From: kettenis <kettenis@openbsd.org>
Date: Thu, 11 Jul 2024 12:07:39 +0000 (+0000)
Subject: Use FEAT_RNG to feed entropy into the random subsystem like we do on amd64.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=35e332b4d486548d643c15788f0c52e9da31eb9a;p=openbsd

Use FEAT_RNG to feed entropy into the random subsystem like we do on amd64.

ok patrick@, deraadt@
---

diff --git a/sys/arch/arm64/arm64/cpu.c b/sys/arch/arm64/arm64/cpu.c
index 000313fa895..47b2534a0bb 100644
--- a/sys/arch/arm64/arm64/cpu.c
+++ b/sys/arch/arm64/arm64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.124 2024/07/10 11:01:24 kettenis Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.125 2024/07/11 12:07:39 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2016 Dale Rahn <drahn@dalerahn.com>
@@ -245,6 +245,7 @@ uint64_t cpu_id_aa64pfr0;
 uint64_t cpu_id_aa64pfr1;
 
 int arm64_has_lse;
+int arm64_has_rng;
 #ifdef CRYPTO
 int arm64_has_aes;
 #endif
@@ -273,6 +274,9 @@ struct cfdriver cpu_cd = {
 	NULL, "cpu", DV_DULL
 };
 
+struct timeout cpu_rng_to;
+void	cpu_rng(void *);
+
 void	cpu_opp_init(struct cpu_info *, uint32_t);
 void	cpu_psci_init(struct cpu_info *);
 void	cpu_psci_idle_cycle(void);
@@ -286,6 +290,25 @@ void	cpu_kstat_attach(struct cpu_info *ci);
 void	cpu_opp_kstat_attach(struct cpu_info *ci);
 #endif
 
+void
+cpu_rng(void *arg)
+{
+	struct timeout *to = arg;
+	uint64_t rndr;
+	int ret;
+
+	ret = __builtin_arm_rndrrs(&rndr);
+	if (ret)
+		ret = __builtin_arm_rndr(&rndr);
+	if (ret == 0) {
+		enqueue_randomness(rndr & 0xffffffff);
+		enqueue_randomness(rndr >> 32);
+	}
+
+	if (to)
+		timeout_add_msec(to, 1000);
+}
+
 /*
  * Enable mitigation for Spectre-V2 branch target injection
  * vulnerabilities (CVE-2017-5715).
@@ -667,6 +690,7 @@ cpu_identify(struct cpu_info *ci)
 	if (ID_AA64ISAR0_RNDR(id) >= ID_AA64ISAR0_RNDR_IMPL) {
 		printf("%sRNDR", sep);
 		sep = ",";
+		arm64_has_rng = 1;
 	}
 
 	if (ID_AA64ISAR0_TLB(id) >= ID_AA64ISAR0_TLB_IOS) {
@@ -1139,6 +1163,11 @@ cpu_attach(struct device *parent, struct device *dev, void *aux)
 		}
 
 		cpu_init();
+
+		if (arm64_has_rng) {
+			timeout_set(&cpu_rng_to, cpu_rng, &cpu_rng_to);
+			cpu_rng(&cpu_rng_to);
+		}
 #ifdef MULTIPROCESSOR
 	}
 #endif
diff --git a/sys/arch/arm64/conf/Makefile.arm64 b/sys/arch/arm64/conf/Makefile.arm64
index 837b1fe656d..371e1f99a5a 100644
--- a/sys/arch/arm64/conf/Makefile.arm64
+++ b/sys/arch/arm64/conf/Makefile.arm64
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile.arm64,v 1.48 2024/07/02 10:25:16 kettenis Exp $
+#	$OpenBSD: Makefile.arm64,v 1.49 2024/07/11 12:07:40 kettenis Exp $
 
 # For instructions on building kernels consult the config(8) and options(4)
 # manual pages.
@@ -56,7 +56,7 @@ CWARNFLAGS=	-Werror -Wall -Wimplicit-function-declaration \
 		-Wno-unused-but-set-variable -Wno-gnu-folding-constant \
 		-Wframe-larger-than=2047
 
-CMACHFLAGS=	-march=armv8-a+nofp+nosimd \
+CMACHFLAGS=	-march=armv8-a+nofp+nosimd+rng \
 		-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer \
 		-ffixed-x18
 CMACHFLAGS+=	-ffreestanding ${NOPIE_FLAGS}