[U-Boot,v1] tools/imagetool: remove linker script

Commit a93648d197df48fa46dd55f925ff70468bd81c71 introduced linker generated
lists for imagetool which is the base for some host tools (mkimage, dumpimage,
et al.).  Unfortunately some host tool chains do not support the used type of
linker scripts. Therefore this commit broke these host-tools for them, namely
FreeBSD and Darwin (OS/X).

This commit tries to fix this. In order to have a clean distinction between host
and embedded code space we need to introduce our own linker generated list
instead of re-using the available linker_lists.h provided functionality.  So we
copy the implementation used in linux kernel script/mod/file2alias.c which has
the very same problem (cause it is a host tool). This code also comes with an
abstraction for Mach-O binary format used in Darwin systems.

Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
Cc: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
---
It is highly encouraged to have a clear distinction between host stuff and
embedded stuff. We have the __KERNEL__/__UBOOT__ preprocessor directive to do
so, lets respect it and do not pollute the host space with the embedded stuff.

Wait a minute ... wasn't there a stdint.h discussion these
days? Isn't this exactly the same thing but the other way round?

Changes in v1:
- disable ASLR for host tools on OS X, it generates a linker warning

 Makefile            |    5 +++++
 tools/Makefile      |    2 --
 tools/imagetool.c   |   35 ++++++++++++++++----------------
 tools/imagetool.h   |   56 +++++++++++++++++++++++++++++++++++++++++----------
 tools/imagetool.lds |   24 ----------------------
 5 files changed, 67 insertions(+), 55 deletions(-)
 delete mode 100644 tools/imagetool.lds

Hi Andreas,

On 8 February 2015 at 16:06, Andreas Bießmann
<andreas.devel@googlemail.com> wrote:
> Commit a93648d197df48fa46dd55f925ff70468bd81c71 introduced linker generated
> lists for imagetool which is the base for some host tools (mkimage, dumpimage,
> et al.).  Unfortunately some host tool chains do not support the used type of
> linker scripts. Therefore this commit broke these host-tools for them, namely
> FreeBSD and Darwin (OS/X).
>
> This commit tries to fix this. In order to have a clean distinction between host
> and embedded code space we need to introduce our own linker generated list
> instead of re-using the available linker_lists.h provided functionality.  So we
> copy the implementation used in linux kernel script/mod/file2alias.c which has
> the very same problem (cause it is a host tool). This code also comes with an
> abstraction for Mach-O binary format used in Darwin systems.
>
> Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
> Cc: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
> ---
> It is highly encouraged to have a clear distinction between host stuff and
> embedded stuff. We have the __KERNEL__/__UBOOT__ preprocessor directive to do
> so, lets respect it and do not pollute the host space with the embedded stuff.

I think this is a reference ot the defining of __KERNEL__ in
imagetool.h. That is apparently needed for linker_lists.h although I
really don't see why. It should be possible to adjust either
compiler.h or linker_lsits.h to work around this.

>
> Wait a minute ... wasn't there a stdint.h discussion these
> days? Isn't this exactly the same thing but the other way round?

I think that is a separate topic and as mentioned there I feel this is
a feature of the toolchain, not the host.

>
> Changes in v1:
> - disable ASLR for host tools on OS X, it generates a linker warning
>
>  Makefile            |    5 +++++
>  tools/Makefile      |    2 --
>  tools/imagetool.c   |   35 ++++++++++++++++----------------
>  tools/imagetool.h   |   56 +++++++++++++++++++++++++++++++++++++++++----------
>  tools/imagetool.lds |   24 ----------------------
>  5 files changed, 67 insertions(+), 55 deletions(-)
>  delete mode 100644 tools/imagetool.lds
>
> diff --git a/Makefile b/Makefile
> index 92faed6..aca8587 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -281,6 +281,11 @@ os_x_before        = $(shell if [ $(DARWIN_MAJOR_VERSION) -le $(1) -a \
>  HOSTCC       = $(call os_x_before, 10, 5, "cc", "gcc")
>  HOSTCFLAGS  += $(call os_x_before, 10, 4, "-traditional-cpp")
>  HOSTLDFLAGS += $(call os_x_before, 10, 5, "-multiply_defined suppress")
> +
> +# since Lion (10.7) ASLR is on by default, but we use linker generated lists
> +# in some host tools which is a problem then ... so disable ASLR for these
> +# tools
> +HOSTLDFLAGS += $(call os_x_before, 10, 7, "", "-Xlinker -no_pie")
>  endif
>
>  # Decide whether to build built-in, modular, or both.
> diff --git a/tools/Makefile b/tools/Makefile
> index 6e1ce79..ea76a3e 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -124,8 +124,6 @@ HOSTLOADLIBES_dumpimage := $(HOSTLOADLIBES_mkimage)
>  HOSTLOADLIBES_fit_info := $(HOSTLOADLIBES_mkimage)
>  HOSTLOADLIBES_fit_check_sign := $(HOSTLOADLIBES_mkimage)
>
> -HOSTLDFLAGS += -T $(srctree)/tools/imagetool.lds
> -
>  hostprogs-$(CONFIG_EXYNOS5250) += mkexynosspl
>  hostprogs-$(CONFIG_EXYNOS5420) += mkexynosspl
>  HOSTCFLAGS_mkexynosspl.o := -pedantic
> diff --git a/tools/imagetool.c b/tools/imagetool.c
> index 148e466..4b0b73d 100644
> --- a/tools/imagetool.c
> +++ b/tools/imagetool.c
> @@ -12,16 +12,16 @@
>
>  struct image_type_params *imagetool_get_type(int type)
>  {
> -       struct image_type_params *curr;
> -       struct image_type_params *start = ll_entry_start(
> -                       struct image_type_params, image_type);
> -       struct image_type_params *end = ll_entry_end(
> -                       struct image_type_params, image_type);
> +       struct image_type_params **curr;
> +       INIT_SECTION(image_type);
> +
> +       struct image_type_params **start = __start_image_type;
> +       struct image_type_params **end = __stop_image_type;
>
>         for (curr = start; curr != end; curr++) {
> -               if (curr->check_image_type) {
> -                       if (!curr->check_image_type(type))
> -                               return curr;
> +               if ((*curr)->check_image_type) {
> +                       if (!(*curr)->check_image_type(type))
> +                               return *curr;
>                 }
>         }
>         return NULL;
> @@ -34,16 +34,15 @@ int imagetool_verify_print_header(
>         struct image_tool_params *params)
>  {
>         int retval = -1;
> -       struct image_type_params *curr;
> +       struct image_type_params **curr;
> +       INIT_SECTION(image_type);
>
> -       struct image_type_params *start = ll_entry_start(
> -                       struct image_type_params, image_type);
> -       struct image_type_params *end = ll_entry_end(
> -                       struct image_type_params, image_type);
> +       struct image_type_params **start = __start_image_type;
> +       struct image_type_params **end = __stop_image_type;
>
>         for (curr = start; curr != end; curr++) {
> -               if (curr->verify_header) {
> -                       retval = curr->verify_header((unsigned char *)ptr,
> +               if ((*curr)->verify_header) {
> +                       retval = (*curr)->verify_header((unsigned char *)ptr,
>                                                      sbuf->st_size, params);
>
>                         if (retval == 0) {
> @@ -51,12 +50,12 @@ int imagetool_verify_print_header(
>                                  * Print the image information  if verify is
>                                  * successful
>                                  */
> -                               if (curr->print_header) {
> -                                       curr->print_header(ptr);
> +                               if ((*curr)->print_header) {
> +                                       (*curr)->print_header(ptr);
>                                 } else {
>                                         fprintf(stderr,
>                                                 "%s: print_header undefined for %s\n",
> -                                               params->cmdname, curr->name);
> +                                               params->cmdname, (*curr)->name);
>                                 }
>                                 break;
>                         }
> diff --git a/tools/imagetool.h b/tools/imagetool.h
> index f35dec7..3e15b4e 100644
> --- a/tools/imagetool.h
> +++ b/tools/imagetool.h
> @@ -20,15 +20,6 @@
>  #include <unistd.h>
>  #include <u-boot/sha1.h>
>
> -/* define __KERNEL__ in order to get the definitions
> - * required by the linker list. This is probably not
> - * the best way to do this */
> -#ifndef __KERNEL__
> -#define __KERNEL__
> -#include <linker_lists.h>
> -#undef __KERNEL__
> -#endif /* __KERNEL__ */
> -
>  #include "fdt_host.h"
>
>  #define ARRAY_SIZE(x)          (sizeof(x) / sizeof((x)[0]))
> @@ -194,6 +185,46 @@ int imagetool_save_subimage(
>
>  void pbl_load_uboot(int fd, struct image_tool_params *mparams);
>
> +#define ___cat(a, b) a ## b
> +#define __cat(a, b) ___cat(a, b)
> +
> +/* we need some special handling for this host tool running eventually on
> + * Darwin. The Mach-O section handling is a bit different than ELF section
> + * handling. The differnces in detail are:
> + *  a) we have segments which have sections
> + *  b) we need a API call to get the respective section symbols */
> +#if defined(__MACH__)
> +#include <mach-o/getsect.h>
> +
> +#define INIT_SECTION(name)  do {                                       \
> +               unsigned long name ## _len;                             \
> +               char *__cat(pstart_, name) = getsectdata("__TEXT",      \
> +                       #name, &__cat(name, _len));                     \
> +               char *__cat(pstop_, name) = __cat(pstart_, name) +      \
> +                       __cat(name, _len);                              \
> +               __cat(__start_, name) = (void *)__cat(pstart_, name);   \
> +               __cat(__stop_, name) = (void *)__cat(pstop_, name);     \
> +       } while (0)
> +#define SECTION(name)   __attribute__((section("__TEXT, " #name)))
> +
> +struct image_type_params **__start_image_type, **__stop_image_type;
> +#else
> +#define INIT_SECTION(name) /* no-op for ELF */
> +#define SECTION(name)   __attribute__((section(#name)))
> +
> +/* We construct a table of pointers in an ELF section (pointers generally
> + * go unpadded by gcc).  ld creates boundary syms for us. */
> +extern struct image_type_params *__start_image_type[], *__stop_image_type[];
> +#endif /* __MACH__ */

(Repeating as I comment on your RFC patch instead of this)

If I understand this correctly, in both cases we put things in a
separate section so that all the pieces get collected together. The
only difference seems to be the naming of the section - for MACH it
has a __TEXT prefix. Is that right? If so, I wonder if this should go
in linker_list.h?

For access to the data, here we are using a list of pointers to the
struct rather than a list of struct. Why is that? I can't see that
this is required by the MACH system.

If that is correct, then it should be easy to support linker_list on MACH, by:

- Adding a __TEXT prefix to all the section() bits in linker_lists.h
- Changing any access to the lists to use INIT_SECTION instead of
going there directly

Then we should be able to support running sandbox.

Does that sound feasible?

> +
> +#if !defined(__used)
> +# if __GNUC__ == 3 && __GNUC_MINOR__ < 3
> +#  define __used                       __attribute__((__unused__))
> +# else
> +#  define __used                       __attribute__((__used__))
> +# endif
> +#endif
> +
>  #define U_BOOT_IMAGE_TYPE( \
>                 _id, \
>                 _name, \
> @@ -208,7 +239,8 @@ void pbl_load_uboot(int fd, struct image_tool_params *mparams);
>                 _fflag_handle, \
>                 _vrec_header \
>         ) \
> -       ll_entry_declare(struct image_type_params, _id, image_type) = { \
> +       static struct image_type_params __cat(image_type_, _id) = \
> +       { \
>                 .name = _name, \
>                 .header_size = _header_size, \
>                 .hdr = _header, \
> @@ -220,6 +252,8 @@ void pbl_load_uboot(int fd, struct image_tool_params *mparams);
>                 .check_image_type = _check_image_type, \
>                 .fflag_handle = _fflag_handle, \
>                 .vrec_header = _vrec_header \
> -       }
> +       }; \
> +       static struct image_type_params *SECTION(image_type) __used \
> +               __cat(image_type_ptr_, _id) = &__cat(image_type_, _id)
>
>  #endif /* _IMAGETOOL_H_ */
> diff --git a/tools/imagetool.lds b/tools/imagetool.lds
> deleted file mode 100644
> index 7e92b4a..0000000
> --- a/tools/imagetool.lds
> +++ /dev/null
> @@ -1,24 +0,0 @@
> -/*
> - * Copyright (c) 2011-2012 The Chromium OS Authors.
> - * Use of this source code is governed by a BSD-style license that can be
> - * found in the LICENSE file.
> - *
> - * SPDX-License-Identifier:    GPL-2.0+
> - */
> -
> -SECTIONS
> -{
> -
> -       . = ALIGN(4);
> -       .u_boot_list : {
> -               KEEP(*(SORT(.u_boot_list*)));
> -       }
> -
> -       __u_boot_sandbox_option_start = .;
> -       _u_boot_sandbox_getopt : { *(.u_boot_sandbox_getopt) }
> -       __u_boot_sandbox_option_end = .;
> -
> -       __bss_start = .;
> -}
> -
> -INSERT BEFORE .data;
> --
> 1.7.10.4
>

Regards,
Simon

On Mon, Feb 09, 2015 at 12:06:10AM +0100, Andreas Bießmann wrote:

> Commit a93648d197df48fa46dd55f925ff70468bd81c71 introduced linker generated
> lists for imagetool which is the base for some host tools (mkimage, dumpimage,
> et al.).  Unfortunately some host tool chains do not support the used type of
> linker scripts. Therefore this commit broke these host-tools for them, namely
> FreeBSD and Darwin (OS/X).
> 
> This commit tries to fix this. In order to have a clean distinction between host
> and embedded code space we need to introduce our own linker generated list
> instead of re-using the available linker_lists.h provided functionality.  So we
> copy the implementation used in linux kernel script/mod/file2alias.c which has
> the very same problem (cause it is a host tool). This code also comes with an
> abstraction for Mach-O binary format used in Darwin systems.
> 
> Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
> Cc: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>

Applied to u-boot/master, thanks!