kernel.git/arch/sparc/Kconfig, branch linux-4.7.y

lib/GCD.c: use binary GCD algorithm instead of Euclidean

2016-05-21T00:58:30Z

The binary GCD algorithm is based on the following facts: 1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2) 2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b) 3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b) Even on x86 machines with reasonable division hardware, the binary algorithm runs about 25% faster (80% the execution time) than the division-based Euclidian algorithm. On platforms like Alpha and ARMv6 where division is a function call to emulation code, it's even more significant. There are two variants of the code here, depending on whether a fast __ffs (find least significant set bit) instruction is available. This allows the unpredictable branches in the bit-at-a-time shifting loop to be eliminated. If fast __ffs is not available, the "even/odd" GCD variant is used. I use the following code to benchmark: #include #include #include #include #include #include #define swap(a, b) \ do { \ a ^= b; \ b ^= a; \ a ^= b; \ } while (0) unsigned long gcd0(unsigned long a, unsigned long b) { unsigned long r; if (a < b) { swap(a, b); } if (b == 0) return a; while ((r = a % b) != 0) { a = b; b = r; } return b; } unsigned long gcd1(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); for (;;) { a >>= __builtin_ctzl(a); if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd2(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; for (;;) { while (!(a & r)) a >>= 1; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } unsigned long gcd3(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); if (b == 1) return r & -r; for (;;) { a >>= __builtin_ctzl(a); if (a == 1) return r & -r; if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd4(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; if (b == r) return r; for (;;) { while (!(a & r)) a >>= 1; if (a == r) return r; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = { gcd0, gcd1, gcd2, gcd3, gcd4, }; #define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0])) #if defined(__x86_64__) #define rdtscll(val) do { \ unsigned long __a,__d; \ __asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \ (val) = ((unsigned long long)__a) | (((unsigned long long)__d)<<32); \ } while(0) static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { unsigned long long start, end; unsigned long long ret; unsigned long gcd_res; rdtscll(start); gcd_res = gcd(a, b); rdtscll(end); if (end >= start) ret = end - start; else ret = ~0ULL - start + 1 + end; *res = gcd_res; return ret; } #else static inline struct timespec read_time(void) { struct timespec time; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time); return time; } static inline unsigned long long diff_time(struct timespec start, struct timespec end) { struct timespec temp; if ((end.tv_nsec - start.tv_nsec) < 0) { temp.tv_sec = end.tv_sec - start.tv_sec - 1; temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec; } else { temp.tv_sec = end.tv_sec - start.tv_sec; temp.tv_nsec = end.tv_nsec - start.tv_nsec; } return temp.tv_sec * 1000000000ULL + temp.tv_nsec; } static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { struct timespec start, end; unsigned long gcd_res; start = read_time(); gcd_res = gcd(a, b); end = read_time(); *res = gcd_res; return diff_time(start, end); } #endif static inline unsigned long get_rand() { if (sizeof(long) == 8) return (unsigned long)rand() << 32 | rand(); else return rand(); } int main(int argc, char **argv) { unsigned int seed = time(0); int loops = 100; int repeats = 1000; unsigned long (*res)[TEST_ENTRIES]; unsigned long long elapsed[TEST_ENTRIES]; int i, j, k; for (;;) { int opt = getopt(argc, argv, "n:r:s:"); /* End condition always first */ if (opt == -1) break; switch (opt) { case 'n': loops = atoi(optarg); break; case 'r': repeats = atoi(optarg); break; case 's': seed = strtoul(optarg, NULL, 10); break; default: /* You won't actually get here. */ break; } } res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops); memset(elapsed, 0, sizeof(elapsed)); srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); /* Do we have args? */ unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); unsigned long long min_elapsed[TEST_ENTRIES]; for (k = 0; k < repeats; k++) { for (i = 0; i < TEST_ENTRIES; i++) { unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &res[j][i]); if (k == 0 || min_elapsed[i] > tmp) min_elapsed[i] = tmp; } } for (i = 0; i < TEST_ENTRIES; i++) elapsed[i] += min_elapsed[i]; } for (i = 0; i < TEST_ENTRIES; i++) printf("gcd%d: elapsed %llu\n", i, elapsed[i]); k = 0; srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); for (i = 1; i < TEST_ENTRIES; i++) { if (res[j][i] != res[j][0]) break; } if (i < TEST_ENTRIES) { if (k == 0) { k = 1; fprintf(stderr, "Error:\n"); } fprintf(stderr, "gcd(%lu, %lu): ", a, b); for (i = 0; i < TEST_ENTRIES; i++) fprintf(stderr, "%ld%s", res[j][i], i < TEST_ENTRIES - 1 ? ", " : "\n"); } } if (k == 0) fprintf(stderr, "PASS\n"); free(res); return 0; } Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got: zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 10174 gcd1: elapsed 2120 gcd2: elapsed 2902 gcd3: elapsed 2039 gcd4: elapsed 2812 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9309 gcd1: elapsed 2280 gcd2: elapsed 2822 gcd3: elapsed 2217 gcd4: elapsed 2710 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9589 gcd1: elapsed 2098 gcd2: elapsed 2815 gcd3: elapsed 2030 gcd4: elapsed 2718 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9914 gcd1: elapsed 2309 gcd2: elapsed 2779 gcd3: elapsed 2228 gcd4: elapsed 2709 PASS [akpm@linux-foundation.org: avoid #defining a CONFIG_ variable] Signed-off-by: Zhaoxiu Zeng Signed-off-by: George Spelvin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

printk/nmi: generic solution for safe printk in NMI

2016-05-21T00:58:30Z

printk() takes some locks and could not be used a safe way in NMI context. The chance of a deadlock is real especially when printing stacks from all CPUs. This particular problem has been addressed on x86 by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). The patchset brings two big advantages. First, it makes the NMI backtraces safe on all architectures for free. Second, it makes all NMI messages almost safe on all architectures (the temporary buffer is limited. We still should keep the number of messages in NMI context at minimum). Note that there already are several messages printed in NMI context: WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE handlers. These are not easy to avoid. This patch reuses most of the code and makes it generic. It is useful for all messages and architectures that support NMI. The alternative printk_func is set when entering and is reseted when leaving NMI context. It queues IRQ work to copy the messages into the main ring buffer in a safe context. __printk_nmi_flush() copies all available messages and reset the buffer. Then we could use a simple cmpxchg operations to get synchronized with writers. There is also used a spinlock to get synchronized with other flushers. We do not longer use seq_buf because it depends on external lock. It would be hard to make all supported operations safe for a lockless use. It would be confusing and error prone to make only some operations safe. The code is put into separate printk/nmi.c as suggested by Steven Rostedt. It needs a per-CPU buffer and is compiled only on architectures that call nmi_enter(). This is achieved by the new HAVE_NMI Kconfig flag. The are MN10300 and Xtensa architectures. We need to clean up NMI handling there first. Let's do it separately. The patch is heavily based on the draft from Peter Zijlstra, see https://lkml.org/lkml/2015/6/10/327 [arnd@arndb.de: printk-nmi: use %zu format string for size_t] [akpm@linux-foundation.org: min_t->min - all types are size_t here] Signed-off-by: Petr Mladek Suggested-by: Peter Zijlstra Suggested-by: Steven Rostedt Cc: Jan Kara Acked-by: Russell King [arm part] Cc: Daniel Thompson Cc: Jiri Kosina Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Ralf Baechle Cc: Benjamin Herrenschmidt Cc: Martin Schwidefsky Cc: David Miller Cc: Daniel Thompson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

exit_thread: remove empty bodies

2016-05-21T00:58:30Z

Define HAVE_EXIT_THREAD for archs which want to do something in exit_thread. For others, let's define exit_thread as an empty inline. This is a cleanup before we change the prototype of exit_thread to accept a task parameter. [akpm@linux-foundation.org: fix mips] Signed-off-by: Jiri Slaby Cc: "David S. Miller" Cc: "H. Peter Anvin" Cc: "James E.J. Bottomley" Cc: Aurelien Jacquiot Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Chen Liqin Cc: Chris Metcalf Cc: Chris Zankel Cc: David Howells Cc: Fenghua Yu Cc: Geert Uytterhoeven Cc: Guan Xuetao Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: James Hogan Cc: Jeff Dike Cc: Jesper Nilsson Cc: Jiri Slaby Cc: Jonas Bonn Cc: Koichi Yasutake Cc: Lennox Wu Cc: Ley Foon Tan Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mikael Starvik Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Rich Felker Cc: Richard Henderson Cc: Richard Kuo Cc: Richard Weinberger Cc: Russell King Cc: Steven Miao Cc: Thomas Gleixner Cc: Tony Luck Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'gpio-v4.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

2016-05-18T00:39:42Z

Pull GPIO updates from Linus Walleij: "This is the bulk of GPIO changes for kernel cycle v4.7: Core infrastructural changes: - Support for natively single-ended GPIO driver stages. This means that if the hardware has registers to configure open drain or open source configuration, we use that rather than (as we did before) try to emulate it by switching the line to an input to get high impedance. This is also documented throughly in Documentation/gpio/driver.txt for those of you who did not understand one word of what I just wrote. - Start to do away with the unnecessarily complex and unitelligible ARCH_REQUIRE_GPIOLIB and ARCH_WANT_OPTIONAL_GPIOLIB, another evolutional artifact from the time when the GPIO subsystem was unmaintained. Archs can now just select GPIOLIB and be done with it, cleanups to arches will trickle in for the next kernel. Some minor archs ACKed the changes immediately so these are included in this pull request. - Advancing the use of the data pointer inside the GPIO device for storing driver data by switching the PowerPC, Super-H Unicore and a few other subarches or subsystem drivers in ALSA SoC, Input, serial, SSB, staging etc to use it. - The initialization now reads the input/output state of the GPIO lines, so that each GPIO descriptor knows - if this callback is implemented - whether the line is input or output. This also reflects nicely in userspace "lsgpio". - It is now possible to name GPIO producer names, line names, from the device tree. (Platform data has been supported for a while). I bet we will get a similar mechanism for ACPI one of those days. This makes is possible to get sensible producer names for e.g. GPIO rails in "lsgpio" in userspace. New drivers: - New driver for the Loongson1. - The XLP driver now supports Broadcom Vulcan ARM64. - The IT87 driver now supports IT8620 and IT8628. - The PCA953X driver now supports Galileo Gen2. Driver improvements: - MCP23S08 was switched to use the gpiolib irqchip helpers and now also suppors level-triggered interrupts. - 74x164 and RCAR now supports the .set_multiple() callback - AMDPT was converted to use generic GPIO. - TC3589x, TPS65218, SX150X, F7188X, MENZ127, VX855, WM831X, WM8994 support the new single ended callback for open drain and in some cases open source. - Implement the .get_direction() callback for a few more drivers like PL061, Xgene. Cleanups: - Paul Gortmaker combed through the drivers and de-modularized those who are not really modules. - Move the GPIO poweroff DT bindings to the power subdir where they belong. - Rename gpio-generic.c to gpio-mmio.c, which is much more to the point. That's what it is handling, nothing more, nothing less" * tag 'gpio-v4.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (126 commits) MIPS: do away with ARCH_[WANT_OPTIONAL|REQUIRE]_GPIOLIB gpio: zevio: make it explicitly non-modular gpio: timberdale: make it explicitly non-modular gpio: stmpe: make it explicitly non-modular gpio: sodaville: make it explicitly non-modular pinctrl: sh-pfc: Let gpio_chip.to_irq() return zero on error gpio: dwapb: Add ACPI device ID for DWAPB GPIO controller on X-Gene platforms gpio: dt-bindings: add wd,mbl-gpio bindings gpio: of: make it possible to name GPIO lines gpio: make gpiod_to_irq() return negative for NO_IRQ gpio: xgene: implement .get_direction() gpio: xgene: Enable ACPI support for X-Gene GFC GPIO driver gpio: tegra: Implement gpio_get_direction callback gpio: set up initial state from .get_direction() gpio: rename gpio-generic.c into gpio-mmio.c gpio: generic: fix GPIO_GENERIC_PLATFORM is set to module case gpio: dwapb: add gpio-signaled acpi event support gpio: dwapb: convert device node to fwnode gpio: dwapb: remove name from dwapb_port_property gpio/qoriq: select IRQ_DOMAIN ...

bpf: split HAVE_BPF_JIT into cBPF and eBPF variant

2016-05-16T17:49:31Z

Split the HAVE_BPF_JIT into two for distinguishing cBPF and eBPF JITs. Current cBPF ones: # git grep -n HAVE_CBPF_JIT arch/ arch/arm/Kconfig:44: select HAVE_CBPF_JIT arch/mips/Kconfig:18: select HAVE_CBPF_JIT if !CPU_MICROMIPS arch/powerpc/Kconfig:129: select HAVE_CBPF_JIT arch/sparc/Kconfig:35: select HAVE_CBPF_JIT Current eBPF ones: # git grep -n HAVE_EBPF_JIT arch/ arch/arm64/Kconfig:61: select HAVE_EBPF_JIT arch/s390/Kconfig:126: select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES arch/x86/Kconfig:94: select HAVE_EBPF_JIT if X86_64 Later code also needs this facility to check for eBPF JITs. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

sparc: remove ARCH_WANT_OPTIONAL_GPIOLIB

2016-04-26T12:06:15Z

This symbols is not needed to get access to selecting the GPIOLIB anymore: any arch can select GPIOLIB. Cc: Michael Büsch Cc: sparclinux@vger.kernel.org Acked-by: David S. Miller Signed-off-by: Linus Walleij

dma-mapping: always provide the dma_map_ops based implementation

2016-01-21T01:09:18Z

Move the generic implementation to now that all architectures support it and remove the HAVE_DMA_ATTR Kconfig symbol now that everyone supports them. [valentinrothberg@gmail.com: remove leftovers in Kconfig] Signed-off-by: Christoph Hellwig Cc: "David S. Miller" Cc: Aurelien Jacquiot Cc: Chris Metcalf Cc: David Howells Cc: Geert Uytterhoeven Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Helge Deller Cc: James Hogan Cc: Jesper Nilsson Cc: Koichi Yasutake Cc: Ley Foon Tan Cc: Mark Salter Cc: Mikael Starvik Cc: Steven Miao Cc: Vineet Gupta Cc: Christian Borntraeger Cc: Joerg Roedel Cc: Sebastian Ott Signed-off-by: Valentin Rothberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Kconfig: remove HAVE_LATENCYTOP_SUPPORT

2016-01-16T19:17:23Z

As illustrated by commit a3afe70b83fd ("[S390] latencytop s390 support."), HAVE_LATENCYTOP_SUPPORT is defined by an architecture to advertise an implementation of save_stack_trace_tsk. However, as of 9212ddb5eada ("stacktrace: provide save_stack_trace_tsk() weak alias") a dummy implementation is provided if STACKTRACE=y. Given that LATENCYTOP already depends on STACKTRACE_SUPPORT and selects STACKTRACE, we can remove HAVE_LATENCYTOP_SUPPORT altogether. Signed-off-by: Will Deacon Acked-by: Heiko Carstens Cc: Vineet Gupta Cc: Russell King Cc: James Hogan Cc: Michal Simek Cc: Helge Deller Acked-by: Michael Ellerman Cc: "David S. Miller" Cc: Guan Xuetao Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sparc: time: Replace update_persistent_clock() with CONFIG_RTC_SYSTOHC

2015-06-24T23:13:43Z

On Sparc systems, update_persistent_clock() uses RTC drivers to do the job, it makes more sense to hand it over to CONFIG_RTC_SYSTOHC. In the long run, all the update_persistent_clock() should migrate to proper class RTC drivers if any and use CONFIG_RTC_SYSTOHC instead. Signed-off-by: Xunlei Pang Acked-by: David S. Miller Signed-off-by: Alexandre Belloni

sparc: expose number of page table levels

2015-04-14T23:49:02Z

We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by: Kirill A. Shutemov Cc: "David S. Miller" Tested-by: Guenter Roeck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds