Kernel/LibC: Use builtin functions over inline asm

Getting flags and saving/restoring sse state and reading TSC can be done
using compiler builtins

kernel/include/kernel/Processor.h

@@ -82,8 +82,11 @@ namespace Kernel
 
 		static InterruptState get_interrupt_state()
 		{
-			uintptr_t flags;
+#if ARCH(x86_64)
-			asm volatile("pushf; pop %0" : "=rm"(flags));
+			const auto flags = __builtin_ia32_readeflags_u64();
+#elif ARCH(i686)
+			const auto flags = __builtin_ia32_readeflags_u32();
+#endif
 			if (flags & (1 << 9))
 				return InterruptState::Enabled;
 			return InterruptState::Disabled;

kernel/kernel/Processor.cpp

@@ -304,29 +304,15 @@ namespace Kernel
 
 	void Processor::update_tsc()
 	{
-		const auto read_tsc =
-			[]() -> uint64_t {
-				uint32_t high, low;
-				asm volatile("lfence; rdtsc" : "=d"(high), "=a"(low));
-				return (static_cast<uint64_t>(high) << 32) | low;
-			};
-
 		auto& sgettime = shared_page().cpus[current_index()].gettime_local;
 		sgettime.seq = sgettime.seq + 1;
 		sgettime.last_ns = SystemTimer::get().ns_since_boot_no_tsc();
-		sgettime.last_tsc = read_tsc();
+		sgettime.last_tsc = __builtin_ia32_rdtsc();
 		sgettime.seq = sgettime.seq + 1;
 	}
 
 	uint64_t Processor::ns_since_boot_tsc()
 	{
-		const auto read_tsc =
-			[]() -> uint64_t {
-				uint32_t high, low;
-				asm volatile("lfence; rdtsc" : "=d"(high), "=a"(low));
-				return (static_cast<uint64_t>(high) << 32) | low;
-			};
-
 		const auto& shared_page = Processor::shared_page();
 		const auto& sgettime = shared_page.gettime_shared;
 		const auto& lgettime = shared_page.cpus[current_index()].gettime_local;
@@ -334,7 +320,7 @@ namespace Kernel
 		auto state = get_interrupt_state();
 		set_interrupt_state(InterruptState::Disabled);
 
-		const auto current_ns = lgettime.last_ns + (((read_tsc() - lgettime.last_tsc) * sgettime.mult) >> sgettime.shift);
+		const auto current_ns = lgettime.last_ns + (((__builtin_ia32_rdtsc() - lgettime.last_tsc) * sgettime.mult) >> sgettime.shift);
 
 		set_interrupt_state(state);
 

kernel/kernel/Thread.cpp

@@ -908,9 +908,9 @@ namespace Kernel
 	void Thread::save_sse()
 	{
 #if ARCH(x86_64)
-		asm volatile("fxsave64 %0" :: "m"(m_sse_storage));
+		__builtin_ia32_fxsave64(m_sse_storage);
 #elif ARCH(i686)
-		asm volatile("fxsave %0" :: "m"(m_sse_storage));
+		__builtin_ia32_fxsave(m_sse_storage);
 #else
 #error
 #endif
@@ -919,9 +919,9 @@ namespace Kernel
 	void Thread::load_sse()
 	{
 #if ARCH(x86_64)
-		asm volatile("fxrstor64 %0" :: "m"(m_sse_storage));
+		__builtin_ia32_fxrstor64(m_sse_storage);
 #elif ARCH(i686)
-		asm volatile("fxrstor %0" :: "m"(m_sse_storage));
+		__builtin_ia32_fxrstor(m_sse_storage);
 #else
 #error
 #endif

kernel/kernel/Timer/Timer.cpp

@@ -80,13 +80,6 @@ namespace Kernel
 	{
 		// take 5x 50 ms samples and use the median value
 
-		const auto read_tsc =
-			[]() -> uint64_t {
-				uint32_t high, low;
-				asm volatile("lfence; rdtsc" : "=d"(high), "=a"(low));
-				return (static_cast<uint64_t>(high) << 32) | low;
-			};
-
 		constexpr size_t tsc_sample_count = 5;
 		constexpr size_t tsc_sample_ns = 50'000'000;
 
@@ -95,10 +88,10 @@ namespace Kernel
 		{
 			const auto start_ns = m_timer->ns_since_boot();
 
-			const auto start_tsc = read_tsc();
+			const auto start_tsc = __builtin_ia32_rdtsc();
 			while (m_timer->ns_since_boot() < start_ns + tsc_sample_ns)
 				Processor::pause();
-			const auto stop_tsc = read_tsc();
+			const auto stop_tsc = __builtin_ia32_rdtsc();
 
 			const auto stop_ns = m_timer->ns_since_boot();
 

userspace/libraries/LibC/time.cpp

@@ -38,13 +38,6 @@ int clock_gettime(clockid_t clock_id, struct timespec* tp)
 			return cpu;
 		};
 
-	const auto read_tsc =
-		[]() -> uint64_t {
-			uint32_t high, low;
-			asm volatile("lfence; rdtsc" : "=d"(high), "=a"(low));
-			return (static_cast<uint64_t>(high) << 32) | low;
-		};
-
 	for (;;)
 	{
 		const auto cpu = get_cpu();
@@ -56,7 +49,7 @@ int clock_gettime(clockid_t clock_id, struct timespec* tp)
 		if (old_seq & 1)
 			continue;
 
-		const auto monotonic_ns = lgettime.last_ns + (((read_tsc() - lgettime.last_tsc) * sgettime.mult) >> sgettime.shift);
+		const auto monotonic_ns = lgettime.last_ns + (((__builtin_ia32_rdtsc() - lgettime.last_tsc) * sgettime.mult) >> sgettime.shift);
 
 		if (old_seq != lgettime.seq || cpu != get_cpu())
 			continue;