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>
Pull x86/pti updates from Thomas Gleixner:
"Another set of melted spectrum related changes:
- Code simplifications and cleanups for RSB and retpolines.
- Make the indirect calls in KVM speculation safe.
- Whitelist CPUs which are known not to speculate from Meltdown and
prepare for the new CPUID flag which tells the kernel that a CPU is
not affected.
- A less rigorous variant of the module retpoline check which merily
warns when a non-retpoline protected module is loaded and reflects
that fact in the sysfs file.
- Prepare for Indirect Branch Prediction Barrier support.
- Prepare for exposure of the Speculation Control MSRs to guests, so
guest OSes which depend on those "features" can use them. Includes
a blacklist of the broken microcodes. The actual exposure of the
MSRs through KVM is still being worked on"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Simplify indirect_branch_prediction_barrier()
x86/retpoline: Simplify vmexit_fill_RSB()
x86/cpufeatures: Clean up Spectre v2 related CPUID flags
x86/cpu/bugs: Make retpoline module warning conditional
x86/bugs: Drop one "mitigation" from dmesg
x86/nospec: Fix header guards names
x86/alternative: Print unadorned pointers
x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
x86/msr: Add definitions for new speculation control MSRs
x86/cpufeatures: Add AMD feature bits for Speculation Control
x86/cpufeatures: Add Intel feature bits for Speculation Control
x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
module/retpoline: Warn about missing retpoline in module
KVM: VMX: Make indirect call speculation safe
KVM: x86: Make indirect calls in emulator speculation safe
There's a risk that a kernel which has full retpoline mitigations becomes
vulnerable when a module gets loaded that hasn't been compiled with the
right compiler or the right option.
To enable detection of that mismatch at module load time, add a module info
string "retpoline" at build time when the module was compiled with
retpoline support. This only covers compiled C source, but assembler source
or prebuilt object files are not checked.
If a retpoline enabled kernel detects a non retpoline protected module at
load time, print a warning and report it in the sysfs vulnerability file.
[ tglx: Massaged changelog ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: gregkh@linuxfoundation.org
Cc: torvalds@linux-foundation.org
Cc: jeyu@kernel.org
Cc: arjan@linux.intel.com
Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org
The trailing semicolon is an empty statement that does no operation.
Removing it since it doesn't do anything.
Signed-off-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Partially revert commit 2fa3656829 ("kbuild: soften MODULE_LICENSE
check") so that modpost detects modules that do not have a
MODULE_LICENSE.
Sam's commit also changed the fatal error to a warning, which I am
leaving as is.
This gives advance notice of when a module has no license and will taint
the kernel if the module is loaded.
This produces the following warnings on x86_64 allmodconfig:
MODPOST 6520 modules
WARNING: modpost: missing MODULE_LICENSE() in drivers/auxdisplay/img-ascii-lcd.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-ath79.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-iop.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/accel/kxsd9-i2c.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/adc/qcom-vadc-common.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/mtk-vcodec/mtk-vcodec-common.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/soc_camera/soc_scale_crop.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/mtd/nand/denali_pci.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/net/phy/cortina.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/pinctrl/pxa/pinctrl-pxa2xx.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/power/reset/zx-reboot.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/rpmsg/qcom_glink_native.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/staging/comedi/drivers/ni_atmio.o
WARNING: modpost: missing MODULE_LICENSE() in net/9p/9pnet_xen.o
WARNING: modpost: missing MODULE_LICENSE() in sound/soc/codecs/snd-soc-pcm512x-spi.o
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Summary of modules changes for the 4.14 merge window:
- Minor code cleanups and fixes
- modpost: avoid building modules that have names that exceed the size
of the name field in struct module
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"Summary of modules changes for the 4.14 merge window:
- minor code cleanups and fixes
- modpost: avoid building modules that have names that exceed the
size of the name field in struct module"
* tag 'modules-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Remove const attribute from alias for MODULE_DEVICE_TABLE
module: fix ddebug_remove_module()
modpost: abort if module name is too long
There is code duplication between sec_name() and sech_name(). Simplify
sec_name() by re-using sech_name(). Also, move them up to remove the
forward declaration of sec_name().
Link: http://lkml.kernel.org/r/1502248721-22009-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Module name has a limited length, but currently the build system
allows the build finishing even if the module name is too long.
CC /root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.o
/root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.c:9:2:
warning: initializer-string for array of chars is too long [enabled by default]
.name = KBUILD_MODNAME,
^
but it's merely a warning.
This patch adds the check of the module name length in modpost and stops
the build properly.
Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Accessing the mod structure (e.g. for mod->name) prior to having completed
check_modstruct_version() can result in writing garbage to the error logs
if the layout of the mod structure loaded from disk doesn't match the
running kernel's mod structure layout. This kind of mismatch will become
much more likely if a kernel is built with different randomization seed
for the struct layout randomization plugin.
Instead, add and use a new modinfo string for logging the module name.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
The '__unreachable' and '__func_stack_frame_non_standard' sections are
only used at compile time. They're discarded for vmlinux but they
should also be discarded for modules.
Since this is a recurring pattern, prefix the section names with
".discard.". It's a nice convention and vmlinux.lds.h already discards
such sections.
Also remove the 'a' (allocatable) flag from the __unreachable section
since it doesn't make sense for a discarded section.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: d1091c7fa3 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This add the kbuild infrastructure that will allow architectures to emit
vmlinux symbol CRCs as 32-bit offsets to another location in the kernel
where the actual value is stored. This works around problems with CRCs
being mistaken for relocatable symbols on kernels that self relocate at
runtime (i.e., powerpc with CONFIG_RELOCATABLE=y)
For the kbuild side of things, this comes down to the following:
- introducing a Kconfig symbol MODULE_REL_CRCS
- adding a -R switch to genksyms to instruct it to emit the CRC symbols
as references into the .rodata section
- making modpost distinguish such references from absolute CRC symbols
by the section index (SHN_ABS)
- making kallsyms disregard non-absolute symbols with a __crc_ prefix
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull kbuild updates from Michal Marek:
- prototypes for x86 asm-exported symbols (Adam Borowski) and a warning
about missing CRCs (Nick Piggin)
- asm-exports fix for LTO (Nicolas Pitre)
- thin archives improvements (Nick Piggin)
- linker script fix for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION (Nick
Piggin)
- genksyms support for __builtin_va_list keyword
- misc minor fixes
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
x86/kbuild: enable modversions for symbols exported from asm
kbuild: fix scripts/adjust_autoksyms.sh* for the no modules case
scripts/kallsyms: remove last remnants of --page-offset option
make use of make variable CURDIR instead of calling pwd
kbuild: cmd_export_list: tighten the sed script
kbuild: minor improvement for thin archives build
kbuild: modpost warn if export version crc is missing
kbuild: keep data tables through dead code elimination
kbuild: improve linker compatibility with lib-ksyms.o build
genksyms: Regenerate parser
kbuild/genksyms: handle va_list type
kbuild: thin archives for multi-y targets
kbuild: kallsyms allow 3-pass generation if symbols size has changed
This catches the failing ceph CRC on with:
LD vmlinux.o
MODPOST vmlinux.o
WARNING: EXPORT symbol "ceph_monc_do_statfs" [vmlinux] version
generation failed, symbol will not be versioned.
When the modules referring to exported symbols are built, there is an
existing warning for missing CRC, but it's not always the case such
any such module will be built, and in any case it is useful to get a
warning at the source.
This gets a little verbose with CONFIG_DEBUG_SECTION_MISMATCH,
producing a warning with each object linked, but I didn't think
that warranted extra complexity to avoid.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
valgrind complains that memory is not freed after allocation
with realloc() called from main() and write_dump().
So let us free the allocated memory properly.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Link: http://lkml.kernel.org/r/1470166981-6461-1-git-send-email-xypron.glpk@gmx.de
Signed-off-by: Jessica Yu <jeyu@redhat.com>
When doing an nmi backtrace of many cores, most of which are idle, the
output is a little overwhelming and very uninformative. Suppress
messages for cpus that are idling when they are interrupted and just
emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".
We do this by grouping all the cpuidle code together into a new
.cpuidle.text section, and then checking the address of the interrupted
PC to see if it lies within that section.
This commit suitably tags x86 and tile idle routines, and only adds in
the minimal framework for other architectures.
Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Tested-by: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PowerPC64 uses the symbol .TOC. much as other targets use
_GLOBAL_OFFSET_TABLE_. It identifies the value of the GOT pointer (or in
powerpc parlance, the TOC pointer). Global offset tables are generally
local to an executable or shared library, or in the kernel, module. Thus
it does not make sense for a module to resolve a relocation against
.TOC. to the kernel's .TOC. value. A module has its own .TOC., and
indeed the powerpc64 module relocation processing ignores the kernel
value of .TOC. and instead calculates a module-local value.
This patch removes code involved in exporting the kernel .TOC., tweaks
modpost to ignore an undefined .TOC., and the module loader to twiddle
the section symbol so that .TOC. isn't seen as undefined.
Note that if the kernel was compiled with -msingle-pic-base then ELFv2
would not have function global entry code setting up r2. In that case
the module call stubs would need to be modified to set up r2 using the
kernel .TOC. value, requiring some of this code to be reinstated.
mpe: Furthermore a change in binutils master (not yet released) causes
the current way we handle the TOC to no longer work when building with
MODVERSIONS=y and RELOCATABLE=n. The symptom is that modules can not be
loaded due to there being no version found for TOC.
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: Alan Modra <amodra@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In our ARC toolchain the default linker script includes special
sections used for code and data located in special fast memory.
To avoid warnings we add these sections i.e. .cmem* and .fmt_slot*
to white list.
Signed-off-by: Noam Camus <noamc@ezchip.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The section mismatch warning can be easy to miss during the kernel build
process. Allow it to be marked as fatal to be easily caught and prevent
bugs from slipping in.
Setting CONFIG_SECTION_MISMATCH_WARN_ONLY=y causes these warnings to be
non-fatal, since there are a number of section mismatches when using
allmodconfig on some architectures, and we do not want to break these
builds by default.
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Change-Id: Ic346706e3297c9f0d790e3552aa94e5cff9897a6
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Module symbols have a limited length, but currently the build system
allows the build finishing even if the driver code contains a too long
symbol name, which eventually overflows the modversion_info[] item.
The compiler may catch at compiling *.mod.c like
CC xxx.mod.o
xxx.mod.c:18:16: warning: initializer-string for array of chars is too long
but it's merely a warning.
This patch adds the check of the symbol length in modpost and stops
the build properly.
Currently MODULE_NAME_LEN is defined in modpost.c instead of referring
to the definition in kernel header because including linux/module.h is
messy and we must cover cross-compilation.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The tilegx and tilepro compilers use .coldtext for their unlikely
executed text section name, so an __attribute__((cold)) function
will (when compiled with higher optimization levels) land in
the .coldtext section.
Modify modpost to add .coldtext to the set of OTHER_TEXT_SECTIONS
so we don't get warnings about referencing such a section in an
__ex_table block, and then also modify arch/tile/lib/memcpy_user_64.c
so that it uses plain ".coldtext" instead of ".coldtext.memcpy".
The latter naming is a relic of an earlier use of -ffunction-sections,
which we no longer use by default.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Currently an allyesconfig build [gcc-4.9.1] can generate the following:
WARNING: vmlinux.o(.text.unlikely+0x3864): Section mismatch in
reference from the function cpumask_empty.constprop.3() to the
variable .init.data:nmi_ipi_mask
which comes from the cpumask_empty usage in arch/x86/kernel/nmi_selftest.c.
Normally we would not see a symbol entry for cpumask_empty since it is:
static inline bool cpumask_empty(const struct cpumask *srcp)
however in this case, the variant of the symbol gets emitted when GCC does
constant propagation optimization.
Fix things up so that any locally optimized constprop variants don't warn
when accessing variables that live in the __init sections.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Currently the match() function supports a leading * to match any
prefix and a trailing * to match any suffix. However there currently
is not a combination of both that can be used to target matches of
whole families of functions that share a common substring.
Here we expand the *foo and foo* match to also support *foo* with
the goal of targeting compiler generated symbol names that contain
strings like ".constprop." and ".isra."
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Trying to match the SHT_NUL section isn't useful and causes build failures
on parisc and mn10300 since the addition of section strict white-listing
and __ex_table sanitizing.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 050e57fd59 ("modpost: add strict white-listing when referencing....")
Fixes: 52dc0595d5 ("modpost: handle relocations mismatch in __ex_table.")
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
As Guenter pointed out, we were never really calculating the extable entry
size because the pointer arithmetic was simply wrong. We want to check
we're handling the second relocation in __ex_table to infer an entry size,
but we were using (void*) pointers instead of Elf_Rel[a]* ones.
This fixes the problem by moving that check in the caller (since we can
deal with different types of relocations) and add is_second_extable_reloc()
to make the whole thing more readable.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
As Guenter pointed out, we want to assert that extable_entry_size has been
discovered and not the other way around. Moreover, this sanity check is
only valid when we're not dealing with the first relocation in __ex_table,
since we have not discovered the extable entry size at that point.
This was leading to a divide-by-zero on some architectures and make the
build fail.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
52dc0595d5 introduced OTHER_TEXT_SECTIONS for identifying what
sections could validly have __ex_table entries. Unfortunately, it
wasn't tested with -ffunction-sections, which some architectures
use.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
32-bit and 64-bit ARM use these sections to store executable code, so
they must be whitelisted in modpost's table of valid text sections.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
struct section_check is used as a generic way of describing what
relocations are authorized/forbidden when running modpost. This commit
tries to describe how each field is used.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (Fixed "mist"ake)
__ex_table is a simple table section where each entry is a pair of
addresses - the first address is an address which can fault in kernel
space, and the second address points to where the kernel should jump to
when handling that fault. This is how copy_from_user() does not crash the
kernel if userspace gives a borked pointer for example.
If one of these addresses point to a non-executable section, something is
seriously wrong since it either means the kernel will never fault from
there or it will not be able to jump to there. As both cases are serious
enough, we simply error out in these cases so the build fails and the
developper has to fix the issue.
In case the section is executable, but it isn't referenced in our list of
authorized sections to point to from __ex_table, we just dump a warning
giving more information about it. We do this in case the new section is
executable but isn't supposed to be executed by the kernel. This happened
with .altinstr_replacement, which is executable but is only used to copy
instructions from - we should never have our instruction pointer pointing
in .altinstr_replacement. Admitedly, a proper fix in that case would be to
just set .altinstr_replacement NX, but we need to warn about future cases
like this.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (added long casts)
This will be useful when we want to have special handlers which need to go
through more hops to print useful information to the user.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
sched.text and .kprobes.text should behave exactly like .text with regards
to how we should warn about referencing sections which might get discarded
at runtime.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
