linux-kernel - [PATCH v3 2/3] powerpc/powernv: wire up rng during setup

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Message-Id: <20220611151015.548325-3-Jason@zx2c4.com>
Date:   Sat, 11 Jun 2022 17:10:14 +0200
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     "Jason A. Donenfeld" <Jason@...c4.com>, stable@...r.kernel.org,
        Christophe Leroy <christophe.leroy@...roup.eu>
Subject: [PATCH v3 2/3] powerpc/powernv: wire up rng during setup_arch

The platform's RNG must be available before random_init() in order to be
useful for initial seeding, which in turn means that it needs to be
called from setup_arch(), rather than from an init call. Fortunately,
each platform already has a setup_arch function pointer, which means
it's easy to wire this up. This commit also removes some noisy log
messages that don't add much.

Cc: stable@...r.kernel.org
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>
Fixes: a4da0d50b2a0 ("powerpc: Implement arch_get_random_long/int() for powernv")
Signed-off-by: Jason A. Donenfeld <Jason@...c4.com>
---
 arch/powerpc/platforms/powernv/powernv.h |  2 ++
 arch/powerpc/platforms/powernv/rng.c     | 18 +++++-------------
 arch/powerpc/platforms/powernv/setup.c   |  2 ++
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h
index e297bf4abfcb..fd3f5e1eb10b 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -42,4 +42,6 @@ ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);
 u32 __init memcons_get_size(struct memcons *mc);
 struct memcons *__init memcons_init(struct device_node *node, const char *mc_prop_name);
 
+void powernv_rng_init(void);
+
 #endif /* _POWERNV_H */
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
index e3d44b36ae98..c86bf097e407 100644
--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -17,6 +17,7 @@
 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/smp.h>
+#include "powernv.h"
 
 #define DARN_ERR 0xFFFFFFFFFFFFFFFFul
 
@@ -84,24 +85,20 @@ static int powernv_get_random_darn(unsigned long *v)
 	return 1;
 }
 
-static int __init initialise_darn(void)
+static void __init initialise_darn(void)
 {
 	unsigned long val;
 	int i;
 
 	if (!cpu_has_feature(CPU_FTR_ARCH_300))
-		return -ENODEV;
+		return;
 
 	for (i = 0; i < 10; i++) {
 		if (powernv_get_random_darn(&val)) {
 			ppc_md.get_random_seed = powernv_get_random_darn;
-			return 0;
+			return;
 		}
 	}
-
-	pr_warn("Unable to use DARN for get_random_seed()\n");
-
-	return -EIO;
 }
 
 int powernv_get_random_long(unsigned long *v)
@@ -163,14 +160,12 @@ static __init int rng_create(struct device_node *dn)
 
 	rng_init_per_cpu(rng, dn);
 
-	pr_info_once("Registering arch random hook.\n");
-
 	ppc_md.get_random_seed = powernv_get_random_long;
 
 	return 0;
 }
 
-static __init int rng_init(void)
+void __init powernv_rng_init(void)
 {
 	struct device_node *dn;
 	int rc;
@@ -188,7 +183,4 @@ static __init int rng_init(void)
 	}
 
 	initialise_darn();
-
-	return 0;
 }
-machine_subsys_initcall(powernv, rng_init);
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 824c3ad7a0fa..a5fcb6796b22 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -203,6 +203,8 @@ static void __init pnv_setup_arch(void)
 	pnv_check_guarded_cores();
 
 	/* XXX PMCS */
+
+	powernv_rng_init();
 }
 
 static void __init pnv_init(void)
-- 
2.35.1