1. 19 Oct, 2016 1 commit
  2. 15 Oct, 2016 1 commit
  3. 08 Oct, 2016 1 commit
  4. 05 Oct, 2016 1 commit
  5. 13 Sep, 2016 2 commits
  6. 02 Aug, 2016 1 commit
  7. 26 Jul, 2016 1 commit
  8. 25 Jun, 2016 1 commit
  9. 21 May, 2016 2 commits
    • Zhaoxiu Zeng's avatar
      lib/GCD.c: use binary GCD algorithm instead of Euclidean · fff7fb0b
      Zhaoxiu Zeng authored
      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 <stdio.h>
      	#include <stdlib.h>
      	#include <stdint.h>
      	#include <string.h>
      	#include <time.h>
      	#include <unistd.h>
      
      	#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: 's avatarZhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
      Signed-off-by: 's avatarGeorge Spelvin <linux@horizon.com>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      fff7fb0b
    • Jiri Slaby's avatar
      exit_thread: remove empty bodies · 5f56a5df
      Jiri Slaby authored
      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: 's avatarJiri Slaby <jslaby@suse.cz>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Chen Liqin <liqin.linux@gmail.com>
      Cc: Chris Metcalf <cmetcalf@mellanox.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Fenghua Yu <fenghua.yu@intel.com>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
      Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
      Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: James Hogan <james.hogan@imgtec.com>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Jesper Nilsson <jesper.nilsson@axis.com>
      Cc: Jiri Slaby <jslaby@suse.cz>
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
      Cc: Lennox Wu <lennox.wu@gmail.com>
      Cc: Ley Foon Tan <lftan@altera.com>
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Michal Simek <monstr@monstr.eu>
      Cc: Mikael Starvik <starvik@axis.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Rich Felker <dalias@libc.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Steven Miao <realmz6@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      5f56a5df
  10. 04 May, 2016 1 commit
    • James Hogan's avatar
      asm-generic: Drop renameat syscall from default list · b0da6d44
      James Hogan authored
      The newer renameat2 syscall provides all the functionality provided by
      the renameat syscall and adds flags, so future architectures won't need
      to include renameat.
      
      Therefore drop the renameat syscall from the generic syscall list unless
      __ARCH_WANT_RENAMEAT is defined by the architecture's unistd.h prior to
      including asm-generic/unistd.h, and adjust all architectures using the
      generic syscall list to define it so that no in-tree architectures are
      affected.
      Signed-off-by: 's avatarJames Hogan <james.hogan@imgtec.com>
      Acked-by: 's avatarVineet Gupta <vgupta@synopsys.com>
      Cc: linux-arch@vger.kernel.org
      Cc: linux-snps-arc@lists.infradead.org
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: linux-c6x-dev@linux-c6x.org
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: linux-hexagon@vger.kernel.org
      Cc: linux-metag@vger.kernel.org
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: linux@lists.openrisc.net
      Cc: Chen Liqin <liqin.linux@gmail.com>
      Cc: Lennox Wu <lennox.wu@gmail.com>
      Cc: Chris Metcalf <cmetcalf@mellanox.com>
      Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
      Cc: Ley Foon Tan <lftan@altera.com>
      Cc: nios2-dev@lists.rocketboards.org
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Cc: uclinux-h8-devel@lists.sourceforge.jp
      Signed-off-by: 's avatarArnd Bergmann <arnd@arndb.de>
      b0da6d44
  11. 14 Mar, 2016 2 commits
    • Alexander Duyck's avatar
      ipv6: Pass proto to csum_ipv6_magic as __u8 instead of unsigned short · 1e940829
      Alexander Duyck authored
      This patch updates csum_ipv6_magic so that it correctly recognizes that
      protocol is a unsigned 8 bit value.
      
      This will allow us to better understand what limitations may or may not be
      present in how we handle the data.  For example there are a number of
      places that call htonl on the protocol value.  This is likely not necessary
      and can be replaced with a multiplication by ntohl(1) which will be
      converted to a shift by the compiler.
      Signed-off-by: 's avatarAlexander Duyck <aduyck@mirantis.com>
      Signed-off-by: 's avatarDavid S. Miller <davem@davemloft.net>
      1e940829
    • Alexander Duyck's avatar
      ipv4: Update parameters for csum_tcpudp_magic to their original types · 01cfbad7
      Alexander Duyck authored
      This patch updates all instances of csum_tcpudp_magic and
      csum_tcpudp_nofold to reflect the types that are usually used as the source
      inputs.  For example the protocol field is populated based on nexthdr which
      is actually an unsigned 8 bit value.  The length is usually populated based
      on skb->len which is an unsigned integer.
      
      This addresses an issue in which the IPv6 function csum_ipv6_magic was
      generating a checksum using the full 32b of skb->len while
      csum_tcpudp_magic was only using the lower 16 bits.  As a result we could
      run into issues when attempting to adjust the checksum as there was no
      protocol agnostic way to update it.
      
      With this change the value is still truncated as many architectures use
      "(len + proto) << 8", however this truncation only occurs for values
      greater than 16776960 in length and as such is unlikely to occur as we stop
      the inner headers at ~64K in size.
      
      I did have to make a few minor changes in the arm, mn10300, nios2, and
      score versions of the function in order to support these changes as they
      were either using things such as an OR to combine the protocol and length,
      or were using ntohs to convert the length which would have truncated the
      value.
      
      I also updated a few spots in terms of whitespace and type differences for
      the addresses.  Most of this was just to make sure all of the definitions
      were in sync going forward.
      Signed-off-by: 's avatarAlexander Duyck <aduyck@mirantis.com>
      Signed-off-by: 's avatarDavid S. Miller <davem@davemloft.net>
      01cfbad7
  12. 10 Feb, 2016 1 commit
    • David Howells's avatar
      KEYS: CONFIG_KEYS_DEBUG_PROC_KEYS is no longer an option · 50d35015
      David Howells authored
      CONFIG_KEYS_DEBUG_PROC_KEYS is no longer an option as /proc/keys is now
      mandatory if the keyrings facility is enabled (it's used by libkeyutils in
      userspace).
      
      The defconfig references were removed with:
      
      	perl -p -i -e 's/CONFIG_KEYS_DEBUG_PROC_KEYS=y\n//' \
      	    `git grep -l CONFIG_KEYS_DEBUG_PROC_KEYS=y`
      
      and the integrity Kconfig fixed by hand.
      Signed-off-by: 's avatarDavid Howells <dhowells@redhat.com>
      cc: Andreas Ziegler <andreas.ziegler@fau.de>
      cc: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
      50d35015
  13. 30 Jan, 2016 1 commit
    • Toshi Kani's avatar
      arch: Set IORESOURCE_SYSTEM_RAM flag for System RAM · 35d98e93
      Toshi Kani authored
      Set IORESOURCE_SYSTEM_RAM in flags of resource ranges with
      "System RAM", "Kernel code", "Kernel data", and "Kernel bss".
      
      Note that:
      
       - IORESOURCE_SYSRAM (i.e. modifier bit) is set in flags when
         IORESOURCE_MEM is already set. IORESOURCE_SYSTEM_RAM is defined
         as (IORESOURCE_MEM|IORESOURCE_SYSRAM).
      
       - Some archs do not set 'flags' for children nodes, such as
         "Kernel code".  This patch does not change 'flags' in this
         case.
      Signed-off-by: 's avatarToshi Kani <toshi.kani@hpe.com>
      Signed-off-by: 's avatarBorislav Petkov <bp@suse.de>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Luis R. Rodriguez <mcgrof@suse.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Toshi Kani <toshi.kani@hp.com>
      Cc: linux-arch@vger.kernel.org
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: linux-mips@linux-mips.org
      Cc: linux-mm <linux-mm@kvack.org>
      Cc: linux-parisc@vger.kernel.org
      Cc: linux-s390@vger.kernel.org
      Cc: linux-sh@vger.kernel.org
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: sparclinux@vger.kernel.org
      Link: http://lkml.kernel.org/r/1453841853-11383-7-git-send-email-bp@alien8.deSigned-off-by: 's avatarIngo Molnar <mingo@kernel.org>
      35d98e93
  14. 10 Aug, 2015 1 commit
    • Viresh Kumar's avatar
      score/time: Migrate to new 'set-state' interface · 07d93ebd
      Viresh Kumar authored
      Migrate score driver to the new 'set-state' interface provided by
      clockevents core, the earlier 'set-mode' interface is marked obsolete
      now.
      
      This also enables us to implement callbacks for new states of clockevent
      devices, for example: ONESHOT_STOPPED.
      
      We weren't doing anything in ONESHOT/SHUTDOWN/RESUME modes and so
      callbacks for them aren't implemented.
      
      Cc: Chen Liqin <liqin.linux@gmail.com>
      Cc: Lennox Wu <lennox.wu@gmail.com>
      Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
      Signed-off-by: 's avatarViresh Kumar <viresh.kumar@linaro.org>
      Signed-off-by: 's avatarDaniel Lezcano <daniel.lezcano@linaro.org>
      07d93ebd
  15. 04 Aug, 2015 1 commit
  16. 17 Jul, 2015 1 commit
  17. 08 Jul, 2015 1 commit
    • Chris Metcalf's avatar
      Make asm/word-at-a-time.h available on all architectures · a6e2f029
      Chris Metcalf authored
      Added the x86 implementation of word-at-a-time to the
      generic version, which previously only supported big-endian.
      
      Omitted the x86-specific load_unaligned_zeropad(), which in
      any case is also not present for the existing BE-only
      implementation of a word-at-a-time, and is only used under
      CONFIG_DCACHE_WORD_ACCESS.
      
      Added as a "generic-y" to the Kbuilds of all architectures
      that didn't previously have it.
      Signed-off-by: 's avatarChris Metcalf <cmetcalf@ezchip.com>
      a6e2f029
  18. 25 Jun, 2015 1 commit
    • Laurent Dufour's avatar
      mm: new mm hook framework · 2ae416b1
      Laurent Dufour authored
      CRIU is recreating the process memory layout by remapping the checkpointee
      memory area on top of the current process (criu).  This includes remapping
      the vDSO to the place it has at checkpoint time.
      
      However some architectures like powerpc are keeping a reference to the
      vDSO base address to build the signal return stack frame by calling the
      vDSO sigreturn service.  So once the vDSO has been moved, this reference
      is no more valid and the signal frame built later are not usable.
      
      This patch serie is introducing a new mm hook framework, and a new
      arch_remap hook which is called when mremap is done and the mm lock still
      hold.  The next patch is adding the vDSO remap and unmap tracking to the
      powerpc architecture.
      
      This patch (of 3):
      
      This patch introduces a new set of header file to manage mm hooks:
      - per architecture empty header file (arch/x/include/asm/mm-arch-hooks.h)
      - a generic header (include/linux/mm-arch-hooks.h)
      
      The architecture which need to overwrite a hook as to redefine it in its
      header file, while architecture which doesn't need have nothing to do.
      
      The default hooks are defined in the generic header and are used in the
      case the architecture is not defining it.
      
      In a next step, mm hooks defined in include/asm-generic/mm_hooks.h should
      be moved here.
      Signed-off-by: 's avatarLaurent Dufour <ldufour@linux.vnet.ibm.com>
      Suggested-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Pavel Emelyanov <xemul@parallels.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Ingo Molnar <mingo@kernel.org>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      2ae416b1
  19. 10 Jun, 2015 1 commit
    • Guenter Roeck's avatar
      score: Fix exception handler label · 80524e93
      Guenter Roeck authored
      The latest version of modinfo fails to compile score architecture
      targets with the following error.
      
      FATAL: The relocation at __ex_table+0x634 references
      section "__ex_table" which is not executable, IOW
      the kernel will fault if it ever tries to
      jump to it.  Something is seriously wrong
      and should be fixed.
      
      The probem is caused by a bad label in an __ex_table entry.
      Acked-by: 's avatarLennox Wu <lennox.wu@gmail.com>
      Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
      Signed-off-by: 's avatarGuenter Roeck <linux@roeck-us.net>
      80524e93
  20. 19 May, 2015 3 commits
  21. 13 May, 2015 1 commit
  22. 12 Apr, 2015 1 commit
  23. 13 Feb, 2015 1 commit
    • Andy Lutomirski's avatar
      all arches, signal: move restart_block to struct task_struct · f56141e3
      Andy Lutomirski authored
      If an attacker can cause a controlled kernel stack overflow, overwriting
      the restart block is a very juicy exploit target.  This is because the
      restart_block is held in the same memory allocation as the kernel stack.
      
      Moving the restart block to struct task_struct prevents this exploit by
      making the restart_block harder to locate.
      
      Note that there are other fields in thread_info that are also easy
      targets, at least on some architectures.
      
      It's also a decent simplification, since the restart code is more or less
      identical on all architectures.
      
      [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
      Signed-off-by: 's avatarAndy Lutomirski <luto@amacapital.net>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: David Miller <davem@davemloft.net>
      Acked-by: Richard Weinberger's avatarRichard Weinberger <richard@nod.at>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
      Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
      Cc: Steven Miao <realmz6@gmail.com>
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: Mikael Starvik <starvik@axis.com>
      Cc: Jesper Nilsson <jesper.nilsson@axis.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Michal Simek <monstr@monstr.eu>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
      Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Chen Liqin <liqin.linux@gmail.com>
      Cc: Lennox Wu <lennox.wu@gmail.com>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Signed-off-by: 's avatarJames Hogan <james.hogan@imgtec.com>
      Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      f56141e3
  24. 12 Feb, 2015 1 commit
  25. 10 Feb, 2015 1 commit
  26. 29 Jan, 2015 1 commit
    • Linus Torvalds's avatar
      vm: add VM_FAULT_SIGSEGV handling support · 33692f27
      Linus Torvalds authored
      The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
      "you should SIGSEGV" error, because the SIGSEGV case was generally
      handled by the caller - usually the architecture fault handler.
      
      That results in lots of duplication - all the architecture fault
      handlers end up doing very similar "look up vma, check permissions, do
      retries etc" - but it generally works.  However, there are cases where
      the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.
      
      In particular, when accessing the stack guard page, libsigsegv expects a
      SIGSEGV.  And it usually got one, because the stack growth is handled by
      that duplicated architecture fault handler.
      
      However, when the generic VM layer started propagating the error return
      from the stack expansion in commit fee7e49d ("mm: propagate error
      from stack expansion even for guard page"), that now exposed the
      existing VM_FAULT_SIGBUS result to user space.  And user space really
      expected SIGSEGV, not SIGBUS.
      
      To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
      duplicate architecture fault handlers about it.  They all already have
      the code to handle SIGSEGV, so it's about just tying that new return
      value to the existing code, but it's all a bit annoying.
      
      This is the mindless minimal patch to do this.  A more extensive patch
      would be to try to gather up the mostly shared fault handling logic into
      one generic helper routine, and long-term we really should do that
      cleanup.
      
      Just from this patch, you can generally see that most architectures just
      copied (directly or indirectly) the old x86 way of doing things, but in
      the meantime that original x86 model has been improved to hold the VM
      semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
      "newer" things, so it would be a good idea to bring all those
      improvements to the generic case and teach other architectures about
      them too.
      Reported-and-tested-by: 's avatarTakashi Iwai <tiwai@suse.de>
      Tested-by: 's avatarJan Engelhardt <jengelh@inai.de>
      Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
      Cc: linux-arch@vger.kernel.org
      Cc: stable@vger.kernel.org
      Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
      33692f27
  27. 10 Dec, 2014 1 commit
  28. 10 Oct, 2014 1 commit
  29. 04 Oct, 2014 5 commits
  30. 13 Sep, 2014 1 commit
  31. 08 Sep, 2014 1 commit