random: remove get_random_bytes_arch() and add rng_has_arch_random()

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0673250d6489..6d8ccb200c5c 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -433,12 +433,9 @@  static void _get_random_bytes(void *buf, size_t len)
 /*
  * This function is the exported kernel interface.  It returns some
  * number of good random numbers, suitable for key generation, seeding
- * TCP sequence numbers, etc.  It does not rely on the hardware random
- * number generator.  For random bytes direct from the hardware RNG
- * (when available), use get_random_bytes_arch(). In order to ensure
- * that the randomness provided by this function is okay, the function
- * wait_for_random_bytes() should be called and return 0 at least once
- * at any point prior.
+ * TCP sequence numbers, etc. In order to ensure that the randomness
+ * by this function is okay, the function wait_for_random_bytes()
+ * should be called and return 0 at least once at any point prior.
  */
 void get_random_bytes(void *buf, size_t len)
 {
@@ -655,33 +652,6 @@  unsigned long randomize_page(unsigned long start, unsigned long range)
 	return start + (get_random_long() % range << PAGE_SHIFT);
 }
 
-/*
- * This function will use the architecture-specific hardware random
- * number generator if it is available. It is not recommended for
- * use. Use get_random_bytes() instead. It returns the number of
- * bytes filled in.
- */
-size_t __must_check get_random_bytes_arch(void *buf, size_t len)
-{
-	size_t left = len;
-	u8 *p = buf;
-
-	while (left) {
-		unsigned long v;
-		size_t block_len = min_t(size_t, left, sizeof(unsigned long));
-
-		if (!arch_get_random_long(&v))
-			break;
-
-		memcpy(p, &v, block_len);
-		p += block_len;
-		left -= block_len;
-	}
-
-	return len - left;
-}
-EXPORT_SYMBOL(get_random_bytes_arch);
-
 
 /**********************************************************************
  *
@@ -919,6 +889,8 @@  static int random_pm_notification(struct notifier_block *nb, unsigned long actio
 
 static struct notifier_block pm_notifier = { .notifier_call = random_pm_notification };
 
+static bool used_arch_random;
+
 /*
  * The first collection of entropy occurs at system boot while interrupts
  * are still turned off. Here we push in latent entropy, RDSEED, a timestamp,
@@ -956,6 +928,7 @@  int __init random_init(const char *command_line)
 		crng_reseed();
 	else if (trust_cpu)
 		credit_init_bits(arch_bytes * 8);
+	used_arch_random = arch_bytes * 8 >= POOL_READY_BITS;
 
 	WARN_ON(register_pm_notifier(&pm_notifier));
 
@@ -964,6 +937,15 @@  int __init random_init(const char *command_line)
 	return 0;
 }
 
+/*
+ * Returns whether arch randomness has been mixed into the
+ * initial state of the RNG.
+ */
+bool rng_has_arch_random(void)
+{
+	return used_arch_random;
+}
+
 /*
  * Add device- or boot-specific data to the input pool to help
  * initialize it.
diff --git a/include/linux/random.h b/include/linux/random.h
index fc82f1dc36f1..6af130c6edb9 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -38,7 +38,6 @@  static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) {
 #endif
 
 void get_random_bytes(void *buf, size_t len);
-size_t __must_check get_random_bytes_arch(void *buf, size_t len);
 u32 get_random_u32(void);
 u64 get_random_u64(void);
 static inline unsigned int get_random_int(void)
@@ -77,6 +76,7 @@  unsigned long randomize_page(unsigned long start, unsigned long range);
 
 int __init random_init(const char *command_line);
 bool rng_is_initialized(void);
+bool rng_has_arch_random(void);
 int wait_for_random_bytes(void);
 int register_random_ready_notifier(struct notifier_block *nb);
 int unregister_random_ready_notifier(struct notifier_block *nb);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 40d26a07a133..20e9887faaaa 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -776,12 +776,11 @@  static struct notifier_block random_ready = {
 
 static int __init initialize_ptr_random(void)
 {
-	int key_size = sizeof(ptr_key);
 	int ret;
 
-	/* Use hw RNG if available. */
-	if (get_random_bytes_arch(&ptr_key, key_size) == key_size) {
-		static_branch_disable(&not_filled_random_ptr_key);
+	/* Don't bother waiting for RNG to be ready if RDRAND is mixed in already. */
+	if (rng_has_arch_random()) {
+		enable_ptr_key_workfn(&enable_ptr_key_work);
 		return 0;
 	}