Commit Graph

167 Commits

Author SHA1 Message Date
Michael Neuling 70a54a4fae powerpc: Fix single step emulation of 32bit overflowed branches
Check truncate_if_32bit() on final write to nip.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 16:55:13 +10:00
Michael Neuling 280a5ba22c powerpc/pseries: Improve stream generation comments in copypage/user
No code changes, just documenting what's happening a little better.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-01 08:29:26 +10:00
Suzuki K. Poulose 5e249d4528 uprobes/powerpc: Add dependency on single step emulation
Uprobes uses emulate_step in sstep.c, but we haven't explicitly specified
the dependency. On pseries HAVE_HW_BREAKPOINT protects us, but 44x has no
such luxury.

Consolidate other users that depend on sstep and create a new config option.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Cc: linuxppc-dev@ozlabs.org
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-01-29 11:35:06 +11:00
Anton Blanchard 1fbe9cf259 powerpc: Build kernel with -mcmodel=medium
Finally remove the two level TOC and build with -mcmodel=medium.

Unfortunately we can't build modules with -mcmodel=medium due to
the tricks the kernel module loader plays with percpu data:

# -mcmodel=medium breaks modules because it uses 32bit offsets from
# the TOC pointer to create pointers where possible. Pointers into the
# percpu data area are created by this method.
#
# The kernel module loader relocates the percpu data section from the
# original location (starting with 0xd...) to somewhere in the base
# kernel percpu data space (starting with 0xc...). We need a full
# 64bit relocation for this to work, hence -mcmodel=large.

On older kernels we fall back to the two level TOC (-mminimal-toc)

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-01-10 17:00:31 +11:00
Nishanth Aravamudan c8adfeccee powerpc: Fix VMX fix for memcpy case
In 2fae7cdb60 ("powerpc: Fix VMX in
interrupt check in POWER7 copy loops"), Anton inadvertently
introduced a regression for memcpy on POWER7 machines. copyuser and
memcpy diverge slightly in their use of cr1 (copyuser doesn't use it,
but memcpy does) and you end up clobbering that register with your fix.
That results in (taken from an FC18 kernel):

[   18.824604] Unrecoverable VMX/Altivec Unavailable Exception f20 at c000000000052f40
[   18.824618] Oops: Unrecoverable VMX/Altivec Unavailable Exception, sig: 6 [#1]
[   18.824623] SMP NR_CPUS=1024 NUMA pSeries
[   18.824633] Modules linked in: tg3(+) be2net(+) cxgb4(+) ipr(+) sunrpc xts lrw gf128mul dm_crypt dm_round_robin dm_multipath linear raid10 raid456 async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx raid1 raid0 scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh_alua squashfs cramfs
[   18.824705] NIP: c000000000052f40 LR: c00000000020b874 CTR: 0000000000000512
[   18.824709] REGS: c000001f1fef7790 TRAP: 0f20   Not tainted  (3.6.0-0.rc6.git0.2.fc18.ppc64)
[   18.824713] MSR: 8000000000009032 <SF,EE,ME,IR,DR,RI>  CR: 4802802e  XER: 20000010
[   18.824726] SOFTE: 0
[   18.824728] CFAR: 0000000000000f20
[   18.824731] TASK = c000000fa7128400[0] 'swapper/24' THREAD: c000000fa7480000 CPU: 24
GPR00: 00000000ffffffc0 c000001f1fef7a10 c00000000164edc0 c000000f9b9a8120
GPR04: c000000f9b9a8124 0000000000001438 0000000000000060 03ffffff064657ee
GPR08: 0000000080000000 0000000000000010 0000000000000020 0000000000000030
GPR12: 0000000028028022 c00000000ff25400 0000000000000001 0000000000000000
GPR16: 0000000000000000 7fffffffffffffff c0000000016b2180 c00000000156a500
GPR20: c000000f968c7a90 c0000000131c31d8 c000001f1fef4000 c000000001561d00
GPR24: 000000000000000a 0000000000000000 0000000000000001 0000000000000012
GPR28: c000000fa5c04f80 00000000000008bc c0000000015c0a28 000000000000022e
[   18.824792] NIP [c000000000052f40] .memcpy_power7+0x5a0/0x7c4
[   18.824797] LR [c00000000020b874] .pcpu_free_area+0x174/0x2d0
[   18.824800] Call Trace:
[   18.824803] [c000001f1fef7a10] [c000000000052c14] .memcpy_power7+0x274/0x7c4 (unreliable)
[   18.824809] [c000001f1fef7b10] [c00000000020b874] .pcpu_free_area+0x174/0x2d0
[   18.824813] [c000001f1fef7bb0] [c00000000020ba88] .free_percpu+0xb8/0x1b0
[   18.824819] [c000001f1fef7c50] [c00000000043d144] .throtl_pd_exit+0x94/0xd0
[   18.824824] [c000001f1fef7cf0] [c00000000043acf8] .blkg_free+0x88/0xe0
[   18.824829] [c000001f1fef7d90] [c00000000018c048] .rcu_process_callbacks+0x2e8/0x8a0
[   18.824835] [c000001f1fef7e90] [c0000000000a8ce8] .__do_softirq+0x158/0x4d0
[   18.824840] [c000001f1fef7f90] [c000000000025ecc] .call_do_softirq+0x14/0x24
[   18.824845] [c000000fa7483650] [c000000000010e80] .do_softirq+0x160/0x1a0
[   18.824850] [c000000fa74836f0] [c0000000000a94a4] .irq_exit+0xf4/0x120
[   18.824854] [c000000fa7483780] [c000000000020c44] .timer_interrupt+0x154/0x4d0
[   18.824859] [c000000fa7483830] [c000000000003be0] decrementer_common+0x160/0x180
[   18.824866] --- Exception: 901 at .plpar_hcall_norets+0x84/0xd4
[   18.824866]     LR = .check_and_cede_processor+0x48/0x80
[   18.824871] [c000000fa7483b20] [c00000000007f018] .check_and_cede_processor+0x18/0x80 (unreliable)
[   18.824877] [c000000fa7483b90] [c00000000007f104] .dedicated_cede_loop+0x84/0x150
[   18.824883] [c000000fa7483c50] [c0000000006bc030] .cpuidle_enter+0x30/0x50
[   18.824887] [c000000fa7483cc0] [c0000000006bc9f4] .cpuidle_idle_call+0x104/0x720
[   18.824892] [c000000fa7483d80] [c000000000070af8] .pSeries_idle+0x18/0x40
[   18.824897] [c000000fa7483df0] [c000000000019084] .cpu_idle+0x1a4/0x380
[   18.824902] [c000000fa7483ec0] [c0000000008a4c18] .start_secondary+0x520/0x528
[   18.824907] [c000000fa7483f90] [c0000000000093f0] .start_secondary_prolog+0x10/0x14
[   18.824911] Instruction dump:
[   18.824914] 38840008 90030000 90e30004 38630008 7ca62850 7cc300d0 78c7e102 7cf01120
[   18.824923] 78c60660 39200010 39400020 39600030 <7e00200c> 7c0020ce 38840010 409f001c
[   18.824935] ---[ end trace 0bb95124affaaa45 ]---
[   18.825046] Unrecoverable VMX/Altivec Unavailable Exception f20 at c000000000052d08

I believe the right fix is to make memcpy match usercopy and not use
cr1.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@kernel.org> [v3.6]
2012-10-04 18:02:43 +10:00
Tiejun Chen 8e9f693715 powerpc/kprobe: Don't emulate store when kprobe stwu r1
We don't do the real store operation for kprobing 'stwu Rx,(y)R1'
since this may corrupt the exception frame, now we will do this
operation safely in exception return code after migrate current
exception frame below the kprobed function stack.

So we only update gpr[1] here and trigger a thread flag to mask
this.

Note we should make sure if we trigger kernel stack over flow.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-18 15:32:45 +10:00
Benjamin Herrenschmidt 636802ef96 powerpc: Don't use __put_user() in patch_instruction
patch_instruction() can be called very early on ppc32, when the kernel
isn't yet running at it's linked address. That can cause the !
is_kernel_addr() test in __put_user() to trip and call might_sleep()
which is very bad at that point during boot.

Use a lower level function instead for now, at least until we get to
rework ppc32 boot process to do the code patching later, like ppc64
does.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-05 16:05:23 +10:00
Anton Blanchard 2fae7cdb60 powerpc: Fix VMX in interrupt check in POWER7 copy loops
The enhanced prefetch hint patches corrupt the condition register
that was used to check if we are in interrupt. Fix this by using cr1.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-08-24 20:26:09 +10:00
Anton Blanchard dad477ccd6 powerpc: POWER7 copy_to_user/copy_from_user patch applied twice
"powerpc: Use enhanced touch instructions in POWER7
copy_to_user/copy_from_user" was applied twice. Remove one.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-08-24 20:26:09 +10:00
Stephen Rothwell 1d5a436d2c powerpc: Put the gpr save/restore functions in their own section
This allows the linker to know that calls to them do not need to switch
TOC and stop errors like the following when linking large configurations:

powerpc64-linux-ld: drivers/built-in.o: In function `.gpiochip_is_requested':
(.text+0x4): sibling call optimization to `_savegpr0_29' does not allow automatic multiple TOCs; recompile with -mminimal-toc or -fno-optimize-sibling-calls, or make `_savegpr0_29' extern

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-11 14:19:59 +10:00
Michael Neuling e55174e911 powerpc: Fixes for instructions not using correct register naming
These macros are using integers where they could be using logical
names since they take registers.

We are going to enforce this soon, so fix these up now.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-10 19:18:16 +10:00
Michael Neuling 86e32fdce7 powerpc: Change mtcrf to use real register names
mtocrf define is just a wrapper around the real instructions so we can
just use real register names here (ie. lower case).

Also remove braces in macro so this is possible.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-10 19:18:11 +10:00
Michael Neuling 44ce6a5ee7 powerpc: Merge STK_REG/PARAM/FRAMESIZE
Merge the defines of STACKFRAMESIZE, STK_REG, STK_PARAM from different
places.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-10 19:18:03 +10:00
Michael Neuling c75df6f96c powerpc: Fix usage of register macros getting ready for %r0 change
Anything that uses a constructed instruction (ie. from ppc-opcode.h),
need to use the new R0 macro, as %r0 is not going to work.

Also convert usages of macros where we are just determining an offset
(usually for a load/store), like:
	std	r14,STK_REG(r14)(r1)
Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since
it's just calculating an offset.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-10 19:17:55 +10:00
Anton Blanchard cf8fb5533f powerpc: Optimise the 64bit optimised __clear_user
I blame Mikey for this. He elevated my slightly dubious testcase:

to benchmark status. And naturally we need to be number 1 at creating
zeros. So lets improve __clear_user some more.

As Paul suggests we can use dcbz for large lengths. This patch gets
the destination cacheline aligned then uses dcbz on whole cachelines.

Before:
10485760000 bytes (10 GB) copied, 0.414744 s, 25.3 GB/s

After:
10485760000 bytes (10 GB) copied, 0.268597 s, 39.0 GB/s

39 GB/s, a new record.

Signed-off-by: Anton Blanchard <anton@samba.org>
Tested-by: Olof Johansson <olof@lixom.net>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:48 +10:00
Anton Blanchard b3f271e86e powerpc: POWER7 optimised memcpy using VMX and enhanced prefetch
Implement a POWER7 optimised memcpy using VMX and enhanced prefetch
instructions.

This is a copy of the POWER7 optimised copy_to_user/copy_from_user
loop. Detailed implementation and performance details can be found in
commit a66086b819 (powerpc: POWER7 optimised
copy_to_user/copy_from_user using VMX).

I noticed memcpy issues when profiling a RAID6 workload:

	.memcpy
	.async_memcpy
	.async_copy_data
	.__raid_run_ops
	.handle_stripe
	.raid5d
	.md_thread

I created a simplified testcase by building a RAID6 array with 4 1GB
ramdisks (booting with brd.rd_size=1048576):

# mdadm -CR -e 1.2 /dev/md0 --level=6 -n4 /dev/ram[0-3]

I then timed how long it took to write to the entire array:

# dd if=/dev/zero of=/dev/md0 bs=1M

Before: 892 MB/s
After:  999 MB/s

A 12% improvement.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:46 +10:00
Anton Blanchard bce4b4bd91 powerpc: Use enhanced touch instructions in POWER7 copy_to_user/copy_from_user
Version 2.06 of the POWER ISA introduced enhanced touch instructions,
allowing us to specify a number of attributes including the length of
a stream.

This patch adds a software stream for both loads and stores in the
POWER7 copy_tofrom_user loop. Since the setup is quite complicated
and we have to use an eieio to ensure correct ordering of the "GO"
command we only do this for copies above 4kB.

To quantify any performance improvements we need a working set
bigger than the caches so we operate on a 1GB file:

# dd if=/dev/zero of=/tmp/foo bs=1M count=1024

And we compare how fast we can read the file:

# dd if=/tmp/foo of=/dev/null bs=1M

before: 7.7 GB/s
after:  9.6 GB/s

A 25% improvement.

The worst case for this patch will be a completely L1 cache contained
copy of just over 4kB. We can test this with the copy_to_user
testcase we used to tune copy_tofrom_user originally:

http://ozlabs.org/~anton/junkcode/copy_to_user.c

# time ./copy_to_user2 -l 4224 -i 10000000

before: 6.807 s
after:  6.946 s

A 2% slowdown, which seems reasonable considering our data is unlikely
to be completely L1 contained.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:45 +10:00
Anton Blanchard fde69282b7 powerpc: POWER7 optimised copy_page using VMX and enhanced prefetch
Implement a POWER7 optimised copy_page using VMX and enhanced
prefetch instructions. We use enhanced prefetch hints to prefetch
both the load and store side. We copy a cacheline at a time and
fall back to regular loads and stores if we are unable to use VMX
(eg we are in an interrupt).

The following microbenchmark was used to assess the impact of
the patch:

http://ozlabs.org/~anton/junkcode/page_fault_file.c

We test MAP_PRIVATE page faults across a 1GB file, 100 times:

# time ./page_fault_file -p -l 1G -i 100

Before: 22.25s
After:  18.89s

17% faster

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:44 +10:00
Anton Blanchard 6f7839e542 powerpc: Rename copyuser_power7_vmx.c to vmx-helper.c
Subsequent patches will add more VMX library functions and it makes
sense to keep all the c-code helper functions in the one file.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:43 +10:00
Anton Blanchard a9514dc69d powerpc: Use enhanced touch instructions in POWER7 copy_to_user/copy_from_user
Version 2.06 of the POWER ISA introduced enhanced touch instructions,
allowing us to specify a number of attributes including the length of
a stream.

This patch adds a software stream for both loads and stores in the
POWER7 copy_tofrom_user loop. Since the setup is quite complicated
and we have to use an eieio to ensure correct ordering of the "GO"
command we only do this for copies above 4kB.

To quantify any performance improvements we need a working set
bigger than the caches so we operate on a 1GB file:

# dd if=/dev/zero of=/tmp/foo bs=1M count=1024

And we compare how fast we can read the file:

# dd if=/tmp/foo of=/dev/null bs=1M

before: 7.7 GB/s
after:  9.6 GB/s

A 25% improvement.

The worst case for this patch will be a completely L1 cache contained
copy of just over 4kB. We can test this with the copy_to_user
testcase we used to tune copy_tofrom_user originally:

http://ozlabs.org/~anton/junkcode/copy_to_user.c

# time ./copy_to_user2 -l 4224 -i 10000000

before: 6.807 s
after:  6.946 s

A 2% slowdown, which seems reasonable considering our data is unlikely
to be completely L1 contained.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:42 +10:00
Anton Blanchard 17968fbbd1 powerpc: 64bit optimised __clear_user
I noticed __clear_user high up in a profile of one of my RAID stress
tests. The testcase was doing a dd from /dev/zero which ends up
calling __clear_user.

__clear_user is basically a loop with a single 4 byte store which
is horribly slow. We can do much better by aligning the desination
and doing 32 bytes of 8 byte stores in a loop.

The following testcase was used to verify the patch:

http://ozlabs.org/~anton/junkcode/stress_clear_user.c

To show the improvement in performance I ran a dd from /dev/zero
to /dev/null on a POWER7 box:

Before:

# dd if=/dev/zero of=/dev/null bs=1M count=10000
10485760000 bytes (10 GB) copied, 3.72379 s, 2.8 GB/s

After:

# time dd if=/dev/zero of=/dev/null bs=1M count=10000
10485760000 bytes (10 GB) copied, 0.728318 s, 14.4 GB/s

Over 5x faster.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:41 +10:00
Steven Rostedt b6e3796834 powerpc: Have patch_instruction detect faults
For ftrace to use the patch_instruction code, it needs to check for
faults on write. Ftrace updates code all over the kernel, and we need to
know if code is updated or not due to protections that are placed on
some portions of the kernel. If ftrace does not detect a fault, it will
error later on, and it will be much more difficult to find the problem.

By changing patch_instruction() to detect faults, then ftrace will be
able to make use of it too.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-03 14:14:38 +10:00
Paul Mackerras 1629372caa powerpc: Use the new generic strncpy_from_user() and strnlen_user()
This is much the same as for SPARC except that we can do the find_zero()
function more efficiently using the count-leading-zeroes instructions.
Tested on 32-bit and 64-bit PowerPC.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-27 21:00:07 -07:00
Anton Blanchard 694caf0255 powerpc: Remove CONFIG_POWER4_ONLY
Remove CONFIG_POWER4_ONLY, the option is badly named and only does two
things:

- It wraps the MMU segment table code. With feature fixups there is
  little downside to compiling this in.

- It uses the newer mtocrf instruction in various assembly functions.
  Instead of making this a compile option just do it at runtime via
  a feature fixup.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-30 15:37:26 +10:00
David Howells ae3a197e3d Disintegrate asm/system.h for PowerPC
Disintegrate asm/system.h for PowerPC.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: linuxppc-dev@lists.ozlabs.org
2012-03-28 18:30:02 +01:00
Stephen Rothwell f5339277eb powerpc: Remove FW_FEATURE ISERIES from arch code
This is no longer selectable, so just remove all the dependent code.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-21 11:16:11 +11:00
Anton Blanchard a66086b819 powerpc: POWER7 optimised copy_to_user/copy_from_user using VMX
Implement a POWER7 optimised copy_to_user/copy_from_user using VMX.
For large aligned copies this new loop is over 10% faster, and for
large unaligned copies it is over 200% faster.

If we take a fault we fall back to the old version, this keeps
things relatively simple and easy to verify.

On POWER7 unaligned stores rarely slow down - they only flush when
a store crosses a 4KB page boundary. Furthermore this flush is
handled completely in hardware and should be 20-30 cycles.

Unaligned loads on the other hand flush much more often - whenever
crossing a 128 byte cache line, or a 32 byte sector if either sector
is an L1 miss.

Considering this information we really want to get the loads aligned
and not worry about the alignment of the stores. Microbenchmarks
confirm that this approach is much faster than the current unaligned
copy loop that uses shifts and rotates to ensure both loads and
stores are aligned.

We also want to try and do the stores in cacheline aligned, cacheline
sized chunks. If the store queue is unable to merge an entire
cacheline of stores then the L2 cache will have to do a
read/modify/write. Even worse, we will serialise this with the stores
in the next iteration of the copy loop since both iterations hit
the same cacheline.

Based on this, the new loop does the following things:

1 - 127 bytes
Get the source 8 byte aligned and use 8 byte loads and stores. Pretty
boring and similar to how the current loop works.

128 - 4095 bytes
Get the source 8 byte aligned and use 8 byte loads and stores,
1 cacheline at a time. We aren't doing the stores in cacheline
aligned chunks so we will potentially serialise once per cacheline.
Even so it is much better than the loop we have today.

4096 - bytes
If both source and destination have the same alignment get them both
16 byte aligned, then get the destination cacheline aligned. Do
cacheline sized loads and stores using VMX.

If source and destination do not have the same alignment, we get the
destination cacheline aligned, and use permute to do aligned loads.

In both cases the VMX loop should be optimal - we always do aligned
loads and stores and are always doing stores in cacheline aligned,
cacheline sized chunks.

To be able to use VMX we must be careful about interrupts and
sleeping. We don't use the VMX loop when in an interrupt (which should
be rare anyway) and we wrap the VMX loop in disable/enable_pagefault
and fall back to the existing copy_tofrom_user loop if we do need to
sleep.

The VMX breakpoint of 4096 bytes was chosen using this microbenchmark:

http://ozlabs.org/~anton/junkcode/copy_to_user.c

Since we are using VMX and there is a cost to saving and restoring
the user VMX state there are two broad cases we need to benchmark:

- Best case - userspace never uses VMX

- Worst case - userspace always uses VMX

In reality a userspace process will sit somewhere between these two
extremes. Since we need to test both aligned and unaligned copies we
end up with 4 combinations. The point at which the VMX loop begins to
win is:

0% VMX
aligned		2048 bytes
unaligned	2048 bytes

100% VMX
aligned		16384 bytes
unaligned	8192 bytes

Considering this is a microbenchmark, the data is hot in cache and
the VMX loop has better store queue merging properties we set the
breakpoint to 4096 bytes, a little below the unaligned breakpoints.

Some future optimisations we can look at:

- Looking at the perf data, a significant part of the cost when a
  task is always using VMX is the extra exception we take to restore
  the VMX state. As such we should do something similar to the x86
  optimisation that restores FPU state for heavy users. ie:

        /*
         * If the task has used fpu the last 5 timeslices, just do a full
         * restore of the math state immediately to avoid the trap; the
         * chances of needing FPU soon are obviously high now
         */
        preload_fpu = tsk_used_math(next_p) && next_p->fpu_counter > 5;

  and

        /*
         * fpu_counter contains the number of consecutive context switches
         * that the FPU is used. If this is over a threshold, the lazy fpu
         * saving becomes unlazy to save the trap. This is an unsigned char
         * so that after 256 times the counter wraps and the behavior turns
         * lazy again; this to deal with bursty apps that only use FPU for
         * a short time
         */

- We could create a paca bit to mirror the VMX enabled MSR bit and check
  that first, avoiding multiple calls to calling enable_kernel_altivec.
  That should help with iovec based system calls like readv.

- We could have two VMX breakpoints, one for when we know the user VMX
  state is loaded into the registers and one when it isn't. This could
  be a second bit in the paca so we can calculate the break points quickly.

- One suggestion from Ben was to save and restore the VSX registers
  we use inline instead of using enable_kernel_altivec.

[BenH: Fixed a problem with preempt and fixed build without CONFIG_ALTIVEC]

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-19 14:40:40 +11:00
Anton Blanchard d715e433b7 powerpc: Copy down exception vectors after feature fixups
kdump fails because we try to execute an HV only instruction. Feature
fixups are being applied after we copy the exception vectors down to 0
so they miss out on any updates.

We have always had this issue but it only became critical in v3.0
when we added CFAR support (breaks POWER5) and v3.1 when we added
POWERNV (breaks everyone).

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org> [v3.0+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-16 14:47:54 +11:00
Paul Gortmaker 4b16f8e2d6 powerpc: various straight conversions from module.h --> export.h
All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure.  We can shift them off to the
export.h header which is a way smaller footprint and thus
realize some compile time gains.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:44 -04:00
Linus Torvalds 82aff107f8 Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (152 commits)
  powerpc: Fix hard CPU IDs detection
  powerpc/pmac: Update via-pmu to new syscore_ops
  powerpc/kvm: Fix the build for 32-bit Book 3S (classic) processors
  powerpc/kvm: Fix kvmppc_core_pending_dec
  powerpc: Remove last piece of GEMINI
  powerpc: Fix for Pegasos keyboard and mouse
  powerpc: Make early memory scan more resilient to out of order nodes
  powerpc/pseries/iommu: Cleanup ddw naming
  powerpc/pseries/iommu: Find windows after kexec during boot
  powerpc/pseries/iommu: Remove ddw property when destroying window
  powerpc/pseries/iommu: Add additional checks when changing iommu mask
  powerpc/pseries/iommu: Use correct return type in dupe_ddw_if_already_created
  powerpc: Remove unused/obsolete CONFIG_XICS
  misc: Add CARMA DATA-FPGA Programmer support
  misc: Add CARMA DATA-FPGA Access Driver
  powerpc: Make IRQ_NOREQUEST last to clear, first to set
  powerpc: Integrated Flash controller device tree bindings
  powerpc/85xx: Create dts of each core in CAMP mode for P1020RDB
  powerpc/85xx: Fix PCIe IDSEL for Px020RDB
  powerpc/85xx: P2020 DTS: re-organize dts files
  ...
2011-05-20 13:28:01 -07:00
Linus Torvalds 268bb0ce3e sanitize <linux/prefetch.h> usage
Commit e66eed651f ("list: remove prefetching from regular list
iterators") removed the include of prefetch.h from list.h, which
uncovered several cases that had apparently relied on that rather
obscure header file dependency.

So this fixes things up a bit, using

   grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
   grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')

to guide us in finding files that either need <linux/prefetch.h>
inclusion, or have it despite not needing it.

There are more of them around (mostly network drivers), but this gets
many core ones.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-20 12:50:29 -07:00
Milton Miller a56555e573 powerpc: Remove alloc_maybe_bootmem for zalloc version
Replace all remaining callers of alloc_maybe_bootmem with
zalloc_maybe_bootmem.   The callsite in pci_dn is followed with a
memset to clear the memory, and not zeroing at the other callsites
in the celleb fake pci code could lead to following uninitialized
memory as pointers or even freeing said pointers on error paths.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-19 15:30:57 +10:00
Anton Blanchard 40f1ce7fb7 powerpc: Remove ioremap_flags
We have a confusing number of ioremap functions. Make things just a
bit simpler by merging ioremap_flags and ioremap_prot.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-19 14:30:43 +10:00
Anton Blanchard d988f0e3f8 powerpc: Simplify 4k/64k copy_page logic
To make it easier to add optimised versions of copy_page, remove
the 4kB loop for 64kB pages and just do all the work in copy_page.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-19 14:30:42 +10:00
Michael Ellerman b91e136cdf powerpc: Use MSR_64BIT in sstep.c, fix kprobes on BOOK3E
We check MSR_SF a lot in sstep.c, to decide if we need to emulate the
truncation of values when running in 32-bit mode. Factor out that code
into a helper, and convert it and the other uses to use MSR_64BIT.

This fixes a bug on BOOK3E where kprobes would end up returning to a
32-bit address, because regs->nip was truncated, because (msr & MSR_SF)
was false.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-27 14:18:46 +10:00
Michael Ellerman c0337288ab powerpc: Ensure the else case of feature sections will fit
When we create an alternative feature section, the else case must be the
same size or smaller than the body. This is because when we patch the
else case in we just overwrite the body, so there must be room.

Up to now we just did this by inspection, but it's quite easy to enforce
it in the assembler, so we should.

The only change is to add the ifgt block, but that effects the alignment
of the tabs and so the whole macro is modified.

Also add a test, but #if 0 it because we don't want to break the build.
Anyone who's modifying the feature macros should enable the test.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:33 +11:00
Anton Blanchard b5f9b6665b powerpc: Hardcode popcnt instructions for old assemblers
The popcnt instructions went into binutils relatively recently. As with a
number of other instructions, create macros and hardcode them.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-12-09 15:35:30 +11:00
Anton Blanchard 64ff312876 powerpc: Add support for popcnt instructions
POWER5 added popcntb, and POWER7 added popcntw and popcntd. As a first step
this patch does all the work out of line, but it would be nice to implement
them as inlines with an out of line fallback.

The performance issue with hweight was noticed when disabling SMT on a large
(192 thread) POWER7 box. The patch improves that testcase by about 8%.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-11-29 15:48:17 +11:00
matt mooney 4108d9ba90 powerpc/Makefiles: Change to new flag variables
Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-10-13 16:19:22 +11:00
Sean MacLennan cd64d1697c powerpc: mtmsrd not defined
Replace the BOOK3S_64 specific mtmsrd with the generic MTMSRD macro.
Only enable ldstfp when CONFIG_PPC_FPU is set.

Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-09-02 14:07:34 +10:00
Sean MacLennan 025c0186a0 powerpc: Fix incorrect .stabs entry for copy_32.S
Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-09-02 14:07:34 +10:00
Paul Mackerras 8154c5d22d powerpc: Abstract indexing of lppaca structs
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: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-09-02 14:07:31 +10:00
Anton Blanchard 8c77391475 powerpc: Add 64bit csum_and_copy_to_user
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: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-09-02 14:07:30 +10:00
Anton Blanchard fdd374b62c powerpc: Optimise 64bit csum_partial_copy_generic and add csum_and_copy_from_user
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: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-09-02 14:07:30 +10:00
Anton Blanchard 9b83ecb0a3 powerpc: Optimise 64bit csum_partial
The main loop of csum_partial runs very slowly on recent POWER CPUs. After some
analysis on both POWER6 and POWER7 I came up with routine below. First we get
the source aligned to a double word, ignoring any odd alignment to keep things
simple. Then we do 64 bytes at a time, with an entry and exit limb of a further
64 bytes. On both POWER6 and POWER7 this should be as fast as we can go since
we are limited by the latency of the adde instructions.

To test this I forced checksumming on over loopback and ran socklib (a
simple TCP benchmark). On a POWER6 575 throughput improved by 11% with
this patch.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-09-02 14:07:29 +10:00
Benjamin Herrenschmidt 5f07aa7524 Merge commit 'paulus-perf/master' into next 2010-07-09 11:25:48 +10:00
Stephen Rothwell 3880ecb05b powerpc: Fix feature-fixup tests for gcc 4.5
The feature-fixup test declare some extern void variables and then take
their addresses.  Fix this by declaring them as extern u8 instead.

Fixes these warnings (treated as errors):

  CC      arch/powerpc/lib/feature-fixups.o
cc1: warnings being treated as errors
arch/powerpc/lib/feature-fixups.c: In function 'test_cpu_macros':
arch/powerpc/lib/feature-fixups.c:293:23: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:294:9: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:297:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:297:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c: In function 'test_fw_macros':
arch/powerpc/lib/feature-fixups.c:306:23: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:307:9: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:310:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:310:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c: In function 'test_lwsync_macros':
arch/powerpc/lib/feature-fixups.c:321:23: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:322:9: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:326:3: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:326:3: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:329:3: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:329:3: error: taking address of expression of type 'void'

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-07-08 18:11:41 +10:00
Stephen Rothwell 7fca5dc8aa powerpc: Fix module building for gcc 4.5 and 64 bit
Gcc 4.5 is now generating out of line register save and restore
in the function prefix and postfix when we use -Os.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-07-08 18:11:38 +10:00
K.Prasad 5aae8a5370 powerpc, hw_breakpoints: Implement hw_breakpoints for 64-bit server processors
Implement perf-events based hw-breakpoint interfaces for PowerPC
64-bit server (Book III S) processors.  This allows access to a
given location to be used as an event that can be counted or
profiled by the perf_events subsystem.

This is done using the DABR (data breakpoint register), which can
also be used for process debugging via ptrace.  When perf_event
hw_breakpoint support is configured in, the perf_event subsystem
manages the DABR and arbitrates access to it, and ptrace then
creates a perf_event when it is requested to set a data breakpoint.

[Adopted suggestions from Paul Mackerras <paulus@samba.org> to
- emulate_step() all system-wide breakpoints and single-step only the
  per-task breakpoints
- perform arch-specific cleanup before unregistration through
  arch_unregister_hw_breakpoint()
]

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2010-06-22 19:40:50 +10:00
Paul Mackerras 0016a4cf55 powerpc: Emulate most Book I instructions in emulate_step()
This extends the emulate_step() function to handle a large proportion
of the Book I instructions implemented on current 64-bit server
processors.  The aim is to handle all the load and store instructions
used in the kernel, plus all of the instructions that appear between
l[wd]arx and st[wd]cx., so this handles the Altivec/VMX lvx and stvx
and the VSX lxv2dx and stxv2dx instructions (implemented in POWER7).

The new code can emulate user mode instructions, and checks the
effective address for a load or store if the saved state is for
user mode.  It doesn't handle little-endian mode at present.

For floating-point, Altivec/VMX and VSX instructions, it checks
that the saved MSR has the enable bit for the relevant facility
set, and if so, assumes that the FP/VMX/VSX registers contain
valid state, and does loads or stores directly to/from the
FP/VMX/VSX registers, using assembly helpers in ldstfp.S.

Instructions supported now include:
* Loads and stores, including some but not all VMX and VSX instructions,
  and lmw/stmw
* Atomic loads and stores (l[dw]arx, st[dw]cx.)
* Arithmetic instructions (add, subtract, multiply, divide, etc.)
* Compare instructions
* Rotate and mask instructions
* Shift instructions
* Logical instructions (and, or, xor, etc.)
* Condition register logical instructions
* mtcrf, cntlz[wd], exts[bhw]
* isync, sync, lwsync, ptesync, eieio
* Cache operations (dcbf, dcbst, dcbt, dcbtst)

The overflow-checking arithmetic instructions are not included, but
they appear not to be ever used in C code.

This uses decimal values for the minor opcodes in the switch statements
because that is what appears in the Power ISA specification, thus it is
easier to check that they are correct if they are in decimal.

If this is used to single-step an instruction where a data breakpoint
interrupt occurred, then there is the possibility that the instruction
is a lwarx or ldarx.  In that case we have to be careful not to lose the
reservation until we get to the matching st[wd]cx., or we'll never make
forward progress.  One alternative is to try to arrange that we can
return from interrupts and handle data breakpoint interrupts without
losing the reservation, which means not using any spinlocks, mutexes,
or atomic ops (including bitops).  That seems rather fragile.  The
other alternative is to emulate the larx/stcx and all the instructions
in between.  This is why this commit adds support for a wide range
of integer instructions.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2010-06-22 19:40:29 +10:00