From db8899d1faa6fc6e3ea8b89684e5a623df9909ed Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 19 Jul 2010 16:17:04 -0700 Subject: [PATCH] dos: change the link procedure to use negative pointers below DGROUP Use negative pointer values below DGROUP, i.e. for the .payload segment. This makes it a lot easier to figure out if we are dealing with pointers that shouldn't come from where they do, since the DGROUP and .payload segments no longer overlap, and in fact are congruent. Signed-off-by: H. Peter Anvin --- dos/Makefile | 4 ++-- dos/dosexe.ld | 10 ++++++---- dos/getsetsl.c | 2 +- libinstaller/syslxint.h | 4 +--- 4 files changed, 10 insertions(+), 10 deletions(-) diff --git a/dos/Makefile b/dos/Makefile index 3d19ff2..9f48962 100755 --- a/dos/Makefile +++ b/dos/Makefile @@ -31,10 +31,10 @@ SRCS = syslinux.c \ ../libinstaller/syslxopt.c \ ../libinstaller/setadv.c \ ../libinstaller/bootsect_bin.c \ - ../libinstaller/ldlinux_bin.c \ ../libinstaller/mbr_bin.c \ $(wildcard ../libfat/*.c) -OBJS = header.o crt0.o $(patsubst %.c,%.o,$(notdir $(SRCS))) +OBJS = header.o crt0.o ldlinux.o \ + $(patsubst %.c,%.o,$(notdir $(SRCS))) LIBOBJS = int2526.o conio.o memcpy.o memset.o memmove.o skipatou.o atou.o \ malloc.o free.o getopt_long.o getsetsl.o strchr.o strtoul.o \ strntoumax.o argv.o printf.o __divdi3.o __udivmoddi4.o diff --git a/dos/dosexe.ld b/dos/dosexe.ld index 4612b30..c67c506 100755 --- a/dos/dosexe.ld +++ b/dos/dosexe.ld @@ -26,20 +26,22 @@ SECTIONS __header_size = .; __payload_lma = .; - . = 0; + . = 0x100000000 - syslinux_ldlinux_size; .payload : AT (__payload_lma) { __payload_start = .; - ldlinux_bin.o(.data) + *(.payload) __payload_end = .; } __payload_len = __payload_end - __payload_start; __payload_dwords = __payload_len >> 2; - . = ALIGN(16); - __text_lma = __payload_lma + .; + __text_lma = __payload_lma + syslinux_ldlinux_size; __payload_sseg = (__payload_lma - __text_lma) >> 4; _exe_text_seg = (__text_lma - __header_size) >> 4; + __assert1 = ASSERT((__payload_len == syslinux_ldlinux_size), + "syslinux_ldlinux_size must equal the size of .payload"); + . = 0; .text : AT (__text_lma) { *(.text .stub .text.* .gnu.linkonce.t.*) diff --git a/dos/getsetsl.c b/dos/getsetsl.c index a48f3df..5c1dbbd 100644 --- a/dos/getsetsl.c +++ b/dos/getsetsl.c @@ -87,7 +87,7 @@ void memcpy_to_sl(void *dst, const void *src, size_t len) uint16_t seg; uint16_t off; - seg = ldlinux_seg + ((size_t)dst >> 4); + seg = ds() + ((size_t)dst >> 4); off = (size_t)dst & 15; asm volatile("pushw %%es ; " diff --git a/libinstaller/syslxint.h b/libinstaller/syslxint.h index f16c2e5..b8e872a 100644 --- a/libinstaller/syslxint.h +++ b/libinstaller/syslxint.h @@ -111,8 +111,6 @@ static inline void set_64(uint64_t *p, uint64_t v) */ #ifdef __MSDOS__ -extern uint16_t ldlinux_seg; /* Defined in dos/syslinux.c */ - static inline __attribute__ ((const)) uint16_t ds(void) { @@ -125,7 +123,7 @@ static inline void *set_fs(const void *p) { uint16_t seg; - seg = ldlinux_seg + ((size_t) p >> 4); + seg = ds() + ((size_t) p >> 4); asm volatile ("movw %0,%%fs"::"rm" (seg)); return (void *)((size_t) p & 0xf); } -- 2.7.4