linux-toradex.git/scripts/mod/modpost.h, branch v6.13

modpost: work around unaligned data access error

2024-12-28T14:31:09+00:00

With the latest binutils, modpost fails with a bus error on some
architectures such as ARM and sparc64.

Since binutils commit 1f1b5e506bf0 ("bfd/ELF: restrict file alignment
for object files"), the byte offset to each section (sh_offset) in
relocatable ELF is no longer guaranteed to be aligned.

modpost parses MODULE_DEVICE_TABLE() data structures, which are usually
located in the .rodata section. If it is not properly aligned, unaligned
access errors may occur.

To address the issue, this commit imports the get_unaligned() helper
from include/linux/unaligned.h.

The get_unaligned_native() helper caters to the endianness in addition
to handling the unaligned access.

I slightly refactored do_pcmcia_entry() and do_input() to avoid writing
back to an unaligned address. (We would need the put_unaligned() helper
to do that.)

The addend_*_rel() functions need similar adjustments because the .text
sections are not aligned either.

It seems that the .symtab, .rel.* and .rela.* sections are still aligned.
Keep normal pointer access for these sections to avoid unnecessary
performance costs.

Reported-by: Paulo Pisati 
Reported-by: Matthias Klose 
Closes: https://sourceware.org/bugzilla/show_bug.cgi?id=32435
Reported-by: John Paul Adrian Glaubitz 
Closes: https://sourceware.org/bugzilla/show_bug.cgi?id=32493
Signed-off-by: Masahiro Yamada 
Tested-by: John Paul Adrian Glaubitz

modpost: distinguish same module paths from different dump files

2024-12-21T03:42:10+00:00

Since commit 13b25489b6f8 ("kbuild: change working directory to external
module directory with M="), module paths are always relative to the top
of the external module tree.

The module paths recorded in Module.symvers are no longer globally unique
when they are passed via KBUILD_EXTRA_SYMBOLS for building other external
modules, which may result in false-positive "exported twice" errors.
Such errors should not occur because external modules should be able to
override in-tree modules.

To address this, record the dump file path in struct module and check it
when searching for a module.

Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=")
Reported-by: Jon Hunter 
Closes: https://lore.kernel.org/all/eb21a546-a19c-40df-b821-bbba80f19a3d@nvidia.com/
Signed-off-by: Masahiro Yamada 
Tested-by: Jon Hunter

modpost: move strstarts() to modpost.h

2024-11-27T23:46:02+00:00

This macro is useful in file2alias.c as well.

Signed-off-by: Masahiro Yamada

modpost: introduce module_alias_printf() helper

2024-11-27T23:42:58+00:00

The generic ->do_entry() handler is currently limited to returning
a single alias string.

However, this is not flexible enough for several subsystems, which
currently require their own implementations:

 - do_usb_table()
 - do_of_table()
 - do_pnp_device_entry()
 - do_pnp_card_entries()

This commit introduces a helper function so that these special cases can
add multiple MODULE_ALIAS() and then migrate to the generic framework.

Signed-off-by: Masahiro Yamada

modpost: simplify modpost_log()

2024-09-01T11:34:50+00:00

With commit cda5f94e88b4 ("modpost: avoid using the alias attribute"),
only two log levels remain: LOG_WARN and LOG_ERROR. Simplify this by
making it a boolean variable.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nathan Chancellor

modpost: replace the use of NOFAIL() with xmalloc() etc.

2024-09-01T11:34:48+00:00

I think x*alloc() functions are cleaner.

Signed-off-by: Masahiro Yamada

modpost: detect endianness on run-time

2024-09-01T11:33:32+00:00

Endianness is currently detected on compile-time, but we can defer this
until run-time. This change avoids re-executing scripts/mod/mk_elfconfig
even if modpost in the linux-headers package needs to be rebuilt for a
foreign architecture.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nicolas Schier

kbuild: move some helper headers from scripts/kconfig/ to scripts/include/

2024-07-21T14:10:43+00:00

Move array_size.h, hashtable.h, list.h, list_types.h from scripts/kconfig/
to scripts/include/.

These headers will be useful for other host programs.

Remove scripts/mod/list.h.

Signed-off-by: Masahiro Yamada

modpost: avoid using the alias attribute

2024-01-31T14:24:27+00:00

Aiden Leong reported modpost fails to build on macOS since commit
16a473f60edc ("modpost: inform compilers that fatal() never returns"):

  scripts/mod/modpost.c:93:21: error: aliases are not supported on darwin

Nathan's research indicates that Darwin seems to support weak aliases
at least [1]. Although the situation might be improved in future Clang
versions, we can achieve a similar outcome without relying on it.

This commit makes fatal() a macro of error() + exit(1) in modpost.h, as
compilers recognize that exit() never returns.

[1]: https://github.com/llvm/llvm-project/issues/71001

Fixes: 16a473f60edc ("modpost: inform compilers that fatal() never returns")
Reported-by: Aiden Leong 
Closes: https://lore.kernel.org/all/d9ac2960-6644-4a87-b5e4-4bfb6e0364a8@aibsd.com/
Signed-off-by: Masahiro Yamada

modpost: inform compilers that fatal() never returns

2023-12-10T06:34:37+00:00

The function fatal() never returns because modpost_log() calls exit(1)
when LOG_FATAL is passed.

Inform compilers of this fact so that unreachable code flow can be
identified at compile time.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nathan Chancellor