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 <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

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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 <masahiroy@kernel.org>

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 <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

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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 <masahiroy@kernel.org>

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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 <aiden.leong@aibsd.com>
Closes: https://lore.kernel.org/all/d9ac2960-6644-4a87-b5e4-4bfb6e0364a8@aibsd.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

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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 <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

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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 <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <jbrennen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

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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 <masahiroy@kernel.org>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>

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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>
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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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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 <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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modpost: traverse unresolved symbols in order

Currently, modpost manages unresolved in a singly linked list; it adds
a new node to the head, and traverses the list from new to old.

Use a doubly lin

modpost: traverse unresolved symbols in order

Currently, modpost manages unresolved in a singly linked list; it adds
a new node to the head, and traverses the list from new to old.

Use a doubly linked list to keep the order in the symbol table in the
ELF file.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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modpost: traverse modules in order

Currently, modpost manages modules in a singly linked list; it adds
a new node to the head, and traverses the list from new to old.

It works, but the error messag

modpost: traverse modules in order

Currently, modpost manages modules in a singly linked list; it adds
a new node to the head, and traverses the list from new to old.

It works, but the error messages are shown in the reverse order.

If you have a Makefile like this:

obj-m += foo.o bar.o

then, modpost shows error messages in bar.o, foo.o, in this order.

Use a doubly linked list to keep the order in modules.order; use
list_add_tail() for the node addition and list_for_each_entry() for
the list traverse.

Now that the kernel's list macros have been imported to modpost, I will
use them actively going forward.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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modpost: change mod->gpl_compatible to bool type

Currently, mod->gpl_compatible is tristate; it is set to -1 by default,
then to 1 or 0 when MODULE_LICENSE() is found.

Maybe, -1 was chosen to repre

modpost: change mod->gpl_compatible to bool type

Currently, mod->gpl_compatible is tristate; it is set to -1 by default,
then to 1 or 0 when MODULE_LICENSE() is found.

Maybe, -1 was chosen to represent the 'unknown' license, but it is not
useful.

The current code:

if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);

... only cares whether gpl_compatible is zero or not.

Change it to a bool type with the initial value 'true', which has no
functional change.

The default value should be 'true' instead of 'false'.

Since commit 1d6cd3929360 ("modpost: turn missing MODULE_LICENSE() into
error"), unknown module license is an error.

The error message, "missing MODULE_LICENSE()" is enough to explain the
issue. It is not sensible to show another message, "GPL-incompatible
module ... uses GPL-only symbol".

Add comments to explain this.

While I was here, I renamed gpl_compatible to is_gpl_compatible for
clarification, and also slightly refactored the code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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modpost: use bool type where appropriate

Use 'bool' to clarify that the valid value is true or false.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulnie

modpost: use bool type where appropriate

Use 'bool' to clarify that the valid value is true or false.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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modpost: move struct namespace_list to modpost.c

There is no good reason to define struct namespace_list in modpost.h

struct module has pointers to struct namespace_list, but that does
not require

modpost: move struct namespace_list to modpost.c

There is no good reason to define struct namespace_list in modpost.h

struct module has pointers to struct namespace_list, but that does
not require the definition of struct namespace_list.

Move it to modpost.c.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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modpost: remove useless export_from_sec()

With commit 1743694eb235 ("modpost: stop symbol preloading for
modversion CRC") applied, now export_from_sec() is useless.

handle_symbol() is called for ev

modpost: remove useless export_from_sec()

With commit 1743694eb235 ("modpost: stop symbol preloading for
modversion CRC") applied, now export_from_sec() is useless.

handle_symbol() is called for every symbol in the ELF.

When 'symname' does not start with "__ksymtab", export_from_sec() is
called, and the returned value is stored in 'export'.

It is used in the last part of handle_symbol():

if (strstarts(symname, "__ksymtab_")) {
name = symname + strlen("__ksymtab_");
sym_add_exported(name, mod, export);
}

'export' is used only when 'symname' starts with "__ksymtab_".

So, the value returned by export_from_sec() is never used.

Remove useless export_from_sec(). This makes further cleanups possible.

I put the temporary code:

export = export_unknown;

Otherwise, I would get the compiler warning:

warning: 'export' may be used uninitialized in this function [-Wmaybe-uninitialized]

This is apparently false positive because

if (strstarts(symname, "__ksymtab_")

... is a stronger condition than:

if (strstarts(symname, "__ksymtab")

Anyway, this part will be cleaned up by the next commit.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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