1. 16 Mar, 2018 1 commit
    • Arnd Bergmann's avatar
      arch: remove blackfin port · 4ba66a97
      Arnd Bergmann authored
      The Analog Devices Blackfin port was added in 2007 and was rather
      active for a while, but all work on it has come to a standstill
      over time, as Analog have changed their product line-up.
      
      Aaron Wu confirmed that the architecture port is no longer relevant,
      and multiple people suggested removing blackfin independently because
      of some of its oddities like a non-working SMP port, and the amount of
      duplication between the chip variants, which cause extra work when
      doing cross-architecture changes.
      
      Link: https://docs.blackfin.uclinux.org/Acked-by: default avatarAaron Wu <Aaron.Wu@analog.com>
      Acked-by: Bryan Wu's avatarBryan Wu <cooloney@gmail.com>
      Cc: Steven Miao <realmz6@gmail.com>
      Cc: Mike Frysinger <vapier@chromium.org>
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      4ba66a97
  2. 13 Feb, 2018 1 commit
  3. 03 Mar, 2017 1 commit
    • David Howells's avatar
      statx: Add a system call to make enhanced file info available · a528d35e
      David Howells authored
      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: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      a528d35e
  4. 30 Dec, 2016 1 commit
  5. 10 Oct, 2016 1 commit
  6. 20 Jun, 2016 1 commit
    • Steven Rostedt (Red Hat)'s avatar
      tracing: Add trace_printk sample code · aad108aa
      Steven Rostedt (Red Hat) authored
      Add sample code to test trace_printk(). The trace_printk() functions should
      never be used in production code. This makes testing it a bit more
      difficult. Having a sample module that can test use cases of trace_printk()
      can help out.
      
      Currently it just tests trace_printk() where it will be converted into:
      
       trace_bputs()
       trace_puts()
       trace_bprintk()
      
      as well as staying as the normal _trace_printk().
      
      It also tests its use in interrupt context as that will test the auxilery
      buffers.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      aad108aa
  7. 09 May, 2016 1 commit
    • Arnd Bergmann's avatar
      [media] samples: v4l: from Documentation to samples directory · 0185f850
      Arnd Bergmann authored
      With the new autoksyms support, we can run into a situation where
      the v4l pci skeleton module is the only one using some exported
      symbols that get dropped because they are never referenced by
      the kernel otherwise, causing a build problem:
      
      ERROR: "vb2_dma_contig_memops" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      ERROR: "vb2_dma_contig_init_ctx_attrs" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      ERROR: "v4l2_match_dv_timings" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      ERROR: "v4l2_find_dv_timings_cap" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      ERROR: "v4l2_valid_dv_timings" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      ERROR: "v4l2_enum_dv_timings_cap" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      ERROR: "vb2_dma_contig_cleanup_ctx" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
      
      Specifically, we do look in the samples directory for users of
      symbols, but not the Documentation directory.
      
      This solves the build problem by moving the connector sample into
      the same directory as the other samples.
      
      Fixes: 23121ca2 ("kbuild: create/adjust generated/autoksyms.h")
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      0185f850
  8. 28 Apr, 2016 2 commits
  9. 14 Oct, 2015 1 commit
  10. 22 Dec, 2014 1 commit
  11. 25 Jan, 2013 1 commit
  12. 14 Apr, 2012 1 commit
    • Will Drewry's avatar
      Documentation: prctl/seccomp_filter · 8ac270d1
      Will Drewry authored
      Documents how system call filtering using Berkeley Packet
      Filter programs works and how it may be used.
      Includes an example for x86 and a semi-generic
      example using a macro-based code generator.
      Acked-by: default avatarEric Paris <eparis@redhat.com>
      Signed-off-by: default avatarWill Drewry <wad@chromium.org>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      
      v18: - added acked by
           - update no new privs numbers
      v17: - remove @ComPat note and add Pitfalls section for arch checking
             (keescook@chromium.org)
      v16: -
      v15: -
      v14: - rebase/nochanges
      v13: - rebase on to 88ebdda6
      v12: - comment on the ptrace_event use
           - update arch support comment
           - note the behavior of SECCOMP_RET_DATA when there are multiple filters
             (keescook@chromium.org)
           - lots of samples/ clean up incl 64-bit bpf-direct support
             (markus@chromium.org)
           - rebase to linux-next
      v11: - overhaul return value language, updates (keescook@chromium.org)
           - comment on do_exit(SIGSYS)
      v10: - update for SIGSYS
           - update for new seccomp_data layout
           - update for ptrace option use
      v9: - updated bpf-direct.c for SIGILL
      v8: - add PR_SET_NO_NEW_PRIVS to the samples.
      v7: - updated for all the new stuff in v7: TRAP, TRACE
          - only talk about PR_SET_SECCOMP now
          - fixed bad JLE32 check (coreyb@linux.vnet.ibm.com)
          - adds dropper.c: a simple system call disabler
      v6: - tweak the language to note the requirement of
            PR_SET_NO_NEW_PRIVS being called prior to use. (luto@mit.edu)
      v5: - update sample to use system call arguments
          - adds a "fancy" example using a macro-based generator
          - cleaned up bpf in the sample
          - update docs to mention arguments
          - fix prctl value (eparis@redhat.com)
          - language cleanup (rdunlap@xenotime.net)
      v4: - update for no_new_privs use
          - minor tweaks
      v3: - call out BPF <-> Berkeley Packet Filter (rdunlap@xenotime.net)
          - document use of tentative always-unprivileged
          - guard sample compilation for i386 and x86_64
      v2: - move code to samples (corbet@lwn.net)
      Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
      8ac270d1
  13. 08 Feb, 2012 1 commit
    • Ohad Ben-Cohen's avatar
      samples/rpmsg: add an rpmsg driver sample · 779b96d2
      Ohad Ben-Cohen authored
      Add an rpmsg driver sample, which demonstrates how to communicate with
      an AMP-configured remote processor over the rpmsg bus.
      
      Note how once probed, the driver can immediately start sending messages
      using the rpmsg_send() API, without having to worry about creating endpoints
      or allocating rpmsg addresses: all that work is done by the rpmsg bus,
      and the required information is already embedded in the rpmsg channel
      that the driver is probed with.
      
      In this sample, the driver simply sends a "Hello World!" message to the remote
      processor repeatedly.
      
      Designed with Brian Swetland <swetland@google.com>.
      Signed-off-by: default avatarOhad Ben-Cohen <ohad@wizery.com>
      Cc: Brian Swetland <swetland@google.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Grant Likely <grant.likely@secretlab.ca>
      Cc: Tony Lindgren <tony@atomide.com>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Greg KH <greg@kroah.com>
      Cc: Stephen Boyd <sboyd@codeaurora.org>
      779b96d2
  14. 22 Mar, 2011 1 commit
  15. 29 Oct, 2010 1 commit
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  18. 02 Jun, 2009 1 commit
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  23. 19 Oct, 2007 1 commit