c6x: switch to saner kernel_execve() semantics

ACKed-by: Mark Salter <msalter@redhat.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/c6x/Kconfig

@@ -18,6 +18,7 @@ config C6X
 	select OF_EARLY_FLATTREE
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	select MODULES_USE_ELF_RELA
 
 config MMU

arch/c6x/include/uapi/asm/unistd.h

@@ -14,7 +14,6 @@
  *   more details.
  */
 
-#define __ARCH_WANT_KERNEL_EXECVE
 #define __ARCH_WANT_SYS_EXECVE
 
 /* Use the standard ABI for syscalls. */

arch/c6x/kernel/entry.S

@@ -413,19 +413,9 @@ ENTRY(ret_from_kernel_thread)
 0:
 	B	.S2	B10		   /* call fn */
 	LDW	.D2T1	*+SP(REGS_A1+8),A4 /* get arg */
-	MVKL	.S2	sys_exit,B11
-	MVKH	.S2	sys_exit,B11
-	ADDKPC	.S2	0f,B3,1
-0:
-	BNOP	.S2	B11,5	/* jump to sys_exit */
+	ADDKPC	.S2	ret_from_fork_2,B3,3
 ENDPROC(ret_from_kernel_thread)
 
-ENTRY(ret_from_kernel_execve)
-	GET_THREAD_INFO A12
-	BNOP	.S2	syscall_exit,4
-	ADD	.D2X	A4,-8,SP
-ENDPROC(ret_from_kernel_execve)
-
 	;;
 	;; These are the interrupt handlers, responsible for calling __do_IRQ()
 	;; int6 is used for syscalls (see _system_call entry)