Subject: port-sparc/2180: _{set,long}jmp(3) assumes 8-byte alignment
To: None <gnats-bugs@NetBSD.ORG>
From: Michael Eriksson T/N <Michael.Eriksson@era-t.ericsson.se>
List: netbsd-bugs
Date: 03/06/1996 11:54:16
>Number:         2180
>Category:       port-sparc
>Synopsis:       _{set,long}jmp(3) assumes 8-byte alignment
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar  6 06:20:07 1996
>Last-Modified:
>Originator:     Michael Eriksson T/N
>Organization:
>Release:        1.1
>Environment:

System: NetBSD abro 1.1 NetBSD 1.1 (MAVERICK) #0: Tue Dec 19 08:52:19 MET 1995 eramer@abro:/usr/src/sys/arch/sparc/compile/MAVERICK sparc

Sun IPX running vanilla NetBSD 1.1.

>Description:

_setjmp(3) and _longjmp(3) use machine instructions std and ldd,
respectively, which assume that the jmp_buf is 8-byte aligned.

>How-To-Repeat:

Run the program below, and watch it crash with SIGBUS.

#include <setjmp.h>

struct {
  int i;
  jmp_buf env;
} foo;

main()
{
  _setjmp(foo.env);
}

>Fix:

*** _setjmp.S.orig	Sat Oct 14 01:44:06 1995
--- _setjmp.S	Wed Mar  6 10:12:19 1996
***************
*** 56,63 ****
  #include "DEFS.h"
  
  ENTRY(_setjmp)
! 	std	%sp, [%o0+0]	/* caller's stack pointer and return pc */
! 	st	%fp, [%o0+8]	/* store caller's frame pointer */
  	retl
  	 clr	%o0		! return 0
  
--- 56,64 ----
  #include "DEFS.h"
  
  ENTRY(_setjmp)
! 	st	%sp, [%o0+0]	/* caller's stack pointer */
! 	st	%o7, [%o0+4]	/* ...return pc */
! 	st	%fp, [%o0+8]	/* ...frame pointer */
  	retl
  	 clr	%o0		! return 0
  
***************
*** 73,79 ****
  	bl,a	1b		! if below,
  	 restore		!    pop frame and loop
  	be,a	2f		! if there,
! 	 ldd	[%g1+0], %o2	!    fetch return %sp and pc, and get out
  
  Lbotch:
  	call	_longjmperror	! otherwise, went too far; bomb out
--- 74,80 ----
  	bl,a	1b		! if below,
  	 restore		!    pop frame and loop
  	be,a	2f		! if there,
! 	 ld	[%g1+0], %o2	!    fetch return %sp, and get out
  
  Lbotch:
  	call	_longjmperror	! otherwise, went too far; bomb out
***************
*** 86,90 ****
--- 87,92 ----
  	 mov	%o2, %sp	! it is OK, put it in place
  	b,a	Lbotch
  3:
+ 	ld	[%g1+4], %o3	! fetch pc
  	jmp	%o3 + 8		! success, return %g6
  	 mov	%g6, %o0
>Audit-Trail:
>Unformatted: