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67b6662559
Currently, the "run_size" variable holds the total kernel size
(size of code plus brk and bss) and is calculated via the shell script
arch/x86/tools/calc_run_size.sh. It gets the file offset and mem size
of the .bss and .brk sections from the vmlinux, and adds them as follows:
run_size = $(( $offsetA + $sizeA + $sizeB ))
However, this is not correct (it is too large). To illustrate, here's
a walk-through of the script's calculation, compared to the correct way
to find it.
First, offsetA is found as the starting address of the first .bss or
.brk section seen in the ELF file. The sizeA and sizeB values are the
respective section sizes.
[bhe@x1 linux]$ objdump -h vmlinux
vmlinux: file format elf64-x86-64
Sections:
Idx Name Size VMA LMA File off Algn
27 .bss 00170000 ffffffff81ec8000 0000000001ec8000 012c8000 2**12
ALLOC
28 .brk 00027000 ffffffff82038000 0000000002038000 012c8000 2**0
ALLOC
Here, offsetA is 0x012c8000, with sizeA at 0x00170000 and sizeB at
0x00027000. The resulting run_size is 0x145f000:
0x012c8000 + 0x00170000 + 0x00027000 = 0x145f000
However, if we instead examine the ELF LOAD program headers, we see a
different picture.
[bhe@x1 linux]$ readelf -l vmlinux
Elf file type is EXEC (Executable file)
Entry point 0x1000000
There are 5 program headers, starting at offset 64
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000200000 0xffffffff81000000 0x0000000001000000
0x0000000000b5e000 0x0000000000b5e000 R E 200000
LOAD 0x0000000000e00000 0xffffffff81c00000 0x0000000001c00000
0x0000000000145000 0x0000000000145000 RW 200000
LOAD 0x0000000001000000 0x0000000000000000 0x0000000001d45000
0x0000000000018158 0x0000000000018158 RW 200000
LOAD 0x000000000115e000 0xffffffff81d5e000 0x0000000001d5e000
0x000000000016a000 0x0000000000301000 RWE 200000
NOTE 0x000000000099bcac 0xffffffff8179bcac 0x000000000179bcac
0x00000000000001bc 0x00000000000001bc 4
Section to Segment mapping:
Segment Sections...
00 .text .notes __ex_table .rodata __bug_table .pci_fixup .tracedata
__ksymtab __ksymtab_gpl __ksymtab_strings __init_rodata __param
__modver
01 .data .vvar
02 .data..percpu
03 .init.text .init.data .x86_cpu_dev.init .parainstructions
.altinstructions .altinstr_replacement .iommu_table .apicdrivers
.exit.text .smp_locks .bss .brk
04 .notes
As mentioned, run_size needs to be the size of the running kernel
including .bss and .brk. We can see from the Section/Segment mapping
above that .bss and .brk are included in segment 03 (which corresponds
to the final LOAD program header). To find the run_size, we calculate
the end of the LOAD segment from its PhysAddr start (0x0000000001d5e000)
and its MemSiz (0x0000000000301000), minus the physical load address of
the kernel (the first LOAD segment's PhysAddr: 0x0000000001000000). The
resulting run_size is 0x105f000:
0x0000000001d5e000 + 0x0000000000301000 - 0x0000000001000000 = 0x105f000
So, from this we can see that the existing run_size calculation is
0x400000 too high. And, as it turns out, the correct run_size is
actually equal to VO_end - VO_text, which is certainly easier to calculate.
_end: 0xffffffff8205f000
_text:0xffffffff81000000
0xffffffff8205f000 - 0xffffffff81000000 = 0x105f000
As a result, run_size is a simple constant, so we don't need to pass it
around; we already have voffset.h for such things. We can share voffset.h
between misc.c and header.S instead of getting run_size in other ways.
This patch moves voffset.h creation code to boot/compressed/Makefile,
and switches misc.c to use the VO_end - VO_text calculation for run_size.
Dependence before:
boot/header.S ==> boot/voffset.h ==> vmlinux
boot/header.S ==> compressed/vmlinux ==> compressed/misc.c
Dependence after:
boot/header.S ==> compressed/vmlinux ==> compressed/misc.c ==> boot/voffset.h ==> vmlinux
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
[ Rewrote the changelog. ]
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: lasse.collin@tukaani.org
Fixes: e6023367d7
("x86, kaslr: Prevent .bss from overlaping initrd")
Link: http://lkml.kernel.org/r/1461888548-32439-5-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
190 lines
6.4 KiB
Makefile
190 lines
6.4 KiB
Makefile
#
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# arch/x86/boot/Makefile
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#
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# This file is subject to the terms and conditions of the GNU General Public
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# License. See the file "COPYING" in the main directory of this archive
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# for more details.
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#
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# Copyright (C) 1994 by Linus Torvalds
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# Changed by many, many contributors over the years.
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#
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KASAN_SANITIZE := n
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OBJECT_FILES_NON_STANDARD := y
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# Kernel does not boot with kcov instrumentation here.
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# One of the problems observed was insertion of __sanitizer_cov_trace_pc()
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# callback into middle of per-cpu data enabling code. Thus the callback observed
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# inconsistent state and crashed. We are interested mostly in syscall coverage,
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# so boot code is not interesting anyway.
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KCOV_INSTRUMENT := n
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# If you want to preset the SVGA mode, uncomment the next line and
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# set SVGA_MODE to whatever number you want.
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# Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
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# The number is the same as you would ordinarily press at bootup.
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SVGA_MODE := -DSVGA_MODE=NORMAL_VGA
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targets := vmlinux.bin setup.bin setup.elf bzImage
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targets += fdimage fdimage144 fdimage288 image.iso mtools.conf
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subdir- := compressed
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setup-y += a20.o bioscall.o cmdline.o copy.o cpu.o cpuflags.o cpucheck.o
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setup-y += early_serial_console.o edd.o header.o main.o memory.o
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setup-y += pm.o pmjump.o printf.o regs.o string.o tty.o video.o
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setup-y += video-mode.o version.o
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setup-$(CONFIG_X86_APM_BOOT) += apm.o
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# The link order of the video-*.o modules can matter. In particular,
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# video-vga.o *must* be listed first, followed by video-vesa.o.
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# Hardware-specific drivers should follow in the order they should be
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# probed, and video-bios.o should typically be last.
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setup-y += video-vga.o
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setup-y += video-vesa.o
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setup-y += video-bios.o
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targets += $(setup-y)
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hostprogs-y := tools/build
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hostprogs-$(CONFIG_X86_FEATURE_NAMES) += mkcpustr
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include \
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-include include/generated/autoconf.h \
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-D__EXPORTED_HEADERS__
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ifdef CONFIG_X86_FEATURE_NAMES
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$(obj)/cpu.o: $(obj)/cpustr.h
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quiet_cmd_cpustr = CPUSTR $@
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cmd_cpustr = $(obj)/mkcpustr > $@
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targets += cpustr.h
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$(obj)/cpustr.h: $(obj)/mkcpustr FORCE
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$(call if_changed,cpustr)
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endif
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clean-files += cpustr.h
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# ---------------------------------------------------------------------------
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KBUILD_CFLAGS := $(USERINCLUDE) $(REALMODE_CFLAGS) -D_SETUP
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KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
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GCOV_PROFILE := n
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UBSAN_SANITIZE := n
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$(obj)/bzImage: asflags-y := $(SVGA_MODE)
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quiet_cmd_image = BUILD $@
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cmd_image = $(obj)/tools/build $(obj)/setup.bin $(obj)/vmlinux.bin \
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$(obj)/zoffset.h $@
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$(obj)/bzImage: $(obj)/setup.bin $(obj)/vmlinux.bin $(obj)/tools/build FORCE
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$(call if_changed,image)
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@echo 'Kernel: $@ is ready' ' (#'`cat .version`')'
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OBJCOPYFLAGS_vmlinux.bin := -O binary -R .note -R .comment -S
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$(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE
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$(call if_changed,objcopy)
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SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
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sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(startup_32\|startup_64\|efi32_stub_entry\|efi64_stub_entry\|efi_pe_entry\|input_data\|_end\|_ehead\|_text\|z_.*\)$$/\#define ZO_\2 0x\1/p'
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quiet_cmd_zoffset = ZOFFSET $@
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cmd_zoffset = $(NM) $< | sed -n $(sed-zoffset) > $@
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targets += zoffset.h
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$(obj)/zoffset.h: $(obj)/compressed/vmlinux FORCE
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$(call if_changed,zoffset)
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AFLAGS_header.o += -I$(obj)
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$(obj)/header.o: $(obj)/zoffset.h
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LDFLAGS_setup.elf := -T
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$(obj)/setup.elf: $(src)/setup.ld $(SETUP_OBJS) FORCE
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$(call if_changed,ld)
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OBJCOPYFLAGS_setup.bin := -O binary
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$(obj)/setup.bin: $(obj)/setup.elf FORCE
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$(call if_changed,objcopy)
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$(obj)/compressed/vmlinux: FORCE
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$(Q)$(MAKE) $(build)=$(obj)/compressed $@
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# Set this if you want to pass append arguments to the
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# bzdisk/fdimage/isoimage kernel
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FDARGS =
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# Set this if you want an initrd included with the
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# bzdisk/fdimage/isoimage kernel
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FDINITRD =
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image_cmdline = default linux $(FDARGS) $(if $(FDINITRD),initrd=initrd.img,)
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$(obj)/mtools.conf: $(src)/mtools.conf.in
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sed -e 's|@OBJ@|$(obj)|g' < $< > $@
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# This requires write access to /dev/fd0
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bzdisk: $(obj)/bzImage $(obj)/mtools.conf
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MTOOLSRC=$(obj)/mtools.conf mformat a: ; sync
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syslinux /dev/fd0 ; sync
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echo '$(image_cmdline)' | \
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MTOOLSRC=$(src)/mtools.conf mcopy - a:syslinux.cfg
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if [ -f '$(FDINITRD)' ] ; then \
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MTOOLSRC=$(obj)/mtools.conf mcopy '$(FDINITRD)' a:initrd.img ; \
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fi
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MTOOLSRC=$(obj)/mtools.conf mcopy $(obj)/bzImage a:linux ; sync
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# These require being root or having syslinux 2.02 or higher installed
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fdimage fdimage144: $(obj)/bzImage $(obj)/mtools.conf
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dd if=/dev/zero of=$(obj)/fdimage bs=1024 count=1440
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MTOOLSRC=$(obj)/mtools.conf mformat v: ; sync
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syslinux $(obj)/fdimage ; sync
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echo '$(image_cmdline)' | \
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MTOOLSRC=$(obj)/mtools.conf mcopy - v:syslinux.cfg
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if [ -f '$(FDINITRD)' ] ; then \
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MTOOLSRC=$(obj)/mtools.conf mcopy '$(FDINITRD)' v:initrd.img ; \
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fi
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MTOOLSRC=$(obj)/mtools.conf mcopy $(obj)/bzImage v:linux ; sync
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fdimage288: $(obj)/bzImage $(obj)/mtools.conf
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dd if=/dev/zero of=$(obj)/fdimage bs=1024 count=2880
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MTOOLSRC=$(obj)/mtools.conf mformat w: ; sync
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syslinux $(obj)/fdimage ; sync
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echo '$(image_cmdline)' | \
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MTOOLSRC=$(obj)/mtools.conf mcopy - w:syslinux.cfg
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if [ -f '$(FDINITRD)' ] ; then \
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MTOOLSRC=$(obj)/mtools.conf mcopy '$(FDINITRD)' w:initrd.img ; \
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fi
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MTOOLSRC=$(obj)/mtools.conf mcopy $(obj)/bzImage w:linux ; sync
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isoimage: $(obj)/bzImage
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-rm -rf $(obj)/isoimage
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mkdir $(obj)/isoimage
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for i in lib lib64 share end ; do \
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if [ -f /usr/$$i/syslinux/isolinux.bin ] ; then \
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cp /usr/$$i/syslinux/isolinux.bin $(obj)/isoimage ; \
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break ; \
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fi ; \
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if [ $$i = end ] ; then exit 1 ; fi ; \
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done
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cp $(obj)/bzImage $(obj)/isoimage/linux
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echo '$(image_cmdline)' > $(obj)/isoimage/isolinux.cfg
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if [ -f '$(FDINITRD)' ] ; then \
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cp '$(FDINITRD)' $(obj)/isoimage/initrd.img ; \
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fi
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mkisofs -J -r -o $(obj)/image.iso -b isolinux.bin -c boot.cat \
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-no-emul-boot -boot-load-size 4 -boot-info-table \
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$(obj)/isoimage
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isohybrid $(obj)/image.iso 2>/dev/null || true
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rm -rf $(obj)/isoimage
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bzlilo: $(obj)/bzImage
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if [ -f $(INSTALL_PATH)/vmlinuz ]; then mv $(INSTALL_PATH)/vmlinuz $(INSTALL_PATH)/vmlinuz.old; fi
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if [ -f $(INSTALL_PATH)/System.map ]; then mv $(INSTALL_PATH)/System.map $(INSTALL_PATH)/System.old; fi
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cat $(obj)/bzImage > $(INSTALL_PATH)/vmlinuz
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cp System.map $(INSTALL_PATH)/
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if [ -x /sbin/lilo ]; then /sbin/lilo; else /etc/lilo/install; fi
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install:
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sh $(srctree)/$(src)/install.sh $(KERNELRELEASE) $(obj)/bzImage \
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System.map "$(INSTALL_PATH)"
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