927185c124
The kernel uses the OUTPUT_FORMAT linker script command in it's linker
scripts. Most of the time, the -m option is passed to the linker with
correct architecture, but sometimes (at least for x86_64) the -m option
contradicts the OUTPUT_FORMAT directive.
Specifically, arch/x86/boot and arch/x86/realmode/rm produce i386 object
files, but are linked with the -m elf_x86_64 linker flag when building
for x86_64.
The GNU linker manpage doesn't explicitly state any tie-breakers between
-m and OUTPUT_FORMAT. But with BFD and Gold linkers, OUTPUT_FORMAT
overrides the emulation value specified with the -m option.
LLVM lld has a different behavior, however. When supplied with
contradicting -m and OUTPUT_FORMAT values it fails with the following
error message:
ld.lld: error: arch/x86/realmode/rm/header.o is incompatible with elf_x86_64
Therefore, just add the correct -m after the incorrect one (it overrides
it), so the linker invocation looks like this:
ld -m elf_x86_64 -z max-page-size=0x200000 -m elf_i386 --emit-relocs -T \
realmode.lds header.o trampoline_64.o stack.o reboot.o -o realmode.elf
This is not a functional change for GNU ld, because (although not
explicitly documented) OUTPUT_FORMAT overrides -m EMULATION.
Tested by building x86_64 kernel with GNU gcc/ld toolchain and booting
it in QEMU.
[ bp: massage and clarify text. ]
Suggested-by: Dmitry Golovin <dima@golovin.in>
Signed-off-by: George Rimar <grimar@accesssoftek.com>
Signed-off-by: Tri Vo <trong@android.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Tri Vo <trong@android.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Matz <matz@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: morbo@google.com
Cc: ndesaulniers@google.com
Cc: ruiu@google.com
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190111201012.71210-1-trong@android.com
157 lines
5.2 KiB
Makefile
157 lines
5.2 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 := $(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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silent_redirect_image = >/dev/null
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cmd_image = $(obj)/tools/build $(obj)/setup.bin $(obj)/vmlinux.bin \
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$(obj)/zoffset.h $@ $($(quiet)redirect_image)
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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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@$(kecho) '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$(objtree)/$(obj)
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$(obj)/header.o: $(obj)/zoffset.h
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LDFLAGS_setup.elf := -m elf_i386 -T
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$(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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quiet_cmd_genimage = GENIMAGE $3
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cmd_genimage = sh $(srctree)/$(src)/genimage.sh $2 $3 $(obj)/bzImage \
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$(obj)/mtools.conf '$(image_cmdline)' $(FDINITRD)
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# This requires write access to /dev/fd0
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bzdisk: $(obj)/bzImage $(obj)/mtools.conf
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$(call cmd,genimage,bzdisk,/dev/fd0)
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# These require being root or having syslinux 2.02 or higher installed
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fdimage fdimage144: $(obj)/bzImage $(obj)/mtools.conf
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$(call cmd,genimage,fdimage144,$(obj)/fdimage)
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@$(kecho) 'Kernel: $(obj)/fdimage is ready'
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fdimage288: $(obj)/bzImage $(obj)/mtools.conf
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$(call cmd,genimage,fdimage288,$(obj)/fdimage)
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@$(kecho) 'Kernel: $(obj)/fdimage is ready'
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isoimage: $(obj)/bzImage
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$(call cmd,genimage,isoimage,$(obj)/image.iso)
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@$(kecho) 'Kernel: $(obj)/image.iso is ready'
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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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