[Build system]
- add CONFIG_UNUSED_KSYMS_WHITELIST, which will be useful to define
a fixed set of export symbols for Generic Kernel Image (GKI)
- allow to run 'make dt_binding_check' without .config
- use full schema for checking DT examples in *.yaml files
- make modpost fail for missing MODULE_IMPORT_NS(), which makes more
sense because we know the produced modules are never loadable
- Remove unused 'AS' variable
[Kconfig]
- sanitize DEFCONFIG_LIST, and remove ARCH_DEFCONFIG from Kconfig files
- relax the 'imply' behavior so that symbols implied by y can become m
- make 'imply' obey 'depends on' in order to make 'imply' really weak
[Misc]
- add documentation on building the kernel with Clang/LLVM
- revive __HAVE_ARCH_STRLEN for 32bit sparc to use optimized strlen()
- fix warning from deb-pkg builds when CONFIG_DEBUG_INFO=n
- various script and Makefile cleanups
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Merge tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
"Build system:
- add CONFIG_UNUSED_KSYMS_WHITELIST, which will be useful to define a
fixed set of export symbols for Generic Kernel Image (GKI)
- allow to run 'make dt_binding_check' without .config
- use full schema for checking DT examples in *.yaml files
- make modpost fail for missing MODULE_IMPORT_NS(), which makes more
sense because we know the produced modules are never loadable
- Remove unused 'AS' variable
Kconfig:
- sanitize DEFCONFIG_LIST, and remove ARCH_DEFCONFIG from Kconfig
files
- relax the 'imply' behavior so that symbols implied by 'y' can
become 'm'
- make 'imply' obey 'depends on' in order to make 'imply' really weak
Misc:
- add documentation on building the kernel with Clang/LLVM
- revive __HAVE_ARCH_STRLEN for 32bit sparc to use optimized strlen()
- fix warning from deb-pkg builds when CONFIG_DEBUG_INFO=n
- various script and Makefile cleanups"
* tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
Makefile: Update kselftest help information
kbuild: deb-pkg: fix warning when CONFIG_DEBUG_INFO is unset
kbuild: add outputmakefile to no-dot-config-targets
kbuild: remove AS variable
net: wan: wanxl: refactor the firmware rebuild rule
net: wan: wanxl: use $(M68KCC) instead of $(M68KAS) for rebuilding firmware
net: wan: wanxl: use allow to pass CROSS_COMPILE_M68k for rebuilding firmware
kbuild: add comment about grouped target
kbuild: add -Wall to KBUILD_HOSTCXXFLAGS
kconfig: remove unused variable in qconf.cc
sparc: revive __HAVE_ARCH_STRLEN for 32bit sparc
kbuild: refactor Makefile.dtbinst more
kbuild: compute the dtbs_install destination more simply
Makefile: disallow data races on gcc-10 as well
kconfig: make 'imply' obey the direct dependency
kconfig: allow symbols implied by y to become m
net: drop_monitor: use IS_REACHABLE() to guard net_dm_hw_report()
modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n
modpost: rework and consolidate logging interface
kbuild: allow to run dt_binding_check without kernel configuration
...
Core:
- Consolidation of the vDSO build infrastructure to address the
difficulties of cross-builds for ARM64 compat vDSO libraries by
restricting the exposure of header content to the vDSO build.
This is achieved by splitting out header content into separate
headers. which contain only the minimaly required information which is
necessary to build the vDSO. These new headers are included from the
kernel headers and the vDSO specific files.
- Enhancements to the generic vDSO library allowing more fine grained
control over the compiled in code, further reducing architecture
specific storage and preparing for adopting the generic library by PPC.
- Cleanup and consolidation of the exit related code in posix CPU timers.
- Small cleanups and enhancements here and there
Drivers:
- The obligatory new drivers: Ingenic JZ47xx and X1000 TCU support
- Correct the clock rate of PIT64b global clock
- setup_irq() cleanup
- Preparation for PWM and suspend support for the TI DM timer
- Expand the fttmr010 driver to support ast2600 systems
- The usual small fixes, enhancements and cleanups all over the place
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Merge tag 'timers-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timekeeping and timer updates from Thomas Gleixner:
"Core:
- Consolidation of the vDSO build infrastructure to address the
difficulties of cross-builds for ARM64 compat vDSO libraries by
restricting the exposure of header content to the vDSO build.
This is achieved by splitting out header content into separate
headers. which contain only the minimaly required information which
is necessary to build the vDSO. These new headers are included from
the kernel headers and the vDSO specific files.
- Enhancements to the generic vDSO library allowing more fine grained
control over the compiled in code, further reducing architecture
specific storage and preparing for adopting the generic library by
PPC.
- Cleanup and consolidation of the exit related code in posix CPU
timers.
- Small cleanups and enhancements here and there
Drivers:
- The obligatory new drivers: Ingenic JZ47xx and X1000 TCU support
- Correct the clock rate of PIT64b global clock
- setup_irq() cleanup
- Preparation for PWM and suspend support for the TI DM timer
- Expand the fttmr010 driver to support ast2600 systems
- The usual small fixes, enhancements and cleanups all over the
place"
* tag 'timers-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits)
Revert "clocksource/drivers/timer-probe: Avoid creating dead devices"
vdso: Fix clocksource.h macro detection
um: Fix header inclusion
arm64: vdso32: Enable Clang Compilation
lib/vdso: Enable common headers
arm: vdso: Enable arm to use common headers
x86/vdso: Enable x86 to use common headers
mips: vdso: Enable mips to use common headers
arm64: vdso32: Include common headers in the vdso library
arm64: vdso: Include common headers in the vdso library
arm64: Introduce asm/vdso/processor.h
arm64: vdso32: Code clean up
linux/elfnote.h: Replace elf.h with UAPI equivalent
scripts: Fix the inclusion order in modpost
common: Introduce processor.h
linux/ktime.h: Extract common header for vDSO
linux/jiffies.h: Extract common header for vDSO
linux/time64.h: Extract common header for vDSO
linux/time32.h: Extract common header for vDSO
linux/time.h: Extract common header for vDSO
...
In the process of creating the source file of a module modpost injects a
set of includes that are not required if the compilation unit is
statically built into the kernel.
The order of inclusion of the headers can cause redefinition problems
(e.g.):
In file included from include/linux/elf.h:5:0,
from include/linux/module.h:18,
from crypto/arc4.mod.c:2:
#define ELF_OSABI ELFOSABI_LINUX
In file included from include/linux/elfnote.h:62:0,
from include/linux/build-salt.h:4,
from crypto/arc4.mod.c:1:
include/uapi/linux/elf.h:363:0: note: this is the location of
the previous definition
#define ELF_OSABI ELFOSABI_NONE
The issue was exposed during the development of the series [1].
[1] https://lore.kernel.org/lkml/20200306133242.26279-1-vincenzo.frascino@arm.com/
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Link: https://lkml.kernel.org/r/20200320145351.32292-17-vincenzo.frascino@arm.com
(uint16_t) st_shndx is limited to 65535(i.e. SHN_XINDEX) so sym_get_data() gets
wrong section index by st_shndx if requested symbol contains extended section
index that is more than 65535. In this case, we need to get proper section index
by .symtab_shndx section.
Module.symvers generated by building kernel with "-ffunction-sections -fdata-sections"
shows the issue.
Fixes: 56067812d5 ("kbuild: modversions: add infrastructure for emitting relative CRCs")
Fixes: e84f9fbbec ("modpost: refactor namespace_from_kstrtabns() to not hard-code section name")
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
In order to preserve backwards compatability with kmod tools, we have to
move the namespace field in Module.symvers last, as the depmod -e -E
option looks at the first three fields in Module.symvers to check symbol
versions (and it's expected they stay in the original order of crc,
symbol, module).
In addition, update an ancient comment above read_dump() in modpost that
suggested that the export type field in Module.symvers was optional. I
suspect that there were historical reasons behind that comment that are
no longer accurate. We have been unconditionally printing the export
type since 2.6.18 (commit bd5cbcedf4), which is over a decade ago now.
Fix up read_dump() to treat each field as non-optional. I suspect the
original read_dump() code treated the export field as optional in order
to support pre <= 2.6.18 Module.symvers (which did not have the export
type field). Note that although symbol namespaces are optional, the
field will not be omitted from Module.symvers if a symbol does not have
a namespace. In this case, the field will simply be empty and the next
delimiter or end of line will follow.
Cc: stable@vger.kernel.org
Fixes: cb9b55d21f ("modpost: add support for symbol namespaces")
Tested-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently when CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, modpost
only warns when a module is missing namespace imports. Under this
configuration, such a module cannot be loaded into the kernel anyway, as
the module loader would reject it. We might as well return a build
error when a module is missing namespace imports under
CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, so that the build
warning does not go ignored/unnoticed.
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Rework modpost's logging interface by consolidating merror(), warn(), and
fatal() to use a single function, modpost_log(). Introduce different
logging levels (WARN, ERROR, FATAL) as well. The purpose of this cleanup is
to reduce code duplication when deciding whether or not to warn or error
out based on a condition.
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Commit 8d5290149e ("[SPARC]: Deal with glibc changing macro names in
modpost.c") was more than 14 years ago. STT_SPARC_REGISTER is hopefully
defined in elf.h of recent C libraries.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
When 'exported twice' is warned, let sym_add_exported() return without
updating the symbol info. This respects the previous export, which is
ordered first in modules.order
This simplifies the code too.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Now that there is no overwrap between symbols from ELF files and
ones from Module.symvers.
So, the 'exported twice' warning should be reported irrespective
of where the symbol in question came from.
The exceptional case is external module; in some cases, we build
an external module to provide a different version/variant of the
corresponding in-kernel module, overriding the same set of exported
symbols.
You can see this use-case in upstream; tools/testing/nvdimm/libnvdimm.ko
replaces drivers/nvdimm/libnvdimm.ko in order to link it against mocked
version of core kernel symbols.
So, let's relax the 'exported twice' warning when building external
modules. The multiple export from external modules is warned only
when the previous one is from vmlinux or itself.
With this refactoring, the ugly preloading goes away.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
It is complicated to add mocked-up symbols for pre-handling CRC.
Handle CRC after all the export symbols in the relevant module
are registered.
Call handle_modversion() after the handle_symbol() iteration.
In some cases, I see atand-alone __crc_* without __ksymtab_*.
For example, ARCH=arm allyesconfig produces __crc_ccitt_veneer and
__crc_itu_t_veneer. I guess they come from crc_ccitt, crc_itu_t,
respectively. Since __*_veneer are auto-generated symbols, just
ignore them.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This function handles not only modversions, but also unresolved
symbols, export symbols, etc.
Rename it to a more proper function name.
While I was here, I also added the 'const' qualifier to *sym.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, namespace_from_kstrtabns() relies on the fact that
namespace strings are recorded in the __ksymtab_strings section.
Actually, it is coded in include/linux/export.h, but modpost does
not need to hard-code the section name.
Elf_Sym::st_shndx holds the index of the relevant section. Using it is
a more portable way to get the namespace string.
Make namespace_from_kstrtabns() simply call sym_get_data(), and delete
the info->ksymtab_strings .
While I was here, I added more 'const' qualifiers to pointers.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
When CONFIG_MODULE_REL_CRCS is enabled, the value of __crc_* is not
an absolute value, but the address to the CRC data embedded in the
.rodata section.
Getting the data pointed by the symbol value is somewhat complex.
Split it out into a new helper, sym_get_data().
I will reuse it to refactor namespace_from_kstrtabns() in the next
commit.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The local variable, ns_entry, is unneeded.
While I was here, I also cleaned up the comparison with NULL or 0.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
The modpost, with the -d option given, generates per-module .ns_deps
files.
Kbuild generates per-module .mod files to carry module information.
This is convenient because Make handles multiple jobs in parallel
when the -j option is given.
On the other hand, the modpost always runs as a single thread.
I do not see a strong reason to produce separate .ns_deps files.
This commit changes the modpost to generate just one file,
modules.nsdeps, each line of which has the following format:
<module_name>: <list of missing namespaces>
Please note it contains *missing* namespaces instead of required ones.
So, modules.nsdeps is empty if the namespace dependency is all good.
This will work more efficiently because spatch will no longer process
already imported namespaces. I removed the '(if needed)' from the
nsdeps log since spatch is invoked only when needed.
This also solves the stale .ns_deps problem reported by Jessica Yu:
https://lkml.org/lkml/2019/10/28/467
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>
'make nsdeps' invokes the modpost three times at most; before linking
vmlinux, before building modules, and finally for generating .ns_deps
files. Running the modpost again and again is not efficient.
The last two can be unified. When the -d option is given, the modpost
still does the usual job, and in addition, generates .ns_deps files.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
Since commit 040fcc819a ("kbuild: improved modversioning support for
external modules"), the external module build reads Module.symvers in
the directory of the module itself, then dumps symbols back into it.
It accumulates stale symbols in the file when you build an external
module incrementally.
The idea behind it was, as the commit log explained, you can copy
Modules.symvers from one module to another when you need to pass symbol
information between two modules. However, the manual copy of the file
sounds questionable to me, and containing stale symbols is a downside.
Some time later, commit 0d96fb20b7 ("kbuild: Add new Kbuild variable
KBUILD_EXTRA_SYMBOLS") introduced a saner approach.
So, this commit removes the former one. Going forward, the external
module build dumps symbols into Module.symvers to be carried via
KBUILD_EXTRA_SYMBOLS, but never reads it automatically.
With the -I option removed, there is no one to set the external_module
flag unless KBUILD_EXTRA_SYMBOLS is passed. Now the -i option does it
instead.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The introduction of Symbol Namespaces changed the naming schema of the
__ksymtab entries from __kysmtab__symbol to __ksymtab_NAMESPACE.symbol.
That caused some breakages in tools that depend on the name layout in
either the binaries(vmlinux,*.ko) or in System.map. E.g. kmod's depmod
would not be able to read System.map without a patch to support symbol
namespaces. A warning reported by depmod for namespaced symbols would
look like
depmod: WARNING: [...]/uas.ko needs unknown symbol usb_stor_adjust_quirks
In order to address this issue, revert to the original naming scheme and
rather read the __kstrtabns_<symbol> entries and their corresponding
values from __ksymtab_strings to update the namespace values for
symbols. After having read all symbols and handled them in
handle_modversions(), the symbols are created. In a second pass, read
the __kstrtabns_ entries and update the namespaces accordingly.
Fixes: 8651ec01da ("module: add support for symbol namespaces.")
Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Setting the symbol namespace of a symbol within sym_add_exported feels
displaced and lead to issues in the current implementation of symbol
namespaces. This patch makes updating the namespace an explicit call to
decouple it from adding a symbol to the export list.
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Let the function 'sym_update_namespace' take care of updating the
namespace for a symbol. While this currently only replaces one single
location where namespaces are updated, in a following patch, this
function will get more call sites.
The function signature is intentionally close to sym_update_crc and
taking the name by char* seems like unnecessary work as the symbol has
to be looked up again. In a later patch of this series, this concern
will be addressed.
This function ensures that symbol::namespace is either NULL or has a
valid non-empty value. Previously, the empty string was considered 'no
namespace' as well and this lead to confusion.
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
- Fix broken external module builds due to a modpost bug in read_dump(),
where the namespace was not being strdup'd and sym->namespace would be
set to bogus data.
- Various namespace-related kbuild fixes and cleanups thanks to
Masahiro Yamada.
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull module fixes from Jessica Yu:
"Code cleanups and kbuild/namespace related fixups from Masahiro.
Most importantly, it fixes a namespace-related modpost issue for
external module builds
- Fix broken external module builds due to a modpost bug in
read_dump(), where the namespace was not being strdup'd and
sym->namespace would be set to bogus data.
- Various namespace-related kbuild fixes and cleanups thanks to
Masahiro Yamada"
* tag 'modules-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
doc: move namespaces.rst from kbuild/ to core-api/
nsdeps: make generated patches independent of locale
nsdeps: fix hashbang of scripts/nsdeps
kbuild: fix build error of 'make nsdeps' in clean tree
module: rename __kstrtab_ns_* to __kstrtabns_* to avoid symbol conflict
modpost: fix broken sym->namespace for external module builds
module: swap the order of symbol.namespace
scripts: add_namespace: Fix coccicheck failed
Currently, external module builds produce tons of false-positives:
WARNING: module <mod> uses symbol <sym> from namespace <ns>, but does not import it.
Here, the <ns> part shows a random string.
When you build external modules, the symbol info of vmlinux and
in-kernel modules are read from $(objtree)/Module.symvers, but
read_dump() is buggy in multiple ways:
[1] When the modpost is run for vmlinux and in-kernel modules,
sym_extract_namespace() allocates memory for the namespace. On the
other hand, read_dump() does not, then sym->namespace will point to
somewhere in the line buffer of get_next_line(). The data in the
buffer will be replaced soon, and sym->namespace will end up with
pointing to unrelated data. As a result, check_exports() will show
random strings in the warning messages.
[2] When there is no namespace, sym_extract_namespace() returns NULL.
On the other hand, read_dump() sets namespace to an empty string "".
(but, it will be later replaced with unrelated data due to bug [1].)
The check_exports() shows a warning unless exp->namespace is NULL,
so every symbol read from read_dump() emits the warning, which is
mostly false positive.
To address [1], sym_add_exported() calls strdup() for s->namespace.
The namespace from sym_extract_namespace() must be freed to avoid
memory leak.
For [2], I changed the if-conditional in check_exports().
This commit also fixes sym_add_exported() to set s->namespace correctly
when the symbol is preloaded.
Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Currently, EXPORT_SYMBOL_NS(_GPL) constructs the kernel symbol as
follows:
__ksymtab_SYMBOL.NAMESPACE
The sym_extract_namespace() in modpost allocates memory for the part
SYMBOL.NAMESPACE when '.' is contained. One problem is that the pointer
returned by strdup() is lost because the symbol name will be copied to
malloc'ed memory by alloc_symbol(). No one will keep track of the
pointer of strdup'ed memory.
sym->namespace still points to the NAMESPACE part. So, you can free it
with complicated code like this:
free(sym->namespace - strlen(sym->name) - 1);
It complicates memory free.
To fix it elegantly, I swapped the order of the symbol and the
namespace as follows:
__ksymtab_NAMESPACE.SYMBOL
then, simplified sym_extract_namespace() so that it allocates memory
only for the NAMESPACE part.
I prefer this order because it is intuitive and also matches to major
languages. For example, NAMESPACE::NAME in C++, MODULE.NAME in Python.
Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Johannes Berg reports lots of modpost warnings on ARCH=um builds:
WARNING: "rename" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "lseek" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "ftruncate64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "getuid" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "lseek64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "unlink" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "pwrite64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "close" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "opendir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "pread64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "syscall" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "readdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "readdir64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "futimes" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__lxstat" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "write" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "closedir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__xstat" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fsync" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__lxstat64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__fxstat64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "telldir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "printf" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "readlink" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__sprintf_chk" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "link" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "rmdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fdatasync" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "truncate" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "statfs" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__errno_location" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__xmknod" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "open64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "truncate64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "open" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "read" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "chown" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "chmod" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "utime" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fchmod" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "seekdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "ioctl" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "dup2" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "statfs64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "utimes" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "mkdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fchown" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__guard" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "symlink" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "access" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__stack_smash_handler" [vmlinux] is a static EXPORT_SYMBOL
When you run "make", the modpost is run twice; before linking vmlinux,
and before building modules. All the warnings above are from the second
modpost.
The offending symbols are defined not in vmlinux, but in the C library.
The first modpost is run against the relocatable vmlinux.o, and those
warnings are nicely suppressed because the SH_UNDEF entries from the
symbol table clear the ->is_static flag.
The second modpost is run against the executable vmlinux (+ modules),
where those symbols have been resolved, but the definitions do not
exist.
This commit fixes it in a straightforward way; suppress the static
EXPORT_SYMBOL warnings from "vmlinux".
Without this commit, we see valid warnings twice anyway. For example,
ARCH=arm64 defconfig shows the following warning twice:
WARNING: "HYPERVISOR_platform_op" [vmlinux] is a static EXPORT_SYMBOL_GPL
So, it is reasonable to suppress the second one.
Fixes: 15bfc2348d ("modpost: check for static EXPORT_SYMBOL* functions")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Denis Efremov <efremov@linux.com>
Summary of modules changes for the 5.4 merge window:
- Introduce exported symbol namespaces.
This new feature allows subsystem maintainers to partition and
categorize their exported symbols into explicit namespaces. Module
authors are now required to import the namespaces they need.
Some of the main motivations of this feature include: allowing kernel
developers to better manage the export surface, allow subsystem
maintainers to explicitly state that usage of some exported symbols
should only be limited to certain users (think: inter-module or
inter-driver symbols, debugging symbols, etc), as well as more easily
limiting the availability of namespaced symbols to other parts of the
kernel. With the module import requirement, it is also easier to spot
the misuse of exported symbols during patch review. Two new macros are
introduced: EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL(). The API is
thoroughly documented in Documentation/kbuild/namespaces.rst.
- Some small code and kbuild cleanups here and there.
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Merge tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"The main bulk of this pull request introduces a new exported symbol
namespaces feature. The number of exported symbols is increasingly
growing with each release (we're at about 31k exports as of 5.3-rc7)
and we currently have no way of visualizing how these symbols are
"clustered" or making sense of this huge export surface.
Namespacing exported symbols allows kernel developers to more
explicitly partition and categorize exported symbols, as well as more
easily limiting the availability of namespaced symbols to other parts
of the kernel. For starters, we have introduced the USB_STORAGE
namespace to demonstrate the API's usage. I have briefly summarized
the feature and its main motivations in the tag below.
Summary:
- Introduce exported symbol namespaces.
This new feature allows subsystem maintainers to partition and
categorize their exported symbols into explicit namespaces. Module
authors are now required to import the namespaces they need.
Some of the main motivations of this feature include: allowing
kernel developers to better manage the export surface, allow
subsystem maintainers to explicitly state that usage of some
exported symbols should only be limited to certain users (think:
inter-module or inter-driver symbols, debugging symbols, etc), as
well as more easily limiting the availability of namespaced symbols
to other parts of the kernel.
With the module import requirement, it is also easier to spot the
misuse of exported symbols during patch review.
Two new macros are introduced: EXPORT_SYMBOL_NS() and
EXPORT_SYMBOL_NS_GPL(). The API is thoroughly documented in
Documentation/kbuild/namespaces.rst.
- Some small code and kbuild cleanups here and there"
* tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Remove leftover '#undef' from export header
module: remove unneeded casts in cmp_name()
module: move CONFIG_UNUSED_SYMBOLS to the sub-menu of MODULES
module: remove redundant 'depends on MODULES'
module: Fix link failure due to invalid relocation on namespace offset
usb-storage: export symbols in USB_STORAGE namespace
usb-storage: remove single-use define for debugging
docs: Add documentation for Symbol Namespaces
scripts: Coccinelle script for namespace dependencies.
modpost: add support for generating namespace dependencies
export: allow definition default namespaces in Makefiles or sources
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
modpost: add support for symbol namespaces
module: add support for symbol namespaces.
export: explicitly align struct kernel_symbol
module: support reading multiple values per modinfo tag
Use the __section() shorthand. This avoids escaping double-quotes,
and improves the readability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This makes *.mod.c much more readable. I confirmed depmod still
produced the same modules.dep file.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This patch adds an option to modpost to generate a <module>.ns_deps file
per module, containing the namespace dependencies for that module.
E.g. if the linked module my-module.ko would depend on the symbol
myfunc.MY_NS in the namespace MY_NS, the my-module.ns_deps file created
by modpost would contain the entry MY_NS to express the namespace
dependency of my-module imposed by using the symbol myfunc.
These files can subsequently be used by static analysis tools (like
coccinelle scripts) to address issues with missing namespace imports. A
later patch of this series will introduce such a script 'nsdeps' and a
corresponding make target to automatically add missing
MODULE_IMPORT_NS() definitions to the module's sources. For that it uses
the information provided in the generated .ns_deps files.
Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Add support for symbols that are exported into namespaces. For that,
extract any namespace suffix from the symbol name. In addition, emit a
warning whenever a module refers to an exported symbol without
explicitly importing the namespace that it is defined in. This patch
consistently adds the namespace suffix to symbol names exported into
Module.symvers.
Example warning emitted by modpost in case of the above violation:
WARNING: module ums-usbat uses symbol usb_stor_resume from namespace
USB_STORAGE, but does not import it.
Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Add NOFAIL check for the strndup call, because the function
allocates memory and can return NULL. All calls to strdup in
modpost are checked with NOFAIL.
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This patch adds a check to warn about static EXPORT_SYMBOL* functions
during the modpost. In most of the cases, a static symbol marked for
exporting is an odd combination that should be fixed either by deleting
the exporting mark or by removing the static attribute and adding the
appropriate declaration to headers.
This check could help to detect the following problems:
1. 550113d4e9 ("i2c: add newly exported functions to the header, too")
2. 54638c6eaf ("net: phy: make exported variables non-static")
3. 98ef2046f2 ("mm: remove the exporting of totalram_pages")
4. 73df167c81 ("s390/zcrypt: remove the exporting of ap_query_configuration")
5. a57caf8c52 ("sunrpc/cache: remove the exporting of cache_seq_next")
6. e4e4730698 ("crypto: skcipher - remove the exporting of skcipher_walk_next")
7. 14b4c48bb1 ("gve: Remove the exporting of gve_probe")
8. 9b79ee9773 ("scsi: libsas: remove the exporting of sas_wait_eh")
9. ...
The build time impact is very limited and is almost at the unnoticeable
level (< 1 sec).
Acked-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Fix commit 56067812d5 ("kbuild: modversions: add infrastructure for
emitting relative CRCs") where CRCs are interpreted in host byte order
rather than proper kernel byte order. The bug is conditional on
CONFIG_MODULE_REL_CRCS.
For example, when loading a BE module into a BE kernel compiled with a LE
system, the error "disagrees about version of symbol module_layout" is
produced. A message such as "Found checksum D7FA6856 vs module 5668FAD7"
will be given with debug enabled, which indicates an obvious endian
problem within __kcrctab within the kernel image.
The general solution is to use the macro TO_NATIVE, as is done in
similar cases throughout modpost.c. With this correction it has been
verified that a BE kernel compiled with a LE system accepts BE modules.
This change has also been verified with a LE kernel compiled with a LE
system, in which case TO_NATIVE returns its value unmodified since the
byte orders match. This is by far the common case.
Fixes: 56067812d5 ("kbuild: modversions: add infrastructure for emitting relative CRCs")
Signed-off-by: Fredrik Noring <noring@nocrew.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Unless CONFIG_DEBUG_SECTION_MISMATCH is enabled, modpost only shows
the number of section mismatches.
If you want to know the symbols causing the issue, you need to rebuild
with CONFIG_DEBUG_SECTION_MISMATCH. It is tedious.
I think it is fine to show annoying warning when a new section mismatch
comes in.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Probably, this is just a matter of the order of error/warning
messages. Merge the two for-loops.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
You do not need to iterate over all modules for resetting ->seen flag
because add_depends() is only interested in modules that export symbols
referenced from the given 'mod'.
This also avoids shadowing the 'modules' parameter of add_depends().
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
During development of a serial console driver with a gcc 8.2.0
toolchain for RISC-V, the following modpost warning appeared:
----
WARNING: vmlinux.o(.data+0x19b10): Section mismatch in reference from the variable .LANCHOR1 to the function .init.text:sifive_serial_console_setup()
The variable .LANCHOR1 references
the function __init sifive_serial_console_setup()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console
----
".LANCHOR1" is an ELF local symbol, automatically created by gcc's section
anchor generation code:
https://gcc.gnu.org/onlinedocs/gccint/Anchored-Addresses.htmlhttps://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/varasm.c;h=cd9591a45617464946dcf9a126dde277d9de9804;hb=9fb89fa845c1b2e0a18d85ada0b077c84508ab78#l7473
This was verified by compiling the kernel with -fno-section-anchors
and observing that the ".LANCHOR1" ELF local symbol disappeared, and
modpost no longer warned about the section mismatch. The serial
driver code idiom triggering the warning is standard Linux serial
driver practice that has a specific whitelist inclusion in modpost.c.
I'm neither a modpost nor an ELF expert, but naively, it doesn't seem
useful for modpost to report section mismatch warnings caused by ELF
local symbols by default. Local symbols have compiler-generated
names, and thus bypass modpost's whitelisting algorithm, which relies
on the presence of a non-autogenerated symbol name. This increases
the likelihood that false positive warnings will be generated (as in
the above case).
Thus, disable section mismatch reporting on ELF local symbols. The
rationale here is similar to that of commit 2e3a10a155 ("ARM: avoid
ARM binutils leaking ELF local symbols") and of similar code already
present in modpost.c:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/mod/modpost.c?h=v4.19-rc4&id=7876320f88802b22d4e2daf7eb027dd14175a0f8#n1256
This third version of the patch implements a suggestion from Masahiro
Yamada <yamada.masahiro@socionext.com> to restructure the code as an
additional pattern matching step inside secref_whitelist(), and
further improves the patch description.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Drop modpost command line switches that are no longer used by
makefile.modpost, upon request from Sam Ravnborg <sam@ravnborg.org>,
who wrote:
modpost is not supposed to be used outside the kernel build. [...]
I checked if there were any options supported by modpost that
was not configurable in Makefile.modpost.
And I could see that the -M and -K options in getopt() were leftovers.
The code that used these option was dropped in:
commit a8773769d1 ("Kbuild: clear marker out of modpost")
Could you add a patch that delete these on top of what you already have.
https://lore.kernel.org/lkml/20181020140835.GA3351@ravnborg.org/
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
If an ARM mapping symbol shares an address with a valid symbol,
find_elf_symbol can currently return the mapping symbol instead, as the
symbol is not validated. This can result in confusing warnings:
WARNING: vmlinux.o(.text+0x18f4028): Section mismatch in reference
from the function set_reset_devices() to the variable .init.text:$x.0
This change adds a call to is_valid_name to find_elf_symbol, similarly
to how it's already used in find_elf_symbol2.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
In Fedora, the debug information is packaged separately (foo-debuginfo) and
can be installed separately. There's been a long standing issue where only
one version of a debuginfo info package can be installed at a time. There's
been an effort for Fedora for parallel debuginfo to rectify this problem.
Part of the requirement to allow parallel debuginfo to work is that build ids
are unique between builds. The existing upstream rpm implementation ensures
this by re-calculating the build-id using the version and release as a
seed. This doesn't work 100% for the kernel because of the vDSO which is
its own binary and doesn't get updated when embedded.
Fix this by adding some data in an ELF note for both the kernel and modules.
The data is controlled via a Kconfig option so distributions can set it
to an appropriate value to ensure uniqueness between builds.
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, strstarts() is only used in export_from_secname().
Use it more widely to improve the code readability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
get_(next_)modinfo takes a pointer and length pair of the .modinfo
section. Instead, pass struct elf_info pointer to reduce the number
of function arguments.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG.
They were removed by commit 4ba66a9760 ("arch: remove blackfin port"),
commit bb6fb6dfcc ("metag: Remove arch/metag/"), respectively.
No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX,
hence VMLINUX_SYMBOL_STR(foo) can be simplify replaced with "foo".
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
