Squash commits for public release

kernel/include/platform/x86/fpu/fpu.h

@@ -0,0 +1,51 @@
+#ifndef _KERNEL_PLATFORM_X86_FPU_FPU_H
+#define _KERNEL_PLATFORM_X86_FPU_FPU_H
+
+#include <libkern/types.h>
+#include <platform/x86/registers.h>
+
+#define FPU_STATE_ALIGNMENT (16)
+
+typedef struct {
+    uint8_t buffer[512];
+#ifdef __x86_64__
+    // Space for YMM.
+    uint8_t ext_save_area[256];
+#endif
+} __attribute__((aligned(FPU_STATE_ALIGNMENT))) fpu_state_t;
+
+void fpu_handler();
+void fpu_init();
+void fpu_init_state(fpu_state_t* new_fpu_state);
+
+static inline void fpu_save(fpu_state_t* fpu_state)
+{
+    asm volatile("fxsave %0"
+                 : "=m"(*fpu_state));
+}
+
+static inline void fpu_restore(fpu_state_t* fpu_state)
+{
+    asm volatile("fxrstor %0"
+                 :
+                 : "m"(*fpu_state));
+}
+
+static inline int fpu_is_avail()
+{
+    return (((read_cr0() >> 3) & 0b1) == 0b0);
+}
+
+static inline void fpu_make_avail()
+{
+    asm volatile("clts");
+}
+
+static inline void fpu_make_unavail()
+{
+    // Set TS bit of cr0 to 1.
+    uintptr_t cr0 = read_cr0() | (1 << 3);
+    write_cr0(cr0);
+}
+
+#endif //_KERNEL_PLATFORM_X86_FPU_FPU_H