linux_dsm_epyc7002/arch/powerpc
Paul Mackerras 01c9348c76 powerpc: Use hardware RNG for arch_get_random_seed_* not arch_get_random_*
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>
2015-07-23 19:52:03 +10:00
..
boot Devicetree changes for v4.2 2015-07-01 19:40:18 -07:00
configs Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into next 2015-06-19 17:23:48 +10:00
crypto crypto: powerpc/md5 - use md5 IV MD5_HX instead of their raw value 2015-05-18 12:20:20 +08:00
include powerpc: Use hardware RNG for arch_get_random_seed_* not arch_get_random_* 2015-07-23 19:52:03 +10:00
kernel powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers 2015-07-23 19:43:11 +10:00
kvm The bulk of the changes here is for x86. And for once it's not 2015-06-24 09:36:49 -07:00
lib powerpc updates for 4.2 2015-06-24 08:46:32 -07:00
math-emu powerpc: Correct emulated mtfsf instruction 2014-04-07 10:33:11 +10:00
mm powerpc: Add plain English description for alignment exception oopses 2015-07-06 20:24:35 +10:00
net ppc: bpf: Add SKF_AD_CPU for ppc32 2015-02-20 15:19:43 -05:00
oprofile powerpc: Remove mtmsrd(), use existing mtmsr() 2015-07-13 15:47:28 +10:00
perf powerpc/perf/24x7: Fix lockdep warning 2015-07-08 15:18:04 +10:00
platforms powerpc: Use hardware RNG for arch_get_random_seed_* not arch_get_random_* 2015-07-23 19:52:03 +10:00
sysdev powerpc/iommu: Cleanup setting of DMA base/offset 2015-07-13 10:10:55 +10:00
xmon powerpc updates for 3.20 2015-02-11 18:15:38 -08:00
Kconfig powerpc/iommu: Support "hybrid" iommu/direct DMA ops for coherent_mask < dma_mask 2015-07-13 10:10:55 +10:00
Kconfig.debug powerpc: Make STRICT_MM_TYPECHECKS a config option 2015-05-11 19:53:59 +10:00
Makefile powerpc: Don't use gcc specific options on clang 2015-06-11 17:33:05 +10:00
relocs_check.sh powerpc: Convert relocs_check to a shell script using grep 2015-03-23 14:47:39 +11:00