kernel/linux.git/arch/powerpc/lib/Makefile, branch linux-5.9.y

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-04T17:09:05+00:00

commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Acked-by: Michael Ellerman Cc: Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman

Revert "x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()"

2020-11-04T17:08:28+00:00

This reverts commit a85748ed9eb70108f9605558f2754ca94ee91401 which is commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. We had a mistake when merging a later patch in this series due to some file movements, so revert this change for now, as we will add it back in a later commit. Signed-off-by: Greg Kroah-Hartman

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-01T11:47:03+00:00

powerpc/64s: Implement queued spinlocks and rwlocks

2020-07-26T14:01:23+00:00

These have shown significantly improved performance and fairness when spinlock contention is moderate to high on very large systems. With this series including subsequent patches, on a 16 socket 1536 thread POWER9, a stress test such as same-file open/close from all CPUs gets big speedups, 11620op/s aggregate with simple spinlocks vs 384158op/s (33x faster), where the difference in throughput between the fastest and slowest thread goes from 7x to 1.4x. Thanks to the fast path being identical in terms of atomics and barriers (after a subsequent optimisation patch), single threaded performance is not changed (no measurable difference). On smaller systems, performance and fairness seems to be generally improved. Using dbench on tmpfs as a test (that starts to run into kernel spinlock contention), a 2-socket OpenPOWER POWER9 system was tested with bare metal and KVM guest configurations. Results can be found here: https://github.com/linuxppc/issues/issues/305#issuecomment-663487453 Observations are: - Queued spinlocks are equal when contention is insignificant, as expected and as measured with microbenchmarks. - When there is contention, on bare metal queued spinlocks have better throughput and max latency at all points. - When virtualised, queued spinlocks are slightly worse approaching peak throughput, but significantly better throughput and max latency at all points beyond peak, until queued spinlock maximum latency rises when clients are 2x vCPUs. The regressions haven't been analysed very well yet, there are a lot of things that can be tuned, particularly the paravirtualised locking, but the numbers already look like a good net win even on relatively small systems. Signed-off-by: Nicholas Piggin Acked-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200724131423.1362108-4-npiggin@gmail.com

powerpc: Test prefixed code patching

2020-05-18T14:11:02+00:00

Expand the code-patching self-tests to includes tests for patching prefixed instructions. Signed-off-by: Jordan Niethe [mpe: Use CONFIG_PPC64 not __powerpc64__] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-25-jniethe5@gmail.com

powerpc: Add a probe_user_read_inst() function

2020-05-18T14:10:37+00:00

Introduce a probe_user_read_inst() function to use in cases where probe_user_read() is used for getting an instruction. This will be more useful for prefixed instructions. Signed-off-by: Jordan Niethe Reviewed-by: Alistair Popple [mpe: Don't write to *inst on error, fold in __user annotations] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-14-jniethe5@gmail.com

powerpc/memcpy: Add memcpy_mcsafe for pmem

2019-08-21T12:23:48+00:00

The pmem infrastructure uses memcpy_mcsafe in the pmem layer so as to convert machine check exceptions into a return value on failure in case a machine check exception is encountered during the memcpy. The return value is the number of bytes remaining to be copied. This patch largely borrows from the copyuser_power7 logic and does not add the VMX optimizations, largely to keep the patch simple. If needed those optimizations can be folded in. Signed-off-by: Balbir Singh [arbab@linux.ibm.com: Added symbol export] Co-developed-by: Santosh Sivaraj Signed-off-by: Santosh Sivaraj Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190820081352.8641-7-santosh@fossix.org

powerpc/32: activate ARCH_HAS_PMEM_API and ARCH_HAS_UACCESS_FLUSHCACHE

2019-08-05T08:53:04+00:00

PPC32 also have flush_dcache_range() so it can also support ARCH_HAS_PMEM_API and ARCH_HAS_UACCESS_FLUSHCACHE without changes. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/a682a2f9db308c5cfe77e45aa3352e41bc9f4e33.1564554634.git.christophe.leroy@c-s.fr

powerpc/lib: only build ldstfp.o when CONFIG_PPC_FPU is set

2019-05-28T02:08:11+00:00

The entire code in ldstfp.o is enclosed into #ifdef CONFIG_PPC_FPU, so there is no point in building it when this config is not selected. Fixes: cd64d1697cf0 ("powerpc: mtmsrd not defined") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc/lib: fix redundant inclusion of quad.o

2019-05-28T02:08:11+00:00

quad.o is only for PPC64, and already included in obj64-y, so it doesn't have to be in obj-y Fixes: 31bfdb036f12 ("powerpc: Use instruction emulation infrastructure to handle alignment faults") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman