modpost: introduce get_basename() helper

The logic to retrieve the basename appears multiple times.
Factor out the common pattern into a helper function.

I copied kbasename() from include/linux/str

modpost: introduce get_basename() helper

The logic to retrieve the basename appears multiple times.
Factor out the common pattern into a helper function.

I copied kbasename() from include/linux/string.h and renamed it
to get_basename().

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>

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kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS

Linus observed that the symbol_request(utf8_data_table) call fails when
CONFIG_UNICODE=y and CONFIG_TRIM_UNUSED_KSYMS=y.

sym

kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS

Linus observed that the symbol_request(utf8_data_table) call fails when
CONFIG_UNICODE=y and CONFIG_TRIM_UNUSED_KSYMS=y.

symbol_get() relies on the symbol data being present in the ksymtab for
symbol lookups. However, EXPORT_SYMBOL_GPL(utf8_data_table) is dropped
due to CONFIG_TRIM_UNUSED_KSYMS, as no module references it in this case.

Probably, this has been broken since commit dbacb0ef670d ("kconfig option
for TRIM_UNUSED_KSYMS").

This commit addresses the issue by leveraging modpost. Symbol names
passed to symbol_get() are recorded in the special .no_trim_symbol
section, which is then parsed by modpost to forcibly keep such symbols.
The .no_trim_symbol section is discarded by the linker scripts, so there
is no impact on the size of the final vmlinux or modules.

This commit cannot resolve the issue for direct calls to __symbol_get()
because the symbol name is not known at compile-time.

Although symbol_get() may eventually be deprecated, this workaround
should be good enough meanwhile.

Reported-by: Linus Torvalds <[email protected]>
Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

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modpost: work around unaligned data access error

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

Since binutils commit 1f1b5e506bf0 ("bfd/ELF

modpost: work around unaligned data access error

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 <[email protected]>
Reported-by: Matthias Klose <[email protected]>
Closes: https://sourceware.org/bugzilla/show_bug.cgi?id=32435
Reported-by: John Paul Adrian Glaubitz <[email protected]>
Closes: https://sourceware.org/bugzilla/show_bug.cgi?id=32493
Signed-off-by: Masahiro Yamada <[email protected]>
Tested-by: John Paul Adrian Glaubitz <[email protected]>

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modpost: distinguish same module paths from different dump files

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

modpost: distinguish same module paths from different dump files

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 <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Masahiro Yamada <[email protected]>
Tested-by: Jon Hunter <[email protected]>

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modpost: move strstarts() to modpost.h

This macro is useful in file2alias.c as well.

Signed-off-by: Masahiro Yamada <[email protected]>

modpost: introduce module_alias_printf() helper

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

However, this is not flexible enough for several subsystems

modpost: introduce module_alias_printf() helper

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 <[email protected]>

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modpost: simplify modpost_log()

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 variab

modpost: simplify modpost_log()

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 <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>

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

I think x*alloc() functions are cleaner.

Signed-off-by: Masahiro Yamada <[email protected]>

modpost: detect endianness on run-time

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 modpos

modpost: detect endianness on run-time

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 <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>

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

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

These headers will be usef

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

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 <[email protected]>

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modpost: avoid using the alias attribute

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

scripts/mod/modpo

modpost: avoid using the alias attribute

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 <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Masahiro Yamada <[email protected]>

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modpost: inform compilers that fatal() never returns

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

Inform compilers of this fact so that unreachab

modpost: inform compilers that fatal() never returns

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 <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>

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modpost: move __attribute__((format(printf, 2, 3))) to modpost.h

This attribute must be added to the function declaration in a header
for comprehensive checking of all the callsites.

Fixes: 6d9a89e

modpost: move __attribute__((format(printf, 2, 3))) to modpost.h

This attribute must be added to the function declaration in a header
for comprehensive checking of all the callsites.

Fixes: 6d9a89ea4b06 ("kbuild: declare the modpost error functions as printf like")
Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>

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modpost: define TO_NATIVE() using bswap_* functions

The current TO_NATIVE() has some limitations:

1) You cannot cast the argument.

2) You cannot pass a variable marked as 'const'.

3) Passing a

modpost: define TO_NATIVE() using bswap_* functions

The current TO_NATIVE() has some limitations:

1) You cannot cast the argument.

2) You cannot pass a variable marked as 'const'.

3) Passing an array is a bug, but it is not detected.

Impelement TO_NATIVE() using bswap_*() functions. These are GNU
extensions. If we face portability issues, we can port the code from
include/uapi/linux/swab.h.

With this change, get_rel_type_and_sym() can be simplified by casting
the arguments directly.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: Optimize symbol search from linear to binary search

Modify modpost to use binary search for converting addresses back
into symbol references. Previously it used linear search.

This change

modpost: Optimize symbol search from linear to binary search

Modify modpost to use binary search for converting addresses back
into symbol references. Previously it used linear search.

This change saves a few seconds of wall time for defconfig builds,
but can save several minutes on allyesconfigs.

Before:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
198.38user 1.27system 3:19.71elapsed

After:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
11.91user 0.85system 0:12.78elapsed

Signed-off-by: Jack Brennen <[email protected]>
Tested-by: Nick Desaulniers <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

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modpost: clean up MIPS64 little endian relocation code

MIPS64 little endian target has an odd encoding of r_info.

This commit makes the special handling less ugly. It is still ugly,
but #if conditi

modpost: clean up MIPS64 little endian relocation code

MIPS64 little endian target has an odd encoding of r_info.

This commit makes the special handling less ugly. It is still ugly,
but #if conditionals will go away, at least.

Signed-off-by: Masahiro Yamada <[email protected]>

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kbuild: generate KSYMTAB entries by modpost

Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPOR

kbuild: generate KSYMTAB entries by modpost

Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPORT_SYMBOL() is placed in *.c or *.S.

For further cleanups, this commit applies a similar approach to the
entire data structure of EXPORT_SYMBOL().

The EXPORT_SYMBOL() compilation is split into two stages.

When a source file is compiled, EXPORT_SYMBOL() will be converted into
a dummy symbol in the .export_symbol section.

For example,

EXPORT_SYMBOL(foo);
EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE);

will be encoded into the following assembly code:

.section ".export_symbol","a"
__export_symbol_foo:
.asciz "" /* license */
.asciz "" /* name space */
.balign 8
.quad foo /* symbol reference */
.previous

.section ".export_symbol","a"
__export_symbol_bar:
.asciz "GPL" /* license */
.asciz "BAR_NAMESPACE" /* name space */
.balign 8
.quad bar /* symbol reference */
.previous

They are mere markers to tell modpost the name, license, and namespace
of the symbols. They will be dropped from the final vmlinux and modules
because the *(.export_symbol) will go into /DISCARD/ in the linker script.

Then, modpost extracts all the information about EXPORT_SYMBOL() from the
.export_symbol section, and generates the final C code:

KSYMTAB_FUNC(foo, "", "");
KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE");

KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct
kernel_symbol that will be linked to the vmlinux or a module.

With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S
files, providing the following benefits.

[1] Deprecate EXPORT_DATA_SYMBOL()

In the old days, EXPORT_SYMBOL() was only available in C files. To export
a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file.
arch/arm/kernel/armksyms.c is one example written in the classic manner.

Commit 22823ab419d8 ("EXPORT_SYMBOL() for asm") removed this limitation.
Since then, EXPORT_SYMBOL() can be placed close to the symbol definition
in *.S files. It was a nice improvement.

However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL()
for data objects on some architectures.

In the new approach, modpost checks symbol's type (STT_FUNC or not),
and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly.

There are only two users of EXPORT_DATA_SYMBOL:

EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S)
EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S)

They are transformed as follows and output into .vmlinux.export.c

KSYMTAB_DATA(empty_zero_page, "_gpl", "");
KSYMTAB_DATA(ia64_ivt, "", "");

The other EXPORT_SYMBOL users in ia64 assembly are output as
KSYMTAB_FUNC().

EXPORT_DATA_SYMBOL() is now deprecated.

[2] merge <linux/export.h> and <asm-generic/export.h>

There are two similar header implementations:

include/linux/export.h for .c files
include/asm-generic/export.h for .S files

Ideally, the functionality should be consistent between them, but they
tend to diverge.

Commit 8651ec01daed ("module: add support for symbol namespaces.") did
not support the namespace for *.S files.

This commit shifts the essential implementation part to C, which supports
EXPORT_SYMBOL_NS() for *.S files.

<asm/export.h> and <asm-generic/export.h> will remain as a wrapper of
<linux/export.h> for a while.

They will be removed after #include <asm/export.h> directives are all
replaced with #include <linux/export.h>.

[3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit)

When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.

We can do this better now; modpost can selectively emit KSYMTAB entries
that are really used by modules.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: remove is_shndx_special() check from section_rel(a)

This check is unneeded. Without it, sec_name() will returns the null
string "", then section_mismatch() will return immediately.

Anyway,

modpost: remove is_shndx_special() check from section_rel(a)

This check is unneeded. Without it, sec_name() will returns the null
string "", then section_mismatch() will return immediately.

Anyway, special section indices rarely appear in these loops.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: refactor get_secindex()

SPECIAL() is only used in get_secindex(). Squash it.

Make the code more readable with more comments.

Signed-off-by: Masahiro Yamada <[email protected]>

modpost: remove unused Elf_Sword macro

Commit 9ad21c3f3ecf ("kbuild: try harder to find symbol names in
modpost") added Elf_Sword (in a wrong way), but did not use it at all.

BTW, the current code

modpost: remove unused Elf_Sword macro

Commit 9ad21c3f3ecf ("kbuild: try harder to find symbol names in
modpost") added Elf_Sword (in a wrong way), but did not use it at all.

BTW, the current code looks weird.

The fix for the 32-bit part would be:

Elf64_Sword --> Elf32_Sword

(inconsistet prefix, Elf32_ vs Elf64_)

The fix for the 64-bit part would be:

Elf64_Sxword --> Elf64_Sword

(the size is different between Sword and Sxword)

Note:

Elf32_Sword == Elf64_Sword == int32_t
Elf32_Sxword == Elf64_Sxword == int64_t

Anyway, let's drop unused code instead of fixing it.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: use sym_get_data() to get module device_table data

Use sym_get_data() to replace the long code.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <ndesaul

modpost: use sym_get_data() to get module device_table data

Use sym_get_data() to replace the long code.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: reuse ARRAY_SIZE() macro for section_mismatch()

Move ARRAY_SIZE() from file2alias.c to modpost.h to reuse it in
section_mismatch().

Also, move the variable 'check' inside the for-loop.

Si

modpost: reuse ARRAY_SIZE() macro for section_mismatch()

Move ARRAY_SIZE() from file2alias.c to modpost.h to reuse it in
section_mismatch().

Also, move the variable 'check' inside the for-loop.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: remove left-over cross_compile declaration

This is a remnant of commit 6543becf26ff ("mod/file2alias: make
modalias generation safe for cross compiling").

Signed-off-by: Masahiro Yamada <m

modpost: remove left-over cross_compile declaration

This is a remnant of commit 6543becf26ff ("mod/file2alias: make
modalias generation safe for cross compiling").

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: dump Module.symvers in the same order of modules.order

modpost dumps the exported symbols into Module.symvers, but currently
in random order because it iterates in the hash table.

Add a li

modpost: dump Module.symvers in the same order of modules.order

modpost dumps the exported symbols into Module.symvers, but currently
in random order because it iterates in the hash table.

Add a linked list of exported symbols in struct module, so we can
iterate on symbols per module.

This commit makes Module.symvers much more readable; the outer loop in
write_dump() iterates over the modules in the order of modules.order,
and the inner loop dumps symbols in each module.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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modpost: traverse the namespace_list in order

Use the doubly linked list to traverse the list in the added order.
This makes the code more consistent.

Signed-off-by: Masahiro Yamada <masahiroy@kern

modpost: traverse the namespace_list in order

Use the doubly linked list to traverse the list in the added order.
This makes the code more consistent.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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