Kernel: Save fpu state and flags in signal handler

This was causing some weird crashes :D

kernel/arch/i686/Signal.S

@@ -7,9 +7,6 @@
 
 .global signal_trampoline
 signal_trampoline:
-	pushl %ebp
-	movl %esp, %ebp
-
 	pusha
 
 	movl 40(%esp), %edi
@@ -19,16 +16,22 @@ signal_trampoline:
 	movl %esp, %ebp
 	andl $-16, %esp
 
+	subl $512, %esp
+	fxsave (%esp)
+
 	subl $12, %esp
 	pushl %edi
 	call *%eax
 	addl $16, %esp
 
+	fxrstor (%esp)
+	addl $512, %esp
+
 	// restore stack
 	movl %ebp, %esp
 	popa
 
-	leave
 	addl $8, %esp
+	popf
 
 	ret

kernel/arch/x86_64/Signal.S

@@ -30,8 +30,14 @@ signal_trampoline:
 	movq %rsp, %rbp
 	andq $-16, %rsp
 
+	subq $512, %rsp
+	fxsave64 (%rsp)
+
 	call *%rax
 
+	fxrstor64 (%rsp)
+	addq $512, %rsp
+
 	// restore stack
 	movq %rbp, %rsp
 	popq %r15
@@ -51,6 +57,7 @@ signal_trampoline:
 	popq %rax
 
 	addq $16, %rsp
+	popfq
 
 	// return over red-zone
 	ret $128