1. 07 2月, 2019 1 次提交
  2. 26 1月, 2019 1 次提交
    • A
      arch: add split IPC system calls where needed · 0d6040d4
      Arnd Bergmann 提交于
      The IPC system call handling is highly inconsistent across architectures,
      some use sys_ipc, some use separate calls, and some use both.  We also
      have some architectures that require passing IPC_64 in the flags, and
      others that set it implicitly.
      
      For the addition of a y2038 safe semtimedop() system call, I chose to only
      support the separate entry points, but that requires first supporting
      the regular ones with their own syscall numbers.
      
      The IPC_64 is now implied by the new semctl/shmctl/msgctl system
      calls even on the architectures that require passing it with the ipc()
      multiplexer.
      
      I'm not adding the new semtimedop() or semop() on 32-bit architectures,
      those will get implemented using the new semtimedop_time64() version
      that gets added along with the other time64 calls.
      Three 64-bit architectures (powerpc, s390 and sparc) get semtimedop().
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
      Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
      0d6040d4
  3. 06 6月, 2018 1 次提交
    • M
      x86: Wire up restartable sequence system call · 05c17ced
      Mathieu Desnoyers 提交于
      Wire up the rseq system call on x86 32/64.
      
      This provides an ABI improving the speed of a user-space getcpu
      operation on x86 by removing the need to perform a function call, "lsl"
      instruction, or system call on the fast path, as well as improving the
      speed of user-space operations on per-cpu data.
      Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Joel Fernandes <joelaf@google.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Dave Watson <davejwatson@fb.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: "H . Peter Anvin" <hpa@zytor.com>
      Cc: Chris Lameter <cl@linux.com>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Andrew Hunter <ahh@google.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
      Cc: Paul Turner <pjt@google.com>
      Cc: Boqun Feng <boqun.feng@gmail.com>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Ben Maurer <bmaurer@fb.com>
      Cc: linux-api@vger.kernel.org
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Link: https://lkml.kernel.org/r/20180602124408.8430-8-mathieu.desnoyers@efficios.com
      05c17ced
  4. 03 5月, 2018 1 次提交
    • C
      aio: implement io_pgetevents · 7a074e96
      Christoph Hellwig 提交于
      This is the io_getevents equivalent of ppoll/pselect and allows to
      properly mix signals and aio completions (especially with IOCB_CMD_POLL)
      and atomically executes the following sequence:
      
      	sigset_t origmask;
      
      	pthread_sigmask(SIG_SETMASK, &sigmask, &origmask);
      	ret = io_getevents(ctx, min_nr, nr, events, timeout);
      	pthread_sigmask(SIG_SETMASK, &origmask, NULL);
      
      Note that unlike many other signal related calls we do not pass a sigmask
      size, as that would get us to 7 arguments, which aren't easily supported
      by the syscall infrastructure.  It seems a lot less painful to just add a
      new syscall variant in the unlikely case we're going to increase the
      sigset size.
      Signed-off-by: NChristoph Hellwig <hch@lst.de>
      Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
      7a074e96
  5. 09 4月, 2018 3 次提交
    • D
      syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*() · d5a00528
      Dominik Brodowski 提交于
      This rename allows us to have a coherent syscall stub naming convention on
      64-bit x86 (0xffffffff prefix removed):
      
       810f0af0 t            kernel_waitid	# common (32/64) kernel helper
      
       <inline>            __do_sys_waitid	# inlined helper doing actual work
       810f0be0 t          __se_sys_waitid	# C func calling inlined helper
      
       <inline>     __do_compat_sys_waitid	# inlined helper doing actual work
       810f0d80 t   __se_compat_sys_waitid	# compat C func calling inlined helper
      
       810f2080 T         __x64_sys_waitid	# x64 64-bit-ptregs -> C stub
       810f20b0 T        __ia32_sys_waitid	# ia32 32-bit-ptregs -> C stub[*]
       810f2470 T __ia32_compat_sys_waitid	# ia32 32-bit-ptregs -> compat C stub
       810f2490 T  __x32_compat_sys_waitid	# x32 64-bit-ptregs -> compat C stub
      
          [*] This stub is unused, as the syscall table links
      	__ia32_compat_sys_waitid instead of __ia32_sys_waitid as we need
      	a compat variant here.
      Suggested-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20180409105145.5364-4-linux@dominikbrodowski.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d5a00528
    • D
      syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention · 5ac9efa3
      Dominik Brodowski 提交于
      Tidy the naming convention for compat syscall subs. Hints which describe
      the purpose of the stub go in front and receive a double underscore to
      denote that they are generated on-the-fly by the COMPAT_SYSCALL_DEFINEx()
      macro.
      
      For the generic case, this means:
      
      t            kernel_waitid	# common C function (see kernel/exit.c)
      
          __do_compat_sys_waitid	# inlined helper doing the actual work
      				# (takes original parameters as declared)
      
      T   __se_compat_sys_waitid	# sign-extending C function calling inlined
      				# helper (takes parameters of type long,
      				# casts them to unsigned long and then to
      				# the declared type)
      
      T        compat_sys_waitid      # alias to __se_compat_sys_waitid()
      				# (taking parameters as declared), to
      				# be included in syscall table
      
      For x86, the naming is as follows:
      
      t            kernel_waitid	# common C function (see kernel/exit.c)
      
          __do_compat_sys_waitid	# inlined helper doing the actual work
      				# (takes original parameters as declared)
      
      t   __se_compat_sys_waitid      # sign-extending C function calling inlined
      				# helper (takes parameters of type long,
      				# casts them to unsigned long and then to
      				# the declared type)
      
      T __ia32_compat_sys_waitid	# IA32_EMULATION 32-bit-ptregs -> C stub,
      				# calls __se_compat_sys_waitid(); to be
      				# included in syscall table
      
      T  __x32_compat_sys_waitid	# x32 64-bit-ptregs -> C stub, calls
      				# __se_compat_sys_waitid(); to be included
      				# in syscall table
      
      If only one of IA32_EMULATION and x32 is enabled, __se_compat_sys_waitid()
      may be inlined into the stub __{ia32,x32}_compat_sys_waitid().
      Suggested-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20180409105145.5364-3-linux@dominikbrodowski.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
      5ac9efa3
    • D
      syscalls/core, syscalls/x86: Clean up syscall stub naming convention · e145242e
      Dominik Brodowski 提交于
      Tidy the naming convention for compat syscall subs. Hints which describe
      the purpose of the stub go in front and receive a double underscore to
      denote that they are generated on-the-fly by the SYSCALL_DEFINEx() macro.
      
      For the generic case, this means (0xffffffff prefix removed):
      
       810f08d0 t     kernel_waitid	# common C function (see kernel/exit.c)
      
       <inline>     __do_sys_waitid	# inlined helper doing the actual work
      				# (takes original parameters as declared)
      
       810f1aa0 T   __se_sys_waitid	# sign-extending C function calling inlined
      				# helper (takes parameters of type long;
      				# casts them to the declared type)
      
       810f1aa0 T        sys_waitid	# alias to __se_sys_waitid() (taking
      				# parameters as declared), to be included
      				# in syscall table
      
      For x86, the naming is as follows:
      
       810efc70 t     kernel_waitid	# common C function (see kernel/exit.c)
      
       <inline>     __do_sys_waitid	# inlined helper doing the actual work
      				# (takes original parameters as declared)
      
       810efd60 t   __se_sys_waitid	# sign-extending C function calling inlined
      				# helper (takes parameters of type long;
      				# casts them to the declared type)
      
       810f1140 T __ia32_sys_waitid	# IA32_EMULATION 32-bit-ptregs -> C stub,
      				# calls __se_sys_waitid(); to be included
      				# in syscall table
      
       810f1110 T        sys_waitid	# x86 64-bit-ptregs -> C stub, calls
      				# __se_sys_waitid(); to be included in
      				# syscall table
      
      For x86, sys_waitid() will be re-named to __x64_sys_waitid in a follow-up
      patch.
      Suggested-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20180409105145.5364-2-linux@dominikbrodowski.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
      e145242e
  6. 05 4月, 2018 1 次提交
    • D
      syscalls/x86: Use 'struct pt_regs' based syscall calling for IA32_EMULATION and x32 · ebeb8c82
      Dominik Brodowski 提交于
      Extend ARCH_HAS_SYSCALL_WRAPPER for i386 emulation and for x32 on 64-bit
      x86.
      
      For x32, all we need to do is to create an additional stub for each
      compat syscall which decodes the parameters in x86-64 ordering, e.g.:
      
      	asmlinkage long __compat_sys_x32_xyzzy(struct pt_regs *regs)
      	{
      		return c_SyS_xyzzy(regs->di, regs->si, regs->dx);
      	}
      
      For i386 emulation, we need to teach compat_sys_*() to take struct
      pt_regs as its only argument, e.g.:
      
      	asmlinkage long __compat_sys_ia32_xyzzy(struct pt_regs *regs)
      	{
      		return c_SyS_xyzzy(regs->bx, regs->cx, regs->dx);
      	}
      
      In addition, we need to create additional stubs for common syscalls
      (that is, for syscalls which have the same parameters on 32-bit and
      64-bit), e.g.:
      
      	asmlinkage long __sys_ia32_xyzzy(struct pt_regs *regs)
      	{
      		return c_sys_xyzzy(regs->bx, regs->cx, regs->dx);
      	}
      
      This approach avoids leaking random user-provided register content down
      the call chain.
      
      This patch is based on an original proof-of-concept
      
       | From: Linus Torvalds <torvalds@linux-foundation.org>
       | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
      
      and was split up and heavily modified by me, in particular to base it on
      ARCH_HAS_SYSCALL_WRAPPER.
      Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      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: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20180405095307.3730-6-linux@dominikbrodowski.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
      ebeb8c82
  7. 03 4月, 2018 2 次提交
  8. 07 3月, 2018 3 次提交
  9. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman 提交于
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  10. 27 10月, 2017 1 次提交
    • M
      x86/build: Beautify build log of syscall headers · af8e9470
      Masahiro Yamada 提交于
      This makes the build log look nicer.
      
      Before:
        SYSTBL  arch/x86/entry/syscalls/../../include/generated/asm/syscalls_32.h
        SYSHDR  arch/x86/entry/syscalls/../../include/generated/asm/unistd_32_ia32.h
        SYSHDR  arch/x86/entry/syscalls/../../include/generated/asm/unistd_64_x32.h
        SYSTBL  arch/x86/entry/syscalls/../../include/generated/asm/syscalls_64.h
        SYSHDR  arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_32.h
        SYSHDR  arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_64.h
        SYSHDR  arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_x32.h
      
      After:
        SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
        SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
        SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
        SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
        SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
        SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
        SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
      Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      Acked-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: linux-kbuild@vger.kernel.org
      Link: http://lkml.kernel.org/r/1509077470-2735-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      af8e9470
  11. 18 4月, 2017 1 次提交
    • A
      Remove compat_sys_getdents64() · 2611dc19
      Al Viro 提交于
      Unlike normal compat syscall variants, it is needed only for
      biarch architectures that have different alignement requirements for
      u64 in 32bit and 64bit ABI *and* have __put_user() that won't handle
      a store of 64bit value at 32bit-aligned address.  We used to have one
      such (ia64), but its biarch support has been gone since 2010 (after
      being broken in 2008, which went unnoticed since nobody had been using
      it).
      
      It had escaped removal at the same time only because back in 2004
      a patch that switched several syscalls on amd64 from private wrappers to
      generic compat ones had switched to use of compat_sys_getdents64(), which
      hadn't needed (or used) a compat wrapper on amd64.
      
      Let's bury it - it's at least 7 years overdue.
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2611dc19
  12. 20 3月, 2017 1 次提交
    • K
      x86/syscalls/32: Wire up arch_prctl on x86-32 · 79170fda
      Kyle Huey 提交于
      Hook up arch_prctl to call do_arch_prctl() on x86-32, and in 32 bit compat
      mode on x86-64. This allows to have arch_prctls that are not specific to 64
      bits.
      
      On UML, simply stub out this syscall.
      Signed-off-by: NKyle Huey <khuey@kylehuey.com>
      Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
      Cc: kvm@vger.kernel.org
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: linux-kselftest@vger.kernel.org
      Cc: Nadav Amit <nadav.amit@gmail.com>
      Cc: Robert O'Callahan <robert@ocallahan.org>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Len Brown <len.brown@intel.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: user-mode-linux-devel@lists.sourceforge.net
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: user-mode-linux-user@lists.sourceforge.net
      Cc: David Matlack <dmatlack@google.com>
      Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
      Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
      Cc: linux-fsdevel@vger.kernel.org
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Link: http://lkml.kernel.org/r/20170320081628.18952-7-khuey@kylehuey.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      79170fda
  13. 03 3月, 2017 1 次提交
    • D
      statx: Add a system call to make enhanced file info available · a528d35e
      David Howells 提交于
      Add a system call to make extended file information available, including
      file creation and some attribute flags where available through the
      underlying filesystem.
      
      The getattr inode operation is altered to take two additional arguments: a
      u32 request_mask and an unsigned int flags that indicate the
      synchronisation mode.  This change is propagated to the vfs_getattr*()
      function.
      
      Functions like vfs_stat() are now inline wrappers around new functions
      vfs_statx() and vfs_statx_fd() to reduce stack usage.
      
      ========
      OVERVIEW
      ========
      
      The idea was initially proposed as a set of xattrs that could be retrieved
      with getxattr(), but the general preference proved to be for a new syscall
      with an extended stat structure.
      
      A number of requests were gathered for features to be included.  The
      following have been included:
      
       (1) Make the fields a consistent size on all arches and make them large.
      
       (2) Spare space, request flags and information flags are provided for
           future expansion.
      
       (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
           __s64).
      
       (4) Creation time: The SMB protocol carries the creation time, which could
           be exported by Samba, which will in turn help CIFS make use of
           FS-Cache as that can be used for coherency data (stx_btime).
      
           This is also specified in NFSv4 as a recommended attribute and could
           be exported by NFSD [Steve French].
      
       (5) Lightweight stat: Ask for just those details of interest, and allow a
           netfs (such as NFS) to approximate anything not of interest, possibly
           without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
           Dilger] (AT_STATX_DONT_SYNC).
      
       (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
           its cached attributes are up to date [Trond Myklebust]
           (AT_STATX_FORCE_SYNC).
      
      And the following have been left out for future extension:
      
       (7) Data version number: Could be used by userspace NFS servers [Aneesh
           Kumar].
      
           Can also be used to modify fill_post_wcc() in NFSD which retrieves
           i_version directly, but has just called vfs_getattr().  It could get
           it from the kstat struct if it used vfs_xgetattr() instead.
      
           (There's disagreement on the exact semantics of a single field, since
           not all filesystems do this the same way).
      
       (8) BSD stat compatibility: Including more fields from the BSD stat such
           as creation time (st_btime) and inode generation number (st_gen)
           [Jeremy Allison, Bernd Schubert].
      
       (9) Inode generation number: Useful for FUSE and userspace NFS servers
           [Bernd Schubert].
      
           (This was asked for but later deemed unnecessary with the
           open-by-handle capability available and caused disagreement as to
           whether it's a security hole or not).
      
      (10) Extra coherency data may be useful in making backups [Andreas Dilger].
      
           (No particular data were offered, but things like last backup
           timestamp, the data version number and the DOS archive bit would come
           into this category).
      
      (11) Allow the filesystem to indicate what it can/cannot provide: A
           filesystem can now say it doesn't support a standard stat feature if
           that isn't available, so if, for instance, inode numbers or UIDs don't
           exist or are fabricated locally...
      
           (This requires a separate system call - I have an fsinfo() call idea
           for this).
      
      (12) Store a 16-byte volume ID in the superblock that can be returned in
           struct xstat [Steve French].
      
           (Deferred to fsinfo).
      
      (13) Include granularity fields in the time data to indicate the
           granularity of each of the times (NFSv4 time_delta) [Steve French].
      
           (Deferred to fsinfo).
      
      (14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
           Note that the Linux IOC flags are a mess and filesystems such as Ext4
           define flags that aren't in linux/fs.h, so translation in the kernel
           may be a necessity (or, possibly, we provide the filesystem type too).
      
           (Some attributes are made available in stx_attributes, but the general
           feeling was that the IOC flags were to ext[234]-specific and shouldn't
           be exposed through statx this way).
      
      (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
           Michael Kerrisk].
      
           (Deferred, probably to fsinfo.  Finding out if there's an ACL or
           seclabal might require extra filesystem operations).
      
      (16) Femtosecond-resolution timestamps [Dave Chinner].
      
           (A __reserved field has been left in the statx_timestamp struct for
           this - if there proves to be a need).
      
      (17) A set multiple attributes syscall to go with this.
      
      ===============
      NEW SYSTEM CALL
      ===============
      
      The new system call is:
      
      	int ret = statx(int dfd,
      			const char *filename,
      			unsigned int flags,
      			unsigned int mask,
      			struct statx *buffer);
      
      The dfd, filename and flags parameters indicate the file to query, in a
      similar way to fstatat().  There is no equivalent of lstat() as that can be
      emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags.  There is
      also no equivalent of fstat() as that can be emulated by passing a NULL
      filename to statx() with the fd of interest in dfd.
      
      Whether or not statx() synchronises the attributes with the backing store
      can be controlled by OR'ing a value into the flags argument (this typically
      only affects network filesystems):
      
       (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
           respect.
      
       (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
           its attributes with the server - which might require data writeback to
           occur to get the timestamps correct.
      
       (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
           network filesystem.  The resulting values should be considered
           approximate.
      
      mask is a bitmask indicating the fields in struct statx that are of
      interest to the caller.  The user should set this to STATX_BASIC_STATS to
      get the basic set returned by stat().  It should be noted that asking for
      more information may entail extra I/O operations.
      
      buffer points to the destination for the data.  This must be 256 bytes in
      size.
      
      ======================
      MAIN ATTRIBUTES RECORD
      ======================
      
      The following structures are defined in which to return the main attribute
      set:
      
      	struct statx_timestamp {
      		__s64	tv_sec;
      		__s32	tv_nsec;
      		__s32	__reserved;
      	};
      
      	struct statx {
      		__u32	stx_mask;
      		__u32	stx_blksize;
      		__u64	stx_attributes;
      		__u32	stx_nlink;
      		__u32	stx_uid;
      		__u32	stx_gid;
      		__u16	stx_mode;
      		__u16	__spare0[1];
      		__u64	stx_ino;
      		__u64	stx_size;
      		__u64	stx_blocks;
      		__u64	__spare1[1];
      		struct statx_timestamp	stx_atime;
      		struct statx_timestamp	stx_btime;
      		struct statx_timestamp	stx_ctime;
      		struct statx_timestamp	stx_mtime;
      		__u32	stx_rdev_major;
      		__u32	stx_rdev_minor;
      		__u32	stx_dev_major;
      		__u32	stx_dev_minor;
      		__u64	__spare2[14];
      	};
      
      The defined bits in request_mask and stx_mask are:
      
      	STATX_TYPE		Want/got stx_mode & S_IFMT
      	STATX_MODE		Want/got stx_mode & ~S_IFMT
      	STATX_NLINK		Want/got stx_nlink
      	STATX_UID		Want/got stx_uid
      	STATX_GID		Want/got stx_gid
      	STATX_ATIME		Want/got stx_atime{,_ns}
      	STATX_MTIME		Want/got stx_mtime{,_ns}
      	STATX_CTIME		Want/got stx_ctime{,_ns}
      	STATX_INO		Want/got stx_ino
      	STATX_SIZE		Want/got stx_size
      	STATX_BLOCKS		Want/got stx_blocks
      	STATX_BASIC_STATS	[The stuff in the normal stat struct]
      	STATX_BTIME		Want/got stx_btime{,_ns}
      	STATX_ALL		[All currently available stuff]
      
      stx_btime is the file creation time, stx_mask is a bitmask indicating the
      data provided and __spares*[] are where as-yet undefined fields can be
      placed.
      
      Time fields are structures with separate seconds and nanoseconds fields
      plus a reserved field in case we want to add even finer resolution.  Note
      that times will be negative if before 1970; in such a case, the nanosecond
      fields will also be negative if not zero.
      
      The bits defined in the stx_attributes field convey information about a
      file, how it is accessed, where it is and what it does.  The following
      attributes map to FS_*_FL flags and are the same numerical value:
      
      	STATX_ATTR_COMPRESSED		File is compressed by the fs
      	STATX_ATTR_IMMUTABLE		File is marked immutable
      	STATX_ATTR_APPEND		File is append-only
      	STATX_ATTR_NODUMP		File is not to be dumped
      	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs
      
      Within the kernel, the supported flags are listed by:
      
      	KSTAT_ATTR_FS_IOC_FLAGS
      
      [Are any other IOC flags of sufficient general interest to be exposed
      through this interface?]
      
      New flags include:
      
      	STATX_ATTR_AUTOMOUNT		Object is an automount trigger
      
      These are for the use of GUI tools that might want to mark files specially,
      depending on what they are.
      
      Fields in struct statx come in a number of classes:
      
       (0) stx_dev_*, stx_blksize.
      
           These are local system information and are always available.
      
       (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
           stx_size, stx_blocks.
      
           These will be returned whether the caller asks for them or not.  The
           corresponding bits in stx_mask will be set to indicate whether they
           actually have valid values.
      
           If the caller didn't ask for them, then they may be approximated.  For
           example, NFS won't waste any time updating them from the server,
           unless as a byproduct of updating something requested.
      
           If the values don't actually exist for the underlying object (such as
           UID or GID on a DOS file), then the bit won't be set in the stx_mask,
           even if the caller asked for the value.  In such a case, the returned
           value will be a fabrication.
      
           Note that there are instances where the type might not be valid, for
           instance Windows reparse points.
      
       (2) stx_rdev_*.
      
           This will be set only if stx_mode indicates we're looking at a
           blockdev or a chardev, otherwise will be 0.
      
       (3) stx_btime.
      
           Similar to (1), except this will be set to 0 if it doesn't exist.
      
      =======
      TESTING
      =======
      
      The following test program can be used to test the statx system call:
      
      	samples/statx/test-statx.c
      
      Just compile and run, passing it paths to the files you want to examine.
      The file is built automatically if CONFIG_SAMPLES is enabled.
      
      Here's some example output.  Firstly, an NFS directory that crosses to
      another FSID.  Note that the AUTOMOUNT attribute is set because transiting
      this directory will cause d_automount to be invoked by the VFS.
      
      	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
      	statx(/warthog/data) = 0
      	results=7ff
      	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
      	Device: 00:26           Inode: 1703937     Links: 125
      	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
      	Access: 2016-11-24 09:02:12.219699527+0000
      	Modify: 2016-11-17 10:44:36.225653653+0000
      	Change: 2016-11-17 10:44:36.225653653+0000
      	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
      
      Secondly, the result of automounting on that directory.
      
      	[root@andromeda ~]# /tmp/test-statx /warthog/data
      	statx(/warthog/data) = 0
      	results=7ff
      	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
      	Device: 00:27           Inode: 2           Links: 125
      	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
      	Access: 2016-11-24 09:02:12.219699527+0000
      	Modify: 2016-11-17 10:44:36.225653653+0000
      	Change: 2016-11-17 10:44:36.225653653+0000
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      a528d35e
  14. 18 10月, 2016 1 次提交
    • D
      x86, pkeys: remove cruft from never-merged syscalls · eac0ca77
      Dave Hansen 提交于
      pkey_set() and pkey_get() were syscalls present in older versions
      of the protection keys patches.  The syscall number definitions
      were inadvertently left in place.  This patch removes them.
      
      I did a git grep and verified that these are the last places in
      the tree that these appear, save for the protection_keys.c tests
      and Documentation.  Those spots talk about functions called
      pkey_get/set() which are wrappers for the direct PKRU
      instructions, not the syscalls.
      Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-arch@vger.kernel.org
      Cc: mgorman@techsingularity.net
      Cc: arnd@arndb.de
      Cc: linux-api@vger.kernel.org
      Cc: linux-mm@kvack.org
      Cc: luto@kernel.org
      Cc: akpm@linux-foundation.org
      Fixes: f9afc619 ("x86: Wire up protection keys system calls")
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      eac0ca77
  15. 05 10月, 2016 1 次提交
  16. 09 9月, 2016 1 次提交
  17. 01 8月, 2016 1 次提交
  18. 15 7月, 2016 1 次提交
    • H
      x86/syscalls: Add compat_sys_preadv64v2/compat_sys_pwritev64v2 · 3ebfd81f
      H.J. Lu 提交于
      Don't use the same syscall numbers for 2 different syscalls:
      
       534	x32	preadv			compat_sys_preadv64
       535	x32	pwritev			compat_sys_pwritev64
       534	x32	preadv2			compat_sys_preadv2
       535	x32	pwritev2		compat_sys_pwritev2
      
      Add compat_sys_preadv64v2() and compat_sys_pwritev64v2() so that 64-bit offset
      is passed in one 64-bit register on x32, similar to compat_sys_preadv64()
      and compat_sys_pwritev64().
      Signed-off-by: NH.J. Lu <hjl.tools@gmail.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/CAMe9rOovCMf-RQfx_n1U_Tu_DX1BYkjtFr%3DQ4-_PFVSj9BCzUA@mail.gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      3ebfd81f
  19. 12 5月, 2016 1 次提交
  20. 13 4月, 2016 1 次提交
  21. 05 3月, 2016 1 次提交
  22. 01 2月, 2016 1 次提交
  23. 29 1月, 2016 6 次提交
  24. 02 12月, 2015 1 次提交
  25. 06 11月, 2015 1 次提交
  26. 09 10月, 2015 1 次提交
  27. 12 9月, 2015 1 次提交
    • M
      sys_membarrier(): system-wide memory barrier (generic, x86) · 5b25b13a
      Mathieu Desnoyers 提交于
      Here is an implementation of a new system call, sys_membarrier(), which
      executes a memory barrier on all threads running on the system.  It is
      implemented by calling synchronize_sched().  It can be used to
      distribute the cost of user-space memory barriers asymmetrically by
      transforming pairs of memory barriers into pairs consisting of
      sys_membarrier() and a compiler barrier.  For synchronization primitives
      that distinguish between read-side and write-side (e.g.  userspace RCU
      [1], rwlocks), the read-side can be accelerated significantly by moving
      the bulk of the memory barrier overhead to the write-side.
      
      The existing applications of which I am aware that would be improved by
      this system call are as follows:
      
      * Through Userspace RCU library (http://urcu.so)
        - DNS server (Knot DNS) https://www.knot-dns.cz/
        - Network sniffer (http://netsniff-ng.org/)
        - Distributed object storage (https://sheepdog.github.io/sheepdog/)
        - User-space tracing (http://lttng.org)
        - Network storage system (https://www.gluster.org/)
        - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf)
        - Financial software (https://lkml.org/lkml/2015/3/23/189)
      
      Those projects use RCU in userspace to increase read-side speed and
      scalability compared to locking.  Especially in the case of RCU used by
      libraries, sys_membarrier can speed up the read-side by moving the bulk of
      the memory barrier cost to synchronize_rcu().
      
      * Direct users of sys_membarrier
        - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198)
      
      Microsoft core dotnet GC developers are planning to use the mprotect()
      side-effect of issuing memory barriers through IPIs as a way to implement
      Windows FlushProcessWriteBuffers() on Linux.  They are referring to
      sys_membarrier in their github thread, specifically stating that
      sys_membarrier() is what they are looking for.
      
      To explain the benefit of this scheme, let's introduce two example threads:
      
      Thread A (non-frequent, e.g. executing liburcu synchronize_rcu())
      Thread B (frequent, e.g. executing liburcu
      rcu_read_lock()/rcu_read_unlock())
      
      In a scheme where all smp_mb() in thread A are ordering memory accesses
      with respect to smp_mb() present in Thread B, we can change each
      smp_mb() within Thread A into calls to sys_membarrier() and each
      smp_mb() within Thread B into compiler barriers "barrier()".
      
      Before the change, we had, for each smp_mb() pairs:
      
      Thread A                    Thread B
      previous mem accesses       previous mem accesses
      smp_mb()                    smp_mb()
      following mem accesses      following mem accesses
      
      After the change, these pairs become:
      
      Thread A                    Thread B
      prev mem accesses           prev mem accesses
      sys_membarrier()            barrier()
      follow mem accesses         follow mem accesses
      
      As we can see, there are two possible scenarios: either Thread B memory
      accesses do not happen concurrently with Thread A accesses (1), or they
      do (2).
      
      1) Non-concurrent Thread A vs Thread B accesses:
      
      Thread A                    Thread B
      prev mem accesses
      sys_membarrier()
      follow mem accesses
                                  prev mem accesses
                                  barrier()
                                  follow mem accesses
      
      In this case, thread B accesses will be weakly ordered. This is OK,
      because at that point, thread A is not particularly interested in
      ordering them with respect to its own accesses.
      
      2) Concurrent Thread A vs Thread B accesses
      
      Thread A                    Thread B
      prev mem accesses           prev mem accesses
      sys_membarrier()            barrier()
      follow mem accesses         follow mem accesses
      
      In this case, thread B accesses, which are ensured to be in program
      order thanks to the compiler barrier, will be "upgraded" to full
      smp_mb() by synchronize_sched().
      
      * Benchmarks
      
      On Intel Xeon E5405 (8 cores)
      (one thread is calling sys_membarrier, the other 7 threads are busy
      looping)
      
      1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call.
      
      * User-space user of this system call: Userspace RCU library
      
      Both the signal-based and the sys_membarrier userspace RCU schemes
      permit us to remove the memory barrier from the userspace RCU
      rcu_read_lock() and rcu_read_unlock() primitives, thus significantly
      accelerating them. These memory barriers are replaced by compiler
      barriers on the read-side, and all matching memory barriers on the
      write-side are turned into an invocation of a memory barrier on all
      active threads in the process. By letting the kernel perform this
      synchronization rather than dumbly sending a signal to every process
      threads (as we currently do), we diminish the number of unnecessary wake
      ups and only issue the memory barriers on active threads. Non-running
      threads do not need to execute such barrier anyway, because these are
      implied by the scheduler context switches.
      
      Results in liburcu:
      
      Operations in 10s, 6 readers, 2 writers:
      
      memory barriers in reader:    1701557485 reads, 2202847 writes
      signal-based scheme:          9830061167 reads,    6700 writes
      sys_membarrier:               9952759104 reads,     425 writes
      sys_membarrier (dyn. check):  7970328887 reads,     425 writes
      
      The dynamic sys_membarrier availability check adds some overhead to
      the read-side compared to the signal-based scheme, but besides that,
      sys_membarrier slightly outperforms the signal-based scheme. However,
      this non-expedited sys_membarrier implementation has a much slower grace
      period than signal and memory barrier schemes.
      
      Besides diminishing the number of wake-ups, one major advantage of the
      membarrier system call over the signal-based scheme is that it does not
      need to reserve a signal. This plays much more nicely with libraries,
      and with processes injected into for tracing purposes, for which we
      cannot expect that signals will be unused by the application.
      
      An expedited version of this system call can be added later on to speed
      up the grace period. Its implementation will likely depend on reading
      the cpu_curr()->mm without holding each CPU's rq lock.
      
      This patch adds the system call to x86 and to asm-generic.
      
      [1] http://urcu.so
      
      membarrier(2) man page:
      
      MEMBARRIER(2)              Linux Programmer's Manual             MEMBARRIER(2)
      
      NAME
             membarrier - issue memory barriers on a set of threads
      
      SYNOPSIS
             #include <linux/membarrier.h>
      
             int membarrier(int cmd, int flags);
      
      DESCRIPTION
             The cmd argument is one of the following:
      
             MEMBARRIER_CMD_QUERY
                    Query  the  set  of  supported commands. It returns a bitmask of
                    supported commands.
      
             MEMBARRIER_CMD_SHARED
                    Execute a memory barrier on all threads running on  the  system.
                    Upon  return from system call, the caller thread is ensured that
                    all running threads have passed through a state where all memory
                    accesses  to  user-space  addresses  match program order between
                    entry to and return from the system  call  (non-running  threads
                    are de facto in such a state). This covers threads from all pro=E2=80=90
                    cesses running on the system.  This command returns 0.
      
             The flags argument needs to be 0. For future extensions.
      
             All memory accesses performed  in  program  order  from  each  targeted
             thread is guaranteed to be ordered with respect to sys_membarrier(). If
             we use the semantic "barrier()" to represent a compiler barrier forcing
             memory  accesses  to  be performed in program order across the barrier,
             and smp_mb() to represent explicit memory barriers forcing full  memory
             ordering  across  the barrier, we have the following ordering table for
             each pair of barrier(), sys_membarrier() and smp_mb():
      
             The pair ordering is detailed as (O: ordered, X: not ordered):
      
                                    barrier()   smp_mb() sys_membarrier()
                    barrier()          X           X            O
                    smp_mb()           X           O            O
                    sys_membarrier()   O           O            O
      
      RETURN VALUE
             On success, these system calls return zero.  On error, -1 is  returned,
             and errno is set appropriately. For a given command, with flags
             argument set to 0, this system call is guaranteed to always return the
             same value until reboot.
      
      ERRORS
             ENOSYS System call is not implemented.
      
             EINVAL Invalid arguments.
      
      Linux                             2015-04-15                     MEMBARRIER(2)
      Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Nicholas Miell <nmiell@comcast.net>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
      Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Stephen Hemminger <stephen@networkplumber.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Pranith Kumar <bobby.prani@gmail.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Shuah Khan <shuahkh@osg.samsung.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5b25b13a
  28. 05 9月, 2015 1 次提交
  29. 21 7月, 2015 1 次提交
    • A
      x86/entry/syscalls: Wire up 32-bit direct socket calls · 9dea5dc9
      Andy Lutomirski 提交于
      On x86_64, there's no socketcall syscall; instead all of the
      socket calls are real syscalls.  For 32-bit programs, we're
      stuck offering the socketcall syscall, but it would be nice to
      expose the direct calls as well.  This will enable seccomp to
      filter socket calls (for new userspace only, but that's fine for
      some applications) and it will provide a tiny performance boost.
      Signed-off-by: NAndy Lutomirski <luto@kernel.org>
      Cc: Alexander Larsson <alexl@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Cosimo Cecchi <cosimo@endlessm.com>
      Cc: Dan Nicholson <nicholson@endlessm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
      Cc: libc-alpha <libc-alpha@sourceware.org>
      Link: http://lkml.kernel.org/r/cb5138299d37d5800e2d135b01a7667fa6115854.1436912629.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      9dea5dc9
  30. 04 6月, 2015 1 次提交
    • I
      x86/asm/entry: Move the arch/x86/syscalls/ definitions to arch/x86/entry/syscalls/ · 1f57d5d8
      Ingo Molnar 提交于
      The build time generated syscall definitions are entry code related, move
      them into the arch/x86/entry/ directory.
      
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      1f57d5d8