Commit MD parts of a loosely functional AMD64 port. This is based on

a heavily stripped down FreeBSD/i386 (brutally stripped down actually) to
attempt to get a stable base to start from.  There is a lot missing still.
Worth noting:
- The kernel runs at 1GB in order to cheat with the pmap code.  pmap uses
  a variation of the PAE code in order to avoid having to worry about 4
  levels of page tables yet.
- It boots in 64 bit "long mode" with a tiny trampoline embedded in the
  i386 loader.  This simplifies locore.s greatly.
- There are still quite a few fragments of i386-specific code that have
  not been translated yet, and some that I cheated and wrote dumb C
  versions of (bcopy etc).
- It has both int 0x80 for syscalls (but using registers for argument
  passing, as is native on the amd64 ABI), and the 'syscall' instruction
  for syscalls.  int 0x80 preserves all registers, 'syscall' does not.
- I have tried to minimize looking at the NetBSD code, except in a couple
  of places (eg: to find which register they use to replace the trashed
  %rcx register in the syscall instruction).  As a result, there is not a
  lot of similarity.  I did look at NetBSD a few times while debugging to
  get some ideas about what I might have done wrong in my first attempt.

1 files changed, 19 insertions, 33 deletions

diff --git a/sys/amd64/include/asm.h b/sys/amd64/include/asm.h
index 30008a2..8ea4122 100644
--- a/sys/amd64/include/asm.h
+++ b/sys/amd64/include/asm.h
@@ -43,19 +43,9 @@
 #include <sys/cdefs.h>
 
 #ifdef PIC
-#define	PIC_PROLOGUE	\
-	pushl	%ebx;	\
-	call	1f;	\
-1:			\
-	popl	%ebx;	\
-	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b],%ebx
-#define	PIC_EPILOGUE	\
-	popl	%ebx
 #define	PIC_PLT(x)	x@PLT
-#define	PIC_GOT(x)	x@GOT(%ebx)
+#define	PIC_GOT(x)	x@GOTPCREL(%rip)
 #else
-#define	PIC_PROLOGUE
-#define	PIC_EPILOGUE
 #define	PIC_PLT(x)	x
 #define	PIC_GOT(x)	x
 #endif
@@ -78,14 +68,14 @@
 
 #ifdef PROF
 #define	ALTENTRY(x)	_ENTRY(x); \
-			pushl %ebp; movl %esp,%ebp; \
+			pushl %rbp; movl %rsp,%rbp; \
 			call PIC_PLT(HIDENAME(mcount)); \
-			popl %ebp; \
+			popl %rbp; \
 			jmp 9f
 #define	ENTRY(x)	_ENTRY(x); \
-			pushl %ebp; movl %esp,%ebp; \
+			pushl %rbp; movl %rsp,%rbp; \
 			call PIC_PLT(HIDENAME(mcount)); \
-			popl %ebp; \
+			popl %rbp; \
 			9:
 #else
 #define	ALTENTRY(x)	_ENTRY(x)
@@ -117,42 +107,38 @@
 #define	ARCH_DISPATCH(x) \
 			_START_ENTRY; \
 			.globl CNAME(x); .type CNAME(x),@function; CNAME(x): ; \
-			PIC_PROLOGUE; \
-			movl PIC_GOT(AVECNAME(x)),%eax; \
-			PIC_EPILOGUE; \
-			jmpl *(%eax)
+			movq PIC_GOT(AVECNAME(x)),%rax; \
+			jmpq *(%rax)
 
 #define	ARCH_SELECT(x)	_START_ENTRY; \
 			.type ASELNAME(x),@function; \
 			ASELNAME(x): \
-			PIC_PROLOGUE; \
 			call PIC_PLT(CNAME(__get_hw_float)); \
-			testl %eax,%eax; \
-			movl PIC_GOT(ANAME(x)),%eax; \
+			testq %rax,%rax; \
+			movq PIC_GOT(ANAME(x)),%rax; \
 			jne 8f; \
-			movl PIC_GOT(GNAME(x)),%eax; \
+			movq PIC_GOT(GNAME(x)),%rax; \
 			8: \
-			movl PIC_GOT(AVECNAME(x)),%edx; \
-			movl %eax,(%edx); \
-			PIC_EPILOGUE; \
-			jmpl *%eax
+			movq PIC_GOT(AVECNAME(x)),%rdx; \
+			movq %rax,(%rdx); \
+			jmpq *%rax
 #else /* !PIC */
 #define	ARCH_DISPATCH(x) \
 			_START_ENTRY; \
 			.globl CNAME(x); .type CNAME(x),@function; CNAME(x): ; \
-			jmpl *AVECNAME(x)
+			jmpw *AVECNAME(x)
 
 #define	ARCH_SELECT(x)	_START_ENTRY; \
 			.type ASELNAME(x),@function; \
 			ASELNAME(x): \
 			call CNAME(__get_hw_float); \
-			testl %eax,%eax; \
-			movl $ANAME(x),%eax; \
+			testw %rax,%rax; \
+			movw $ANAME(x),%rax; \
 			jne 8f; \
-			movl $GNAME(x),%eax; \
+			movw $GNAME(x),%rax; \
 			8: \
-			movl %eax,AVECNAME(x); \
-			jmpl *%eax
+			movw %rax,AVECNAME(x); \
+			jmpw *%rax
 #endif /* PIC */
 
 #define	ARCH_VECTOR(x)	.data; .p2align 2; \