linux-kernel - [PATCH v2 3/9] random: inline leaves of rand

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Message-Id: <20220209011919.493762-4-Jason@zx2c4.com>
Date:   Wed,  9 Feb 2022 02:19:13 +0100
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     tytso@....edu, linux@...inikbrodowski.net, ebiggers@...nel.org,
        "Jason A. Donenfeld" <Jason@...c4.com>,
        Eric Biggers <ebiggers@...gle.com>
Subject: [PATCH v2 3/9] random: inline leaves of rand_initialize()

This is a preparatory commit for the following one. We simply inline the
various functions that rand_initialize() calls that have no other
callers. The compiler was doing this anyway before. Doing this will
allow us to reorganize this after.

Cc: Theodore Ts'o <tytso@....edu>
Cc: Dominik Brodowski <linux@...inikbrodowski.net>
Reviewed-by: Eric Biggers <ebiggers@...gle.com>
Signed-off-by: Jason A. Donenfeld <Jason@...c4.com>
---
 drivers/char/random.c | 90 ++++++++++++++++---------------------------
 1 file changed, 33 insertions(+), 57 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4c79463464c7..81786bef0a8e 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -471,42 +471,6 @@ static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);
 
 static void invalidate_batched_entropy(void);
 
-static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU);
-static int __init parse_trust_cpu(char *arg)
-{
-	return kstrtobool(arg, &trust_cpu);
-}
-early_param("random.trust_cpu", parse_trust_cpu);
-
-static bool __init crng_init_try_arch_early(void)
-{
-	int i;
-	bool arch_init = true;
-	unsigned long rv;
-
-	for (i = 4; i < 16; i++) {
-		if (!arch_get_random_seed_long_early(&rv) &&
-		    !arch_get_random_long_early(&rv)) {
-			rv = random_get_entropy();
-			arch_init = false;
-		}
-		primary_crng.state[i] ^= rv;
-	}
-
-	return arch_init;
-}
-
-static void __init crng_initialize(void)
-{
-	extract_entropy(&primary_crng.state[4], sizeof(u32) * 12);
-	if (crng_init_try_arch_early() && trust_cpu && crng_init < 2) {
-		invalidate_batched_entropy();
-		crng_init = 2;
-		pr_notice("crng init done (trusting CPU's manufacturer)\n");
-	}
-	primary_crng.init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
-}
-
 /*
  * crng_fast_load() can be called by code in the interrupt service
  * path.  So we can't afford to dilly-dally. Returns the number of
@@ -1230,17 +1194,28 @@ int __must_check get_random_bytes_arch(void *buf, int nbytes)
 }
 EXPORT_SYMBOL(get_random_bytes_arch);
 
+static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU);
+static int __init parse_trust_cpu(char *arg)
+{
+	return kstrtobool(arg, &trust_cpu);
+}
+early_param("random.trust_cpu", parse_trust_cpu);
+
 /*
- * init_std_data - initialize pool with system data
- *
- * This function clears the pool's entropy count and mixes some system
- * data into the pool to prepare it for use. The pool is not cleared
- * as that can only decrease the entropy in the pool.
+ * Note that setup_arch() may call add_device_randomness()
+ * long before we get here. This allows seeding of the pools
+ * with some platform dependent data very early in the boot
+ * process. But it limits our options here. We must use
+ * statically allocated structures that already have all
+ * initializations complete at compile time. We should also
+ * take care not to overwrite the precious per platform data
+ * we were given.
  */
-static void __init init_std_data(void)
+int __init rand_initialize(void)
 {
 	int i;
 	ktime_t now = ktime_get_real();
+	bool arch_init = true;
 	unsigned long rv;
 
 	mix_pool_bytes(&now, sizeof(now));
@@ -1251,22 +1226,23 @@ static void __init init_std_data(void)
 		mix_pool_bytes(&rv, sizeof(rv));
 	}
 	mix_pool_bytes(utsname(), sizeof(*(utsname())));
-}
 
-/*
- * Note that setup_arch() may call add_device_randomness()
- * long before we get here. This allows seeding of the pools
- * with some platform dependent data very early in the boot
- * process. But it limits our options here. We must use
- * statically allocated structures that already have all
- * initializations complete at compile time. We should also
- * take care not to overwrite the precious per platform data
- * we were given.
- */
-int __init rand_initialize(void)
-{
-	init_std_data();
-	crng_initialize();
+	extract_entropy(&primary_crng.state[4], sizeof(u32) * 12);
+	for (i = 4; i < 16; i++) {
+		if (!arch_get_random_seed_long_early(&rv) &&
+		    !arch_get_random_long_early(&rv)) {
+			rv = random_get_entropy();
+			arch_init = false;
+		}
+		primary_crng.state[i] ^= rv;
+	}
+	if (arch_init && trust_cpu && crng_init < 2) {
+		invalidate_batched_entropy();
+		crng_init = 2;
+		pr_notice("crng init done (trusting CPU's manufacturer)\n");
+	}
+	primary_crng.init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
+
 	if (ratelimit_disable) {
 		urandom_warning.interval = 0;
 		unseeded_warning.interval = 0;
-- 
2.35.0