[PATCH 10/31] sandbox: Provide a linker script for MSYS2
Simon Glass
sjg at chromium.org
Wed Apr 26 02:50:59 CEST 2023
Hi Pali,
On Tue, 25 Apr 2023 at 13:33, Pali Rohár <pali at kernel.org> wrote:
>
> On Tuesday 25 April 2023 13:23:04 Simon Glass wrote:
> > Hi Pali,
> >
> > On Tue, 25 Apr 2023 at 12:11, Pali Rohár <pali at kernel.org> wrote:
> > >
> > > On Tuesday 25 April 2023 12:01:04 Simon Glass wrote:
> > > > Hi Pali,
> > > >
> > > > On Tue, 25 Apr 2023 at 10:21, Pali Rohár <pali at kernel.org> wrote:
> > > > >
> > > > > On Monday 24 April 2023 17:08:15 Simon Glass wrote:
> > > > > > Add a script to allow the U-Boot sandbox executable to be built for
> > > > > > Windows. Add a note as to why this seems to be necessary for now.
> > > > > >
> > > > > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > > > > ---
> > > > > >
> > > > > > Makefile | 11 +-
> > > > > > arch/sandbox/config.mk | 4 +
> > > > > > arch/sandbox/cpu/u-boot-pe.lds | 447 +++++++++++++++++++++++++++++++++
> > > > > > 3 files changed, 460 insertions(+), 2 deletions(-)
> > > > > > create mode 100644 arch/sandbox/cpu/u-boot-pe.lds
> > > > > >
> > > > > > diff --git a/Makefile b/Makefile
> > > > > > index dd3fcd1782e5..0aa97a2c3b48 100644
> > > > > > --- a/Makefile
> > > > > > +++ b/Makefile
> > > > > > @@ -1730,6 +1730,13 @@ else
> > > > > > u-boot-keep-syms-lto :=
> > > > > > endif
> > > > > >
> > > > > > +ifeq ($(MSYS_VERSION),0)
> > > > > > +add_ld_script := -T u-boot.lds
> > > > > > +else
> > > > > > +add_ld_script := u-boot.lds
> > > > > > +$(warning msys)
> > > > > > +endif
> > > > > > +
> > > > > > # Rule to link u-boot
> > > > > > # May be overridden by arch/$(ARCH)/config.mk
> > > > > > ifeq ($(LTO_ENABLE),y)
> > > > > > @@ -1738,7 +1745,7 @@ quiet_cmd_u-boot__ ?= LTO $@
> > > > > > $(CC) -nostdlib -nostartfiles \
> > > > > > $(LTO_FINAL_LDFLAGS) $(c_flags) \
> > > > > > $(KBUILD_LDFLAGS:%=-Wl,%) $(LDFLAGS_u-boot:%=-Wl,%) -o $@ \
> > > > > > - -T u-boot.lds $(u-boot-init) \
> > > > > > + $(add_ld_script) $(u-boot-init) \
> > > > > > -Wl,--whole-archive \
> > > > > > $(u-boot-main) \
> > > > > > $(u-boot-keep-syms-lto) \
> > > > > > @@ -1749,7 +1756,7 @@ quiet_cmd_u-boot__ ?= LTO $@
> > > > > > else
> > > > > > quiet_cmd_u-boot__ ?= LD $@
> > > > > > cmd_u-boot__ ?= $(LD) $(KBUILD_LDFLAGS) $(LDFLAGS_u-boot) -o $@ \
> > > > > > - -T u-boot.lds $(u-boot-init) \
> > > > > > + $(add_ld_script) $(u-boot-init) \
> > > > > > --whole-archive \
> > > > > > $(u-boot-main) \
> > > > > > --no-whole-archive \
> > > > > > diff --git a/arch/sandbox/config.mk b/arch/sandbox/config.mk
> > > > > > index 2d184c5f652a..e05daf57ef8e 100644
> > > > > > --- a/arch/sandbox/config.mk
> > > > > > +++ b/arch/sandbox/config.mk
> > > > > > @@ -71,3 +71,7 @@ EFI_CRT0 := crt0_sandbox_efi.o
> > > > > > EFI_RELOC := reloc_sandbox_efi.o
> > > > > > AFLAGS_crt0_sandbox_efi.o += -DHOST_ARCH="$(HOST_ARCH)"
> > > > > > CFLAGS_reloc_sandbox_efi.o += -DHOST_ARCH="$(HOST_ARCH)"
> > > > > > +
> > > > > > +ifneq ($(MSYS_VERSION),0)
> > > > > > +LDSCRIPT = $(srctree)/arch/sandbox/cpu/u-boot-pe.lds
> > > > > > +endif
> > > > > > diff --git a/arch/sandbox/cpu/u-boot-pe.lds b/arch/sandbox/cpu/u-boot-pe.lds
> > > > > > new file mode 100644
> > > > > > index 000000000000..031e70fafd03
> > > > > > --- /dev/null
> > > > > > +++ b/arch/sandbox/cpu/u-boot-pe.lds
> > > > > > @@ -0,0 +1,447 @@
> > > > > > +/* SPDX-License-Identifier: GPL-2.0+ */
> > > > > > +/*
> > > > > > + * U-Boot note: This was obtained by using the -verbose linker option. The
> > > > > > + * U-Boot additions are marked below.
> > > > > > + *
> > > > > > + * Ideally we would add sections to the executable, as is done with the Linux
> > > > > > + * build. But PE executables do not appear to work correctly if unexpected
> > > > > > + * sections are present:
> > > > > > + *
> > > > > > + * $ /tmp/b/sandbox/u-boot.exe
> > > > > > + * -bash: /tmp/b/sandbox/u-boot.exe: cannot execute binary file: Exec format error
> > > > > > + *
> > > > > > + * So we take a approach of rewriting the whole file, for now. This will likely
> > > > > > + * break in the future when a toolchain change is made.
> > > > >
> > > > > Why not rather provide "layer" linker script which does this "rewriting"
> > > > > on top of the default linker script? With this way it is not needed to
> > > > > update linker script when a toolchain change it.
> > > > >
> > > >
> > > > How can we reliably do that, though? We don't really know the format
> > > > of the script and where to insert stuff.
> > > >
> > > > Regards,
> > > > Simon
> > >
> > > Well, I do not know what is the current issue. The proposed script in
> >
> > See the comment at the top of the script:
> >
> > + * Ideally we would add sections to the executable, as is done with the Linux
> > + * build. But PE executables do not appear to work correctly if unexpected
> > + * sections are present:
> > + *
> > + * $ /tmp/b/sandbox/u-boot.exe
> > + * -bash: /tmp/b/sandbox/u-boot.exe: cannot execute binary file:
> > Exec format error
> > + *
> > + * So we take a approach of rewriting the whole file, for now. This will likely
> > + * break in the future when a toolchain change is made.
> >
> > > your patch looks like it is copied from some binutils version and then
> > > modified.
> >
> > Yes, exactly.
> >
> > > Also I do not know from which binutils you have copied and
> > > what modification you have done in it.
> >
> > But I have marked this clearly in the script. See /* U-Boot additions
> > from here on */
>
> I read this, but I have not found from which binutils you took it...
> There are many released binutils versions and also each binutils
> version has more PE linker scripts. So it is really hard to track from
> which it comes. -verbose argument show you the final linker script but
> we need to know also from which files it was composed...
$ ld -V
GNU ld (GNU Binutils) 2.40
Supported emulations:
i386pep
i386pe
sglass at DESKTOP-OHNGJ4K MINGW64 ~/u-boot
$ cc -v
Using built-in specs.
COLLECT_GCC=cc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-msys/11.3.0/lto-wrapper.exe
Target: x86_64-pc-msys
Configured with: /c/S/gcc/src/gcc-11.3.0/configure
--build=x86_64-pc-msys --prefix=/usr --libexecdir=/usr/lib
--enable-bootstrap --enable-shared --enable-shared-libgcc
--enable-static --enable-version-specific-runtime-libs
--with-arch=x86-64 --with-tune=generic --disable-multilib
--enable-__cxa_atexit --with-dwarf2
--enable-languages=c,c++,fortran,lto --enable-graphite
--enable-threads=posix --enable-libatomic --enable-libgomp
--disable-libitm --enable-libquadmath --enable-libquadmath-support
--disable-libssp --disable-win32-registry --disable-symvers
--with-gnu-ld --with-gnu-as --disable-isl-version-check
--enable-checking=release --without-libiconv-prefix
--without-libintl-prefix --with-system-zlib --enable-linker-build-id
--with-default-libstdcxx-abi=gcc4-compatible
--enable-libstdcxx-filesystem-ts
Thread model: posix
Supported LTO compression algorithms: zlib
>
> > > So I cannot react or comment
> > > anymore more here.
> > >
> > > My idea is that to write those modifications into new layer script.
> >
> > So I think you are suggesting that I get binutils to emit the default
> > script, then have a script which detects the end of the .rdata section
> > and emits its own stuff in there? That may be more robust, since it is
> > unlikely that the .rdata section will be removed.
>
> Yes, exactly. And you do not need to take and copy default script from
> binutils to u-boot sources. If you write "layer" linker script (I hope
> that this is how it is called in LD documentation), then LD
> automatically uses its own default script and apply your "layer" script
> on it. So with this way you can completely avoid copy+paste files from
> binutils to u-boot repository.
That is considerably more complicated, though.
>
> > But I was rather hoping that someone could help with the core problem,
> > i.e. why I cannot just insert another section into the image, like we
> > do with ELF?
>
> That is interesting. Theoretically it should work but I have not seen it
> widely used outside of NT kernel modules. So maybe there is some bug in
> Windows loader for userspace binaries, or another bug in GNU LD, or just
> a bug in u-boot / linker script.
>
> Could you show linker script which is causing generation of that buggy
> non-working binary? And ideally can you provide also that buggy EXE
> binary? I could try to inspect it, but I do not have time to setup MSYS2
> environment to compile my own buggy EXE binary.
Please see [1] for the file.
sglass at DESKTOP-OHNGJ4K MINGW64 ~/u-boot
$ objdump.exe -h /tmp/b/sandbox/u-boot.exe
/tmp/b/sandbox/u-boot.exe: file format pei-x86-64
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00208b98 0000000100401000 0000000100401000 00000600 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA
1 __u_boot_list 00014960 0000000100609ba0 0000000100609ba0 00209200 2**2
CONTENTS, ALLOC, LOAD, DATA
2 _u_boot_sandbox_getopt 000000c0 000000010061e500
000000010061e500 0021dc00 2**2
CONTENTS, ALLOC, LOAD, DATA
3 .data 00019a20 000000010061f000 000000010061f000 0021de00 2**4
CONTENTS, ALLOC, LOAD, DATA
4 .rodata.ttf.init 00036e10 0000000100639000 0000000100639000
00237a00 2**2
CONTENTS, ALLOC, LOAD, DATA
5 .rodata.splash.init 00001b20 0000000100670000 0000000100670000
0026ea00 2**2
CONTENTS, ALLOC, LOAD, DATA
6 .rodata.helloworld.init 00003030 0000000100672000
0000000100672000 00270600 2**2
CONTENTS, ALLOC, LOAD, DATA
7 .data.efi_runtime 00000170 0000000100676000 0000000100676000
00273800 2**4
CONTENTS, ALLOC, LOAD, DATA
8 .dtb.init.rodata 000007c0 0000000100677000 0000000100677000
00273a00 2**2
CONTENTS, ALLOC, LOAD, DATA
9 .rdata 000a3fe0 0000000100678000 0000000100678000 00274200 2**4
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 .buildid 00000035 000000010071c000 000000010071c000 00318200 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 .rodata.efi_runtime 00000400 000000010071d000 000000010071d000
00318400 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 .pdata 0001785c 000000010071e000 000000010071e000 00318800 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 .xdata 00016f58 0000000100736000 0000000100736000 00330200 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
14 .bss 0001ecc0 000000010074d000 000000010074d000 00000000 2**4
ALLOC
15 .idata 00000894 000000010076c000 000000010076c000 00347200 2**2
CONTENTS, ALLOC, LOAD, DATA
16 .rsrc 000004e8 000000010076d000 000000010076d000 00347c00 2**2
CONTENTS, ALLOC, LOAD, DATA
17 .reloc 00005284 000000010076e000 000000010076e000 00348200 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
18 .debug_aranges 0000b720 0000000100774000 0000000100774000 0034d600 2**0
CONTENTS, READONLY, DEBUGGING
19 .debug_info 00a6c954 0000000100780000 0000000100780000 00358e00 2**0
CONTENTS, READONLY, DEBUGGING
20 .debug_abbrev 000cb6b2 00000001011ed000 00000001011ed000 00dc5800 2**0
CONTENTS, READONLY, DEBUGGING
21 .debug_line 001f646a 00000001012b9000 00000001012b9000 00e91000 2**0
CONTENTS, READONLY, DEBUGGING
22 .debug_frame 000a9bd0 00000001014b0000 00000001014b0000 01087600 2**0
CONTENTS, READONLY, DEBUGGING
23 .debug_str 0001d6c1 000000010155a000 000000010155a000 01131200 2**0
CONTENTS, READONLY, DEBUGGING
24 .debug_loc 004673a1 0000000101578000 0000000101578000 0114ea00 2**0
CONTENTS, READONLY, DEBUGGING
25 .debug_ranges 00060260 00000001019e0000 00000001019e0000 015b5e00 2**0
CONTENTS, READONLY, DEBUGGING
26 .debug_line_str 00000264 0000000101a41000 0000000101a41000 01616200 2**0
CONTENTS, READONLY, DEBUGGING
sglass at DESKTOP-OHNGJ4K MINGW64 ~/u-boot
$ !$
/tmp/b/sandbox/u-boot.exe
-bash: /tmp/b/sandbox/u-boot.exe: cannot execute binary file: Exec format error
Regards,
Simon
[1] https://drive.google.com/file/d/1vtJlvCd1BxkhRtQtUe4YqiRizcUP_zB2/view?usp=share_link
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