Commit Graph

477 Commits

Author SHA1 Message Date
Stephen Rothwell
1dc461f0b0 [PATCH] powerpc: the iSeries vio lan driver changed device type
So the IOMMU table building code needs to match.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:24 +10:00
Jeremy Kerr
4c76e0bcde [PATCH] powerpc: pseries: Use generic dma-window parsing function
Change the pseries iommu init code to use the new of_parse_dma_window()
to parse the ibm,dma-window and ibm,my-dma-window properties of pci and
virtual device nodes.

Also, clean up vio_build_iommu_table() a little.

Tested on pseries, with both vio and pci devices.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:23 +10:00
Jeremy Kerr
d4ad66faec [PATCH] powerpc: Add of_parse_dma_window()
Add a function for generic parsing of dma-window properties (ie,
ibm,dma-window and ibm,my-dma-window) of pci and virtual device nodes.

This function will also be used by cell.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:21 +10:00
jimix@watson.ibm.com
8ae5b2801a [PATCH] powerpc: udbg_printf() formatting attribute
This patch allows the compiler to catch any printf-like mismatches for
udbg_printf().  After some brute force building I've only found issues
with my own code and lparcfg.c It could break some developers, but
IMHO that would be goodness.

Signed-off-by: Jimi Xenidis <jimix@watson.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:19 +10:00
Michael Ellerman
35dd54326e [PATCH] powerpc: Move crashkernel= handling into the kernel.
This was missing a quilt ref.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:18 +10:00
Michael Ellerman
473104134b [PATCH] powerpc: Kdump header cleanup
We need to know the base address of the kdump kernel even when we're not a
kdump kernel, so add a #define for it. Move the logic that sets the kdump
kernelbase into kdump.h instead of page.h.

Rename kdump_setup() to setup_kdump_trampoline() to make it clearer what it's
doing, and add an empty definition for the !CRASH_DUMP case to avoid a

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:16 +10:00
Michael Ellerman
2babf5c2ec [PATCH] powerpc: Unify mem= handling
We currently do mem= handling in three seperate places. And as benh pointed out
I wrote two of them. Now that we parse command line parameters earlier we can
clean this mess up.

Moving the parsing out of prom_init means the device tree might be allocated
above the memory limit. If that happens we'd have to move it. As it happens
we already have logic to do that for kdump, so just genericise it.

This also means we might have reserved regions above the memory limit, if we
do the bootmem allocator will blow up, so we have to modify
lmb_enforce_memory_limit() to truncate the reserves as well.

Tested on P5 LPAR, iSeries, F50, 44p. Tested moving device tree on P5 and
44p and F50.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:15 +10:00
Michael Ellerman
846f77b08c [PATCH] powerpc: Parse early parameters earlier
Currently we have call parse_early_param() earliyish, but not really very
early. In particular, it's not early enough to do things like mem=x or
crashkernel=blah, which is annoying.

So do it earlier. I've checked all the early param handlers, and none of them
look like they should have any trouble with this. I haven't tested the
booke_wdt ones though.

On 32-bit we were doing the CONFIG_CMDLINE logic twice, so don't.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:13 +10:00
Michael Ellerman
480f6f35a1 [PATCH] powerpc: Make early xmon logic immune to location of early parsing
Currently early_xmon() calls directly into debugger() if xmon=early is passed.
This ties the invocation of early xmon to the location of parse_early_param(),
which might change.

Tested on P5 LPAR and F50.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 15:02:12 +10:00
mostrows@watson.ibm.com
9dabbfbab3 [PATCH] powerpc: Create /proc/rtas, /proc/ppc64/rtas if RTAS exists.
Use the existence of RTAS device tree node to determine if
/proc/rtas. /proc/ppc64/rtas are to be created.  Using machine type
is not reliable (i.e. Maple-like machines may have RTAS).

Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 14:35:32 +10:00
Geoff Levand
b26f100d89 [PATCH] powerpc: remove do-nothing cpu setup routines
Removed the do-nothing routines __setup_cpu_power3 and
__setup_cpu_power4 and replaced them with a null pointer check
in the caller.  Also removed the Cell processor specific
routine __setup_cpu_be which improperly accessed the
hypervisor page size configuration at SPR HID6.

Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-19 14:24:18 +10:00
Paul Mackerras
877fbae3d5 Merge branch 'for_paulus' of git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc 2006-05-19 09:23:47 +10:00
Paul Mackerras
f18fc729cd Merge ../linux-2.6 2006-05-05 15:45:48 +10:00
Kumar Gala
7e990266c8 powerpc: provide ppc_md.panic() for both ppc32 & ppc64
Allow boards to provide a panic callback on ppc32.  Moved the code to sets
this up into setup-common.c so its shared between ppc32 & ppc64.  Also moved
do_init_bootmem prototype into setup.h.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2006-05-05 00:02:08 -05:00
Paul Mackerras
d205819e23 [PATCH] powerpc: Use the ibm,pa-features property if available
Forthcoming IBM machines will have a "ibm,pa-features" property on CPU
nodes, that contains bits indicating which optional architecture
features are implemented by the CPU.  This adds code to use the
property, if present, to update our CPU feature bitmaps.  Note that
this means we can both set and clear feature bits based on what
the firmware tells us.

This is based on a patch by Will Schmidt <willschm@us.ibm.com>.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-03 23:06:47 +10:00
Ananth N Mavinakayanahalli
0ccde0a290 [PATCH] powerpc/kprobes: fix singlestep out-of-line
We currently single-step inline if the instruction on which a kprobe is
inserted is a trap variant.

- variants (such as tdnei, used by BUG()) typically evaluate a condition
  and cause a trap only if the condition is satisfied.
- kprobes uses the unconditional "trap" (0x7fe00008) and single-stepping
  again on this instruction, resulting in another trap without
  evaluating the condition is obviously incorrect.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-05-03 23:06:41 +10:00
Linus Torvalds
532f57da40 Merge branch 'audit.b10' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b10' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current:
  [PATCH] Audit Filter Performance
  [PATCH] Rework of IPC auditing
  [PATCH] More user space subject labels
  [PATCH] Reworked patch for labels on user space messages
  [PATCH] change lspp ipc auditing
  [PATCH] audit inode patch
  [PATCH] support for context based audit filtering, part 2
  [PATCH] support for context based audit filtering
  [PATCH] no need to wank with task_lock() and pinning task down in audit_syscall_exit()
  [PATCH] drop task argument of audit_syscall_{entry,exit}
  [PATCH] drop gfp_mask in audit_log_exit()
  [PATCH] move call of audit_free() into do_exit()
  [PATCH] sockaddr patch
  [PATCH] deal with deadlocks in audit_free()
2006-05-01 21:43:05 -07:00
Jeremy Kerr
953039c8df [PATCH] powerpc: Allow devices to register with numa topology
Change of_node_to_nid() to traverse the device tree, looking for a numa id.
Cell uses this to assign ids to SPUs, which are children of the CPU node.
Existing users of of_node_to_nid() are altered to use of_node_to_nid_single(),
which doesn't do the traversal.

Export an attach_sysdev_to_node() function, allowing system devices (eg.
SPUs) to link themselves into the numa topology in sysfs.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-01 18:17:46 -07:00
Al Viro
5411be59db [PATCH] drop task argument of audit_syscall_{entry,exit}
... it's always current, and that's a good thing - allows simpler locking.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-05-01 06:06:18 -04:00
Will Schmidt
5a43ee6562 [PATCH] nvram_print_partitions cosmetic fixup
This is a cosmetic fixup.   When printing the nvram partition table, the
first couple entries have a shorter 'index' value than the others, so
table is a bit askew.   This change makes the table look pretty.
Tested on pseries and g5.   Footnote: yes, this table is normally hidden
behind a DEBUG_NVRAM #define.

Signed-off-by: Will Schmidt <willschm@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-29 18:08:05 +10:00
Olof Johansson
a74e5e5fac [PATCH] powerpc iommu: minor cleanup
A couple of minor renames:

* The iommu_table is no longer a part of the device node structure,
  so devnode_table is misleading
* Rename struct device *-variables to hwdev

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-29 18:08:01 +10:00
Stephen Rothwell
c7f0e8cb56 [PATCH] powerpc: merge the rest of the vio code
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-29 18:02:02 +10:00
Stephen Rothwell
dd721ffd95 [PATCH] powerpc: use a common vio_match_device routine
This requires the compatible properties having vaules that are empty
strings instead of just being empty properties.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-29 18:02:01 +10:00
Stephen Rothwell
e10fa77368 [PATCH] powerpc: use the device tree for the iSeries vio bus probe
As an added bonus, since every vio_dev now has a device_node
associated with it, hotplug now works.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-29 18:02:00 +10:00
Paul Mackerras
29f147d746 Merge branch 'merge' 2006-04-29 16:15:57 +10:00
Anton Blanchard
03054d51a7 [PATCH] powerpc: Add cputable entry for POWER6
Add a cputable entry for the POWER6 processor.

The SIHV and SIPR bits in the mmcra have moved in POWER6, so disable
support for that until oprofile is fixed.

Also tell firmware that we know about POWER6.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-29 10:56:58 +10:00
Andreas Schwab
2833c28aa0 [PATCH] powerpc: Wire up *at syscalls
Wire up *at syscalls.

This patch has been tested on ppc64 (using glibc's testsuite, both 32bit
and 64bit), and compile-tested for ppc32 (I have currently no ppc32 system
available, but I expect no problems).

Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-28 21:04:59 +10:00
David Woodhouse
1269277a5e [PATCH] powerpc: Use check_legacy_ioport() on ppc32 too.
Some people report that we die on some Macs when we are expecting to
catch machine checks after poking at some random I/O address. I'd seen
it happen on my dual G4 with serial ports until we fixed those to use
OF, but now other users are reporting it with i8042.

This expands the use of check_legacy_ioport() to avoid that situation
even on 32-bit kernels.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-28 21:04:55 +10:00
Alan Modra
f749edae5e [PATCH] powerpc64: Fix loading of modules without a .toc section
Normally, ppc64 module .ko files contain a table-of-contents (.toc)
section, but if the module doesn't reference any static or external
data or external procedures, it is possible for gcc/binutils to
generate a .ko that doesn't have a .toc.  Currently the module
loader refuses to load such a module, since it needs the address
of the .toc section to use in relocations.

This patch fixes the problem by using the address of the .stubs
section instead, which is an acceptable substitute in this situation.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-28 21:04:49 +10:00
Paul Mackerras
f709bfac48 powerpc/pseries: Tell firmware our capabilities on new machines
This adds code to call a new firmware method to tell the firmware
what machines and capabilities (such as VMX/Altivec) we support.
This will be needed on POWER5+ and POWER6 machines, and it has no
effect on past and current machines.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-28 16:28:35 +10:00
Chandra Seetharaman
83d722f7e1 [PATCH] Remove __devinit and __cpuinit from notifier_call definitions
Few of the notifier_chain_register() callers use __init in the definition
of notifier_call.  It is incorrect as the function definition should be
available after the initializations (they do not unregister them during
initializations).

This patch fixes all such usages to _not_ have the notifier_call __init
section.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-26 08:30:03 -07:00
Chandra Seetharaman
649bbaa484 [PATCH] Remove __devinitdata from notifier block definitions
Few of the notifier_chain_register() callers use __devinitdata in the
definition of notifier_block data structure.  It is incorrect as the
data structure should be available after the initializations (they do
not unregister them during initializations).

This was leading to an oops when notifier_chain_register() call is
invoked for those callback chains after initialization.

This patch fixes all such usages to _not_ have the notifier_block data
structure in the init data section.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-26 08:27:50 -07:00
Jens Axboe
912d35f867 [PATCH] Add support for the sys_vmsplice syscall
sys_splice() moves data to/from pipes with a file input/output. sys_vmsplice()
moves data to a pipe, with the input being a user address range instead.

This uses an approach suggested by Linus, where we can hold partial ranges
inside the pages[] map. Hopefully this will be useful for network
receive support as well.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-26 10:59:21 +02:00
Paul Mackerras
8833843c87 Merge branch 'merge' 2006-04-22 19:47:24 +10:00
Paul Mackerras
7c8ce71b09 Merge branch 'misc' of master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc into merge 2006-04-22 19:19:06 +10:00
Olof Johansson
4bd174fe1c [PATCH] powerpc: Remove stale iseries global
Not even the iSeries maintainer seems to have access to this legendary
piranha simulator. It adds a bit of ugliness in the common time init
code, and if it's no longer used we might as well be done with it and
remove the bloat.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-22 18:46:11 +10:00
Olof Johansson
e884e9c5f2 [PATCH] powerpc: Quiet PCI init printouts
Quiet some of the more debug related output from the pci probe routines.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-22 18:45:14 +10:00
Olof Johansson
224ad80ac0 [PATCH] powerpc: Quiet time init output
Move time_init console output to KERN_DEBUG prink level. No need to
print it at every boot.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-22 18:45:08 +10:00
Anton Blanchard
c256f4b959 [PATCH] powerpc: remove io_page_mask
Cleanup patch which removes the io_page_mask.  It fixes the reset on
some e1000 devices which is needed for clean kexec reboots.  The legacy
devices which broke with this patch (parallel port and PC speaker) have
now been fixed in Linus' tree.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-22 18:45:05 +10:00
Michael Ellerman
d6c1a90810 [PATCH] powerpc: Disable and EOI interrupts in machine_crash_shutdown()
We've seen several bugs caused by interrupt weirdness in the kdump kernel.
Panicking from an interrupt handler means we fail to EOI the interrupt, and
so the second kernel never gets that interrupt ever again. We also see hangs
on JS20 where we take interrupts in the second kernel early during boot.

This patch fixes both those problems, and although it adds more code to the
crash path I think it is the best solution.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-22 18:44:25 +10:00
Arnd Bergmann
23b2527d5e [PATCH] powerpc/cell: remove BUILD_BUG_ON and add sys_tee to spu_syscall_table
Every time a new syscall gets added, a BUILD_BUG_ON in
arch/powerpc/platforms/cell/spu_callbacks.c gets triggered.
Since the addition of a new syscall is rather harmless,
the error should just be removed.

While we're here, add sys_tee to the list and add a comment
to systbl.S to remind people that there is another list
on powerpc.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-21 22:32:50 +10:00
Olof Johansson
2889773131 [PATCH] powerpc: Lower threshold for DART enablement to 1GB
Turn on the DART already at 1GB. This is needed because of crippled
devices in some systems, i.e. Airport Extreme cards, only supporting
30-bit DMA addresses.

Otherwise, users with between 1 and 2GB of memory will need to manually
enable it with iommu=force, and that's no good.

Some simple performance tests show that there's a slight impact of
enabling DART, but it's in the 1-3% range (kernel build with disk I/O
as well as over NFS).

iommu=off can still be used for those who don't want to deal with the
overhead (and don't need it for any devices).

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-21 22:29:37 +10:00
Olof Johansson
7daa411b81 [PATCH] powerpc: IOMMU support for honoring dma_mask
Some devices don't support full 32-bit DMA address space, which we currently
assume. Add the required mask-passing to the IOMMU allocators.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-21 22:28:55 +10:00
Prasanna S Panchamukhi
46dbe2f4ef [PATCH] Switch Kprobes inline functions to __kprobes for ppc64
Andrew Morton pointed out that compiler might not inline the functions
marked for inline in kprobes.  There-by allowing the insertion of probes
on these kprobes routines, which might cause recursion.

This patch removes all such inline and adds them to kprobes section
there by disallowing probes on all such routines.  Some of the routines
can even still be inlined, since these routines gets executed after the
kprobes had done necessay setup for reentrancy.

Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-19 09:13:53 -07:00
Linus Torvalds
6fbe85f914 Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge
* git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge:
  powerpc: Use correct sequence for putting CPU into nap mode
  [PATCH] spufs: fix context-switch decrementer code
  [PATCH] powerpc32: Set cpu explicitly in kernel compiles
  [PATCH] powerpc/pseries: bugfix: balance calls to pci_device_put
  [PATCH] powerpc: Fix machine detection in prom_init.c
  [PATCH] ppc32: Fix string comparing in platform_notify_map
  [PATCH] powerpc: Avoid __initcall warnings
  [PATCH] powerpc: Ensure runlatch is off in the idle loop
  powerpc: Fix CHRP booting - needs a define_machine call
  powerpc: iSeries has only 256 IRQs
2006-04-18 10:34:24 -07:00
Paul Mackerras
f39224a8c1 powerpc: Use correct sequence for putting CPU into nap mode
We weren't using the recommended sequence for putting the CPU into
nap mode.  When I changed the idle loop, for some reason 7447A cpus
started hanging when we put them into nap mode.  Changing to the
recommended sequence fixes that.

The complexity here is that the recommended sequence is a loop that
keeps putting the cpu back into nap mode.  Clearly we need some way
to break out of the loop when an interrupt (external interrupt,
decrementer, performance monitor) occurs.  Here we use a bit in
the thread_info struct to indicate that we need this, and the exception
entry code notices this and arranges for the exception to return
to the value in the link register, thus breaking out of the loop.
We use a new `local_flags' field in the thread_info which we can
alter without needing to use an atomic update sequence.

The PPC970 has the same recommended sequence, so we do the same thing
there too.

This also fixes a bug in the kernel stack overflow handling code on
32-bit, since it was causing a value that we needed in a register to
get trashed.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-18 21:49:11 +10:00
Michael Ellerman
6f806ceed5 [PATCH] powerpc: Fix machine detection in prom_init.c
In e8222502ee the detection of machine types
in prom_init broke for some machines. We should be checking /device_type
instead of /model. This should make Power3 and Power4 boot again. Haven't
been able to test this.  We also need to relocate before comparing.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-13 09:32:00 -07:00
Anton Blanchard
49c28e4e40 [PATCH] powerpc: Avoid __initcall warnings
Fix __initcall return in proc_rtas_init and rtas_init.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-13 09:27:26 -07:00
Anton Blanchard
ddafddcfc7 [PATCH] powerpc: Ensure runlatch is off in the idle loop
Since external and decrementer interrupts set the runlatch on, we need
to ensure its set off again in the idle loop. At the moment we dont turn
it off in the inner loop.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-04-13 09:27:22 -07:00
Jens Axboe
70524490ee [PATCH] splice: add support for sys_tee()
Basically an in-kernel implementation of tee, which uses splice and the
pipe buffers as an intelligent way to pass data around by reference.

Where the user space tee consumes the input and produces a stdout and
file output, this syscall merely duplicates the data inside a pipe to
another pipe. No data is copied, the output just grabs a reference to the
input pipe data.

Signed-off-by: Jens Axboe <axboe@suse.de>
2006-04-11 15:51:17 +02:00