svn commit: r305865 - in head/sys: amd64/amd64 x86/include

[Bruce Evans]

Author: bde
Date: Fri Sep 16 07:09:35 2016
New Revision: 305865
URL: https://svnweb.freebsd.org/changeset/base/305865

Log:
  Fix decoding of tf_rsp on amd64, and move TF_HAS_STACKREGS() to the
  i386-only section, and fix a comment about the amd64 kernel trapframe
  not having stackregs.
  
  tf_rsp doesn't need decoding on amd64, but had an old clone of i386
  code to do this in 1 place, and since the amd64 kernel trapframe does
  have stackregs, the result was an off-by-16 error for %rsp in an error
  message.

Modified:
  head/sys/amd64/amd64/trap.c
  head/sys/x86/include/frame.h

Modified: head/sys/amd64/amd64/trap.c
==============================================================================
--- head/sys/amd64/amd64/trap.c	Fri Sep 16 06:31:10 2016	(r305864)
+++ head/sys/amd64/amd64/trap.c	Fri Sep 16 07:09:35 2016	(r305865)
@@ -776,7 +776,6 @@ trap_fatal(frame, eva)
 {
 	int code, ss;
 	u_int type;
-	long esp;
 	struct soft_segment_descriptor softseg;
 	char *msg;
 
@@ -807,14 +806,8 @@ trap_fatal(frame, eva)
 	}
 	printf("instruction pointer	= 0x%lx:0x%lx\n",
 	       frame->tf_cs & 0xffff, frame->tf_rip);
-	if (TF_HAS_STACKREGS(frame)) {
-		ss = frame->tf_ss & 0xffff;
-		esp = frame->tf_rsp;
-	} else {
-		ss = GSEL(GDATA_SEL, SEL_KPL);
-		esp = (long)&frame->tf_rsp;
-	}
-	printf("stack pointer	        = 0x%x:0x%lx\n", ss, esp);
+	ss = frame->tf_ss & 0xffff;
+	printf("stack pointer	        = 0x%x:0x%lx\n", ss, frame->tf_rsp);
 	printf("frame pointer	        = 0x%x:0x%lx\n", ss, frame->tf_rbp);
 	printf("code segment		= base 0x%lx, limit 0x%lx, type 0x%x\n",
 	       softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);

Modified: head/sys/x86/include/frame.h
==============================================================================
--- head/sys/x86/include/frame.h	Fri Sep 16 06:31:10 2016	(r305864)
+++ head/sys/x86/include/frame.h	Fri Sep 16 07:09:35 2016	(r305865)
@@ -98,6 +98,15 @@ struct trapframe_vm86 {
 	int	tf_vm86_fs;
 	int	tf_vm86_gs;
 };
+
+/*
+ * This alias for the MI TRAPF_USERMODE() should be used when we don't
+ * care about user mode itself, but need to know if a frame has stack
+ * registers.  The difference is only logical, but on i386 the logic
+ * for using TRAPF_USERMODE() is complicated by sometimes treating vm86
+ * bioscall mode (which is a special ring 3 user mode) as kernel mode.
+ */
+#define	TF_HAS_STACKREGS(tf)	TRAPF_USERMODE(tf)
 #endif /* __i386__ */
 
 #ifdef __amd64__
@@ -136,7 +145,7 @@ struct trapframe {
 	register_t	tf_rip;
 	register_t	tf_cs;
 	register_t	tf_rflags;
-	/* below only when crossing rings (user to kernel) */
+	/* the amd64 frame always has the stack registers */
 	register_t	tf_rsp;
 	register_t	tf_ss;
 };
@@ -146,13 +155,4 @@ struct trapframe {
 #define	TF_HASFPXSTATE	0x4
 #endif /* __amd64__ */
 
-/*
- * This alias for the MI TRAPF_USERMODE() should be used when we don't
- * care about user mode itself, but need to know if a frame has stack
- * registers.  The difference is only logical, but on i386 the logic
- * for using TRAPF_USERMODE() is complicated by sometimes treating vm86
- * bioscall mode (which is a special ring 3 user mode) as kernel mode.
- */
-#define	TF_HAS_STACKREGS(tf)	TRAPF_USERMODE(tf)
-
 #endif /* _MACHINE_FRAME_H_ */