user/sven/linux.git/include/linux/compiler.h, branch v3.18.28

tracing: Fix freak link error caused by branch tracer

2016-03-04T15:18:42Z

[ Upstream commit b33c8ff4431a343561e2319f17c14286f2aa52e2 ] 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 Fixes: ab3c9c686e22 ("branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y") Cc: stable@vger.kernel.org # v2.6.30+ Signed-off-by: Arnd Bergmann Signed-off-by: Steven Rostedt Signed-off-by: Sasha Levin

rcu: Move lockless_dereference() out of rcupdate.h

2015-09-27T16:18:53Z

[ Upstream commit 0a04b0166929405cd833c1cc40f99e862b965ddc ] I want to use lockless_dereference() from seqlock.h, which would mean including rcupdate.h from it, however rcupdate.h already includes seqlock.h. Avoid this by moving lockless_dereference() into compiler.h. This is somewhat tricky since it uses smp_read_barrier_depends() which isn't available there, but its a CPP macro so we can get away with it. The alternative would be moving it into asm/barrier.h, but that would be updating each arch (I can do if people feel that is more appropriate). Cc: Paul McKenney Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Rusty Russell Signed-off-by: Sasha Levin

kernel: make READ_ONCE() valid on const arguments

2015-06-28T17:39:28Z

[ Upstream commit dd36929720f40f17685e841ae0d4c581c165ea60 ] The use of READ_ONCE() causes lots of warnings witht he pending paravirt spinlock fixes, because those ends up having passing a member to a 'const' structure to READ_ONCE(). There should certainly be nothing wrong with using READ_ONCE() with a const source, but the helper function __read_once_size() would cause warnings because it would drop the 'const' qualifier, but also because the destination would be marked 'const' too due to the use of 'typeof'. Use a union of types in READ_ONCE() to avoid this issue. Also make sure to use parenthesis around the macro arguments to avoid possible operator precedence issues. Tested-by: Ingo Molnar Cc: Christian Borntraeger Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)

2015-04-27T20:48:19Z

[ Upstream commit 43239cbe79fc369f5d2160bd7f69e28b5c50a58c ] Feedback has shown that WRITE_ONCE(x, val) is easier to use than ASSIGN_ONCE(val,x). There are no in-tree users yet, so lets change it for 3.19. Signed-off-by: Christian Borntraeger Acked-by: Peter Zijlstra Acked-by: Davidlohr Bueso Acked-by: Paul E. McKenney Signed-off-by: Sasha Levin

kernel: Provide READ_ONCE and ASSIGN_ONCE

2015-04-27T03:02:56Z

[ Upstream commit 230fa253df6352af12ad0a16128760b5cb3f92df ] ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Let's provide READ_ONCE/ASSIGN_ONCE that will do all accesses via scalar types as suggested by Linus Torvalds. Accesses larger than the machines word size cannot be guaranteed to be atomic. These macros will use memcpy and emit a build warning. Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-06-13T02:18:49Z

Pull more perf updates from Ingo Molnar: "A second round of perf updates: - wide reaching kprobes sanitization and robustization, with the hope of fixing all 'probe this function crashes the kernel' bugs, by Masami Hiramatsu. - uprobes updates from Oleg Nesterov: tmpfs support, corner case fixes and robustization work. - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo et al: * Add support to accumulate hist periods (Namhyung Kim) * various fixes, refactorings and enhancements" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits) perf: Differentiate exec() and non-exec() comm events perf: Fix perf_event_comm() vs. exec() assumption uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates perf/documentation: Add description for conditional branch filter perf/x86: Add conditional branch filtering support perf/tool: Add conditional branch filter 'cond' to perf record perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND' uprobes: Teach copy_insn() to support tmpfs uprobes: Shift ->readpage check from __copy_insn() to uprobe_register() perf/x86: Use common PMU interrupt disabled code perf/ARM: Use common PMU interrupt disabled code perf: Disable sampled events if no PMU interrupt perf: Fix use after free in perf_remove_from_context() perf tools: Fix 'make help' message error perf record: Fix poll return value propagation perf tools: Move elide bool into perf_hpp_fmt struct perf tools: Remove elide setup for SORT_MODE__MEMORY mode perf tools: Fix "==" into "=" in ui_browser__warning assignment perf tools: Allow overriding sysfs and proc finding with env var perf tools: Consider header files outside perf directory in tags target ...

compiler.h: avoid sparse errors in __compiletime_error_fallback()

2014-06-04T23:54:14Z

Usually, BUG_ON and friends aren't even evaluated in sparse, but recently compiletime_assert_atomic_type() was added, and that now results in a sparse warning every time it is used. The reason turns out to be the temporary variable, after it sparse no longer considers the value to be a constant, and results in a warning and an error. The error is the more annoying part of this as it suppresses any further warnings in the same file, hiding other problems. Unfortunately the condition cannot be simply expanded out to avoid the temporary variable since it breaks compiletime_assert on old versions of GCC such as GCC 4.2.4 which the latest metag compiler is based on. Therefore #ifndef __CHECKER__ out the __compiletime_error_fallback which uses the potentially negative size array to trigger a conditional compiler error, so that sparse doesn't see it. Signed-off-by: James Hogan Cc: Johannes Berg Cc: Daniel Santos Cc: Luciano Coelho Cc: Peter Zijlstra Cc: Paul E. McKenney Acked-by: Johannes Berg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist

2014-04-24T08:02:56Z

Introduce NOKPROBE_SYMBOL() macro which builds a kprobes blacklist at kernel build time. The usage of this macro is similar to EXPORT_SYMBOL(), placed after the function definition: NOKPROBE_SYMBOL(function); Since this macro will inhibit inlining of static/inline functions, this patch also introduces a nokprobe_inline macro for static/inline functions. In this case, we must use NOKPROBE_SYMBOL() for the inline function caller. When CONFIG_KPROBES=y, the macro stores the given function address in the "_kprobe_blacklist" section. Since the data structures are not fully initialized by the macro (because there is no "size" information), those are re-initialized at boot time by using kallsyms. Signed-off-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Alok Kataria Cc: Ananth N Mavinakayanahalli Cc: Andrew Morton Cc: Anil S Keshavamurthy Cc: Arnd Bergmann Cc: Christopher Li Cc: Chris Wright Cc: David S. Miller Cc: Jan-Simon Möller Cc: Jeremy Fitzhardinge Cc: Linus Torvalds Cc: Randy Dunlap Cc: Rusty Russell Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-sparse@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Ingo Molnar

LLVMLinux: Add support for clang to compiler.h and new compiler-clang.h

2014-04-09T20:44:35Z

Add a compiler-clang.h file to add specific macros needed for compiling the kernel with clang. Initially the only override required is the macro for silencing the compiler for a purposefully uninintialized variable. Author: Mark Charlebois Signed-off-by: Mark Charlebois Signed-off-by: Behan Webster

Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

2014-01-24T02:11:00Z

Pull crypto update from Herbert Xu: "Here is the crypto update for 3.14: - Improved crypto_memneq helper - Use cyprto_memneq in arch-specific crypto code - Replaced orphaned DCP driver with Freescale MXS DCP driver - Added AVX/AVX2 version of AESNI-GCM encode and decode - Added AMD Cryptographic Coprocessor (CCP) driver - Misc fixes" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (41 commits) crypto: aesni - fix build on x86 (32bit) crypto: mxs - Fix sparse non static symbol warning crypto: ccp - CCP device enabled/disabled changes crypto: ccp - Cleanup hash invocation calls crypto: ccp - Change data length declarations to u64 crypto: ccp - Check for caller result area before using it crypto: ccp - Cleanup scatterlist usage crypto: ccp - Apply appropriate gfp_t type to memory allocations crypto: drivers - Sort drivers/crypto/Makefile ARM: mxs: dts: Enable DCP for MXS crypto: mxs - Add Freescale MXS DCP driver crypto: mxs - Remove the old DCP driver crypto: ahash - Fully restore ahash request before completing crypto: aesni - fix build on x86 (32bit) crypto: talitos - Remove redundant dev_set_drvdata crypto: ccp - Remove redundant dev_set_drvdata crypto: crypto4xx - Remove redundant dev_set_drvdata crypto: caam - simplify and harden key parsing crypto: omap-sham - Fix Polling mode for larger blocks crypto: tcrypt - Added speed tests for AEAD crypto alogrithms in tcrypt test suite ...