@@ -117,6 +117,12 @@ GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);
#define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND)
#define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED)
+#define __HAVE_ARCH_GET_RNG_SEED
+extern void arch_get_rng_seed(void *ctx,
+ void (*seed)(void *ctx, u32 data),
+ int bits_per_source,
+ const char *log_prefix);
+
#else
static inline int rdrand_long(unsigned long *v)
@@ -92,6 +92,8 @@ obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch_$(BITS).o
obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
+obj-$(CONFIG_ARCH_RANDOM) += archrandom.o
+
obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o
obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
new file mode 100644
@@ -0,0 +1,51 @@
+/*
+ * This file is part of the Linux kernel.
+ *
+ * Copyright (c) 2014 Andy Lutomirski
+ * Authors: Andy Lutomirski <luto@amacapital.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <asm/archrandom.h>
+
+void arch_get_rng_seed(void *ctx,
+ void (*seed)(void *ctx, u32 data),
+ int bits_per_source,
+ const char *log_prefix)
+{
+ int i;
+ int rdseed_bits = 0, rdrand_bits = 0;
+ char buf[128] = "";
+ char *msgptr = buf;
+
+ for (i = 0; i < bits_per_source; i += 8 * sizeof(long)) {
+ unsigned long rv;
+
+ if (arch_get_random_seed_long(&rv))
+ rdseed_bits += 8 * sizeof(rv);
+ else if (arch_get_random_long(&rv))
+ rdrand_bits += 8 * sizeof(rv);
+ else
+ continue; /* Don't waste time mixing. */
+
+ seed(ctx, (u32)rv);
+#if BITS_PER_LONG > 32
+ seed(ctx, (u32)(rv >> 32));
+#endif
+ }
+
+ if (rdseed_bits)
+ msgptr += sprintf(msgptr, ", %d bits from RDSEED", rdseed_bits);
+ if (rdrand_bits)
+ msgptr += sprintf(msgptr, ", %d bits from RDRAND", rdrand_bits);
+ if (buf[0])
+ pr_info("%s with %s\n", log_prefix, buf + 2);
+}
This does the same thing as the generic implementation, except that it logs how many bits of each type it collected. I want to know whether the initial seeding is working and, if so, whether the RNG is fast enough. (I know that hpa assures me that the hardware RNG is more than fast enough, but I'd still like a direct way to verify this.) Arguably, arch_get_random_seed could be removed now: I'm having some trouble imagining a sensible non-architecture-specific use of it that wouldn't be better served by arch_get_rng_seed. Signed-off-by: Andy Lutomirski <luto@amacapital.net> --- arch/x86/include/asm/archrandom.h | 6 +++++ arch/x86/kernel/Makefile | 2 ++ arch/x86/kernel/archrandom.c | 51 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+) create mode 100644 arch/x86/kernel/archrandom.c