Often all is needed is these small helpers, instead of compiler.h or a
full kprobes.h. This is important for asm helpers, in fact even some
asm/kprobes.h make use of these helpers... instead just keep a generic
asm file with helpers useful for asm code with the least amount of
clutter as possible.
Likewise we need now to also address what to do about this file for both
when architectures have CONFIG_HAVE_KPROBES, and when they do not. Then
for when architectures have CONFIG_HAVE_KPROBES but have disabled
CONFIG_KPROBES.
Right now most asm/kprobes.h do not have guards against CONFIG_KPROBES,
this means most architecture code cannot include asm/kprobes.h safely.
Correct this and add guards for architectures missing them.
Additionally provide architectures that not have kprobes support with
the default asm-generic solution. This lets us force asm/kprobes.h on
the header include/linux/kprobes.h always, but most importantly we can
now safely include just asm/kprobes.h on architecture code without
bringing the full kitchen sink of header files.
Two architectures already provided a guard against CONFIG_KPROBES on its
kprobes.h: sh, arch. The rest of the architectures needed gaurds added.
We avoid including any not-needed headers on asm/kprobes.h unless
kprobes have been enabled.
In a subsequent atomic change we can try now to remove compiler.h from
include/linux/kprobes.h.
During this sweep I've also identified a few architectures defining a
common macro needed for both kprobes and ftrace, that of the definition
of the breakput instruction up. Some refer to this as
BREAKPOINT_INSTRUCTION. This must be kept outside of the #ifdef
CONFIG_KPROBES guard.
[mcgrof@kernel.org: fix arm64 build]
Link: http://lkml.kernel.org/r/CAB=NE6X1WMByuARS4mZ1g9+W=LuVBnMDnh_5zyN0CLADaVh=Jw@mail.gmail.com
[sfr@canb.auug.org.au: fixup for kprobes declarations moving]
Link: http://lkml.kernel.org/r/20170214165933.13ebd4f4@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170203233139.32682-1-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull tracing updates from Steven Rostedt:
"This release has no new tracing features, just clean ups, minor fixes
and small optimizations"
* tag 'trace-v4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (25 commits)
tracing: Remove outdated ring buffer comment
tracing/probes: Fix a warning message to show correct maximum length
tracing: Fix return value check in trace_benchmark_reg()
tracing: Use modern function declaration
jump_label: Reduce the size of struct static_key
tracing/probe: Show subsystem name in messages
tracing/hwlat: Update old comment about migration
timers: Make flags output in the timer_start tracepoint useful
tracing: Have traceprobe_probes_write() not access userspace unnecessarily
tracing: Have COMM event filter key be treated as a string
ftrace: Have set_graph_function handle multiple functions in one write
ftrace: Do not hold references of ftrace_graph_{notrace_}hash out of graph_lock
tracing: Reset parser->buffer to allow multiple "puts"
ftrace: Have set_graph_functions handle write with RDWR
ftrace: Reset fgd->hash in ftrace_graph_write()
ftrace: Replace (void *)1 with a meaningful macro name FTRACE_GRAPH_EMPTY
ftrace: Create a slight optimization on searching the ftrace_hash
tracing: Add ftrace_hash_key() helper function
ftrace: Convert graph filter to use hash tables
ftrace: Expose ftrace_hash_empty and ftrace_lookup_ip
...
Now that constants are traced, it is useful to see the number of constants
that are traced in the likely/unlikely profiler in order to know if they
should be ignored or not.
The likely/unlikely will display a number after the "correct" number if a
"constant" count exists.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This plugin detects any structures that contain __user attributes and
makes sure it is being fully initialized so that a specific class of
information exposure is eliminated. (This plugin was originally designed
to block the exposure of siginfo in CVE-2013-2141.)
Ported from grsecurity/PaX. This version adds a verbose option to the
plugin and the Kconfig.
Signed-off-by: Kees Cook <keescook@chromium.org>
When running the likely/unlikely profiler, one of the results did not look
accurate. It noted that the unlikely() in link_path_walk() was 100%
incorrect. When I added a trace_printk() to see what was happening there, it
became 80% correct! Looking deeper into what whas happening, I found that
gcc split that if statement into two paths. One where the if statement
became a constant, the other path a variable. The other path had the if
statement always hit (making the unlikely there, always false), but since
the #define unlikely() has:
#define unlikely() (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
Where constants are ignored by the branch profiler, the "constant" path
made by the compiler was ignored, even though it was hit 80% of the time.
By just passing the constant value to the __branch_check__() function and
tracing it out of line (as always correct, as likely/unlikely isn't a factor
for constants), then we get back the accurate readings of branches that were
optimized by gcc causing part of the execution to become constant.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull gcc plugins update from Kees Cook:
"This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot
time as possible, hoping to capitalize on any possible variation in
CPU operation (due to runtime data differences, hardware differences,
SMP ordering, thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example
for how to manipulate kernel code using the gcc plugin internals"
* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
latent_entropy: Mark functions with __latent_entropy
gcc-plugins: Add latent_entropy plugin
Pull kbuild updates from Michal Marek:
- EXPORT_SYMBOL for asm source by Al Viro.
This does bring a regression, because genksyms no longer generates
checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
working on a patch to fix this.
Plus, we are talking about functions like strcpy(), which rarely
change prototypes.
- Fixes for PPC fallout of the above by Stephen Rothwell and Nick
Piggin
- fixdep speedup by Alexey Dobriyan.
- preparatory work by Nick Piggin to allow architectures to build with
-ffunction-sections, -fdata-sections and --gc-sections
- CONFIG_THIN_ARCHIVES support by Stephen Rothwell
- fix for filenames with colons in the initramfs source by me.
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
initramfs: Escape colons in depfile
ppc: there is no clear_pages to export
powerpc/64: whitelist unresolved modversions CRCs
kbuild: -ffunction-sections fix for archs with conflicting sections
kbuild: add arch specific post-link Makefile
kbuild: allow archs to select link dead code/data elimination
kbuild: allow architectures to use thin archives instead of ld -r
kbuild: Regenerate genksyms lexer
kbuild: genksyms fix for typeof handling
fixdep: faster CONFIG_ search
ia64: move exports to definitions
sparc32: debride memcpy.S a bit
[sparc] unify 32bit and 64bit string.h
sparc: move exports to definitions
ppc: move exports to definitions
arm: move exports to definitions
s390: move exports to definitions
m68k: move exports to definitions
alpha: move exports to actual definitions
x86: move exports to actual definitions
...
The __latent_entropy gcc attribute can be used only on functions and
variables. If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents. The variable must
be an integer, an integer array type or a structure with integer fields.
These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to
select to build with -ffunction-sections, -fdata-sections, and link
with --gc-sections. It requires some work (documented) to ensure all
unreferenced entrypoints are live, and requires toolchain and build
verification, so it is made a per-arch option for now.
On a random powerpc64le build, this yelds a significant size saving,
it boots and runs fine, but there is a lot I haven't tested as yet, so
these savings may be reduced if there are bugs in the link.
text data bss dec filename
11169741 1180744 1923176 14273661 vmlinux
10445269 1004127 1919707 13369103 vmlinux.dce
~700K text, ~170K data, 6% removed from kernel image size.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
My previous commit:
112dc0c806 ("locking/barriers: Suppress sparse warnings in lockless_dereference()")
caused sparse to complain that (in radix-tree.h) we use sizeof(void)
since that rcu_dereference()s a void *.
Really, all we need is to have the expression *p in here somewhere
to make sure p is a pointer type, and sizeof(*p) was the thing that
came to my mind first to make sure that's done without really doing
anything at runtime.
Another thing I had considered was using typeof(*p), but obviously
we can't just declare a typeof(*p) variable either, since that may
end up being void. Declaring a variable as typeof(*p)* gets around
that, and still checks that typeof(*p) is valid, so do that. This
type construction can't be done for _________p1 because that will
actually be used and causes sparse address space warnings, so keep
a separate unused variable for it.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kbuild-all@01.org
Fixes: 112dc0c806 ("locking/barriers: Suppress sparse warnings in lockless_dereference()")
Link: http://lkml.kernel.org/r/1472192160-4049-1-git-send-email-johannes@sipsolutions.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull libnvdimm updates from Dan Williams:
- Replace pcommit with ADR / directed-flushing.
The pcommit instruction, which has not shipped on any product, is
deprecated. Instead, the requirement is that platforms implement
either ADR, or provide one or more flush addresses per nvdimm.
ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
to the memory controller on a power-fail event.
Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
A flush hint is an mmio address that when written and fenced assures
that all previous posted writes targeting a given dimm have been
flushed to media.
- On-demand ARS (address range scrub).
Linux uses the results of the ACPI ARS commands to track bad blocks
in pmem devices. When latent errors are detected we re-scrub the
media to refresh the bad block list, userspace can also request a
re-scrub at any time.
- Support for the Microsoft DSM (device specific method) command
format.
- Support for EDK2/OVMF virtual disk device memory ranges.
- Various fixes and cleanups across the subsystem.
* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
nfit: do an ARS scrub on hitting a latent media error
nfit: move to nfit/ sub-directory
nfit, libnvdimm: allow an ARS scrub to be triggered on demand
libnvdimm: register nvdimm_bus devices with an nd_bus driver
pmem: clarify a debug print in pmem_clear_poison
x86/insn: remove pcommit
Revert "KVM: x86: add pcommit support"
nfit, tools/testing/nvdimm/: unify shutdown paths
libnvdimm: move ->module to struct nvdimm_bus_descriptor
nfit: cleanup acpi_nfit_init calling convention
nfit: fix _FIT evaluation memory leak + use after free
tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
tools/testing/nvdimm: add virtual ramdisk range
acpi, nfit: treat virtual ramdisk SPA as pmem region
pmem: kill __pmem address space
pmem: kill wmb_pmem()
libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
fs/dax: remove wmb_pmem()
libnvdimm, pmem: flush posted-write queues on shutdown
...
The __pmem address space was meant to annotate codepaths that touch
persistent memory and need to coordinate a call to wmb_pmem(). Now that
wmb_pmem() is gone, there is little need to keep this annotation.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
gcc as far back as at least 3.04 documents the function attribute
__malloc__. Add a shorthand for attaching that to a function
declaration. This was also suggested by Andi Kleen way back in 2002
[1], but didn't get applied, perhaps because gcc at that time generated
the exact same code with and without this attribute.
This attribute tells the compiler that the return value (if non-NULL)
can be assumed not to alias any other valid pointers at the time of the
call.
Please note that the documentation for a range of gcc versions (starting
from around 4.7) contained a somewhat confusing and self-contradicting
text:
The malloc attribute is used to tell the compiler that a function may
be treated as if any non-NULL pointer it returns cannot alias any other
pointer valid when the function returns and *that the memory has
undefined content*. [...] Standard functions with this property include
malloc and *calloc*.
(emphasis mine). The intended meaning has later been clarified [2]:
This tells the compiler that a function is malloc-like, i.e., that the
pointer P returned by the function cannot alias any other pointer valid
when the function returns, and moreover no pointers to valid objects
occur in any storage addressed by P.
What this means is that we can apply the attribute to kmalloc and
friends, and it is ok for the returned memory to have well-defined
contents (__GFP_ZERO). But it is not ok to apply it to kmemdup(), nor
to other functions which both allocate and possibly initialize the
memory with existing pointers. So unless someone is doing something
pretty perverted kstrdup() should also be a fine candidate.
[1] http://thread.gmane.org/gmane.linux.kernel/57172
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56955
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In C programming language, we don't have a easy way to privatize a
member of a structure. However in kernel, sometimes there is a need to
privatize a member in case of potential bugs or misuses.
Fortunately, the noderef attribute of sparse is a way to privatize a
member, as by defining a member as noderef, the address-of operator on
the member will produce a noderef pointer to that member, and if anyone
wants to dereference that kind of pointers to read or modify the member,
sparse will yell.
Based on this, __private modifier and related operation ACCESS_PRIVATE()
are introduced, which could help detect undesigned public uses of
private members of structs. Here is an example of sparse's output if it
detect an undersigned public use:
| kernel/rcu/tree.c:4453:25: warning: incorrect type in argument 1 (different modifiers)
| kernel/rcu/tree.c:4453:25: expected struct raw_spinlock [usertype] *lock
| kernel/rcu/tree.c:4453:25: got struct raw_spinlock [noderef] *<noident>
Also, this patch improves compiler.h a little bit by adding comments for
"#else" and "#endif".
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In my randconfig tests, I came across a bug that involves several
components:
* gcc-4.9 through at least 5.3
* CONFIG_GCOV_PROFILE_ALL enabling -fprofile-arcs for all files
* CONFIG_PROFILE_ALL_BRANCHES overriding every if()
* The optimized implementation of do_div() that tries to
replace a library call with an division by multiplication
* code in drivers/media/dvb-frontends/zl10353.c doing
u32 adc_clock = 450560; /* 45.056 MHz */
if (state->config.adc_clock)
adc_clock = state->config.adc_clock;
do_div(value, adc_clock);
In this case, gcc fails to determine whether the divisor
in do_div() is __builtin_constant_p(). In particular, it
concludes that __builtin_constant_p(adc_clock) is false, while
__builtin_constant_p(!!adc_clock) is true.
That in turn throws off the logic in do_div() that also uses
__builtin_constant_p(), and instead of picking either the
constant- optimized division, and the code in ilog2() that uses
__builtin_constant_p() to figure out whether it knows the answer at
compile time. The result is a link error from failing to find
multiple symbols that should never have been called based on
the __builtin_constant_p():
dvb-frontends/zl10353.c:138: undefined reference to `____ilog2_NaN'
dvb-frontends/zl10353.c:138: undefined reference to `__aeabi_uldivmod'
ERROR: "____ilog2_NaN" [drivers/media/dvb-frontends/zl10353.ko] undefined!
ERROR: "__aeabi_uldivmod" [drivers/media/dvb-frontends/zl10353.ko] undefined!
This patch avoids the problem by changing __trace_if() to check
whether the condition is known at compile-time to be nonzero, rather
than checking whether it is actually a constant.
I see this one link error in roughly one out of 1600 randconfig builds
on ARM, and the patch fixes all known instances.
Link: http://lkml.kernel.org/r/1455312410-1058841-1-git-send-email-arnd@arndb.de
Acked-by: Nicolas Pitre <nico@linaro.org>
Fixes: ab3c9c686e ("branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y")
Cc: stable@vger.kernel.org # v2.6.30+
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
