1. 19 10月, 2019 5 次提交
  2. 18 10月, 2019 2 次提交
  3. 17 10月, 2019 1 次提交
  4. 06 8月, 2019 5 次提交
  5. 22 7月, 2019 7 次提交
  6. 24 5月, 2019 1 次提交
  7. 23 5月, 2019 3 次提交
  8. 22 5月, 2019 1 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. 25 10月, 2017 1 次提交
    • M
      locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns... · 6aa7de05
      Mark Rutland 提交于
      locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
      
      Please do not apply this to mainline directly, instead please re-run the
      coccinelle script shown below and apply its output.
      
      For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
      preference to ACCESS_ONCE(), and new code is expected to use one of the
      former. So far, there's been no reason to change most existing uses of
      ACCESS_ONCE(), as these aren't harmful, and changing them results in
      churn.
      
      However, for some features, the read/write distinction is critical to
      correct operation. To distinguish these cases, separate read/write
      accessors must be used. This patch migrates (most) remaining
      ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
      coccinelle script:
      
      ----
      // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
      // WRITE_ONCE()
      
      // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
      
      virtual patch
      
      @ depends on patch @
      expression E1, E2;
      @@
      
      - ACCESS_ONCE(E1) = E2
      + WRITE_ONCE(E1, E2)
      
      @ depends on patch @
      expression E;
      @@
      
      - ACCESS_ONCE(E)
      + READ_ONCE(E)
      ----
      Signed-off-by: NMark Rutland <mark.rutland@arm.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: davem@davemloft.net
      Cc: linux-arch@vger.kernel.org
      Cc: mpe@ellerman.id.au
      Cc: shuah@kernel.org
      Cc: snitzer@redhat.com
      Cc: thor.thayer@linux.intel.com
      Cc: tj@kernel.org
      Cc: viro@zeniv.linux.org.uk
      Cc: will.deacon@arm.com
      Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6aa7de05
  11. 19 6月, 2017 1 次提交
    • T
      ALSA: firewire-lib: Fix stall of process context at packet error · 4a9bfafc
      Takashi Sakamoto 提交于
      At Linux v3.5, packet processing can be done in process context of ALSA
      PCM application as well as software IRQ context for OHCI 1394. Below is
      an example of the callgraph (some calls are omitted).
      
      ioctl(2) with e.g. HWSYNC
      (sound/core/pcm_native.c)
      ->snd_pcm_common_ioctl1()
        ->snd_pcm_hwsync()
          ->snd_pcm_stream_lock_irq
          (sound/core/pcm_lib.c)
          ->snd_pcm_update_hw_ptr()
            ->snd_pcm_udpate_hw_ptr0()
              ->struct snd_pcm_ops.pointer()
              (sound/firewire/*)
              = Each handler on drivers in ALSA firewire stack
                (sound/firewire/amdtp-stream.c)
                ->amdtp_stream_pcm_pointer()
                  (drivers/firewire/core-iso.c)
                  ->fw_iso_context_flush_completions()
                    ->struct fw_card_driver.flush_iso_completion()
                    (drivers/firewire/ohci.c)
                    = flush_iso_completions()
                      ->struct fw_iso_context.callback.sc
                      (sound/firewire/amdtp-stream.c)
                      = in_stream_callback() or out_stream_callback()
                        ->...
          ->snd_pcm_stream_unlock_irq
      
      When packet queueing error occurs or detecting invalid packets in
      'in_stream_callback()' or 'out_stream_callback()', 'snd_pcm_stop_xrun()'
      is called on local CPU with disabled IRQ.
      
      (sound/firewire/amdtp-stream.c)
      in_stream_callback() or out_stream_callback()
      ->amdtp_stream_pcm_abort()
        ->snd_pcm_stop_xrun()
          ->snd_pcm_stream_lock_irqsave()
          ->snd_pcm_stop()
          ->snd_pcm_stream_unlock_irqrestore()
      
      The process is stalled on the CPU due to attempt to acquire recursive lock.
      
      [  562.630853] INFO: rcu_sched detected stalls on CPUs/tasks:
      [  562.630861]      2-...: (1 GPs behind) idle=37d/140000000000000/0 softirq=38323/38323 fqs=7140
      [  562.630862]      (detected by 3, t=15002 jiffies, g=21036, c=21035, q=5933)
      [  562.630866] Task dump for CPU 2:
      [  562.630867] alsa-source-OXF R  running task        0  6619      1 0x00000008
      [  562.630870] Call Trace:
      [  562.630876]  ? vt_console_print+0x79/0x3e0
      [  562.630880]  ? msg_print_text+0x9d/0x100
      [  562.630883]  ? up+0x32/0x50
      [  562.630885]  ? irq_work_queue+0x8d/0xa0
      [  562.630886]  ? console_unlock+0x2b6/0x4b0
      [  562.630888]  ? vprintk_emit+0x312/0x4a0
      [  562.630892]  ? dev_vprintk_emit+0xbf/0x230
      [  562.630895]  ? do_sys_poll+0x37a/0x550
      [  562.630897]  ? dev_printk_emit+0x4e/0x70
      [  562.630900]  ? __dev_printk+0x3c/0x80
      [  562.630903]  ? _raw_spin_lock+0x20/0x30
      [  562.630909]  ? snd_pcm_stream_lock+0x31/0x50 [snd_pcm]
      [  562.630914]  ? _snd_pcm_stream_lock_irqsave+0x2e/0x40 [snd_pcm]
      [  562.630918]  ? snd_pcm_stop_xrun+0x16/0x70 [snd_pcm]
      [  562.630922]  ? in_stream_callback+0x3e6/0x450 [snd_firewire_lib]
      [  562.630925]  ? handle_ir_packet_per_buffer+0x8e/0x1a0 [firewire_ohci]
      [  562.630928]  ? ohci_flush_iso_completions+0xa3/0x130 [firewire_ohci]
      [  562.630932]  ? fw_iso_context_flush_completions+0x15/0x20 [firewire_core]
      [  562.630935]  ? amdtp_stream_pcm_pointer+0x2d/0x40 [snd_firewire_lib]
      [  562.630938]  ? pcm_capture_pointer+0x19/0x20 [snd_oxfw]
      [  562.630943]  ? snd_pcm_update_hw_ptr0+0x47/0x3d0 [snd_pcm]
      [  562.630945]  ? poll_select_copy_remaining+0x150/0x150
      [  562.630947]  ? poll_select_copy_remaining+0x150/0x150
      [  562.630952]  ? snd_pcm_update_hw_ptr+0x10/0x20 [snd_pcm]
      [  562.630956]  ? snd_pcm_hwsync+0x45/0xb0 [snd_pcm]
      [  562.630960]  ? snd_pcm_common_ioctl1+0x1ff/0xc90 [snd_pcm]
      [  562.630962]  ? futex_wake+0x90/0x170
      [  562.630966]  ? snd_pcm_capture_ioctl1+0x136/0x260 [snd_pcm]
      [  562.630970]  ? snd_pcm_capture_ioctl+0x27/0x40 [snd_pcm]
      [  562.630972]  ? do_vfs_ioctl+0xa3/0x610
      [  562.630974]  ? vfs_read+0x11b/0x130
      [  562.630976]  ? SyS_ioctl+0x79/0x90
      [  562.630978]  ? entry_SYSCALL_64_fastpath+0x1e/0xad
      
      This commit fixes the above bug. This assumes two cases:
      1. Any error is detected in software IRQ context of OHCI 1394 context.
      In this case, PCM substream should be aborted in packet handler. On the
      other hand, it should not be done in any process context. TO distinguish
      these two context, use 'in_interrupt()' macro.
      2. Any error is detect in process context of ALSA PCM application.
      In this case, PCM substream should not be aborted in packet handler
      because PCM substream lock is acquired. The task to abort PCM substream
      should be done in ALSA PCM core. For this purpose, SNDRV_PCM_POS_XRUN is
      returned at 'struct snd_pcm_ops.pointer()'.
      Suggested-by: NClemens Ladisch <clemens@ladisch.de>
      Fixes: e9148ddd("ALSA: firewire-lib: flush completed packets when reading PCM position")
      Cc: <stable@vger.kernel.org> # 4.9+
      Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      4a9bfafc
  12. 07 6月, 2017 1 次提交
    • T
      ALSA: firewire: process packets in 'struct snd_pcm_ops.ack' callback · 875becf8
      Takashi Sakamoto 提交于
      In recent commit for ALSA PCM core, some arrangement is done for
      'struct snd_pcm_ops.ack' callback. This is called when appl_ptr is
      explicitly moved in intermediate buffer for PCM frames, except for
      some cases described later.
      
      For drivers in ALSA firewire stack, usage of this callback has a merit to
      reduce latency between time of PCM frame queueing and handling actual
      packets in recent isochronous cycle, because no need to wait for software
      IRQ context from isochronous context of OHCI 1394.
      
      If this works well in a case that mapped page frame is used for the
      intermediate buffer, user process should execute some commands for ioctl(2)
      to tell the number of handled PCM frames in the intermediate buffer just
      after handling them. Therefore, at present, with a combination of below
      conditions, this doesn't work as expected and user process should wait for
      the software IRQ context as usual:
       - when ALSA PCM core judges page frame mapping is available for status
         data (struct snd_pcm_mmap_status) and control data
         (struct snd_pcm_mmap_control).
       - user process handles PCM frames by loop just with 'snd_pcm_mmap_begin()'
         and 'snd_pcm_mmap_commit()'.
       - user process uses PCM hw plugin in alsa-lib to operate I/O without
         'sync_ptr_ioctl' option.
      
      Unfortunately, major use case include these three conditions.
      Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      875becf8
  13. 12 4月, 2017 1 次提交
  14. 06 4月, 2017 1 次提交
    • T
      ALSA: firewire-lib: add no-header packet processing · 3b196c39
      Takashi Sakamoto 提交于
      As long as investigating Fireface 400, IEC 61883-1/6 is not applied to
      its packet streaming protocol. Remarks of the specific protocol are:
       * Each packet doesn't include CIP headers.
       * 64,0 and 128,0 kHz are supported.
       * The device doesn't necessarily transmit 8,000 packets per second.
       * 0, 1, 2, 3 are used as tag for rx isochronous packets, however 0 is
         used for tx isochronous packets.
      
      On the other hand, there's a common feature. The number of data blocks
      transferred in a second is the same as sampling transmission frequency.
      Current ALSA IEC 61883-1/6 engine already has a method to calculate it and
      this driver can utilize it for rx packets, as well as tx packets.
      
      This commit adds support for the transferring protocol. CIP_NO_HEADERS
      flag is newly added. When this flag is set:
       * Both of 0 (without CIP header) and 1 (with CIP header) are used as tag
         to handle incoming isochronous packet.
       * 0 (without CIP header) is used as tag to transfer outgoing isochronous
         packet.
       * Skip CIP header evaluation.
       * Use unique way to calculate the quadlets of isochronous packet payload.
      
      In ALSA PCM interface, 128.0 kHz is not supported, and the ALSA
      IEC 61883-1/6 engine doesn't support 64.0 kHz. These modes are dropped.
      
      The sequence of rx packet has a remarkable quirk about tag. This will be
      described in later commits.
      Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      3b196c39
  15. 28 3月, 2017 4 次提交
  16. 05 1月, 2017 1 次提交
    • T
      Revert "ALSA: firewire-lib: change structure member with proper type" · e4f34cf6
      Takashi Sakamoto 提交于
      This reverts commit 6b7e95d1. This commit
      is based on a concern about value of the given parameter. It's expected
      to be ORed value with some enumeration-constants, thus often it can not be
      one of the enumeration-constants. I understood that this is out of
      specification and causes implementation-dependent issues.
      
      In C language specification, enumerated type can be interpreted as an
      integer type, in which all of enumeration-constants in corresponding
      enumerator-list can be stored. Implementations can select one of char,
      signed int and unsigned int as its type, and this selection is
      implementation-dependent.
      
      In GCC, a signed integer is selected when at least one of
      enumeration-constants has negative value, else an unsigned integer is
      selected. This behaviour can be switched by -fshort-enums to short type.
      Anyway, the type can be decided after scanning all of
      enumeration-constants.
      
      Totally, there's no rules to constrain the value of enumerated type to
      be one of enumeration-constants. In short, in enumerated type, decision
      of actual type for the type is the most important and
      enumeration-constants are just used for the decision, thus it's permitted
      to have an integer value in a range of enumeration-constants. In our case,
      actual type for the type is currently deterministic to be either char or
      unsigned int. Under GCC, it's unsigned int.
      Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      e4f34cf6
  17. 03 1月, 2017 1 次提交
  18. 12 5月, 2016 1 次提交
    • T
      ALSA: firewire-lib: permit to flush queued packets only in process context for... · 1dba9db0
      Takashi Sakamoto 提交于
      ALSA: firewire-lib: permit to flush queued packets only in process context for better PCM period granularity
      
      These three commits were merged to improve PCM pointer granularity.
      commit 76fb8789 ("ALSA: firewire-lib: taskletize the snd_pcm_period_elapsed() call")
      commit e9148ddd ("ALSA: firewire-lib: flush completed packets when reading PCM position")
      commit 92b862c7 ("ALSA: firewire-lib: optimize packet flushing")
      
      The point of them is to handle queued packets not only in software IRQ
      context of IR/IT contexts, but also in process context. As a result of
      handling packets, period tasklet is scheduled when acrossing PCM period
      boundary. This is to prevent recursive call of
      'struct snd_pcm_ops.pointer()' in the same context.
      
      When the pointer callback is executed in the process context, it's
      better to avoid the second callback in the software IRQ context. The
      software IRQ context runs immediately after scheduled in the process
      context because few packets are queued yet.
      
      For the aim, 'pointer_flush' is used, however it causes a race condition
      between the process context and software IRQ context of IR/IT contexts.
      
      Practically, this race is not so critical because it influences process
      context to skip flushing queued packet and to get worse granularity of
      PCM pointer. The race condition is quite rare but it should be improved
      for stable service.
      
      The similar effect can be achieved by using 'in_interrupt()' macro. This
      commit obsoletes 'pointer_flush' with it.
      Acked-by: NClemens Ladisch <clemens@ladisch.de>
      Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      1dba9db0
  19. 10 5月, 2016 2 次提交
    • T
      ALSA: firewire-lib: enable the same feature as CIP_SKIP_INIT_DBC_CHECK flag · 62f00e40
      Takashi Sakamoto 提交于
      In former commit, drivers in ALSA firewire stack always starts IT context
      before IR context. If IR context starts after packets are transmitted by
      peer unit, packet discontinuity may be detected because the context starts
      in the middle of packet streaming. This situation is rare because IT
      context usually starts immediately. However, it's better to solve this
      issue. This is suppressed with CIP_SKIP_INIT_DBC_CHECK flag.
      
      This commit enables the same feature as CIP_SKIP_INIT_DBC_CHECK.
      Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      62f00e40
    • T
      ALSA: firewire-lib: handle IT/IR contexts in each software interrupt context · dec63cc8
      Takashi Sakamoto 提交于
      In clause 6.3 of IEC 61883-6:2000, there's an explanation about processing
      of presentation timestamp. In the clause, we can see "If a function block
      receives a CIP, processes it and subsequently re-transmits it, then the
      SYT of the outgoing CIP shall be the sum of the incoming SYT and the
      processing delay." ALSA firewire stack has an implementation to partly
      satisfy this specification. Developers assumed the stack to perform as an
      Audio function block[1].
      
      Following to the assumption, current implementation of ALSA firewire stack
      use one software interrupt context to handle both of in/out packets. In
      most case, this is processed in 1394 OHCI IR context independently of the
      opposite context. Thus, this implementation uses longer CPU time in the
      software interrupt context. This is not better for whole system.
      
      Against the assumption, I confirmed that each ASIC for IEC 61883-1/6
      doesn't necessarily expect it to the stack. Thus, current implementation
      of ALSA firewire stack includes over-engineering.
      
      This commit purges the implementation. As a result, packets of one
      direction are handled in one software interrupt context and spends
      minimum CPU time.
      
      [1] [alsa-devel] [PATCH 0/8] [RFC] new driver for Echo Audio's Fireworks based devices
      http://mailman.alsa-project.org/pipermail/alsa-devel/2013-June/062660.htmlSigned-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
      Signed-off-by: NTakashi Iwai <tiwai@suse.de>
      dec63cc8