Commit Graph

636 Commits

Author SHA1 Message Date
Nathan Chancellor
5953f2c7f8 modpost: Add '.ltext' and '.ltext.*' to TEXT_SECTIONS
commit 397586506c3da005b9333ce5947ad01e8018a3be upstream.

After the linked LLVM change, building ARCH=um defconfig results in a
segmentation fault in modpost. Prior to commit a23e7584ecf3 ("modpost:
unify 'sym' and 'to' in default_mismatch_handler()"), there was a
warning:

  WARNING: modpost: vmlinux.o(__ex_table+0x88): Section mismatch in reference to the .ltext:(unknown)
  WARNING: modpost: The relocation at __ex_table+0x88 references
  section ".ltext" which is not in the list of
  authorized sections.  If you're adding a new section
  and/or if this reference is valid, add ".ltext" to the
  list of authorized sections to jump to on fault.
  This can be achieved by adding ".ltext" to
  OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.

The linked LLVM change moves global objects to the '.ltext' (and
'.ltext.*' with '-ffunction-sections') sections with '-mcmodel=large',
which ARCH=um uses. These sections should be handled just as '.text'
and '.text.*' are, so add them to TEXT_SECTIONS.

Cc: stable@vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/1981
Link: 4bf8a68895
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:38 +01:00
Nathan Chancellor
36fbcadc20 modpost: Include '.text.*' in TEXT_SECTIONS
commit 19331e84c3873256537d446afec1f6c507f8c4ef upstream.

Commit 6c730bfc89 ("modpost: handle -ffunction-sections") added
".text.*" to the OTHER_TEXT_SECTIONS macro to fix certain section
mismatch warnings. Unfortunately, this makes it impossible for modpost
to warn about section mismatches with LTO, which implies
'-ffunction-sections', as all functions are put in their own
'.text.<func_name>' sections, which may still reference functions in
sections they are not supposed to, such as __init.

Fix this by moving ".text.*" into TEXT_SECTIONS, so that configurations
with '-ffunction-sections' will see warnings about mismatched sections.

Link: https://lore.kernel.org/Y39kI3MOtVI5BAnV@google.com/
Reported-by: Vincent Donnefort <vdonnefort@google.com>
Reviewed-and-tested-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Stable-dep-of: 846cfbeed09b ("um: Fix adding '-no-pie' for clang")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:38 +01:00
Masahiro Yamada
519b7da44e linux/init: remove __memexit* annotations
commit 6a4e59eeedc3018cb57722eecfcbb49431aeb05f upstream.

We have never used __memexit, __memexitdata, or __memexitconst.

These were unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
[nathan: Remove additional case of XXXEXIT_TO_SOME_EXIT due to lack of
         78dac1a22944 in 6.1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Stable-dep-of: 846cfbeed09b ("um: Fix adding '-no-pie' for clang")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:38 +01:00
Uwe Kleine-König
999ecc936a modpost: Don't let "driver"s reference .exit.*
commit f177cd0c15fcc7bdbb68d8d1a3166dead95314c8 upstream.

Drivers must not reference functions marked with __exit as these likely
are not available when the code is built-in.

There are few creative offenders uncovered for example in ARCH=amd64
allmodconfig builds. So only trigger the section mismatch warning for
W=1 builds.

The dual rule that drivers must not reference .init.* is implemented
since commit 0db2524523 ("modpost: don't allow *driver to reference
.init.*") which however missed that .exit.* should be handled in the
same way.

Thanks to Masahiro Yamada and Arnd Bergmann who gave valuable hints to
find this improvement.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Stable-dep-of: 846cfbeed09b ("um: Fix adding '-no-pie' for clang")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:38 +01:00
Masahiro Yamada
a5767decf7 modpost: propagate W=1 build option to modpost
commit 20ff36856fe00879f82de71fe6f1482ca1b72334 upstream.

"No build warning" is a strong requirement these days, so you must fix
all issues before enabling a new warning flag.

We often add a new warning to W=1 first so that the kbuild test robot
blocks new breakages.

This commit allows modpost to show extra warnings only when W=1
(or KBUILD_EXTRA_WARN=1) is given.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Stable-dep-of: 846cfbeed09b ("um: Fix adding '-no-pie' for clang")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:38 +01:00
Radek Krejci
3e409fb740 modpost: trim leading spaces when processing source files list
[ Upstream commit 5d9a16b2a4d9e8fa028892ded43f6501bc2969e5 ]

get_line() does not trim the leading spaces, but the
parse_source_files() expects to get lines with source files paths where
the first space occurs after the file path.

Fixes: 70f30cfe5b ("modpost: use read_text_file() and get_line() for reading text files")
Signed-off-by: Radek Krejci <radek.krejci@oracle.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-23 09:12:35 +01:00
Masahiro Yamada
a204f9f3cb modpost: fix ishtp MODULE_DEVICE_TABLE built on big-endian host
[ Upstream commit ac96a15a0f0c8812a3aaa587b871cd5527f6d736 ]

When MODULE_DEVICE_TABLE(ishtp, ) is built on a host with a different
endianness from the target architecture, it results in an incorrect
MODULE_ALIAS().

For example, see a case where drivers/platform/x86/intel/ishtp_eclite.c
is built as a module for x86.

If you build it on a little-endian host, you will get the correct
MODULE_ALIAS:

    $ grep MODULE_ALIAS drivers/platform/x86/intel/ishtp_eclite.mod.c
    MODULE_ALIAS("ishtp:{6A19CC4B-D760-4DE3-B14D-F25EBD0FBCD9}");

However, if you build it on a big-endian host, you will get a wrong
MODULE_ALIAS:

    $ grep MODULE_ALIAS drivers/platform/x86/intel/ishtp_eclite.mod.c
    MODULE_ALIAS("ishtp:{BD0FBCD9-F25E-B14D-4DE3-D7606A19CC4B}");

This issue has been unnoticed because the x86 kernel is most likely built
natively on an x86 host.

The guid field must not be reversed because guid_t is an array of __u8.

Fixes: fa443bc3c1 ("HID: intel-ish-hid: add support for MODULE_DEVICE_TABLE()")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20 11:52:12 +01:00
Masahiro Yamada
339148f786 modpost: fix tee MODULE_DEVICE_TABLE built on big-endian host
[ Upstream commit 7f54e00e5842663c2cea501bbbdfa572c94348a3 ]

When MODULE_DEVICE_TABLE(tee, ) is built on a host with a different
endianness from the target architecture, it results in an incorrect
MODULE_ALIAS().

For example, see a case where drivers/char/hw_random/optee-rng.c
is built as a module for ARM little-endian.

If you build it on a little-endian host, you will get the correct
MODULE_ALIAS:

    $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c
    MODULE_ALIAS("tee:ab7a617c-b8e7-4d8f-8301-d09b61036b64*");

However, if you build it on a big-endian host, you will get a wrong
MODULE_ALIAS:

    $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c
    MODULE_ALIAS("tee:646b0361-9bd0-0183-8f4d-e7b87c617aab*");

The same problem also occurs when you enable CONFIG_CPU_BIG_ENDIAN,
and build it on a little-endian host.

This issue has been unnoticed because the ARM kernel is configured for
little-endian by default, and most likely built on a little-endian host
(cross-build on x86 or native-build on ARM).

The uuid field must not be reversed because uuid_t is an array of __u8.

Fixes: 0fc1db9d10 ("tee: add bus driver framework for TEE based devices")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-20 11:52:12 +01:00
Mauricio Faria de Oliveira
8ef7f9acbe modpost: add missing else to the "of" check
[ Upstream commit cbc3d00cf88fda95dbcafee3b38655b7a8f2650a ]

Without this 'else' statement, an "usb" name goes into two handlers:
the first/previous 'if' statement _AND_ the for-loop over 'devtable',
but the latter is useless as it has no 'usb' device_id entry anyway.

Tested with allmodconfig before/after patch; no changes to *.mod.c:

    git checkout v6.6-rc3
    make -j$(nproc) allmodconfig
    make -j$(nproc) olddefconfig

    make -j$(nproc)
    find . -name '*.mod.c' | cpio -pd /tmp/before

    # apply patch

    make -j$(nproc)
    find . -name '*.mod.c' | cpio -pd /tmp/after

    diff -r /tmp/before/ /tmp/after/
    # no difference

Fixes: acbef7b766 ("modpost: fix module autoloading for OF devices with generic compatible property")
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-10 22:00:41 +02:00
Dan Carpenter
dd872d5576 modpost: fix off by one in is_executable_section()
[ Upstream commit 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 ]

The > comparison should be >= to prevent an out of bounds array
access.

Fixes: 52dc0595d5 ("modpost: handle relocations mismatch in __ex_table.")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:21:42 +02:00
Masahiro Yamada
6852d82e6c modpost: fix section mismatch message for R_ARM_{PC24,CALL,JUMP24}
[ Upstream commit 56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d ]

addend_arm_rel() processes R_ARM_PC24, R_ARM_CALL, R_ARM_JUMP24 in a
wrong way.

Here, test code.

[test code for R_ARM_JUMP24]

  .section .init.text,"ax"
  bar:
          bx      lr

  .section .text,"ax"
  .globl foo
  foo:
          b       bar

[test code for R_ARM_CALL]

  .section .init.text,"ax"
  bar:
          bx      lr

  .section .text,"ax"
  .globl foo
  foo:
          push    {lr}
          bl      bar
          pop     {pc}

If you compile it with ARM multi_v7_defconfig, modpost will show the
symbol name, (unknown).

  WARNING: modpost: vmlinux.o: section mismatch in reference: foo (section: .text) -> (unknown) (section: .init.text)

(You need to use GNU linker instead of LLD to reproduce it.)

Fix the code to make modpost show the correct symbol name.

I imported (with adjustment) sign_extend32() from include/linux/bitops.h.

The '+8' is the compensation for pc-relative instruction. It is
documented in "ELF for the Arm Architecture" [1].

  "If the relocation is pc-relative then compensation for the PC bias
  (the PC value is 8 bytes ahead of the executing instruction in Arm
  state and 4 bytes in Thumb state) must be encoded in the relocation
  by the object producer."

[1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst

Fixes: 56a974fa2d ("kbuild: make better section mismatch reports on arm")
Fixes: 6e2e340b59 ("ARM: 7324/1: modpost: Fix section warnings for ARM for many compilers")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:21:41 +02:00
Masahiro Yamada
1df287bd89 modpost: fix section mismatch message for R_ARM_ABS32
[ Upstream commit b7c63520f6703a25eebb4f8138fed764fcae1c6f ]

addend_arm_rel() processes R_ARM_ABS32 in a wrong way.

Here, test code.

  [test code 1]

    #include <linux/init.h>

    int __initdata foo;
    int get_foo(void) { return foo; }

If you compile it with ARM versatile_defconfig, modpost will show the
symbol name, (unknown).

  WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> (unknown) (section: .init.data)

(You need to use GNU linker instead of LLD to reproduce it.)

If you compile it for other architectures, modpost will show the correct
symbol name.

  WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data)

For R_ARM_ABS32, addend_arm_rel() sets r->r_addend to a wrong value.

I just mimicked the code in arch/arm/kernel/module.c.

However, there is more difficulty for ARM.

Here, test code.

  [test code 2]

    #include <linux/init.h>

    int __initdata foo;
    int get_foo(void) { return foo; }

    int __initdata bar;
    int get_bar(void) { return bar; }

With this commit applied, modpost will show the following messages
for ARM versatile_defconfig:

  WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data)
  WARNING: modpost: vmlinux.o: section mismatch in reference: get_bar (section: .text) -> foo (section: .init.data)

The reference from 'get_bar' to 'foo' seems wrong.

I have no solution for this because it is true in assembly level.

In the following output, relocation at 0x1c is no longer associated
with 'bar'. The two relocation entries point to the same symbol, and
the offset to 'bar' is encoded in the instruction 'r0, [r3, #4]'.

  Disassembly of section .text:

  00000000 <get_foo>:
     0: e59f3004          ldr     r3, [pc, #4]   @ c <get_foo+0xc>
     4: e5930000          ldr     r0, [r3]
     8: e12fff1e          bx      lr
     c: 00000000          .word   0x00000000

  00000010 <get_bar>:
    10: e59f3004          ldr     r3, [pc, #4]   @ 1c <get_bar+0xc>
    14: e5930004          ldr     r0, [r3, #4]
    18: e12fff1e          bx      lr
    1c: 00000000          .word   0x00000000

  Relocation section '.rel.text' at offset 0x244 contains 2 entries:
   Offset     Info    Type            Sym.Value  Sym. Name
  0000000c  00000c02 R_ARM_ABS32       00000000   .init.data
  0000001c  00000c02 R_ARM_ABS32       00000000   .init.data

When find_elf_symbol() gets into a situation where relsym->st_name is
zero, there is no guarantee to get the symbol name as written in C.

I am keeping the current logic because it is useful in many architectures,
but the symbol name is not always correct depending on the optimization.
I left some comments in find_tosym().

Fixes: 56a974fa2d ("kbuild: make better section mismatch reports on arm")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:21:41 +02:00
Masahiro Yamada
2be41ef57c modpost: remove broken calculation of exception_table_entry size
[ Upstream commit d0acc76a49aa917c1a455d11d32d34a01e8b2835 ]

find_extable_entry_size() is completely broken. It has awesome comments
about how to calculate sizeof(struct exception_table_entry).

It was based on these assumptions:

  - struct exception_table_entry has two fields
  - both of the fields have the same size

Then, we came up with this equation:

  (offset of the second field) * 2 == (size of struct)

It was true for all architectures when commit 52dc0595d5 ("modpost:
handle relocations mismatch in __ex_table.") was applied.

Our mathematics broke when commit 548acf1923 ("x86/mm: Expand the
exception table logic to allow new handling options") introduced the
third field.

Now, the definition of exception_table_entry is highly arch-dependent.

For x86, sizeof(struct exception_table_entry) is apparently 12, but
find_extable_entry_size() sets extable_entry_size to 8.

I could fix it, but I do not see much value in this code.

extable_entry_size is used just for selecting a slightly different
error message.

If the first field ("insn") references to a non-executable section,

    The relocation at %s+0x%lx references
    section "%s" which is not executable, IOW
    it is not possible for the kernel to fault
    at that address.  Something is seriously wrong
    and should be fixed.

If the second field ("fixup") references to a non-executable section,

    The relocation at %s+0x%lx references
    section "%s" which is not executable, IOW
    the kernel will fault if it ever tries to
    jump to it.  Something is seriously wrong
    and should be fixed.

Merge the two error messages rather than adding even more complexity.

Change fatal() to error() to make it continue running and catch more
possible errors.

Fixes: 548acf1923 ("x86/mm: Expand the exception table logic to allow new handling options")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:21:41 +02:00
Ben Hutchings
0e7ac17634 modpost: Fix processing of CRCs on 32-bit build machines
commit fb27e70f6e408dee5d22b083e7a38a59e6118253 upstream.

modpost now reads CRCs from .*.cmd files, parsing them using strtol().
This is inconsistent with its parsing of Module.symvers and with their
definition as *unsigned* 32-bit values.

strtol() clamps values to [LONG_MIN, LONG_MAX], and when building on a
32-bit system this changes all CRCs >= 0x80000000 to be 0x7fffffff.

Change extract_crcs_for_object() to use strtoul() instead.

Cc: stable@vger.kernel.org
Fixes: f292d875d0 ("modpost: extract symbol versions from *.cmd files")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:53 +02:00
Masahiro Yamada
5b8a9a8fd1 modpost: fix module versioning when a symbol lacks valid CRC
Since commit 7b4537199a ("kbuild: link symbol CRCs at final link,
removing CONFIG_MODULE_REL_CRCS"), module versioning is broken on
some architectures. Loading a module fails with "disagrees about
version of symbol module_layout".

On such architectures (e.g. ARCH=sparc build with sparc64_defconfig),
modpost shows a warning, like follows:

  WARNING: modpost: EXPORT symbol "_mcount" [vmlinux] version generation failed, symbol will not be versioned.
  Is "_mcount" prototyped in <asm/asm-prototypes.h>?

Previously, it was a harmless warning (CRC check was just skipped),
but now wrong CRCs are used for comparison because invalid CRCs are
just skipped.

  $ sparc64-linux-gnu-nm -n vmlinux
    [snip]
  0000000000c2cea0 r __ksymtab__kstrtol
  0000000000c2ceb8 r __ksymtab__kstrtoul
  0000000000c2ced0 r __ksymtab__local_bh_enable
  0000000000c2cee8 r __ksymtab__mcount
  0000000000c2cf00 r __ksymtab__printk
  0000000000c2cf18 r __ksymtab__raw_read_lock
  0000000000c2cf30 r __ksymtab__raw_read_lock_bh
    [snip]
  0000000000c53b34 D __crc__kstrtol
  0000000000c53b38 D __crc__kstrtoul
  0000000000c53b3c D __crc__local_bh_enable
  0000000000c53b40 D __crc__printk
  0000000000c53b44 D __crc__raw_read_lock
  0000000000c53b48 D __crc__raw_read_lock_bh

Please notice __crc__mcount is missing here.

When the module subsystem looks up a CRC that comes after, it results
in reading out a wrong address. For example, when __crc__printk is
needed, the module subsystem reads 0xc53b44 instead of 0xc53b40.

All CRC entries must be output for correct index accessing. Invalid
CRCs will be unused, but are needed to keep the one-to-one mapping
between __ksymtab_* and __crc_*.

The best is to fix all modpost warnings, but several warnings are still
remaining on less popular architectures.

Fixes: 7b4537199a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS")
Reported-by: matoro <matoro_mailinglist_kernel@matoro.tk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: matoro <matoro_mailinglist_kernel@matoro.tk>
2022-08-21 02:47:36 +09:00
Linus Torvalds
0af5cb349a Merge tag 'kbuild-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Remove the support for -O3 (CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3)

 - Fix error of rpm-pkg cross-builds

 - Support riscv for checkstack tool

 - Re-enable -Wformwat warnings for Clang

 - Clean up modpost, Makefiles, and misc scripts

* tag 'kbuild-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits)
  modpost: remove .symbol_white_list field entirely
  modpost: remove unneeded .symbol_white_list initializers
  modpost: add PATTERNS() helper macro
  modpost: shorten warning messages in report_sec_mismatch()
  Revert "Kbuild, lto, workaround: Don't warn for initcall_reference in modpost"
  modpost: use more reliable way to get fromsec in section_rel(a)()
  modpost: add array range check to sec_name()
  modpost: refactor get_secindex()
  kbuild: set EXIT trap before creating temporary directory
  modpost: remove unused Elf_Sword macro
  Makefile.extrawarn: re-enable -Wformat for clang
  kbuild: add dtbs_prepare target
  kconfig: Qt5: tell the user which packages are required
  modpost: use sym_get_data() to get module device_table data
  modpost: drop executable ELF support
  checkstack: add riscv support for scripts/checkstack.pl
  kconfig: shorten the temporary directory name for cc-option
  scripts: headers_install.sh: Update config leak ignore entries
  kbuild: error out if $(INSTALL_MOD_PATH) contains % or :
  kbuild: error out if $(KBUILD_EXTMOD) contains % or :
  ...
2022-08-10 10:40:41 -07:00
Masahiro Yamada
672fb6740c modpost: remove .symbol_white_list field entirely
It is not so useful to have symbol whitelists in arrays. With this
over-engineering, the code is difficult to follow.

Let's do it more directly, and collect the relevant code to one place.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-08-04 20:32:13 +09:00
Masahiro Yamada
1560cb0e18 modpost: remove unneeded .symbol_white_list initializers
The ->symbol_white_list field is referenced in secref_whitelist(),
only when 'fromsec' is data_sections.

        /* Check for pattern 2 */
        if (match(tosec, init_exit_sections) &&
            match(fromsec, data_sections) &&
            match(fromsym, mismatch->symbol_white_list))
                return 0;

If .fromsec is not data sections, the .symbol_white_list member is
not used by anyone.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-08-04 20:32:13 +09:00
Masahiro Yamada
7452dd26a5 modpost: add PATTERNS() helper macro
This will be useful to define a NULL-terminated array inside a function
call.

Currently, string arrays passed to match() are defined in separate
places:

    static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
    static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
    static const char *const optim_symbols[] = { "*.constprop.*", NULL };

            ...

            /* Check for pattern 5 */
            if (match(fromsec, text_sections) &&
                match(tosec, init_sections) &&
                match(fromsym, optim_symbols))
                    return 0;

With the new helper macro, you can list the patterns directly in the
function call, like this:

            /* Check for pattern 5 */
            if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
                match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
                match(fromsym, PATTERNS("*.contprop.*")))
                    return 0;

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-08-04 20:32:13 +09:00
Masahiro Yamada
072dd2c892 modpost: shorten warning messages in report_sec_mismatch()
Each section mismatch results in long warning messages. Too much.

Make each warning fit in one line, and remove a lot of messy code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-08-04 20:32:13 +09:00
Masahiro Yamada
a25efd6ef1 Revert "Kbuild, lto, workaround: Don't warn for initcall_reference in modpost"
This reverts commit 77ab21adae.

Even after 8 years later, GCC LTO has not been upstreamed. Also, it said
"This is a workaround". If this is needed in the future, it should be
added in a proper way.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Jiri Slaby <jirislaby@kernel.org>
2022-08-04 20:27:17 +09:00
Masahiro Yamada
5419aa2a8d modpost: use more reliable way to get fromsec in section_rel(a)()
The section name of Rel and Rela starts with ".rel" and ".rela"
respectively (but, I do not know whether this is specification or
convention).

For example, ".rela.text" holds relocation entries applied to the
".text" section.

So, the code chops the ".rel" or ".rela" prefix to get the name of
the section to which the relocation applies.

However, I do not like to skip 4 or 5 bytes blindly because it is
potential memory overrun.

The ELF specification provides a more reliable way to do this.

 - The sh_info field holds extra information, whose interpretation
   depends on the section type

 - If the section type is SHT_REL or SHT_RELA, the sh_info field holds
   the section header index of the section to which the relocation
   applies.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-08-03 22:58:10 +09:00
Masahiro Yamada
125ed24a4a modpost: add array range check to sec_name()
The section index is always positive, so the argument, secindex, should
be unsigned.

Also, inserted the array range check.

If sym->st_shndx is a special section index (between SHN_LORESERVE and
SHN_HIRESERVE), there is no corresponding section header.

For example, if a symbol specifies an absolute value, sym->st_shndx is
SHN_ABS (=0xfff1).

The current users do not cause the out-of-range access of
info->sechddrs[], but it is better to avoid such a pitfall.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-08-03 22:58:10 +09:00
Masahiro Yamada
36b0f0deed 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>
2022-08-03 22:56:46 +09:00
Masahiro Yamada
7193cda917 modpost: remove unused Elf_Sword macro
Commit 9ad21c3f3e ("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>
2022-08-03 19:37:59 +09:00