svn commit: r205494 - user/jmallett/octeon/lib/libc/mips/sys

[Juli Mallett]

Author: jmallett
Date: Tue Mar 23 00:31:56 2010
New Revision: 205494
URL: http://svn.freebsd.org/changeset/base/205494

Log:
  o) Load the address of cerror into t9 before restoring the gp and sp.  We waste
     the load in the case of no error in exchange for not duplicating the gp and
     sp restore code.
  o) Don't overwrite ra when calling cerror -- jr not jalr.
  
  This makes truss work.
  
  Sponsored by:	Packet Forensics.

Modified:
  user/jmallett/octeon/lib/libc/mips/sys/ptrace.S

Modified: user/jmallett/octeon/lib/libc/mips/sys/ptrace.S
==============================================================================
--- user/jmallett/octeon/lib/libc/mips/sys/ptrace.S	Mon Mar 22 23:33:40 2010	(r205493)
+++ user/jmallett/octeon/lib/libc/mips/sys/ptrace.S	Tue Mar 23 00:31:56 2010	(r205494)
@@ -59,13 +59,13 @@ NESTED_NOPROFILE(ptrace, CALLFRAME_SIZ, 
 	li		v0, SYS_ptrace
 	syscall
 
+	# Load __cerror's address using our gp, then restore it.
+	PTR_LA		t9, __cerror
 	RESTORE_GP64
 	PTR_ADDU	sp, sp, CALLFRAME_SIZ
 
 	bne		a3, zero, 1f
 
 	j		ra
-1:
-	PTR_LA		t9, __cerror
-	jalr		t9
+1:	j		t9
 END(ptrace)