svn commit: r259097 - projects/amd64_xen_pv/sys/amd64/xen

[Cherry G. Mathew]

Author: cherry
Date: Sun Dec  8 11:03:29 2013
New Revision: 259097
URL: http://svnweb.freebsd.org/changeset/base/259097

Log:
  - Zero out the MSW of %rsi "just in case".
  - Cleanup ABI translation for syscall -> cpu_fetch_syscall_args()
  
  Approved by: gibbs (implicit)

Modified:
  projects/amd64_xen_pv/sys/amd64/xen/exception.S

Modified: projects/amd64_xen_pv/sys/amd64/xen/exception.S
==============================================================================
--- projects/amd64_xen_pv/sys/amd64/xen/exception.S	Sun Dec  8 09:34:56 2013	(r259096)
+++ projects/amd64_xen_pv/sys/amd64/xen/exception.S	Sun Dec  8 11:03:29 2013	(r259097)
@@ -220,7 +220,7 @@
 	movq	PCPU(CURTHREAD),%rdi ;\
 	movq	%rsp, TD_FRAME(%rdi) ;\
 	movl	TF_RFLAGS(%rsp),%esi ;\
-	andl	$PSL_T,%esi	     ;\
+	andq	$PSL_T, %rsi	     ;\
 	call	amd64_syscall
 
 #define SYSRET \
@@ -564,8 +564,7 @@ IDTVEC(syscall_callback)
 	SAVE_SEGMENT_REGS	;
 	SAVE_GENERAL_REGS	;
 	movq	%r11, TF_RFLAGS(%rsp) ; /* Tweak for INTR_EXIT */
-	movq	%r10, %rcx	; /* Translate to C abi */
-	movq	%rcx, TF_RCX(%rsp) ; /* Cosmetic. XXX: discard */
+	movq	%r10, TF_RCX(%rsp) ; /* Translate to C abi. see trap.c:cpu_fetch_syscall_args() */
 	DO_STI_MAYBE		; /* Clobbers %rdi */
 	movq	TF_RDI(%rsp), %rdi ;
 	CALLSYSCALL		;