Kernel/LibC: add flag to enable/disable sse support

SSE support is very experimental and causes GP. I decided to make
SSE not default until I get to fixing it :)

CMakeLists.txt

@@ -20,6 +20,9 @@ if(NOT EXISTS ${CMAKE_CXX_COMPILER})
 	set(CMAKE_CXX_COMPILER g++)
 endif()
 
+add_compile_options(-mno-sse -mno-sse2)
+add_compile_definitions(__enable_sse=0)
+
 project(banan-os CXX)
 
 set(BANAN_BASE_SYSROOT ${CMAKE_SOURCE_DIR}/base-sysroot.tar.gz)

kernel/arch/x86_64/IDT.cpp

@@ -139,10 +139,11 @@ namespace IDT
 
 	extern "C" void cpp_isr_handler(uint64_t isr, uint64_t error, Kernel::InterruptStack& interrupt_stack, const Registers* regs)
 	{
+#if __enable_sse
 		bool from_userspace = (interrupt_stack.cs & 0b11) == 0b11;
-
 		if (from_userspace)
 			Kernel::Thread::current().save_sse();
+#endif
 
 		pid_t tid = Kernel::Scheduler::current_tid();
 		pid_t pid = tid ? Kernel::Process::current().pid() : 0;
@@ -205,19 +206,22 @@ namespace IDT
 
 		ASSERT(Kernel::Thread::current().state() != Kernel::Thread::State::Terminated);
 
+#if __enable_sse
 		if (from_userspace)
 		{
 			ASSERT(Kernel::Thread::current().state() == Kernel::Thread::State::Executing);
 			Kernel::Thread::current().load_sse();
 		}
+#endif
 	}
 
 	extern "C" void cpp_irq_handler(uint64_t irq, Kernel::InterruptStack& interrupt_stack)
 	{
+#if __enable_sse
 		bool from_userspace = (interrupt_stack.cs & 0b11) == 0b11;
-
 		if (from_userspace)
 			Kernel::Thread::current().save_sse();
+#endif
 
 		if (Kernel::Scheduler::current_tid())
 		{
@@ -240,11 +244,13 @@ namespace IDT
 
 		ASSERT(Kernel::Thread::current().state() != Kernel::Thread::State::Terminated);
 
+#if __enable_sse
 		if (from_userspace)
 		{
 			ASSERT(Kernel::Thread::current().state() == Kernel::Thread::State::Executing);
 			Kernel::Thread::current().load_sse();
 		}
+#endif
 	}
 
 	static void flush_idt()

kernel/include/kernel/Thread.h

@@ -82,8 +82,10 @@ namespace Kernel
 
 		bool is_userspace() const { return m_is_userspace; }
 
+#if __enable_sse
 		void save_sse() { asm volatile("fxsave %0" :: "m"(m_sse_storage)); }
 		void load_sse() { asm volatile("fxrstor %0" :: "m"(m_sse_storage)); }
+#endif
 
 	private:
 		Thread(pid_t tid, Process*);
@@ -114,7 +116,9 @@ namespace Kernel
 
 		uint64_t m_terminate_blockers { 0 };
 
+#if __enable_sse
 		alignas(16) uint8_t m_sse_storage[512] {};
+#endif
 
 		friend class Scheduler;
 	};

kernel/kernel/Syscall.cpp

@@ -32,7 +32,9 @@ namespace Kernel
 			return 0;
 		}
 
+#if __enable_sse
 		Thread::current().save_sse();
+#endif
 
 		asm volatile("sti");
 
@@ -205,7 +207,10 @@ namespace Kernel
 			Kernel::panic("Kernel error while returning to userspace {}", ret.error());
 
 		ASSERT(Kernel::Thread::current().state() == Kernel::Thread::State::Executing);
+
+#if __enable_sse
 		Thread::current().load_sse();
+#endif
 
 		if (ret.is_error())
 			return -ret.error().get_error_code();

libc/printf_impl.cpp

@@ -104,6 +104,7 @@ static void integer_to_string(char* buffer, T value, int base, bool upper, forma
 	buffer[offset++] = '\0';
 }
 
+#if __enable_sse
 template<BAN::floating_point T>
 static void floating_point_to_string(char* buffer, T value, bool upper, const format_options_t options)
 {
@@ -227,6 +228,7 @@ static void floating_point_to_exponent_string(char* buffer, T value, bool upper,
 	exponent_options.width = 3;
 	integer_to_string<int>(buffer + offset, exponent, 10, upper, exponent_options);
 }
+#endif
 
 extern "C" int printf_impl(const char* format, va_list arguments, int (*putc_fun)(int, void*), void* data)
 {
@@ -349,6 +351,7 @@ extern "C" int printf_impl(const char* format, va_list arguments, int (*putc_fun
 				format++;
 				break;
 			}
+#if __enable_sse
 			case 'e':
 			case 'E':
 			{
@@ -367,6 +370,7 @@ extern "C" int printf_impl(const char* format, va_list arguments, int (*putc_fun
 				format++;
 				break;
 			}
+#endif
 			case 'g':
 			case 'G':
 				// TODO