solve the bounce buffer problem!

3 files changed, 67 insertions, 13 deletions

diff --git a/sys/arch/i386/stand/libsa/Makefile b/sys/arch/i386/stand/libsa/Makefile
index aba5ea1a4ee..8c1b4bf3004 100644
--- a/sys/arch/i386/stand/libsa/Makefile
+++ b/sys/arch/i386/stand/libsa/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.11 1997/04/28 07:39:00 weingart Exp $
+#	$OpenBSD: Makefile,v 1.12 1997/04/30 18:10:08 mickey Exp $
 
 
 LIB=	sa
@@ -17,7 +17,7 @@ AS+=	-R
 # i386 stuff (so, it will possibly load in the same 64k)
 SRCS=	unixsys.S bioscom.S biosdisk.S bioskbd.S biostime.S biosmem.S gidt.S \
 	debug_i386.S dev_i386.c exec_i386.c biosdev.c gateA20.c memprobe.c \
-	time.c
+	time.c alloca.S
 
 # stand routines
 SRCS+=	alloc.c exit.c exec.c getfile.c gets.c globals.c strcmp.c strlen.c \
diff --git a/sys/arch/i386/stand/libsa/alloca.S b/sys/arch/i386/stand/libsa/alloca.S
new file mode 100644
index 00000000000..6e14bbd3bc6
--- /dev/null
+++ b/sys/arch/i386/stand/libsa/alloca.S
@@ -0,0 +1,58 @@
+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * William Jolitz.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+
+#if defined(LIBC_SCCS)
+	.text
+	.asciz "$OpenBSD: alloca.S,v 1.1 1997/04/30 18:10:06 mickey Exp $"
+#endif
+
+/* like alloc, but automatic automatic free in return */
+
+ENTRY(alloca)
+	popl	%edx		/*  pop return addr */
+	popl	%eax		/*  pop amount to allocate */
+	movl	%esp,%ecx
+	addl	$3,%eax		/*  round up to next word */
+	andl	$-4,%eax
+	subl	%eax,%esp
+	movl	%esp,%eax	/* base of newly allocated space */
+	pushl	8(%ecx)		/* copy possible saved registers */
+	pushl	4(%ecx)
+	pushl	0(%ecx)
+	pushl	%eax		/* dummy to pop at callsite */
+	jmp	%edx		/* "return" */
diff --git a/sys/arch/i386/stand/libsa/biosdev.c b/sys/arch/i386/stand/libsa/biosdev.c
index 073a94eae33..29ec6df94d6 100644
--- a/sys/arch/i386/stand/libsa/biosdev.c
+++ b/sys/arch/i386/stand/libsa/biosdev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: biosdev.c,v 1.14 1997/04/23 14:49:23 weingart Exp $	*/
+/*	$OpenBSD: biosdev.c,v 1.15 1997/04/30 18:10:07 mickey Exp $	*/
 
 /*
  * Copyright (c) 1996 Michael Shalayeff
@@ -189,7 +189,7 @@ biosopen(struct open_file *f, ...)
 		}
 	}
 
-	buf = alloc(DEV_BSIZE);
+	buf = alloca(DEV_BSIZE);
 #ifdef BIOS_DEBUG
 	if (debug)
 		printf("loading disklabel @ %u\n", off);
@@ -201,7 +201,6 @@ biosopen(struct open_file *f, ...)
 		if (debug)
 			printf("failed to read disklabel\n");
 #endif
-		free(buf, 0);
 		free(bd, 0);
 		return errno;
 	}
@@ -211,12 +210,10 @@ biosopen(struct open_file *f, ...)
 		if (debug)
 			printf("%s\n", cp);
 #endif
-		free(buf, 0);
 		free(bd, 0);
 		return EINVAL;
 	}
 
-	free(buf,0);
 	f->f_devdata = bd;
 
 	return 0;
@@ -306,7 +303,9 @@ biosstrategy(void *devdata, int rw,
 		/* use a bounce buffer to not cross 64k DMA boundary */
 		if ((((u_int32_t)buf) & ~0xffff) !=
 		    (((u_int32_t)buf + n * DEV_BSIZE) & ~0xffff)) {
-			bb = alloc(n * DEV_BSIZE);
+			/* XXX we beleive that all the io is buffered
+			   by fs routines, so no big reads anyway */
+			bb = alloca(n * DEV_BSIZE);
 			if (rw != F_READ)
 				bcopy (buf, bb, n * DEV_BSIZE);
 		} else
@@ -338,11 +337,8 @@ biosstrategy(void *devdata, int rw,
 			}
 		}
 
-		if (bb != buf) {
-			if (rw == F_READ)
-				bcopy (bb, buf, n * DEV_BSIZE);
-			free (bb, n * DEV_BSIZE);
-		}
+		if (bb != buf && rw == F_READ)
+			bcopy (bb, buf, n * DEV_BSIZE);
 	}
 
 #ifdef	BIOS_DEBUG