1. 02 9月, 2010 6 次提交
    • P
      powerpc: Account time using timebase rather than PURR · cf9efce0
      Paul Mackerras 提交于
      Currently, when CONFIG_VIRT_CPU_ACCOUNTING is enabled, we use the
      PURR register for measuring the user and system time used by
      processes, as well as other related times such as hardirq and
      softirq times.  This turns out to be quite confusing for users
      because it means that a program will often be measured as taking
      less time when run on a multi-threaded processor (SMT2 or SMT4 mode)
      than it does when run on a single-threaded processor (ST mode), even
      though the program takes longer to finish.  The discrepancy is
      accounted for as stolen time, which is also confusing, particularly
      when there are no other partitions running.
      
      This changes the accounting to use the timebase instead, meaning that
      the reported user and system times are the actual number of real-time
      seconds that the program was executing on the processor thread,
      regardless of which SMT mode the processor is in.  Thus a program will
      generally show greater user and system times when run on a
      multi-threaded processor than on a single-threaded processor.
      
      On pSeries systems on POWER5 or later processors, we measure the
      stolen time (time when this partition wasn't running) using the
      hypervisor dispatch trace log.  We check for new entries in the
      log on every entry from user mode and on every transition from
      kernel process context to soft or hard IRQ context (i.e. when
      account_system_vtime() gets called).  So that we can correctly
      distinguish time stolen from user time and time stolen from system
      time, without having to check the log on every exit to user mode,
      we store separate timestamps for exit to user mode and entry from
      user mode.
      
      On systems that have a SPURR (POWER6 and POWER7), we read the SPURR
      in account_system_vtime() (as before), and then apportion the SPURR
      ticks since the last time we read it between scaled user time and
      scaled system time according to the relative proportions of user
      time and system time over the same interval.  This avoids having to
      read the SPURR on every kernel entry and exit.  On systems that have
      PURR but not SPURR (i.e., POWER5), we do the same using the PURR
      rather than the SPURR.
      
      This disables the DTL user interface in /sys/debug/kernel/powerpc/dtl
      for now since it conflicts with the use of the dispatch trace log
      by the time accounting code.
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      cf9efce0
    • P
      powerpc: Dynamically allocate most lppaca structs · 93c22703
      Paul Mackerras 提交于
      This arranges for the lppaca structs for most cpus to be dynamically
      allocated in the same manner as the paca structs.  If we don't include
      support for legacy iSeries, only the first lppaca is statically
      allocated; the rest are dynamically allocated.  If we include legacy
      iSeries support, then we statically allocate the first 64 lppaca
      structs, since the iSeries hypervisor requires that the lppaca
      structs be present in the data section of the kernel image, but
      legacy iSeries supports at most 64 cpus.
      
      With CONFIG_NR_CPUS, the kernel image size for a typical pSeries config
      went from:
      
         text    data     bss     dec     hex filename
      9524478 4734564 8469944 22728986        15ad11a ../test-1024/vmlinux
      
      to:
      
         text    data     bss     dec     hex filename
      9524482 3751508 8469944 21745934        14bd10e ../test-1024/vmlinux
      
      a reduction of 983052 bytes overall.
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      93c22703
    • P
      powerpc: Abstract indexing of lppaca structs · 8154c5d2
      Paul Mackerras 提交于
      Currently we have the lppaca structs as a simple array of NR_CPUS
      entries, taking up space in the data section of the kernel image.
      In future we would like to allocate them dynamically, so this
      abstracts out the accesses to the array, making it easier to
      change how we locate the lppaca for a given cpu in future.
      Specifically, lppaca[cpu] changes to lppaca_of(cpu).
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      8154c5d2
    • A
      powerpc: Feature nop out reservation clear when stcx checks address · f89451fb
      Anton Blanchard 提交于
      The POWER architecture does not require stcx to check that it is operating
      on the same address as the larx. This means it is possible for an
      an exception handler to execute a larx, get a reservation, decide
      not to do the stcx and then return back with an active reservation. If the
      interrupted code was in the middle of a larx/stcx sequence the stcx could
      incorrectly succeed.
      
      All recent POWER CPUs check the address before letting the stcx succeed
      so we can create a CPU feature and nop it out. As Ben suggested, we can
      only do this in our syscall path because there is a remote possibility
      some kernel code gets interrupted by an exception that ends up operating
      on the same cacheline.
      
      Thanks to Paul Mackerras and Derek Williams for the idea.
      
      To test this I used a very simple null syscall (actually getppid) testcase
      at http://ozlabs.org/~anton/junkcode/null_syscall.c
      
      I tested against 2.6.35-git10 with the following changes against the
      pseries_defconfig:
      
      CONFIG_VIRT_CPU_ACCOUNTING=n
      CONFIG_AUDIT=n
      CONFIG_PPC_4K_PAGES=n
      CONFIG_PPC_64K_PAGES=y
      CONFIG_FORCE_MAX_ZONEORDER=9
      CONFIG_PPC_SUBPAGE_PROT=n
      CONFIG_FUNCTION_TRACER=n
      CONFIG_FUNCTION_GRAPH_TRACER=n
      CONFIG_IRQSOFF_TRACER=n
      CONFIG_STACK_TRACER=n
      
      to remove the overhead of virtual CPU accounting, syscall auditing and
      the ftrace mcount tracers. 64kB pages were enabled to minimise TLB misses.
      
      POWER6: +8.2%
      POWER7: +7.0%
      
      Another suggestion was to use a larx to something in the L1 instead of a stcx.
      This was almost as fast as removing the larx on POWER6, but only 3.5% faster
      on POWER7. We can use this to speed up the reservation clear in our
      exception exit code.
      Signed-off-by: NAnton Blanchard <anton@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      f89451fb
    • A
      powerpc: Add 64bit csum_and_copy_to_user · 8c773914
      Anton Blanchard 提交于
      This adds the equivalent of csum_and_copy_from_user for the receive side so we
      can copy and checksum in one pass. It is modelled on the generic checksum
      routine.
      Signed-off-by: NAnton Blanchard <anton@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      8c773914
    • A
      powerpc: Optimise 64bit csum_partial_copy_generic and add csum_and_copy_from_user · fdd374b6
      Anton Blanchard 提交于
      We use the same core loop as the new csum_partial, adding in the
      stores and exception handling code. To keep things simple we do all the
      exception fixup in csum_and_copy_from_user. This wrapper function is
      modelled on the generic checksum code and is careful to always calculate
      a complete checksum even if we only copied part of the data to userspace.
      
      To test this I forced checksumming on over loopback and ran socklib (a
      simple TCP benchmark). On a POWER6 575 throughput improved by 19% with
      this patch. If I forced both the sender and receiver onto the same cpu
      (with the hope of shifting the benchmark from being cache bandwidth limited
      to cpu limited), adding this patch improved performance by 55%
      Signed-off-by: NAnton Blanchard <anton@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      fdd374b6
  2. 24 8月, 2010 4 次提交
  3. 15 8月, 2010 1 次提交
  4. 11 8月, 2010 4 次提交
    • F
      dma-mapping: remove dma_is_consistent API · 3b9c6c11
      FUJITA Tomonori 提交于
      Architectures implement dma_is_consistent() in different ways (some
      misinterpret the definition of API in DMA-API.txt).  So it hasn't been so
      useful for drivers.  We have only one user of the API in tree.  Unlikely
      out-of-tree drivers use the API.
      
      Even if we fix dma_is_consistent() in some architectures, it doesn't look
      useful at all.  It was invented long ago for some old systems that can't
      allocate coherent memory at all.  It's better to export only APIs that are
      definitely necessary for drivers.
      
      Let's remove this API.
      Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: <linux-arch@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3b9c6c11
    • F
      dma-mapping: unify dma_get_cache_alignment implementations · 4565f017
      FUJITA Tomonori 提交于
      dma_get_cache_alignment returns the minimum DMA alignment.  Architectures
      defines it as ARCH_DMA_MINALIGN (formally ARCH_KMALLOC_MINALIGN).  So we
      can unify dma_get_cache_alignment implementations.
      
      Note that some architectures implement dma_get_cache_alignment wrongly.
      dma_get_cache_alignment() should return the minimum DMA alignment.  So
      fully-coherent architectures should return 1.  This patch also fixes this
      issue.
      Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Cc: <linux-arch@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4565f017
    • F
      dma-mapping: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN · a6eb9fe1
      FUJITA Tomonori 提交于
      Now each architecture has the own dma_get_cache_alignment implementation.
      
      dma_get_cache_alignment returns the minimum DMA alignment.  Architectures
      define it as ARCH_KMALLOC_MINALIGN (it's used to make sure that malloc'ed
      buffer is DMA-safe; the buffer doesn't share a cache with the others).  So
      we can unify dma_get_cache_alignment implementations.
      
      This patch:
      
      dma_get_cache_alignment() needs to know if an architecture defines
      ARCH_KMALLOC_MINALIGN or not (needs to know if architecture has DMA
      alignment restriction).  However, slab.h define ARCH_KMALLOC_MINALIGN if
      architectures doesn't define it.
      
      Let's rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN.
      ARCH_KMALLOC_MINALIGN is used only in the internals of slab/slob/slub
      (except for crypto).
      Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Cc: <linux-arch@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a6eb9fe1
    • H
      tty: Add EXTPROC support for LINEMODE · 26df6d13
      hyc@symas.com 提交于
      This patch is against the 2.6.34 source.
      
      Paraphrased from the 1989 BSD patch by David Borman @ cray.com:
      
           These are the changes needed for the kernel to support
           LINEMODE in the server.
      
           There is a new bit in the termios local flag word, EXTPROC.
           When this bit is set, several aspects of the terminal driver
           are disabled.  Input line editing, character echo, and mapping
           of signals are all disabled.  This allows the telnetd to turn
           off these functions when in linemode, but still keep track of
           what state the user wants the terminal to be in.
      
           New ioctl:
               TIOCSIG         Generate a signal to processes in the
                               current process group of the pty.
      
           There is a new mode for packet driver, the TIOCPKT_IOCTL bit.
           When packet mode is turned on in the pty, and the EXTPROC bit
           is set, then whenever the state of the pty is changed, the
           next read on the master side of the pty will have the TIOCPKT_IOCTL
           bit set.  This allows the process on the server side of the pty
           to know when the state of the terminal has changed; it can then
           issue the appropriate ioctl to retrieve the new state.
      
      Since the original BSD patches accompanied the source code for telnet
      I've left that reference here, but obviously the feature is useful for
      any remote terminal protocol, including ssh.
      
      The corresponding feature has existed in the BSD tty driver since 1989.
      For historical reference, a good copy of the relevant files can be found
      here:
      
      http://anonsvn.mit.edu/viewvc/krb5/trunk/src/appl/telnet/?pathrev=17741Signed-off-by: NHoward Chu <hyc@symas.com>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      
      26df6d13
  5. 10 8月, 2010 1 次提交
    • C
      kmap_atomic: make kunmap_atomic() harder to misuse · 597781f3
      Cesar Eduardo Barros 提交于
      kunmap_atomic() is currently at level -4 on Rusty's "Hard To Misuse"
      list[1] ("Follow common convention and you'll get it wrong"), except in
      some architectures when CONFIG_DEBUG_HIGHMEM is set[2][3].
      
      kunmap() takes a pointer to a struct page; kunmap_atomic(), however, takes
      takes a pointer to within the page itself.  This seems to once in a while
      trip people up (the convention they are following is the one from
      kunmap()).
      
      Make it much harder to misuse, by moving it to level 9 on Rusty's list[4]
      ("The compiler/linker won't let you get it wrong").  This is done by
      refusing to build if the type of its first argument is a pointer to a
      struct page.
      
      The real kunmap_atomic() is renamed to kunmap_atomic_notypecheck()
      (which is what you would call in case for some strange reason calling it
      with a pointer to a struct page is not incorrect in your code).
      
      The previous version of this patch was compile tested on x86-64.
      
      [1] http://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html
      [2] In these cases, it is at level 5, "Do it right or it will always
          break at runtime."
      [3] At least mips and powerpc look very similar, and sparc also seems to
          share a common ancestor with both; there seems to be quite some
          degree of copy-and-paste coding here. The include/asm/highmem.h file
          for these three archs mention x86 CPUs at its top.
      [4] http://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html
      [5] As an aside, could someone tell me why mn10300 uses unsigned long as
          the first parameter of kunmap_atomic() instead of void *?
      Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
      Cc: Russell King <linux@arm.linux.org.uk> (arch/arm)
      Cc: Ralf Baechle <ralf@linux-mips.org> (arch/mips)
      Cc: David Howells <dhowells@redhat.com> (arch/frv, arch/mn10300)
      Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> (arch/mn10300)
      Cc: Kyle McMartin <kyle@mcmartin.ca> (arch/parisc)
      Cc: Helge Deller <deller@gmx.de> (arch/parisc)
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> (arch/parisc)
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> (arch/powerpc)
      Cc: Paul Mackerras <paulus@samba.org> (arch/powerpc)
      Cc: "David S. Miller" <davem@davemloft.net> (arch/sparc)
      Cc: Thomas Gleixner <tglx@linutronix.de> (arch/x86)
      Cc: Ingo Molnar <mingo@redhat.com> (arch/x86)
      Cc: "H. Peter Anvin" <hpa@zytor.com> (arch/x86)
      Cc: Arnd Bergmann <arnd@arndb.de> (include/asm-generic)
      Cc: Rusty Russell <rusty@rustcorp.com.au> ("Hard To Misuse" list)
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      597781f3
  6. 08 8月, 2010 1 次提交
  7. 07 8月, 2010 1 次提交
    • E
      powerpc/5200: add mpc5200_psc_ac97_gpio_reset · cfa6a88c
      Eric Millbrandt 提交于
      Work around a silicon bug in the ac97 reset functionality of the
      mpc5200(b).  The implementation of the ac97 "cold" reset is flawed.
      If the sync and output lines are high when reset is asserted the
      attached ac97 device may go into test mode.  Avoid this by
      reconfiguring the psc to gpio mode and generating the reset manually.
      
      From MPC5200B User's Manual:
      "Some AC97 devices goes to a test mode, if the Sync line is high
      during the Res line is low (reset phase). To avoid this behavior the
      Sync line must be also forced to zero during the reset phase. To do
      that, the pin muxing should switch to GPIO mode and the GPIO control
      register should be used to control the output lines."
      Signed-off-by: NEric Millbrandt <emillbrandt@dekaresearch.com>
      Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
      cfa6a88c
  8. 02 8月, 2010 1 次提交
  9. 01 8月, 2010 5 次提交
  10. 31 7月, 2010 1 次提交
  11. 30 7月, 2010 1 次提交
  12. 29 7月, 2010 2 次提交
    • P
      powerpc: Clean up obsolete code relating to decrementer and timebase · d75d68cf
      Paul Mackerras 提交于
      Since the decrementer and timekeeping code was moved over to using
      the generic clockevents and timekeeping infrastructure, several
      variables and functions have been obsolete and effectively unused.
      This deletes them.
      
      In particular, wakeup_decrementer() is no longer needed since the
      generic code reprograms the decrementer as part of the process of
      resuming the timekeeping code, which happens during sysdev resume.
      Thus the wakeup_decrementer calls in the suspend_enter methods for
      52xx platforms have been removed.  The call in the powermac cpu
      frequency change code has been replaced by set_dec(1), which will
      cause a timer interrupt as soon as interrupts are enabled, and the
      generic code will then reprogram the decrementer with the correct
      value.
      
      This also simplifies the generic_suspend_en/disable_irqs functions
      and makes them static since they are not referenced outside time.c.
      The preempt_enable/disable calls are removed because the generic
      code has disabled all but the boot cpu at the point where these
      functions are called, so we can't be moved to another cpu.
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      d75d68cf
    • P
      powerpc: Rework VDSO gettimeofday to prevent time going backwards · 0e469db8
      Paul Mackerras 提交于
      Currently it is possible for userspace to see the result of
      gettimeofday() going backwards by 1 microsecond, assuming that
      userspace is using the gettimeofday() in the VDSO.  The VDSO
      gettimeofday() algorithm computes the time in "xsecs", which are
      units of 2^-20 seconds, or approximately 0.954 microseconds,
      using the algorithm
      
      	now = (timebase - tb_orig_stamp) * tb_to_xs + stamp_xsec
      
      and then converts the time in xsecs to seconds and microseconds.
      
      The kernel updates the tb_orig_stamp and stamp_xsec values every
      tick in update_vsyscall().  If the length of the tick is not an
      integer number of xsecs, then some precision is lost in converting
      the current time to xsecs.  For example, with CONFIG_HZ=1000, the
      tick is 1ms long, which is 1048.576 xsecs.  That means that
      stamp_xsec will advance by either 1048 or 1049 on each tick.
      With the right conditions, it is possible for userspace to get
      (timebase - tb_orig_stamp) * tb_to_xs being 1049 if the kernel is
      slightly late in updating the vdso_datapage, and then for stamp_xsec
      to advance by 1048 when the kernel does update it, and for userspace
      to then see (timebase - tb_orig_stamp) * tb_to_xs being zero due to
      integer truncation.  The result is that time appears to go backwards
      by 1 microsecond.
      
      To fix this we change the VDSO gettimeofday to use a new field in the
      VDSO datapage which stores the nanoseconds part of the time as a
      fractional number of seconds in a 0.32 binary fraction format.
      (Or put another way, as a 32-bit number in units of 0.23283 ns.)
      This is convenient because we can use the mulhwu instruction to
      convert it to either microseconds or nanoseconds.
      
      Since it turns out that computing the time of day using this new field
      is simpler than either using stamp_xsec (as gettimeofday does) or
      stamp_xtime.tv_nsec (as clock_gettime does), this converts both
      gettimeofday and clock_gettime to use the new field.  The existing
      __do_get_tspec function is converted to use the new field and take
      a parameter in r7 that indicates the desired resolution, 1,000,000
      for microseconds or 1,000,000,000 for nanoseconds.  The __do_get_xsec
      function is then unused and is deleted.
      
      The new algorithm is
      
      	now = ((timebase - tb_orig_stamp) << 12) * tb_to_xs
      		+ (stamp_xtime_seconds << 32) + stamp_sec_fraction
      
      with 'now' in units of 2^-32 seconds.  That is then converted to
      seconds and either microseconds or nanoseconds with
      
      	seconds = now >> 32
      	partseconds = ((now & 0xffffffff) * resolution) >> 32
      
      The 32-bit VDSO code also makes a further simplification: it ignores
      the bottom 32 bits of the tb_to_xs value, which is a 0.64 format binary
      fraction.  Doing so gets rid of 4 multiply instructions.  Assuming
      a timebase frequency of 1GHz or less and an update interval of no
      more than 10ms, the upper 32 bits of tb_to_xs will be at least
      4503599, so the error from ignoring the low 32 bits will be at most
      2.2ns, which is more than an order of magnitude less than the time
      taken to do gettimeofday or clock_gettime on our fastest processors,
      so there is no possibility of seeing inconsistent values due to this.
      
      This also moves update_gtod() down next to its only caller, and makes
      update_vsyscall use the time passed in via the wall_time argument rather
      than accessing xtime directly.  At present, wall_time always points to
      xtime, but that could change in future.
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      0e469db8
  13. 24 7月, 2010 3 次提交
  14. 23 7月, 2010 2 次提交
  15. 19 7月, 2010 1 次提交
  16. 14 7月, 2010 3 次提交
  17. 12 7月, 2010 2 次提交
  18. 09 7月, 2010 1 次提交