add wip context switch to user mode

1 files changed, 34 insertions, 0 deletions

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..f70c558
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp
@@ -0,0 +1,34 @@
+#include "arch/kernel/cpu/segment_register.hpp"
+
+#include "arch/context_switching/interrupt_descriptor_table/segment_selector.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  [[gnu::naked]]
+  auto reload_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"
+                 "ret");
+  }
+
+  [[gnu::naked]]
+  auto set_segment_registers(context_switching::interrupt_descriptor_table::segment_selector segment_selector) -> void
+  {
+    asm volatile("xor %%rax, %%rax\n"
+                 "mov %[input], %%ax\n"
+                 "mov %%rax, %%ss\n"
+                 "mov %%rax, %%ds\n"
+                 "mov %%rax, %%es\n"
+                 "mov %%rax, %%fs\n"
+                 "mov %%rax, %%gs\n"
+                 "ret"
+                 : /* No output from call */
+                 : [input] "m"(segment_selector));
+  }
+
+}  // namespace teachos::arch::kernel::cpu