From fc3f6268d7d33748e85f41ea89af6b88cbde7ff2 Mon Sep 17 00:00:00 2001
From: Li Jinpei <leekingp1994@163.com>
Date: Sun, 25 Jul 2021 01:29:17 +0800
Subject: [PATCH] add linker script to fix binary size

---
 Makefile        | 12 +++++-------
 fs/Makefile     |  1 -
 kernel/Makefile |  4 ++--
 mm/Makefile     |  3 +--
 x86_32.lds.S    | 20 ++++++++++++++++++++
 5 files changed, 28 insertions(+), 12 deletions(-)
 create mode 100644 x86_32.lds.S

diff --git a/Makefile b/Makefile
index 1b3b33e..7815e99 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,5 @@
 AS := as
-LD := ld -m elf_x86_64
-
-LDFLAG := -Ttext 0x0 -s --oformat binary
+LD := ld
 
 image : linux.img
 
@@ -15,16 +13,16 @@ kernel/system : kernel/head.S kernel/*.c mm/*.c kernel/blk_drv/*.c fs/*.c
 		cd kernel; make system; cd ..
 
 bootsect : bootsect.o
-	$(LD) $(LDFLAG) -o $@ $<
+	$(LD) -T x86_32.lds.S -o $@ $<
 
 bootsect.o : bootsect.S
-	$(AS) -o $@ $<
+	$(AS) --32 -o $@ $<
 
 setup : setup.o
-		$(LD) $(LDFLAG) -e _start_setup -o $@ $<
+		$(LD) -T x86_32.lds.S -e _start_setup -o $@ $<
 
 setup.o : setup.S
-		$(AS) -o $@ $<
+		$(AS) --32 -o $@ $<
 clean:
 	rm *.o
 	rm bootsect
diff --git a/fs/Makefile b/fs/Makefile
index 193ad9f..149ff4f 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -1,7 +1,6 @@
 GCC := gcc
 LD  := ld
 CCFLAG := -I../include -nostdinc -ffreestanding -Wall -fomit-frame-pointer -fno-stack-protector -fno-pic -c -m32
-LDFLAG := -Ttext 0x0 -s --oformat binary -m elf_i386
 INCDIR := ../include
 OBJS   := read_write.o buffer.o super.o open.o file_table.o inode.o namei.o fcntl.o char_dev.o bitmap.o truncate.o
 
diff --git a/kernel/Makefile b/kernel/Makefile
index 8c976ab..f4ecbca 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -1,12 +1,12 @@
 GCC := gcc
 CCFLAG := -I../include -nostdinc -ffreestanding -Wall -fomit-frame-pointer -fno-pic -fno-stack-protector -c -m32
-LDFLAG := -Ttext 0x0 -s --oformat binary -m elf_i386
 INCDIR := ../include
 OBJS   := head.o main.o sys_call.o asm.o sched.o printk.o vsprintf.o mktime.o \
 	traps.o fork.o panic.o chr_drv/chr_drv.a blk_drv/blk_drv.a ../mm/mm.o ../lib/lib.a ../fs/fs.o 
 
+
 system: $(OBJS)
-	$(LD) $(LDFLAG) -M -e startup_32 -o $@ $^ > System.map
+	$(LD) -T ../x86_32.lds.S -M -e startup_32 -o $@ $^ > System.map
 
 head.o : head.S
 	$(GCC) -m32 -traditional -c -o $@ $<
diff --git a/mm/Makefile b/mm/Makefile
index e334d0b..f62260d 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -1,7 +1,6 @@
 GCC := gcc
-LD  := ld
+LD := ld
 CCFLAG := -I../include -nostdinc -ffreestanding -Wall -fomit-frame-pointer -fno-pic -fno-stack-protector -c -m32
-LDFLAG := -Ttext 0x0 -s --oformat binary -m elf_i386
 INCDIR := ../include
 OBJS   := swap.o memory.o page.o
 
diff --git a/x86_32.lds.S b/x86_32.lds.S
new file mode 100644
index 0000000..c19de30
--- /dev/null
+++ b/x86_32.lds.S
@@ -0,0 +1,20 @@
+OUTPUT_FORMAT("binary")
+OUTPUT_ARCH(i386)
+SECTIONS
+{
+    .text 0x00 :
+    {
+        *(.text)
+    /*
+        *(.text.unlikely .text.*_unlikely .text.unlikely.*)
+        *(.text.exit .text.exit.*)
+        *(.text.startup .text.startup.*)
+        *(.text.hot .text.hot.*)
+        *(SORT(.text.sorted.*))
+        *(.text .stub .text.* .gnu.linkonce.t.*)
+        */
+    }
+  . = 0x200;
+  _end = .; PROVIDE (end = .);
+    /DISCARD/ : {*(*)}
+}
-- 
Gitee