Merge tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull more random number generator updates from Jason Donenfeld:
 "Two remaining changes that are now possible after you merged a few
  other trees:

   - #include <asm/archrandom.h> can be removed from random.h now,
     making the direct use of the arch_random_* API more of a private
     implementation detail between the archs and random.c, rather than
     something for general consumers.

   - Two additional uses of prandom_u32_max() snuck in during the
     initial phase of pulls, so these have been converted to
     get_random_u32_below(), and now the deprecated prandom_u32_max()
     alias -- which was just a wrapper around get_random_u32_below() --
     can be removed.

  In addition, there is one fix:

   - Check efi_rt_services_supported() before attempting to use an EFI
     runtime function.

     This affected EFI systems that disable runtime services yet still
     boot via EFI (e.g. the reporter's Lenovo Thinkpad X13s laptop), as
     well systems where EFI runtime services have been forcibly
     disabled, such as on PREEMPT_RT.

     On those machines, a very early and hard to diagnose crash would
     happen, preventing boot"

* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  prandom: remove prandom_u32_max()
  efi: random: fix NULL-deref when refreshing seed
  random: do not include <asm/archrandom.h> from random.h

10 files changed, 10 insertions, 11 deletions

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 6d041993a45dcc..9b10e57040c6c7 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -59,6 +59,7 @@
 #include <asm/xmon.h>
 #include <asm/cputhreads.h>
 #include <mm/mmu_decl.h>
+#include <asm/archrandom.h>
 #include <asm/fadump.h>
 #include <asm/udbg.h>
 #include <asm/hugetlb.h>
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 2094f575c53294..2b6091349daa25 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -52,6 +52,7 @@
 #include <linux/hugetlb.h>
 #include <linux/kmemleak.h>
 
+#include <asm/archrandom.h>
 #include <asm/boot_data.h>
 #include <asm/ipl.h>
 #include <asm/facility.h>
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 8bb1aa6a7aa3af..7316a822425992 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -36,7 +36,7 @@ static __init void init_cea_offsets(void)
 		unsigned int cea;
 
 again:
-		cea = prandom_u32_max(max_cea);
+		cea = get_random_u32_below(max_cea);
 
 		for_each_possible_cpu(j) {
 			if (cea_offset(j) == cea)
diff --git a/drivers/char/hw_random/powernv-rng.c b/drivers/char/hw_random/powernv-rng.c
index 429e956f34e1c2..47b88de029f2de 100644
--- a/drivers/char/hw_random/powernv-rng.c
+++ b/drivers/char/hw_random/powernv-rng.c
@@ -11,6 +11,7 @@
 #include <linux/platform_device.h>
 #include <linux/random.h>
 #include <linux/hw_random.h>
+#include <asm/archrandom.h>
 
 static int powernv_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 {
diff --git a/drivers/char/hw_random/s390-trng.c b/drivers/char/hw_random/s390-trng.c
index cffa326ddc8d3b..d27e32e9bfee11 100644
--- a/drivers/char/hw_random/s390-trng.c
+++ b/drivers/char/hw_random/s390-trng.c
@@ -23,6 +23,7 @@
 #include <linux/sched/signal.h>
 #include <asm/debug.h>
 #include <asm/cpacf.h>
+#include <asm/archrandom.h>
 
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("IBM Corporation");
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 5885ed574c6aae..ce3ccd172cc868 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -56,6 +56,7 @@
 #include <linux/sched/isolation.h>
 #include <crypto/chacha.h>
 #include <crypto/blake2s.h>
+#include <asm/archrandom.h>
 #include <asm/processor.h>
 #include <asm/irq.h>
 #include <asm/irq_regs.h>
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 31a4090c66b36c..09716eebe8ac3a 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -429,7 +429,9 @@ static int __init efisubsys_init(void)
 		platform_device_register_simple("efi_secret", 0, NULL, 0);
 #endif
 
-	execute_with_initialized_rng(&refresh_nv_rng_seed_nb);
+	if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
+		execute_with_initialized_rng(&refresh_nv_rng_seed_nb);
+
 	return 0;
 
 err_remove_group:
diff --git a/include/linux/prandom.h b/include/linux/prandom.h
index c94c02ba065cd6..f2ed5b72b3d6f2 100644
--- a/include/linux/prandom.h
+++ b/include/linux/prandom.h
@@ -24,12 +24,6 @@ void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
 #define prandom_init_once(pcpu_state)			\
 	DO_ONCE(prandom_seed_full_state, (pcpu_state))
 
-/* Deprecated: use get_random_u32_below() instead. */
-static inline u32 prandom_u32_max(u32 ep_ro)
-{
-	return get_random_u32_below(ep_ro);
-}
-
 /*
  * Handle minimum values for seeds
  */
diff --git a/include/linux/random.h b/include/linux/random.h
index 4a2a1de423cd90..b0a940af4fff54 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -152,8 +152,6 @@ declare_get_random_var_wait(long, unsigned long)
  */
 #include <linux/prandom.h>
 
-#include <asm/archrandom.h>
-
 #ifdef CONFIG_SMP
 int random_prepare_cpu(unsigned int cpu);
 int random_online_cpu(unsigned int cpu);
diff --git a/net/ipv4/tcp_plb.c b/net/ipv4/tcp_plb.c
index bb1a08fda113e1..4bcf7eff95e390 100644
--- a/net/ipv4/tcp_plb.c
+++ b/net/ipv4/tcp_plb.c
@@ -97,7 +97,7 @@ void tcp_plb_update_state_upon_rto(struct sock *sk, struct tcp_plb_state *plb)
 		return;
 
 	pause = READ_ONCE(net->ipv4.sysctl_tcp_plb_suspend_rto_sec) * HZ;
-	pause += prandom_u32_max(pause);
+	pause += get_random_u32_below(pause);
 	plb->pause_until = tcp_jiffies32 + pause;
 
 	/* Reset PLB state upon RTO, since an RTO causes a sk_rethink_txhash() call