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<title>user/sven/linux.git/kernel/module/internal.h, branch v6.14.9</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2025-01-31T20:07:07Z</updated>
<entry>
<title>Merge tag 'kbuild-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild</title>
<updated>2025-01-31T20:07:07Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-01-31T20:07:07Z</published>
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<id>urn:sha1:fd8c09ad0d87783b9b6a27900d66293be45b7bad</id>
<content type='text'>
Pull Kbuild updates from Masahiro Yamada:

 - Support multiple hook locations for maint scripts of Debian package

 - Remove 'cpio' from the build tool requirement

 - Introduce gendwarfksyms tool, which computes CRCs for export symbols
   based on the DWARF information

 - Support CONFIG_MODVERSIONS for Rust

 - Resolve all conflicts in the genksyms parser

 - Fix several syntax errors in genksyms

* tag 'kbuild-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (64 commits)
  kbuild: fix Clang LTO with CONFIG_OBJTOOL=n
  kbuild: Strip runtime const RELA sections correctly
  kconfig: fix memory leak in sym_warn_unmet_dep()
  kconfig: fix file name in warnings when loading KCONFIG_DEFCONFIG_LIST
  genksyms: fix syntax error for attribute before init-declarator
  genksyms: fix syntax error for builtin (u)int*x*_t types
  genksyms: fix syntax error for attribute after 'union'
  genksyms: fix syntax error for attribute after 'struct'
  genksyms: fix syntax error for attribute after abstact_declarator
  genksyms: fix syntax error for attribute before nested_declarator
  genksyms: fix syntax error for attribute before abstract_declarator
  genksyms: decouple ATTRIBUTE_PHRASE from type-qualifier
  genksyms: record attributes consistently for init-declarator
  genksyms: restrict direct-declarator to take one parameter-type-list
  genksyms: restrict direct-abstract-declarator to take one parameter-type-list
  genksyms: remove Makefile hack
  genksyms: fix last 3 shift/reduce conflicts
  genksyms: fix 6 shift/reduce conflicts and 5 reduce/reduce conflicts
  genksyms: reduce type_qualifier directly to decl_specifier
  genksyms: rename cvar_qualifier to type_qualifier
  ...
</content>
</entry>
<entry>
<title>module: Split module_enable_rodata_ro()</title>
<updated>2025-01-26T12:05:24Z</updated>
<author>
<name>Christophe Leroy</name>
<email>christophe.leroy@csgroup.eu</email>
</author>
<published>2024-12-05T19:46:15Z</published>
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<id>urn:sha1:097fd001e1c42b5fd0a6d77cbd855ce373d7e7a2</id>
<content type='text'>
module_enable_rodata_ro() is called twice, once before module init
to set rodata sections readonly and once after module init to set
rodata_after_init section readonly.

The second time, only the rodata_after_init section needs to be
set to read-only, no need to re-apply it to already set rodata.

Split module_enable_rodata_ro() in two.

Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Tested-by: Daniel Gomez &lt;da.gomez@samsung.com&gt;
Reviewed-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Link: https://lore.kernel.org/r/e3b6ff0df7eac281c58bb02cecaeb377215daff3.1733427536.git.christophe.leroy@csgroup.eu
Signed-off-by: Petr Pavlu &lt;petr.pavlu@suse.com&gt;
</content>
</entry>
<entry>
<title>module: Constify 'struct module_attribute'</title>
<updated>2025-01-26T12:05:23Z</updated>
<author>
<name>Thomas Weißschuh</name>
<email>linux@weissschuh.net</email>
</author>
<published>2024-12-16T17:25:10Z</published>
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<id>urn:sha1:f3227ffda07470848abe3cfa2039b21816ce3090</id>
<content type='text'>
These structs are never modified, move them to read-only memory.
This makes the API clearer and also prepares for the constification of
'struct attribute' itself.

While at it, also constify 'modinfo_attrs_count'.

Signed-off-by: Thomas Weißschuh &lt;linux@weissschuh.net&gt;
Reviewed-by: Petr Pavlu &lt;petr.pavlu@suse.com&gt;
Link: https://lore.kernel.org/r/20241216-sysfs-const-attr-module-v1-3-3790b53e0abf@weissschuh.net
Signed-off-by: Petr Pavlu &lt;petr.pavlu@suse.com&gt;
</content>
</entry>
<entry>
<title>modules: Support extended MODVERSIONS info</title>
<updated>2025-01-10T16:25:26Z</updated>
<author>
<name>Matthew Maurer</name>
<email>mmaurer@google.com</email>
</author>
<published>2025-01-03T17:37:01Z</published>
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<id>urn:sha1:54ac1ac8edeb74ff87fc880d1ee58785bdcbe323</id>
<content type='text'>
Adds a new format for MODVERSIONS which stores each field in a separate
ELF section. This initially adds support for variable length names, but
could later be used to add additional fields to MODVERSIONS in a
backwards compatible way if needed. Any new fields will be ignored by
old user tooling, unlike the current format where user tooling cannot
tolerate adjustments to the format (for example making the name field
longer).

Since PPC munges its version records to strip leading dots, we reproduce
the munging for the new format. Other architectures do not appear to
have architecture-specific usage of this information.

Reviewed-by: Sami Tolvanen &lt;samitolvanen@google.com&gt;
Signed-off-by: Matthew Maurer &lt;mmaurer@google.com&gt;
Signed-off-by: Masahiro Yamada &lt;masahiroy@kernel.org&gt;
</content>
</entry>
<entry>
<title>module: get symbol CRC back to unsigned</title>
<updated>2025-01-10T14:01:22Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>masahiroy@kernel.org</email>
</author>
<published>2024-12-28T15:45:28Z</published>
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<id>urn:sha1:1cd9502ee9275c6176a7312863f939cca9506114</id>
<content type='text'>
Commit 71810db27c1c ("modversions: treat symbol CRCs as 32 bit
quantities") changed the CRC fields to s32 because the __kcrctab and
__kcrctab_gpl sections contained relative references to the actual
CRC values stored in the .rodata section when CONFIG_MODULE_REL_CRCS=y.

Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") removed this complexity. Now, the __kcrctab
and __kcrctab_gpl sections directly contain the CRC values in all cases.

The genksyms tool outputs unsigned 32-bit CRC values, so u32 is preferred
over s32.

No functional changes are intended.

Regardless of this change, the CRC value is assigned to the u32 variable
'crcval' before the comparison, as seen in kernel/module/version.c:

    crcval = *crc;

It was previously mandatory (but now optional) in order to avoid sign
extension because the following line previously compared 'unsigned long'
and 's32':

    if (versions[i].crc == crcval)
            return 1;

versions[i].crc is still 'unsigned long' for backward compatibility.

Signed-off-by: Masahiro Yamada &lt;masahiroy@kernel.org&gt;
Reviewed-by: Petr Pavlu &lt;petr.pavlu@suse.com&gt;
</content>
</entry>
<entry>
<title>module: Reformat struct for code style</title>
<updated>2024-10-19T22:02:00Z</updated>
<author>
<name>Matthew Maurer</name>
<email>mmaurer@google.com</email>
</author>
<published>2024-10-15T23:16:46Z</published>
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<id>urn:sha1:2295cf87ed5a6da4564034e4f8ebcce0a0a021ed</id>
<content type='text'>
Using commas to declare struct members makes adding new members to this
struct not as nice with patch management.

Test results linux-modules-kpd succeed [0].

Signed-off-by: Matthew Maurer &lt;mmaurer@google.com&gt;
Reviewed-by: Sami Tolvanen &lt;samitolvanen@google.com&gt;
[mcgrof: add automated test results from kdevops using KPD ]
Link: https://github.com/linux-kdevops/linux-modules-kpd/actions/runs/11420095343 # [0]
Signed-off-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
</content>
</entry>
<entry>
<title>module: Don't ignore errors from set_memory_XX()</title>
<updated>2024-02-16T19:30:43Z</updated>
<author>
<name>Christophe Leroy</name>
<email>christophe.leroy@csgroup.eu</email>
</author>
<published>2024-02-16T08:14:27Z</published>
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<id>urn:sha1:d1909c0221739356f31c721de4743e7d219a56cc</id>
<content type='text'>
set_memory_ro(), set_memory_nx(), set_memory_x() and other helpers
can fail and return an error. In that case the memory might not be
protected as expected and the module loading has to be aborted to
avoid security issues.

Check return value of all calls to set_memory_XX() and handle
error if any.

Add a check to not call set_memory_XX() on NULL pointers as some
architectures may not like it allthough numpages is always 0 in that
case. This also avoid a useless call to set_vm_flush_reset_perms().

Link: https://github.com/KSPP/linux/issues/7
Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Tested-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
</content>
</entry>
<entry>
<title>module: Change module_enable_{nx/x/ro}() to more explicit names</title>
<updated>2024-01-29T20:00:31Z</updated>
<author>
<name>Christophe Leroy</name>
<email>christophe.leroy@csgroup.eu</email>
</author>
<published>2023-12-21T07:24:24Z</published>
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<id>urn:sha1:3559ad395bf02f3dee576dc9acab4ce330ce57b5</id>
<content type='text'>
It's a bit puzzling to see a call to module_enable_nx() followed by a
call to module_enable_x(). This is because one applies on text while
the other applies on data.

Change name to make that more clear.

Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
</content>
</entry>
<entry>
<title>module: Use set_memory_rox()</title>
<updated>2024-01-29T20:00:31Z</updated>
<author>
<name>Christophe Leroy</name>
<email>christophe.leroy@csgroup.eu</email>
</author>
<published>2023-12-21T07:24:23Z</published>
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<id>urn:sha1:ac88ee7d2b87c1f93b89fd9ce5911c2ab2bda816</id>
<content type='text'>
A couple of architectures seem concerned about calling set_memory_ro()
and set_memory_x() too frequently and have implemented a version of
set_memory_rox(), see commit 60463628c9e0 ("x86/mm: Implement native
set_memory_rox()") and commit 22e99fa56443 ("s390/mm: implement
set_memory_rox()")

Use set_memory_rox() in modules when STRICT_MODULES_RWX is set.

Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
</content>
</entry>
<entry>
<title>kbuild: generate KSYMTAB entries by modpost</title>
<updated>2023-06-22T12:17:10Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>masahiroy@kernel.org</email>
</author>
<published>2023-06-11T15:50:52Z</published>
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<id>urn:sha1:ddb5cdbafaaad6b99d7007ae1740403124502d03</id>
<content type='text'>
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 &lt;linux/export.h&gt; and &lt;asm-generic/export.h&gt;

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.

&lt;asm/export.h&gt; and &lt;asm-generic/export.h&gt; will remain as a wrapper of
&lt;linux/export.h&gt; for a while.

They will be removed after #include &lt;asm/export.h&gt; directives are all
replaced with #include &lt;linux/export.h&gt;.

[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 &lt;masahiroy@kernel.org&gt;
Reviewed-by: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
</content>
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