Fix almost ten-years old bug in siglongjmp(), which would not restore a signal

mask of zero (because of flawed logic assuming finding zero in the sigjmp_buf
signal mask means sigsetjmp was invoked with a zero `savemask' argument).

While there, clean comments of all *{set,long}jmp routines, and shave a few
instructions by using bcnd insead of cmp + bb to test for zero values.

Passes the regress tests, and now devel/libsigsegv configure siglongjmp test
will not spin (this test is however flawed as it expects a signal handler
declared as running on the sigaltstack and `returning' through siglongjmp to
be invoked on the signal stack the next time the signal is raised).

3 files changed, 57 insertions, 87 deletions

diff --git a/lib/libc/arch/m88k/gen/_setjmp.S b/lib/libc/arch/m88k/gen/_setjmp.S
index 616d0da9d9c..4e74b39fcb3 100644
--- a/lib/libc/arch/m88k/gen/_setjmp.S
+++ b/lib/libc/arch/m88k/gen/_setjmp.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: _setjmp.S,v 1.8 2005/08/07 16:40:14 espie Exp $ */
+/* $OpenBSD: _setjmp.S,v 1.9 2012/08/12 17:14:39 miod Exp $ */
 /*-
  * Copyright (c) 2002 Steve Murphree, Jr.
  * All rights reserved.
@@ -35,26 +35,20 @@
  * C library -- _setjmp, _longjmp
  *
  *	_longjmp(a,v)
- * will generate a "return(v)" from
- * the last call to
+ * will generate a "return(v)" from the last call to
  *	_setjmp(a)
- * by restoring registers from the stack,
- * The previous signal state is NOT saved
- * or restored.
+ * by restoring registers from the stack.  The previous signal state is
+ * neither saved nor restored.
  *
- * For m88k, we define our jmp_buf length
- * to be the size of 21 longs.  <machine/setjmp.h>
- * The buffer's usage is as follows:
+ * For m88k, we define our jmp_buf length to be the size of 21 (_JBLEN) longs.
+ * The buffer layout is as follows:
  *
  * jmp_buf[0]		return address
- * jmp_buf[1]		signal set (if used)
+ * jmp_buf[1]		unused
  * jmp_buf[2 to 19]	r14 to r31
  * jmp_buf[20]		setjmp type
- *
  */
 
-#include <machine/setjmp.h>
-
 #define	U_SETJMP_SIG	0x1764
 
 /*
@@ -62,7 +56,6 @@ int _setjmp(jmp_buf env);
  */
 ENTRY(_setjmp)
 	st	r1, r2,0	/* save registers to the environment buffer */
-	st	r0, r2,4	/* no signal set */
 	st	r14,r2,8
 	st	r15,r2,12
 	st	r16,r2,16
@@ -81,18 +74,16 @@ ENTRY(_setjmp)
 	st	r29,r2,68
 	st	r30,r2,72
 	st	r31,r2,76
-	or	r4,r0,0		/* clear r4 */
-	or	r4,r0,U_SETJMP_SIG	/* r4 now contains setjmp type */
-	st	r4,r2,80	/* setjmp type to _setjmp */
-	jmp.n	r1		/* return 0 */
-	 or	r2,r0,0
-		
+	or	r4,r0,U_SETJMP_SIG	/* setjmp type to _setjmp */
+	st	r4,r2,80
+	jmp.n	r1
+	 or	r2,r0,0		/* return 0 */
+
 /*
 void _longjmp(jmp_buf env, int val);
  */
 ENTRY(_longjmp)
-	cmp	r4,r2,r0	/* check for bad environment buffer address. */
-	bb1	eq,r4,2f	/* if == 0, abort. */
+	bcnd	eq0,r2,2f	/* check for bad environment buffer address. */
 	ld	r4,r2,80	/* check setjmp type. */
 	cmp	r4,r4,U_SETJMP_SIG	/* should be U_SETJMP_SIG */
 	bb1	ne,r4,2f	/* if != U_SETJMP_SIG, abort. */
diff --git a/lib/libc/arch/m88k/gen/setjmp.S b/lib/libc/arch/m88k/gen/setjmp.S
index 76bd978ddba..e5f145f57de 100644
--- a/lib/libc/arch/m88k/gen/setjmp.S
+++ b/lib/libc/arch/m88k/gen/setjmp.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: setjmp.S,v 1.9 2005/08/07 16:40:14 espie Exp $ */
+/* $OpenBSD: setjmp.S,v 1.10 2012/08/12 17:14:39 miod Exp $ */
 /*-
  * Copyright (c) 2002 Steve Murphree, Jr.
  * All rights reserved.
@@ -35,25 +35,19 @@
  * C library -- setjmp, longjmp
  *
  *	longjmp(a,v)
- * will generate a "return(v)" from
- * the last call to
+ * will generate a "return(v)" from the last call to
  *	setjmp(a)
- * by restoring registers from the stack,
- * and a struct sigcontext, see <signal.h>
+ * by restoring registers from the stack, as well as the signal mask.
  *
- * For m88k, we define our jmp_buf length
- * to be the size of 21 longs.  <machine/setjmp.h>
- * The buffer's usage is as follows:
+ * For m88k, we define our jmp_buf length to be the size of 21 (_JBLEN) longs.
+ * The buffer layout is as follows:
  *
  * jmp_buf[0]		return address
- * jmp_buf[1]		signal set (if used)
+ * jmp_buf[1]		signal set
  * jmp_buf[2 to 19]	r14 to r31
  * jmp_buf[20]		setjmp type
- *
  */
 
-#include <machine/setjmp.h>
-
 #define	SETJMP_SIG	0x5824
 
 /*
@@ -79,16 +73,13 @@ ENTRY(setjmp)
 	st	r29,r2,68
 	st	r30,r2,72
 	st	r31,r2,76
-	or	r4,r0,0		/* clear r4 */
 	or	r4,r0,SETJMP_SIG	/* r4 now contains setjmp type */
 	st	r4,r2,80	/* setjmp type to _setjmp */
-	or	r15,r1,0	/* store return address in r15 */
 	or	r14,r2,0	/* store address of env in r14 */
 	bsr.n	_C_LABEL(sigblock) /* r2 = sigblock(0) */
 	 or	r2,r0,0
-	or	r1,r15,0
 	st	r2,r14,4	/* save signal set in offset 4 of env */
-	ld	r15,r14,12
+	ld	r1,r14,0
 	ld	r14,r14,8
 	jmp.n	r1		/* return 0 */
 	 or	r2,r0,0
@@ -97,13 +88,11 @@ ENTRY(setjmp)
 void longjmp(jmp_buf env, int retval);
  */
 ENTRY(longjmp)
-	cmp	r4,r2,r0	/* check for bad environment buffer address. */
-	bb1	eq,r4,2f	/* if == 0, abort. */
+	bcnd	eq0,r2,2f	/* check for bad environment buffer address. */
 	ld	r4,r2,80	/* check setjmp type. */
 	cmp	r4,r4,SETJMP_SIG	/* should be SETJMP_SIG */
 	bb1	ne,r4,2f	/* if != SETJMP_SIG, abort. */
 	
-	subu	r31,r31,16	/* get a temporary stack */
 	ld	r14,r2,8	/* restore registers from the environment buffer */
 	ld	r15,r2,12
 	ld	r16,r2,16
@@ -120,13 +109,15 @@ ENTRY(longjmp)
 	ld	r27,r2,60
 	ld	r28,r2,64
 	ld	r29,r2,68
-	
+	ld	r30,r2,72
+	ld	r31,r2,76
+
+	subu	r31,r31,16	/* get a temporary stack */
 	st.d	r2,r31,0	/* save r2 and r3 on stack (env + return val) */
 	bsr.n	_C_LABEL(sigsetmask) /* restore the signal set */
 	 ld	r2,r2,4
 	ld.d	r2,r31,0	/* restore r2 and r3 */
-	ld	r30,r2,72	/* restore r30 */
-	ld	r31,r2,76	/* restore r31 (sp)*/
+	addu	r31,r31,16
 	ld	r1,r2,0		/* restore r1 */
 	bcnd.n	ne0,r3,1f
 	 or	r2,r3,r0
diff --git a/lib/libc/arch/m88k/gen/sigsetjmp.S b/lib/libc/arch/m88k/gen/sigsetjmp.S
index 93a3b9d8dbb..019e149a905 100644
--- a/lib/libc/arch/m88k/gen/sigsetjmp.S
+++ b/lib/libc/arch/m88k/gen/sigsetjmp.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: sigsetjmp.S,v 1.10 2005/08/07 16:40:14 espie Exp $ */
+/* $OpenBSD: sigsetjmp.S,v 1.11 2012/08/12 17:14:39 miod Exp $ */
 /*-
  * Copyright (c) 2002 Steve Murphree, Jr.
  * All rights reserved.
@@ -35,29 +35,25 @@
  * C library -- sigsetjmp, siglongjmp
  *
  *	siglongjmp(a,v)
- * will generate a "return(v)" from
- * the last call to
- *	sigsetjmp(a,m)
- * by restoring registers from the stack,
- * The previous signal state is restored if 'm' was non-zero.
+ * will generate a "return(v)" from the last call to
+ *	sigsetjmp(a,savemask)
+ * by restoring registers from the stack, as well as the signal mask if the
+ * `savemask' parameter was non-zero.
  *
- * For m88k, we define our jmp_buf length
- * to be the size of 21 longs.  <machine/setjmp.h>
- * The buffer's usage is as follows:
- *
- * jmp_buf[0]		return address
- * jmp_buf[1]		signal set (if used)
- * jmp_buf[2 to 19]	r14 to r31
- * jmp_buf[20]		setjmp type
+ * For m88k, we define our sigjmp_buf length to be the size of 22 (_JBLEN + 1)
+ * longs.  The buffer layout is as follows:
  *
+ * sigjmp_buf[0]		return address
+ * sigjmp_buf[1]		signal set (if used)
+ * sigjmp_buf[2 to 19]		r14 to r31
+ * sigjmp_buf[20]		setjmp type
+ * sigjmp_buf[21]		value of `savemask' parameter
  */
 
-#include <machine/setjmp.h>
-
 #define	SIGSETJMP_SIG	0x582e
 
 /*
-int sigsetjmp(jmp_buf env, int savemask);
+int sigsetjmp(sigjmp_buf env, int savemask);
  */
 ENTRY(sigsetjmp)
 	st	r1, r2,0	/* save registers to the environment buffer */
@@ -79,25 +75,17 @@ ENTRY(sigsetjmp)
 	st	r29,r2,68
 	st	r30,r2,72
 	st	r31,r2,76
-	or	r4,r0,0		/* clear r4 */
 	or	r4,r0,SIGSETJMP_SIG	/* r4 now contains setjmp type */
 	st	r4,r2,80	/* setjmp type to _setjmp */
-	
-	or	r15,r1,0	/* store return address in r15 */
+	bcnd.n	eq0,r3,1f	/* skip signal stuff if savemask == 0 */
+	 st	r3,r2,84	/* save `savemask' value */
 	or	r14,r2,0	/* store address of env in r14 */
-	or	r13,r3,0	/* store savemask in r13 */
-	
-	cmp	r11,r13,r0	/* see if sigmask == 0 */
-	bb1.n	eq,r11,1f	/* skip sig stuff */
-	 st	r0,r14,4	/* but save 0 set in offset 4 of env first */
-	
 	bsr.n	_C_LABEL(sigblock) /* r2 = sigblock(0) */
 	 or	r2,r0,r0
 	st	r2,r14,4	/* save signal set in offset 4 of env */
-
-1:	or	r1,r15,0
-	ld	r15,r14,12
+	ld	r1,r14,0
 	ld	r14,r14,8
+1:
 	jmp.n	r1		/* return 0 */
 	 or	r2,r0,0
 
@@ -105,13 +93,11 @@ ENTRY(sigsetjmp)
 void siglongjmp(sigjmp_buf env, int val);
  */
 ENTRY(siglongjmp)
-	cmp	r4,r2,r0	/* check for bad environment buffer address. */
-	bb1	eq,r4,3f	/* if == 0, abort. */
+	bcnd	eq0,r2,2f	/* check for bad environment buffer address. */
 	ld	r4,r2,80	/* check setjmp type. */
 	cmp	r4,r4,SIGSETJMP_SIG	/* should be SIGSETJMP_SIG */
-	bb1	ne,r4,3f	/* if != SIGSETJMP_SIG, abort. */
+	bb1	ne,r4,2f	/* if != SIGSETJMP_SIG, abort. */
 	
-	subu	r31,r31,16	/* get a temporary stack */
 	ld	r14,r2,8	/* restore registers from the environment buffer */
 	ld	r15,r2,12
 	ld	r16,r2,16
@@ -128,22 +114,24 @@ ENTRY(siglongjmp)
 	ld	r27,r2,60
 	ld	r28,r2,64
 	ld	r29,r2,68
-	
-	ld	r4,r2,4		/* get the signal set from env */
-	cmp	r4,r4,r0	/* if r2 == 0 then skip signal stuff */
-	bb1	eq,r4,1f
+	ld	r30,r2,72
+	ld	r4,r2,84	/* get `savemask' value */
+	bcnd.n	eq0,r4,1f
+	 ld	r31,r2,76
 
+	subu	r31,r31,16	/* get a temporary stack */
 	st.d	r2,r31,0	/* save r2 and r3 on stack (env + return val) */
 	bsr.n	_C_LABEL(sigsetmask) /* restore the signal set */
 	 ld	r2,r2,4
 	ld.d	r2,r31,0	/* restore r2 and r3 from stack */
-1:	ld	r30,r2,72	/* restore r30 */
-	ld	r31,r2,76	/* restore r31 (sp)*/
-	ld	r1,r2,0		/* restore r1 */
-	bcnd.n	ne0,r3,3f
+	addu	r31,r31,16
+1:
+	bcnd.n	ne0,r3,1f
+	 ld	r1,r2,0		/* restore r1 */
+	or	r3,r0,1		/* never return zero! */
+1:
+	jmp.n	r1
 	 or	r2,r3,r0
-	or	r2,r0,1		/* never return zero! */
-3:	jmp	r1
 
 2:	subu	r31,r31,16	/* get a temporary stack */
 	st	r1,r31,0	/* save r1 on stack (return address) */