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authorHarald Freudenberger <freude@linux.vnet.ibm.com>2017-03-17 10:46:31 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-04-26 13:41:35 +0200
commit4c637cd8de43416c1b1eef6113e7aa06abacf18d (patch)
tree6609483d58b446c515a94b70e91cc55e7fc481a0 /arch/s390
parentf75fa65d70e2423a03c1b7391bfca410d554b1c5 (diff)
downloadlinux-4c637cd8de43416c1b1eef6113e7aa06abacf18d.tar.bz2
s390/crypto: Provide s390 specific arch random functionality.
This patch introduces s390 specific arch random functionality. There exists a generic kernel API for arch specific random number implementation (see include/linux/random.h). Here comes the header file and a very small static code part implementing the arch_random_* API based on the TRNG subfunction coming with the reworked PRNG instruction. The arch random implementation hooks into the kernel initialization and checks for availability of the TRNG function. In accordance to the arch random API all functions return false if the TRNG is not available. Otherwise the new high quality entropy source provides fresh random on each invocation. The s390 arch random feature build is controlled via CONFIG_ARCH_RANDOM. This config option located in arch/s390/Kconfig is enabled by default and appears as entry "s390 architectural random number generation API" in the submenu "Processor type and features" for s390 builds. Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/Kbuild2
-rw-r--r--arch/s390/Kconfig15
-rw-r--r--arch/s390/crypto/Makefile1
-rw-r--r--arch/s390/crypto/arch_random.c31
-rw-r--r--arch/s390/include/asm/archrandom.h69
5 files changed, 117 insertions, 1 deletions
diff --git a/arch/s390/Kbuild b/arch/s390/Kbuild
index e256592eb66e..eae2c64cf69d 100644
--- a/arch/s390/Kbuild
+++ b/arch/s390/Kbuild
@@ -1,7 +1,7 @@
obj-y += kernel/
obj-y += mm/
obj-$(CONFIG_KVM) += kvm/
-obj-$(CONFIG_CRYPTO_HW) += crypto/
+obj-y += crypto/
obj-$(CONFIG_S390_HYPFS_FS) += hypfs/
obj-$(CONFIG_APPLDATA_BASE) += appldata/
obj-y += net/
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 249c2771be0e..ebc0bf7c84d0 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -507,6 +507,21 @@ source kernel/Kconfig.preempt
source kernel/Kconfig.hz
+config ARCH_RANDOM
+ def_bool y
+ prompt "s390 architectural random number generation API"
+ help
+ Enable the s390 architectural random number generation API
+ to provide random data for all consumers within the Linux
+ kernel.
+
+ When enabled the arch_random_* functions declared in linux/random.h
+ are implemented. The implementation is based on the s390 CPACF
+ instruction subfunction TRNG which provides a real true random
+ number generator.
+
+ If unsure, say Y.
+
endmenu
menu "Memory setup"
diff --git a/arch/s390/crypto/Makefile b/arch/s390/crypto/Makefile
index 402c530c6da5..678d9863e3f0 100644
--- a/arch/s390/crypto/Makefile
+++ b/arch/s390/crypto/Makefile
@@ -10,5 +10,6 @@ obj-$(CONFIG_CRYPTO_AES_S390) += aes_s390.o paes_s390.o
obj-$(CONFIG_S390_PRNG) += prng.o
obj-$(CONFIG_CRYPTO_GHASH_S390) += ghash_s390.o
obj-$(CONFIG_CRYPTO_CRC32_S390) += crc32-vx_s390.o
+obj-$(CONFIG_ARCH_RANDOM) += arch_random.o
crc32-vx_s390-y := crc32-vx.o crc32le-vx.o crc32be-vx.o
diff --git a/arch/s390/crypto/arch_random.c b/arch/s390/crypto/arch_random.c
new file mode 100644
index 000000000000..9317b3e645e2
--- /dev/null
+++ b/arch/s390/crypto/arch_random.c
@@ -0,0 +1,31 @@
+/*
+ * s390 arch random implementation.
+ *
+ * Copyright IBM Corp. 2017
+ * Author(s): Harald Freudenberger <freude@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/atomic.h>
+#include <linux/static_key.h>
+#include <asm/cpacf.h>
+
+DEFINE_STATIC_KEY_FALSE(s390_arch_random_available);
+
+atomic64_t s390_arch_random_counter = ATOMIC64_INIT(0);
+EXPORT_SYMBOL(s390_arch_random_counter);
+
+static int __init s390_arch_random_init(void)
+{
+ /* check if subfunction CPACF_PRNO_TRNG is available */
+ if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
+ static_branch_enable(&s390_arch_random_available);
+
+ return 0;
+}
+arch_initcall(s390_arch_random_init);
diff --git a/arch/s390/include/asm/archrandom.h b/arch/s390/include/asm/archrandom.h
new file mode 100644
index 000000000000..6033901a40b2
--- /dev/null
+++ b/arch/s390/include/asm/archrandom.h
@@ -0,0 +1,69 @@
+/*
+ * Kernel interface for the s390 arch_random_* functions
+ *
+ * Copyright IBM Corp. 2017
+ *
+ * Author: Harald Freudenberger <freude@de.ibm.com>
+ *
+ */
+
+#ifndef _ASM_S390_ARCHRANDOM_H
+#define _ASM_S390_ARCHRANDOM_H
+
+#ifdef CONFIG_ARCH_RANDOM
+
+#include <linux/static_key.h>
+#include <linux/atomic.h>
+#include <asm/cpacf.h>
+
+DECLARE_STATIC_KEY_FALSE(s390_arch_random_available);
+extern atomic64_t s390_arch_random_counter;
+
+static void s390_arch_random_generate(u8 *buf, unsigned int nbytes)
+{
+ cpacf_trng(NULL, 0, buf, nbytes);
+ atomic64_add(nbytes, &s390_arch_random_counter);
+}
+
+static inline bool arch_has_random(void)
+{
+ if (static_branch_likely(&s390_arch_random_available))
+ return true;
+ return false;
+}
+
+static inline bool arch_has_random_seed(void)
+{
+ return arch_has_random();
+}
+
+static inline bool arch_get_random_long(unsigned long *v)
+{
+ if (static_branch_likely(&s390_arch_random_available)) {
+ s390_arch_random_generate((u8 *)v, sizeof(*v));
+ return true;
+ }
+ return false;
+}
+
+static inline bool arch_get_random_int(unsigned int *v)
+{
+ if (static_branch_likely(&s390_arch_random_available)) {
+ s390_arch_random_generate((u8 *)v, sizeof(*v));
+ return true;
+ }
+ return false;
+}
+
+static inline bool arch_get_random_seed_long(unsigned long *v)
+{
+ return arch_get_random_long(v);
+}
+
+static inline bool arch_get_random_seed_int(unsigned int *v)
+{
+ return arch_get_random_int(v);
+}
+
+#endif /* CONFIG_ARCH_RANDOM */
+#endif /* _ASM_S390_ARCHRANDOM_H */