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path: root/arch/powerpc/platforms/powernv/rng.c
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2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-23powerpc: Convert to using %pOF instead of full_nameRob Herring
Now that we have a custom printf format specifier, convert users of full_name to use %pOF instead. This is preparation to remove storing of the full path string for each node. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Anatolij Gustschin <agust@denx.de> Cc: Scott Wood <oss@buserror.net> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linuxppc-dev@lists.ozlabs.org Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-08powerpc/powernv: Use darn instruction for get_random_seed() on Power9Matt Brown
This adds powernv_get_random_darn() which utilises the darn instruction, introduced in ISA v3.0/POWER9. The darn instruction can potentially return an error, which is supported by the get_random_seed() API, in normal usage if we see an error we just return that to the caller. However when detecting whether darn is functional at boot we try up to 10 times, before deciding that darn doesn't work and failing the registration of get_random_seed(). That way an intermittent failure at boot doesn't deprive the system of randomness until the next reboot. Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com> [mpe: Move init into a function, tweak change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-10powerpc: Consolidate variants of real-mode MMIOsBenjamin Herrenschmidt
We have all sort of variants of MMIO accessors for the real mode instructions. This creates a clean set of accessors based on Linux normal naming conventions, replacing all occurrences of the old ones in the tree. I have purposefully removed the "out/in" variants in favor of only including __raw variants. Any code using these is already pretty much hand tuned to operate in a very specific environment. I've fixed up the 2 users (only one of them actually needed a barrier in the first place). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-07-23powerpc: Use hardware RNG for arch_get_random_seed_* not arch_get_random_*Paul Mackerras
The hardware RNG on POWER8 and POWER7+ can be relatively slow, since it can only supply one 64-bit value per microsecond. Currently we read it in arch_get_random_long(), but that slows down reading from /dev/urandom since the code in random.c calls arch_get_random_long() for every longword read from /dev/urandom. Since the hardware RNG supplies high-quality entropy on every read, it matches the semantics of arch_get_random_seed_long() better than those of arch_get_random_long(). Therefore this commit makes the code use the POWER8/7+ hardware RNG only for arch_get_random_seed_{long,int} and not for arch_get_random_{long,int}. This won't affect any other PowerPC-based platforms because none of them currently support a hardware RNG. To make it clear that the ppc_md function pointer is used for arch_get_random_seed_*, we rename it from get_random_long to get_random_seed. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-04-21KVM: PPC: Book3S HV: Add fast real-mode H_RANDOM implementation.Michael Ellerman
Some PowerNV systems include a hardware random-number generator. This HWRNG is present on POWER7+ and POWER8 chips and is capable of generating one 64-bit random number every microsecond. The random numbers are produced by sampling a set of 64 unstable high-frequency oscillators and are almost completely entropic. PAPR defines an H_RANDOM hypercall which guests can use to obtain one 64-bit random sample from the HWRNG. This adds a real-mode implementation of the H_RANDOM hypercall. This hypercall was implemented in real mode because the latency of reading the HWRNG is generally small compared to the latency of a guest exit and entry for all the threads in the same virtual core. Userspace can detect the presence of the HWRNG and the H_RANDOM implementation by querying the KVM_CAP_PPC_HWRNG capability. The H_RANDOM hypercall implementation will only be invoked when the guest does an H_RANDOM hypercall if userspace first enables the in-kernel H_RANDOM implementation using the KVM_CAP_PPC_ENABLE_HCALL capability. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28powerpc/powernv: Switch powernv drivers to use machine_xxx_initcall()Michael Ellerman
A lot of the code in platforms/powernv is using non-machine initcalls. That means if a kernel built with powernv support runs on another platform, for example pseries, the initcalls will still run. That is usually OK, because the initcalls will check for something in the device tree or elsewhere before doing anything, so on other platforms they will usually just return. But it's fishy for powernv code to be running on other platforms, so switch them all to be machine initcalls. If we want any of them to run on other platforms in future they should move to sysdev. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-11-21powerpc: Make cpu_to_chip_id() available when SMP=nMichael Ellerman
Up until now we have only used cpu_to_chip_id() in the topology code, which is only used on SMP builds. However my recent commit a4da0d5 "Implement arch_get_random_long/int() for powernv" added a usage when SMP=n, breaking the build. Move cpu_to_chip_id() into prom.c so it is available for SMP=n builds. We would move the extern to prom.h, but that breaks the include in topology.h. Instead we leave it in smp.h, but move it out of the CONFIG_SMP #ifdef. We also need to include asm/smp.h in rng.c, because the linux version skips asm/smp.h on UP. What a mess. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-30powerpc: Add includes to fix powernv/rng.c buildStephen Rothwell
Caused by commit a4da0d50b2a0 ("powerpc: Implement arch_get_random_long/int() for powernv") from the powerpc tree interacting with commit b5b4bb3f6a11 ("of: only include prom.h on sparc") from the dt-rh tree. I added this merge fix patch (which will need to be sent to Linus when these two trees get merged, or could be applied now to the powerpc tree): [ Also add linux/smp.h to get cpu_to_chip_id -- BenH ] Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11powerpc: Implement arch_get_random_long/int() for powernvMichael Ellerman
Add the plumbing to implement arch_get_random_long/int(). It didn't seem worth adding an extra ppc_md hook for int, so we reuse the one for long. Add an implementation for powernv based on the hwrng found in power7+ systems. We whiten the output of the hwrng, and the result passes all the dieharder tests. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>