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2014-01-15powerpc: Add vr save/restore functionsAndreas Schwab
GCC 4.8 now generates out-of-line vr save/restore functions when optimizing for size. They are needed for the raid6 altivec support. Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-30Merge branch 'merge' into nextBenjamin Herrenschmidt
Merge a pile of fixes that went into the "merge" branch (3.13-rc's) such as Anton Little Endian fixes. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-30powerpc: Make 64-bit non-VMX __copy_tofrom_user bi-endianPaul E. McKenney
The powerpc 64-bit __copy_tofrom_user() function uses shifts to handle unaligned invocations. However, these shifts were designed for big-endian systems: On little-endian systems, they must shift in the opposite direction. This commit relies on the C preprocessor to insert the correct shifts into the assembly code. [ This is a rare but nasty LE issue. Most of the time we use the POWER7 optimised __copy_tofrom_user_power7 loop, but when it hits an exception we fall back to the base __copy_tofrom_user loop. - Anton ] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-02powerpc: Move the patch_exception to a common placeKevin Hao
So that it can be used by other codes. No function change. Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-30powerpc: Add VMX optimised xor for RAID5Anton Blanchard
Add a VMX optimised xor, used primarily for RAID5. On a POWER7 blade this is a decent win: 32regs : 17932.800 MB/sec altivec : 19724.800 MB/sec The bigger gain is when the same test is run in SMT4 mode, as it would if there was a lot of work going on: 8regs : 8377.600 MB/sec altivec : 15801.600 MB/sec I tested this against an array created without the patch, and also verified it worked as expected on a little endian kernel. [ Fix !CONFIG_ALTIVEC build -- BenH ] Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-30powerpc: Fix Unaligned LE Floating Point Loads and StoresTom Musta
This patch addresses unaligned single precision floating point loads and stores in the single-step code. The old implementation improperly treated an 8 byte structure as an array of two 4 byte words, which is a classic little endian bug. Signed-off-by: Tom Musta <tmusta@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-30powerpc: Fix Unaligned Loads and StoresTom Musta
This patch modifies the unaligned access routines of the sstep.c module so that it properly reverses the bytes of storage operands in the little endian kernel kernel. This is implemented by breaking an unaligned little endian access into a combination of single byte accesses plus an overal byte reversal operation. Signed-off-by: Tom Musta <tmusta@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11powerpc: Use generic memcpy code in little endianAnton Blanchard
We need to fix some endian issues in our memcpy code. For now just enable the generic memcpy routine for little endian builds. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11powerpc: Use generic checksum code in little endianAnton Blanchard
We need to fix some endian issues in our checksum code. For now just enable the generic checksum routines for little endian builds. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11powerpc: Fix endian issues in VMX copy loopsAnton Blanchard
Fix the permute loops for little endian. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-03powerpc: Restore registers on error exit from csum_partial_copy_generic()Paul E. McKenney
The csum_partial_copy_generic() function saves the PowerPC non-volatile r14, r15, and r16 registers for the main checksum-and-copy loop. Unfortunately, it fails to restore them upon error exit from this loop, which results in silent corruption of these registers in the presumably rare event of an access exception within that loop. This commit therefore restores these register on error exit from the loop. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Anton Blanchard <anton@samba.org> Cc: stable@vger.kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-03powerpc: Fix parameter clobber in csum_partial_copy_generic()Paul E. McKenney
The csum_partial_copy_generic() uses register r7 to adjust the remaining bytes to process. Unfortunately, r7 also holds a parameter, namely the address of the flag to set in case of access exceptions while reading the source buffer. Lacking a quantum implementation of PowerPC, this commit instead uses register r9 to do the adjusting, leaving r7's pointer uncorrupted. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Anton Blanchard <anton@samba.org> Cc: stable@vger.kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-09-25powerpc: Remove ksp_limit on ppc64Benjamin Herrenschmidt
We've been keeping that field in thread_struct for a while, it contains the "limit" of the current stack pointer and is meant to be used for detecting stack overflows. It has a few problems however: - First, it was never actually *used* on 64-bit. Set and updated but not actually exploited - When switching stack to/from irq and softirq stacks, it's update is racy unless we hard disable interrupts, which is costly. This is fine on 32-bit as we don't soft-disable there but not on 64-bit. Thus rather than fixing 2 in order to implement 1 in some hypothetical future, let's remove the code completely from 64-bit. In order to avoid a clutter of ifdef's, we remove the updates from C code completely during interrupt stack switching, and instead maintain it from the asm helper that is used to do the stack switching in the first place. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-27powerpc: Unaligned stores and stmw are broken in emulation codeTom Musta
The stmw instruction was incorrectly decoded as an update form instruction and thus the RA register was being clobbered. Also, the utility routine to write memory to unaligned addresses breaks the operation into smaller aligned accesses but was incorrectly incrementing the address by only one; it needs to increment the address by the size of the smaller aligned chunk. Signed-off-by: Tom Musta <tmusta@us.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-14powerpc: Fix little endian lppaca, slb_shadow and dtl_entryAnton Blanchard
The lppaca, slb_shadow and dtl_entry hypervisor structures are big endian, so we have to byte swap them in little endian builds. LE KVM hosts will also need to be fixed but for now add an #error to remind us. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20powerpc: Fix single step emulation of 32bit overflowed branchesMichael Neuling
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>
2013-06-01powerpc/pseries: Improve stream generation comments in copypage/userMichael Neuling
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>
2013-01-29uprobes/powerpc: Add dependency on single step emulationSuzuki K. Poulose
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>
2013-01-10powerpc: Build kernel with -mcmodel=mediumAnton Blanchard
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>
2012-10-04powerpc: Fix VMX fix for memcpy caseNishanth Aravamudan
In 2fae7cdb60240e2e2d9b378afbf6d9fcce8a3890 ("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]
2012-09-18powerpc/kprobe: Don't emulate store when kprobe stwu r1Tiejun Chen
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>
2012-09-05powerpc: Don't use __put_user() in patch_instructionBenjamin Herrenschmidt
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>
2012-08-24powerpc: Fix VMX in interrupt check in POWER7 copy loopsAnton Blanchard
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>
2012-08-24powerpc: POWER7 copy_to_user/copy_from_user patch applied twiceAnton Blanchard
"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>
2012-07-11powerpc: Put the gpr save/restore functions in their own sectionStephen Rothwell
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>
2012-07-10powerpc: Fixes for instructions not using correct register namingMichael Neuling
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>
2012-07-10powerpc: Change mtcrf to use real register namesMichael Neuling
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>
2012-07-10powerpc: Merge STK_REG/PARAM/FRAMESIZEMichael Neuling
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>
2012-07-10powerpc: Fix usage of register macros getting ready for %r0 changeMichael Neuling
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>
2012-07-03powerpc: Optimise the 64bit optimised __clear_userAnton Blanchard
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>
2012-07-03powerpc: POWER7 optimised memcpy using VMX and enhanced prefetchAnton Blanchard
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 a66086b8197d (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>
2012-07-03powerpc: Use enhanced touch instructions in POWER7 copy_to_user/copy_from_userAnton Blanchard
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>
2012-07-03powerpc: POWER7 optimised copy_page using VMX and enhanced prefetchAnton Blanchard
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>
2012-07-03powerpc: Rename copyuser_power7_vmx.c to vmx-helper.cAnton Blanchard
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>
2012-07-03powerpc: Use enhanced touch instructions in POWER7 copy_to_user/copy_from_userAnton Blanchard
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>
2012-07-03powerpc: 64bit optimised __clear_userAnton Blanchard
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>
2012-07-03powerpc: Have patch_instruction detect faultsSteven Rostedt
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>
2012-05-27powerpc: Use the new generic strncpy_from_user() and strnlen_user()Paul Mackerras
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>
2012-04-30powerpc: Remove CONFIG_POWER4_ONLYAnton Blanchard
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>
2012-03-28Disintegrate asm/system.h for PowerPCDavid Howells
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
2012-03-21powerpc: Remove FW_FEATURE ISERIES from arch codeStephen Rothwell
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>
2011-12-19powerpc: POWER7 optimised copy_to_user/copy_from_user using VMXAnton Blanchard
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>
2011-11-16powerpc: Copy down exception vectors after feature fixupsAnton Blanchard
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>
2011-10-31powerpc: various straight conversions from module.h --> export.hPaul Gortmaker
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>
2011-05-20Merge branch 'merge' of ↵Linus Torvalds
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 ...
2011-05-20sanitize <linux/prefetch.h> usageLinus Torvalds
Commit e66eed651fd1 ("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>
2011-05-19powerpc: Remove alloc_maybe_bootmem for zalloc versionMilton Miller
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>
2011-05-19powerpc: Remove ioremap_flagsAnton Blanchard
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>
2011-05-19powerpc: Simplify 4k/64k copy_page logicAnton Blanchard
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>
2011-04-27powerpc: Use MSR_64BIT in sstep.c, fix kprobes on BOOK3EMichael Ellerman
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>
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