Merge branch 'master' of ssh://terminus.zytor.com/pub/git/syslinux/syslinux

5 files changed, 119 insertions, 41 deletions

diff --git a/dos/Makefile b/dos/Makefile
index 56d2e076..9d8ce33c 100644
--- a/dos/Makefile
+++ b/dos/Makefile
@@ -30,7 +30,8 @@ SRCS     = syslinux.c \
 	   ../libinstaller/mbr_bin.c \
            $(wildcard ../libfat/*.c)
 OBJS	 = crt0.o $(patsubst %.c,%.o,$(notdir $(SRCS)))
-LIBOBJS	 = conio.o memcpy.o memset.o  skipatou.o atou.o malloc.o free.o \
+LIBOBJS	 = int2526.o conio.o memcpy.o memset.o  skipatou.o atou.o \
+	   malloc.o free.o \
 	   argv.o printf.o __divdi3.o __udivmoddi4.o
 
 VPATH = .:../libfat:../libinstaller
@@ -49,8 +50,8 @@ spotless: clean
 
 installer:
 
-syslinux.elf: $(OBJS) libcom.a
-	$(LD) $(LDFLAGS) -o $@ $^
+syslinux.elf: $(OBJS) libcom.a com16.ld
+	$(LD) $(LDFLAGS) -o $@ $(filter-out %.ld,$^)
 
 libcom.a: $(LIBOBJS)
 	-rm -f $@
diff --git a/dos/com16.ld b/dos/com16.ld
index 08a1e95e..5f82b73a 100644
--- a/dos/com16.ld
+++ b/dos/com16.ld
@@ -123,5 +123,8 @@ SECTIONS
   .debug_funcnames 0 : { *(.debug_funcnames) }
   .debug_typenames 0 : { *(.debug_typenames) }
   .debug_varnames  0 : { *(.debug_varnames) }
-  /DISCARD/ : { *(.note.GNU-stack) }
+  /DISCARD/ : {
+  	*(.note.GNU-stack)
+	*(.eh_frame)
+  }
 }
diff --git a/dos/int2526.S b/dos/int2526.S
new file mode 100644
index 00000000..bcb7707e
--- /dev/null
+++ b/dos/int2526.S
@@ -0,0 +1,76 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * int 0x25 and 0x26 direct sector access
+ *
+ * Use assembly wrapper functions for these system calls, since unlike
+ * int 0x21 calls they are "dirty" and can destroy unrelated registers.
+ *
+ * NOTE: these all assume the data buffer is in the data segment, i.e.
+ * %ds == %es == dio.bufseg.
+ *
+ * Usage: int int25_read_sector(drive, dio)
+ * Usage: int int26_write_sector(drive, dio)
+ */
+
+	.code16gcc
+	.text
+
+	.globl	int25_read_sector
+	.type	int25_read_sector, @function
+int25_read_sector:
+	pushl	%ebp
+	pushl	%edi
+	pushl	%esi
+	pushl	%ebx
+
+	decw	%ax		/* AL = drive number (0 = A:) */
+	movw	%dx, %bx	/* BX = dio structure */
+	movw	6(%bx), %dx	/* DX = data buffer */
+	movw	$-1, %cx
+	int	$0x25
+	jc	1f
+	xorw	%ax, %ax	/* Error code: 0 = no error */
+1:
+	popfw
+	movzwl	%ax, %eax
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	popl	%ebp
+	retl
+
+	.globl	int26_write_sector
+	.type	int26_write_sector, @function
+int26_write_sector:
+	pushl	%ebp
+	pushl	%edi
+	pushl	%esi
+	pushl	%ebx
+
+	decw	%ax		/* AL = drive number (0 = A:) */
+	movw	%dx, %bx	/* BX = dio structure */
+	movw	6(%bx), %dx	/* DX = data buffer */
+	movw	$-1, %cx
+	int	$0x26
+	jc	1f
+	xorw	%ax, %ax	/* Error code: 0 = no error */
+1:
+	popfw
+	movzwl	%ax, %eax
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	popl	%ebp
+	retl
diff --git a/dos/mystuff.h b/dos/mystuff.h
index fbf4e75b..25344413 100644
--- a/dos/mystuff.h
+++ b/dos/mystuff.h
@@ -1,6 +1,8 @@
 #ifndef MYSTUFF_H
 #define MYSTUFF_H
 
+#include <inttypes.h>
+
 #define NULL ((void *)0)
 
 unsigned int skip_atou(const char **s);
@@ -11,4 +13,12 @@ static inline int isdigit(int ch)
     return (ch >= '0') && (ch <= '9');
 }
 
+struct diskio {
+    uint32_t startsector;
+    uint16_t sectors;
+    uint16_t bufoffs, bufseg;
+} __attribute__ ((packed));
+int int25_read_sector(unsigned char drive, struct diskio *dio);
+int int26_write_sector(unsigned char drive, struct diskio *dio);
+
 #endif /* MYSTUFF_H */
diff --git a/dos/syslinux.c b/dos/syslinux.c
index 1cdf418b..650c48f6 100644
--- a/dos/syslinux.c
+++ b/dos/syslinux.c
@@ -152,15 +152,8 @@ uint16_t data_segment(void)
     return ds;
 }
 
-struct diskio {
-    uint32_t startsector;
-    uint16_t sectors;
-    uint16_t bufoffs, bufseg;
-} __attribute__ ((packed));
-
 void write_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
 {
-    uint8_t err;
     uint16_t errnum;
     struct diskio dio;
 
@@ -171,21 +164,19 @@ void write_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
     dio.bufoffs = (uintptr_t) buf;
     dio.bufseg = data_segment();
 
-    if (dos_version >= 0x0710) {
-	asm volatile("int $0x21 ; setc %0"
-		     : "=bcdm" (err), "=a" (errnum)
-		     : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
-		       "S" (1), "m" (dio)
-		     : "memory");
-    } else {
-	asm volatile("int $0x26 ; setc %0 ; popfw"
-		     : "=bcdm" (err), "=a" (errnum)
-		     : "a" (drive-1), "b" (&dio), "c" (-1), "d" (buf),
-		       "m" (dio)
-		     : "esi", "memory");
-    }
+    /* Try FAT32-aware system call first */
+    asm volatile("int $0x21 ; jc 1f ; xorw %0,%0\n"
+		 "1:"
+		 : "=a" (errnum)
+		 : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
+		   "S" (1), "m" (dio)
+		 : "memory");
 
-    if (err) {
+    /* If not supported, try the legacy system call (int2526.S) */
+    if (errnum == 0x0001)
+	errnum = int26_write_sector(drive, &dio);
+
+    if (errnum) {
 	dprintf("rv = %04x\n", errnum);
 	die("sector write error");
     }
@@ -193,7 +184,6 @@ void write_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
 
 void read_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
 {
-    uint8_t err;
     uint16_t errnum;
     struct diskio dio;
 
@@ -204,20 +194,18 @@ void read_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
     dio.bufoffs = (uintptr_t) buf;
     dio.bufseg = data_segment();
 
-    if (dos_version >= 0x0710) {
-	asm volatile("int $0x21 ; setc %0"
-		     : "=bcdm" (err), "=a" (errnum)
-		     : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
-		     "S" (0), "m" (dio));
-    } else {
-	asm volatile("int $0x25 ; setc %0 ; popfw"
-		     : "=bcdm" (err), "=a" (errnum)
-		     : "a" (drive-1), "b" (&dio), "c" (-1), "d" (buf),
-		       "m" (dio)
-		     : "esi");
-    }
+    /* Try FAT32-aware system call first */
+    asm volatile("int $0x21 ; jc 1f ; xorw %0,%0\n"
+		 "1:"
+		 : "=a" (errnum)
+		 : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
+		   "S" (0), "m" (dio));
 
-    if (err) {
+    /* If not supported, try the legacy system call (int2526.S) */
+    if (errnum == 0x0001)
+	errnum = int25_read_sector(drive, &dio);
+
+    if (errnum) {
 	dprintf("rv = %04x\n", errnum);
 	die("sector read error");
     }
@@ -411,7 +399,7 @@ static int do_lock(uint8_t level)
     uint8_t err;
 #if 0
     /* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
-    uint16_t lock_call = (dos_version >= 0x0710) ? 0x484A : 0x084A;
+    uint16_t lock_call = (dos_version >= 0x070a) ? 0x484A : 0x084A;
 #else
     uint16_t lock_call = 0x084A; /* MSDN says this is OK for all filesystems */
 #endif
@@ -486,7 +474,7 @@ void unlock_device(int level)
 
 #if 0
     /* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
-    unlock_call = (dos_version >= 0x0710) ? 0x486A : 0x086A;
+    unlock_call = (dos_version >= 0x070a) ? 0x486A : 0x086A;
 #else
     unlock_call = 0x086A;	/* MSDN says this is OK for all filesystems */
 #endif