0 = read_control_register(control_register::CR0);
+    write_control_register(control_register::CR0, static_cast<std::underlying_type<cr0_flags>::type>(flag) | cr0);
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/gdtr.cpp b/arch/x86_64/src/kernel/cpu/gdtr.cpp
new file mode 100644
index 0000000..74a4e1c
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/gdtr.cpp
@@ -0,0 +1,19 @@
+#include "arch/kernel/cpu/gdtr.hpp"
+
+#include "arch/context_switching/segment_descriptor_table/global_descriptor_table_pointer.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto store_global_descriptor_table() -> context_switching::segment_descriptor_table::global_descriptor_table_pointer
+  {
+    context_switching::segment_descriptor_table::global_descriptor_table_pointer current_value{};
+    asm("sgdt %[output]" : [output] "=m"(current_value));
+    return current_value;
+  }
+
+  auto load_global_descriptor_table(
+      context_switching::segment_descriptor_table::global_descriptor_table_pointer const & gdt_pointer) -> void
+  {
+    asm volatile("lgdt %[input]" : /* no output from call */ : [input] "m"(gdt_pointer));
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/idtr.cpp b/arch/x86_64/src/kernel/cpu/idtr.cpp
new file mode 100644
index 0000000..7aa20c1
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/idtr.cpp
@@ -0,0 +1,18 @@
+#include "arch/kernel/cpu/idtr.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto store_interrupt_descriptor_table()
+      -> context_switching::interrupt_descriptor_table::interrupt_descriptor_table_pointer
+  {
+    context_switching::interrupt_descriptor_table::interrupt_descriptor_table_pointer current_value{};
+    asm("sidt %[output]" : [output] "=m"(current_value));
+    return current_value;
+  }
+
+  auto load_interrupt_descriptor_table(
+      context_switching::interrupt_descriptor_table::interrupt_descriptor_table_pointer const & idt_pointer) -> void
+  {
+    asm volatile("lidt %[input]" : /* no output from call */ : [input] "m"(idt_pointer));
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/if.cpp b/arch/x86_64/src/kernel/cpu/if.cpp
new file mode 100644
index 0000000..60a90a3
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/if.cpp
@@ -0,0 +1,7 @@
+namespace teachos::arch::kernel::cpu
+{
+  auto set_interrupt_flag() -> void { asm volatile("sti"); }
+
+  auto clear_interrupt_flag() -> void { asm volatile("cli"); }
+
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/msr.cpp b/arch/x86_64/src/kernel/cpu/msr.cpp
new file mode 100644
index 0000000..9c474a1
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/msr.cpp
@@ -0,0 +1,31 @@
+#include "arch/kernel/cpu/msr.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  namespace
+  {
+    auto constexpr IA32_EFER_ADDRESS = 0xC0000080;
+  }
+
+  auto read_msr(uint32_t msr) -> uint64_t
+  {
+    uint32_t low, high;
+    asm volatile("rdmsr" : "=a"(low), "=d"(high) : "c"(msr));
+    return (static_cast<uint64_t>(high) << 32) | low;
+  }
+
+  auto write_msr(uint32_t msr, uint64_t value) -> void
+  {
+    uint32_t low = value;
+    uint32_t high = value >> 32;
+    asm volatile("wrmsr"
+                 : /* no output from call */
+                 : "c"(msr), "a"(low), "d"(high));
+  }
+
+  auto set_efer_bit(efer_flags flag) -> void
+  {
+    auto const efer = read_msr(IA32_EFER_ADDRESS);
+    write_msr(IA32_EFER_ADDRESS, static_cast<std::underlying_type<efer_flags>::type>(flag) | efer);
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp
new file mode 100644
index 0000000..b08c9c4
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp
@@ -0,0 +1,98 @@
+#include "arch/kernel/cpu/segment_register.hpp"
+
+#include "arch/context_switching/interrupt_descriptor_table/segment_selector.hpp"
+#include "arch/exception_handling/assert.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto reload_data_segment_registers() -> void
+  {
+    asm volatile("xor %%rax, %%rax\n"
+                 "mov %%rax, %%ss\n"
+                 "mov %%rax, %%ds\n"
+                 "mov %%rax, %%es\n"
+                 "mov %%rax, %%fs\n"
+                 "mov %%rax, %%gs\n"
+                 : /* no output from call */
+                 : /* no input to call */
+                 : "rax");
+  }
+
+  auto set_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment) -> void
+  {
+    asm volatile("xor %%rax, %%rax\n"
+                 "mov %[input], %%ax\n"
+                 "mov %%rax, %%ds\n"
+                 "mov %%rax, %%es\n"
+                 "mov %%rax, %%fs\n"
+                 "mov %%rax, %%gs\n"
+                 : /* no output from call */
+                 : [input] "m"(data_segment)
+                 : "rax");
+  }
+
+  auto read_code_segment_register() -> context_switching::interrupt_descriptor_table::segment_selector
+  {
+    context_switching::interrupt_descriptor_table::segment_selector current_value{};
+    asm volatile("mov %%cs, %[output]" : [output] "=r"(current_value));
+    return current_value;
+  }
+
+  auto validate_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment)
+      -> void
+  {
+    context_switching::interrupt_descriptor_table::segment_selector ss{};
+    context_switching::interrupt_descriptor_table::segment_selector ds{};
+    context_switching::interrupt_descriptor_table::segment_selector es{};
+    context_switching::interrupt_descriptor_table::segment_selector fs{};
+    context_switching::interrupt_descriptor_table::segment_selector gs{};
+
+    asm volatile(
+        "mov %%ss, %[ss_output]\n"
+        "mov %%ds, %[ds_output]\n"
+        "mov %%es, %[es_output]\n"
+        "mov %%fs, %[fs_output]\n"
+        "mov %%gs, %[gs_output]\n"
+        : [ss_output] "=r"(ss), [ds_output] "=r"(ds), [es_output] "=r"(es), [fs_output] "=r"(fs), [gs_output] "=r"(gs));
+
+    auto result = (ss == ds && ss == es && ss == fs && ss == gs);
+    exception_handling::assert(result, "[Segment Register] Values in data register are not the same.");
+    result = (ss == data_segment);
+    exception_handling::assert(
+        result, "[Segment Register] Expected Data Segment is not the same as the value in the Stack Segment register.");
+  }
+
+  auto validate_code_segment_register(context_switching::interrupt_descriptor_table::segment_selector code_segment)
+      -> void
+  {
+    auto const cs = read_code_segment_register();
+    exception_handling::assert(
+        cs == code_segment,
+        "[Segment Register] Expected Code Segment is not the same as the value in the Code Segment register.");
+  }
+
+  auto validate_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment,
+                                  context_switching::interrupt_descriptor_table::segment_selector code_segment) -> void
+  {
+    validate_data_segment_registers(data_segment);
+    validate_code_segment_register(code_segment);
+  }
+
+  auto set_code_segment_register(context_switching::interrupt_descriptor_table::segment_selector data_segment,
+                                 context_switching::interrupt_descriptor_table::segment_selector code_segment,
+                                 uint64_t address) -> void
+  {
+    asm volatile("mov %%rsp, %%rax\n"
+                 "push %[data_segment]\n"
+                 "push %%rax\n"
+                 "pushfq\n"
+                 "push %[code_segment]\n"
+                 "mov %[return_function], %%rax\n"
+                 "push %%rax\n"
+                 "iretq\n"
+                 : /* no output from call */
+                 : [data_segment] "m"(data_segment), [code_segment] "m"(code_segment), [return_function] "r"(address)
+                 : "rax");
+  }
+
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/tlb.cpp b/arch/x86_64/src/kernel/cpu/tlb.cpp
new file mode 100644
index 0000000..a09001c
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/tlb.cpp
@@ -0,0 +1,16 @@
+#include "arch/kernel/cpu/tlb.hpp"
+
+#include "arch/kernel/cpu/control_register.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto tlb_flush(memory::paging::virtual_address address) -> void
+  {
+    asm volatile("invlpg (%[input])" : /* no output from call */ : [input] "r"(address) : "memory");
+  }
+
+  auto tlb_flush_all() -> void
+  {
+    write_control_register(cpu::control_register::CR3, read_control_register(cpu::control_register::CR3));
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/cpu/tr.cpp b/arch/x86_64/src/kernel/cpu/tr.cpp
new file mode 100644
index 0000000..a435540
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/tr.cpp
@@ -0,0 +1,16 @@
+#include "arch/kernel/cpu/tr.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto store_task_register() -> uint16_t
+  {
+    uint16_t current_value{};
+    asm("str %[output]" : [output] "=r"(current_value));
+    return current_value;
+  }
+
+  auto load_task_register(uint16_t gdt_offset) -> void
+  {
+    asm volatile("ltr %[input]" : /* no output from call */ : [input] "m"(gdt_offset));
+  }
+}  // namespace teachos::arch::kernel::cpu
diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 472aed5..43b5f90 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -1,9 +1,15 @@
 #include "arch/kernel/main.hpp"
 
+#include "arch/boot/pointers.hpp"
+#include "arch/context_switching/interrupt_descriptor_table/segment_selector.hpp"
+#include "arch/context_switching/main.hpp"
+#include "arch/kernel/cpu/if.hpp"
+#include "arch/kernel/cpu/segment_register.hpp"
 #include "arch/memory/heap/bump_allocator.hpp"
 #include "arch/memory/heap/global_heap_allocator.hpp"
 #include "arch/memory/main.hpp"
 #include "arch/memory/multiboot/reader.hpp"
+#include "arch/stl/vector.hpp"
 #include "arch/video/vga/text.hpp"
 
 namespace teachos::arch::kernel
@@ -55,7 +61,11 @@ namespace teachos::arch::kernel
     // stack_overflow_test(0);
 
     memory::heap::global_heap_allocator::register_heap_allocator(memory::heap::heap_allocator_type::LINKED_LIST);
+    // heap_test();
 
-    heap_test();
+    auto address = memory::heap::global_heap_allocator::kmalloc(8U);
+    (void)address;
+
+    context_switching::switch_to_user_mode();
   }
 }  // namespace teachos::arch::kernel