kernel/linux.git/lib, branch v4.14.111

ARM: 8833/1: Ensure that NEON code always compiles with Clang

2019-04-05T20:31:34+00:00

[ Upstream commit de9c0d49d85dc563549972edc5589d195cd5e859 ] While building arm32 allyesconfig, I ran into the following errors: arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with '-mfloat-abi=softfp -mfpu=neon' In file included from lib/raid6/neon1.c:27: /home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2: error: "NEON support not enabled" Building V=1 showed NEON_FLAGS getting passed along to Clang but __ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang only defining __ARM_NEON__ when targeting armv7, rather than armv6k, which is the '-march' value for allyesconfig. >From lib/Basic/Targets/ARM.cpp in the Clang source: // This only gets set when Neon instructions are actually available, unlike // the VFP define, hence the soft float and arch check. This is subtly // different from gcc, we follow the intent which was that it should be set // when Neon instructions are actually available. if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) { Builder.defineMacro("__ARM_NEON", "1"); Builder.defineMacro("__ARM_NEON__"); // current AArch32 NEON implementations do not support double-precision // floating-point even when it is present in VFP. Builder.defineMacro("__ARM_NEON_FP", "0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP)); } Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets definined by Clang. This doesn't functionally change anything because that code will only run where NEON is supported, which is implicitly armv7. Link: https://github.com/ClangBuiltLinux/linux/issues/287 Suggested-by: Ard Biesheuvel Signed-off-by: Nathan Chancellor Acked-by: Nicolas Pitre Reviewed-by: Nick Desaulniers Reviewed-by: Stefan Agner Signed-off-by: Russell King Signed-off-by: Sasha Levin

kprobes: Prohibit probing on bsearch()

2019-04-05T20:31:33+00:00

[ Upstream commit 02106f883cd745523f7766d90a739f983f19e650 ] Since kprobe breakpoing handler is using bsearch(), probing on this routine can cause recursive breakpoint problem. int3 ->do_int3() ->ftrace_int3_handler() ->ftrace_location() ->ftrace_location_range() ->bsearch() -> int3 Prohibit probing on bsearch(). Signed-off-by: Andrea Righi Acked-by: Masami Hiramatsu Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/154998813406.31052.8791425358974650922.stgit@devbox Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

lib/int_sqrt: optimize initial value compute

2019-04-05T20:31:24+00:00

commit f8ae107eef209bff29a5816bc1aad40d5cd69a80 upstream. The initial value (@m) compute is: m = 1UL << (BITS_PER_LONG - 2); while (m > x) m >>= 2; Which is a linear search for the highest even bit smaller or equal to @x We can implement this using a binary search using __fls() (or better when its hardware implemented). m = 1UL << (__fls(x) & ~1UL); Especially for small values of @x; which are the more common arguments when doing a CDF on idle times; the linear search is near to worst case, while the binary search of __fls() is a constant 6 (or 5 on 32bit) branches. cycles: branches: branch-misses: PRE: hot: 43.633557 +- 0.034373 45.333132 +- 0.002277 0.023529 +- 0.000681 cold: 207.438411 +- 0.125840 45.333132 +- 0.002277 6.976486 +- 0.004219 SOFTWARE FLS: hot: 29.576176 +- 0.028850 26.666730 +- 0.004511 0.019463 +- 0.000663 cold: 165.947136 +- 0.188406 26.666746 +- 0.004511 6.133897 +- 0.004386 HARDWARE FLS: hot: 24.720922 +- 0.025161 20.666784 +- 0.004509 0.020836 +- 0.000677 cold: 132.777197 +- 0.127471 20.666776 +- 0.004509 5.080285 +- 0.003874 Averages computed over all values <128k using a LFSR to generate order. Cold numbers have a LFSR based branch trace buffer 'confuser' ran between each int_sqrt() invocation. Link: http://lkml.kernel.org/r/20171020164644.936577234@infradead.org Signed-off-by: Peter Zijlstra (Intel) Suggested-by: Joe Perches Acked-by: Will Deacon Acked-by: Linus Torvalds Cc: Anshul Garg Cc: Davidlohr Bueso Cc: David Miller Cc: Ingo Molnar Cc: Kees Cook Cc: Matthew Wilcox Cc: Michael Davidson Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Joe Perches Signed-off-by: Greg Kroah-Hartman

rhashtable: Still do rehash when we get EEXIST

2019-04-03T04:25:09+00:00

[ Upstream commit 408f13ef358aa5ad56dc6230c2c7deb92cf462b1 ] As it stands if a shrink is delayed because of an outstanding rehash, we will go into a rescheduling loop without ever doing the rehash. This patch fixes this by still carrying out the rehash and then rescheduling so that we can shrink after the completion of the rehash should it still be necessary. The return value of EEXIST captures this case and other cases (e.g., another thread expanded/rehashed the table at the same time) where we should still proceed with the rehash. Fixes: da20420f83ea ("rhashtable: Add nested tables") Reported-by: Josh Elsasser Signed-off-by: Herbert Xu Tested-by: Josh Elsasser Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

lib/int_sqrt: optimize small argument

2019-03-27T05:13:54+00:00

commit 3f3295709edea6268ff1609855f498035286af73 upstream. The current int_sqrt() computation is sub-optimal for the case of small @x. Which is the interesting case when we're going to do cumulative distribution functions on idle times, which we assume to be a random variable, where the target residency of the deepest idle state gives an upper bound on the variable (5e6ns on recent Intel chips). In the case of small @x, the compute loop: while (m != 0) { b = y + m; y >>= 1; if (x >= b) { x -= b; y += m; } m >>= 2; } can be reduced to: while (m > x) m >>= 2; Because y==0, b==m and until x>=m y will remain 0. And while this is computationally equivalent, it runs much faster because there's less code, in particular less branches. cycles: branches: branch-misses: OLD: hot: 45.109444 +- 0.044117 44.333392 +- 0.002254 0.018723 +- 0.000593 cold: 187.737379 +- 0.156678 44.333407 +- 0.002254 6.272844 +- 0.004305 PRE: hot: 67.937492 +- 0.064124 66.999535 +- 0.000488 0.066720 +- 0.001113 cold: 232.004379 +- 0.332811 66.999527 +- 0.000488 6.914634 +- 0.006568 POST: hot: 43.633557 +- 0.034373 45.333132 +- 0.002277 0.023529 +- 0.000681 cold: 207.438411 +- 0.125840 45.333132 +- 0.002277 6.976486 +- 0.004219 Averages computed over all values <128k using a LFSR to generate order. Cold numbers have a LFSR based branch trace buffer 'confuser' ran between each int_sqrt() invocation. Link: http://lkml.kernel.org/r/20171020164644.876503355@infradead.org Fixes: 30493cc9dddb ("lib/int_sqrt.c: optimize square root algorithm") Signed-off-by: Peter Zijlstra (Intel) Suggested-by: Anshul Garg Acked-by: Linus Torvalds Cc: Davidlohr Bueso Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Will Deacon Cc: Joe Perches Cc: David Miller Cc: Matthew Wilcox Cc: Kees Cook Cc: Michael Davidson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

assoc_array: Fix shortcut creation

2019-03-23T13:35:14+00:00

[ Upstream commit bb2ba2d75a2d673e76ddaf13a9bd30d6a8b1bb08 ] Fix the creation of shortcuts for which the length of the index key value is an exact multiple of the machine word size. The problem is that the code that blanks off the unused bits of the shortcut value malfunctions if the number of bits in the last word equals machine word size. This is due to the "<<" operator being given a shift of zero in this case, and so the mask that should be all zeros is all ones instead. This causes the subsequent masking operation to clear everything rather than clearing nothing. Ordinarily, the presence of the hash at the beginning of the tree index key makes the issue very hard to test for, but in this case, it was encountered due to a development mistake that caused the hash output to be either 0 (keyring) or 1 (non-keyring) only. This made it susceptible to the keyctl/unlink/valid test in the keyutils package. The fix is simply to skip the blanking if the shift would be 0. For example, an index key that is 64 bits long would produce a 0 shift and thus a 'blank' of all 1s. This would then be inverted and AND'd onto the index_key, incorrectly clearing the entire last word. Fixes: 3cb989501c26 ("Add a generic associative array implementation.") Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Sasha Levin

lib/test_kmod.c: potential double free in error handling

2019-03-13T21:03:18+00:00

[ Upstream commit db7ddeab3ce5d64c9696e70d61f45ea9909cd196 ] There is a copy and paste bug so we set "config->test_driver" to NULL twice instead of setting "config->test_fs". Smatch complains that it leads to a double free: lib/test_kmod.c:840 __kmod_config_init() warn: 'config->test_fs' double freed Link: http://lkml.kernel.org/r/20190121140011.GA14283@kadam Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader") Signed-off-by: Dan Carpenter Acked-by: Luis Chamberlain Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

seq_buf: Make seq_buf_puts() null-terminate the buffer

2019-02-12T18:46:08+00:00

[ Upstream commit 0464ed24380905d640030d368cd84a4e4d1e15e2 ] Currently seq_buf_puts() will happily create a non null-terminated string for you in the buffer. This is particularly dangerous if the buffer is on the stack. For example: char buf[8]; char secret = "secret"; struct seq_buf s; seq_buf_init(&s, buf, sizeof(buf)); seq_buf_puts(&s, "foo"); printk("Message is %s\n", buf); Can result in: Message is fooªªªªªsecret We could require all users to memset() their buffer to zero before use. But that seems likely to be forgotten and lead to bugs. Instead we can change seq_buf_puts() to always leave the buffer in a null-terminated state. The only downside is that this makes the buffer 1 character smaller for seq_buf_puts(), but that seems like a good trade off. Link: http://lkml.kernel.org/r/20181019042109.8064-1-mpe@ellerman.id.au Acked-by: Kees Cook Signed-off-by: Michael Ellerman Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Sasha Levin

lib: fix build failure in CONFIG_DEBUG_VIRTUAL test

2019-01-13T09:01:07+00:00

commit 10fdf838e5f540beca466e9d1325999c072e5d3f upstream. On several arches, virt_to_phys() is in io.h Build fails without it: CC lib/test_debug_virtual.o lib/test_debug_virtual.c: In function 'test_debug_virtual_init': lib/test_debug_virtual.c:26:7: error: implicit declaration of function 'virt_to_phys' [-Werror=implicit-function-declaration] pa = virt_to_phys(va); ^ Fixes: e4dace361552 ("lib: add test module for CONFIG_DEBUG_VIRTUAL") CC: stable@vger.kernel.org Signed-off-by: Christophe Leroy Reviewed-by: Kees Cook Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

raid6/ppc: Fix build for clang

2019-01-13T09:01:04+00:00

commit e213574a449f7a57d4202c1869bbc7680b6b5521 upstream. We cannot build these files with clang as it does not allow altivec instructions in assembly when -msoft-float is passed. Jinsong Ji wrote: > We currently disable Altivec/VSX support when enabling soft-float. So > any usage of vector builtins will break. > > Enable Altivec/VSX with soft-float may need quite some clean up work, so > I guess this is currently a limitation. > > Removing -msoft-float will make it work (and we are lucky that no > floating point instructions will be generated as well). This is a workaround until the issue is resolved in clang. Link: https://bugs.llvm.org/show_bug.cgi?id=31177 Link: https://github.com/ClangBuiltLinux/linux/issues/239 Signed-off-by: Joel Stanley Reviewed-by: Nick Desaulniers Signed-off-by: Michael Ellerman [nc: Use 'ifeq ($(cc-name),clang)' instead of 'ifdef CONFIG_CC_IS_CLANG' because that config does not exist in 4.14; the Kconfig rewrite that added that config happened in 4.18] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman