Remove never implemented sbrk and sstk syscalls

Both system calls were stubs returning EOPNOTSUPP and libc did not
provide _ or __sys_ prefixed symbols.  The actual implementation of
sbrk(2) is on top of the undocumented break(2) system call.

Technically this is a change in ABI, but no non-contrived program ever
called these syscalls.

Reviewed by:	kib, emaste
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D42872

4 files changed, 6 insertions, 50 deletions

diff --git a/sys/compat/freebsd32/freebsd32_syscall.h b/sys/compat/freebsd32/freebsd32_syscall.h
index 3123c3b1f74c..bc824b8e04be 100644
--- a/sys/compat/freebsd32/freebsd32_syscall.h
+++ b/sys/compat/freebsd32/freebsd32_syscall.h
@@ -73,8 +73,8 @@
 #define	FREEBSD32_SYS_vfork	66
 				/* 67 is obsolete vread */
 				/* 68 is obsolete vwrite */
-#define	FREEBSD32_SYS_sbrk	69
-#define	FREEBSD32_SYS_sstk	70
+				/* 69 is obsolete sbrk */
+				/* 70 is obsolete sstk */
 				/* 71 is old freebsd32_mmap */
 #define	FREEBSD32_SYS_freebsd11_vadvise	72
 #define	FREEBSD32_SYS_munmap	73
diff --git a/sys/compat/freebsd32/freebsd32_syscalls.c b/sys/compat/freebsd32/freebsd32_syscalls.c
index e64c36b32d00..3e7656cace72 100644
--- a/sys/compat/freebsd32/freebsd32_syscalls.c
+++ b/sys/compat/freebsd32/freebsd32_syscalls.c
@@ -74,8 +74,8 @@ const char *freebsd32_syscallnames[] = {
 	"vfork",			/* 66 = vfork */
 	"obs_vread",			/* 67 = obsolete vread */
 	"obs_vwrite",			/* 68 = obsolete vwrite */
-	"sbrk",			/* 69 = sbrk */
-	"sstk",			/* 70 = sstk */
+	"obs_sbrk",			/* 69 = obsolete sbrk */
+	"obs_sstk",			/* 70 = obsolete sstk */
 	"compat.freebsd32_mmap",		/* 71 = old freebsd32_mmap */
 	"compat11.vadvise",		/* 72 = freebsd11 vadvise */
 	"munmap",			/* 73 = munmap */
diff --git a/sys/compat/freebsd32/freebsd32_sysent.c b/sys/compat/freebsd32/freebsd32_sysent.c
index 2bb45fc3d2e2..179d83186b41 100644
--- a/sys/compat/freebsd32/freebsd32_sysent.c
+++ b/sys/compat/freebsd32/freebsd32_sysent.c
@@ -130,8 +130,8 @@ struct sysent freebsd32_sysent[] = {
 	{ .sy_narg = 0, .sy_call = (sy_call_t *)sys_vfork, .sy_auevent = AUE_VFORK, .sy_flags = 0, .sy_thrcnt = SY_THR_STATIC },	/* 66 = vfork */
 	{ .sy_narg = 0, .sy_call = (sy_call_t *)nosys, .sy_auevent = AUE_NULL, .sy_flags = 0, .sy_thrcnt = SY_THR_ABSENT },			/* 67 = obsolete vread */
 	{ .sy_narg = 0, .sy_call = (sy_call_t *)nosys, .sy_auevent = AUE_NULL, .sy_flags = 0, .sy_thrcnt = SY_THR_ABSENT },			/* 68 = obsolete vwrite */
-	{ .sy_narg = AS(sbrk_args), .sy_call = (sy_call_t *)sys_sbrk, .sy_auevent = AUE_SBRK, .sy_flags = SYF_CAPENABLED, .sy_thrcnt = SY_THR_STATIC },	/* 69 = sbrk */
-	{ .sy_narg = AS(sstk_args), .sy_call = (sy_call_t *)sys_sstk, .sy_auevent = AUE_SSTK, .sy_flags = SYF_CAPENABLED, .sy_thrcnt = SY_THR_STATIC },	/* 70 = sstk */
+	{ .sy_narg = 0, .sy_call = (sy_call_t *)nosys, .sy_auevent = AUE_NULL, .sy_flags = 0, .sy_thrcnt = SY_THR_ABSENT },			/* 69 = obsolete sbrk */
+	{ .sy_narg = 0, .sy_call = (sy_call_t *)nosys, .sy_auevent = AUE_NULL, .sy_flags = 0, .sy_thrcnt = SY_THR_ABSENT },			/* 70 = obsolete sstk */
 	{ compat(AS(ofreebsd32_mmap_args),freebsd32_mmap), .sy_auevent = AUE_MMAP, .sy_flags = SYF_CAPENABLED, .sy_thrcnt = SY_THR_STATIC },	/* 71 = old freebsd32_mmap */
 	{ compat11(AS(freebsd11_vadvise_args),vadvise), .sy_auevent = AUE_O_VADVISE, .sy_flags = 0, .sy_thrcnt = SY_THR_STATIC },	/* 72 = freebsd11 vadvise */
 	{ .sy_narg = AS(munmap_args), .sy_call = (sy_call_t *)sys_munmap, .sy_auevent = AUE_MUNMAP, .sy_flags = SYF_CAPENABLED, .sy_thrcnt = SY_THR_STATIC },	/* 73 = munmap */
diff --git a/sys/compat/freebsd32/freebsd32_systrace_args.c b/sys/compat/freebsd32/freebsd32_systrace_args.c
index fb1fddc6ae5e..0d263b57bf0f 100644
--- a/sys/compat/freebsd32/freebsd32_systrace_args.c
+++ b/sys/compat/freebsd32/freebsd32_systrace_args.c
@@ -421,20 +421,6 @@ systrace_args(int sysnum, void *params, uint64_t *uarg, int *n_args)
 		*n_args = 0;
 		break;
 	}
-	/* sbrk */
-	case 69: {
-		struct sbrk_args *p = params;
-		iarg[a++] = p->incr; /* int */
-		*n_args = 1;
-		break;
-	}
-	/* sstk */
-	case 70: {
-		struct sstk_args *p = params;
-		iarg[a++] = p->incr; /* int */
-		*n_args = 1;
-		break;
-	}
 	/* munmap */
 	case 73: {
 		struct munmap_args *p = params;
@@ -4009,26 +3995,6 @@ systrace_entry_setargdesc(int sysnum, int ndx, char *desc, size_t descsz)
 	/* vfork */
 	case 66:
 		break;
-	/* sbrk */
-	case 69:
-		switch (ndx) {
-		case 0:
-			p = "int";
-			break;
-		default:
-			break;
-		};
-		break;
-	/* sstk */
-	case 70:
-		switch (ndx) {
-		case 0:
-			p = "int";
-			break;
-		default:
-			break;
-		};
-		break;
 	/* munmap */
 	case 73:
 		switch (ndx) {
@@ -9347,16 +9313,6 @@ systrace_return_setargdesc(int sysnum, int ndx, char *desc, size_t descsz)
 		break;
 	/* vfork */
 	case 66:
-	/* sbrk */
-	case 69:
-		if (ndx == 0 || ndx == 1)
-			p = "int";
-		break;
-	/* sstk */
-	case 70:
-		if (ndx == 0 || ndx == 1)
-			p = "int";
-		break;
 	/* munmap */
 	case 73:
 		if (ndx == 0 || ndx == 1)