Merge tag 's390-5.19-5' of git://git.kernel.org/pub/scm/linux/kernel/…

…git/s390/linux

Pull s390 fixes from Alexander Gordeev:

 - Fix purgatory build process so bin2c tool does not get built
   unnecessarily and the Makefile is more consistent with other
   architectures.

 - Return earlier simple design of arch_get_random_seed_long|int() and
   arch_get_random_long|int() callbacks as result of changes in generic
   RNG code.

 - Fix minor comment typos and spelling mistakes.

* tag 's390-5.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/qdio: Fix spelling mistake
  s390/sclp: Fix typo in comments
  s390/archrandom: simplify back to earlier design and initialize earlier
  s390/purgatory: remove duplicated build rule of kexec-purgatory.o
  s390/purgatory: hard-code obj-y in Makefile
  s390: remove unneeded 'select BUILD_BIN2C'

arch/s390/Kconfig

@@ -484,7 +484,6 @@ config KEXEC
 config KEXEC_FILE
 	bool "kexec file based system call"
 	select KEXEC_CORE
-	select BUILD_BIN2C
 	depends on CRYPTO
 	depends on CRYPTO_SHA256
 	depends on CRYPTO_SHA256_S390

arch/s390/crypto/arch_random.c

@@ -4,232 +4,15 @@
  *
  * Copyright IBM Corp. 2017, 2020
  * Author(s): Harald Freudenberger
- *
- * The s390_arch_random_generate() function may be called from random.c
- * in interrupt context. So this implementation does the best to be very
- * fast. There is a buffer of random data which is asynchronously checked
- * and filled by a workqueue thread.
- * If there are enough bytes in the buffer the s390_arch_random_generate()
- * just delivers these bytes. Otherwise false is returned until the
- * worker thread refills the buffer.
- * The worker fills the rng buffer by pulling fresh entropy from the
- * high quality (but slow) true hardware random generator. This entropy
- * is then spread over the buffer with an pseudo random generator PRNG.
- * As the arch_get_random_seed_long() fetches 8 bytes and the calling
- * function add_interrupt_randomness() counts this as 1 bit entropy the
- * distribution needs to make sure there is in fact 1 bit entropy contained
- * in 8 bytes of the buffer. The current values pull 32 byte entropy
- * and scatter this into a 2048 byte buffer. So 8 byte in the buffer
- * will contain 1 bit of entropy.
- * The worker thread is rescheduled based on the charge level of the
- * buffer but at least with 500 ms delay to avoid too much CPU consumption.
- * So the max. amount of rng data delivered via arch_get_random_seed is
- * limited to 4k bytes per second.
  */
 
 #include <linux/kernel.h>
 #include <linux/atomic.h>
 #include <linux/random.h>
-#include <linux/slab.h>
 #include <linux/static_key.h>
-#include <linux/workqueue.h>
-#include <linux/moduleparam.h>
 #include <asm/cpacf.h>
 
 DEFINE_STATIC_KEY_FALSE(s390_arch_random_available);
 
 atomic64_t s390_arch_random_counter = ATOMIC64_INIT(0);
 EXPORT_SYMBOL(s390_arch_random_counter);
-
-#define ARCH_REFILL_TICKS (HZ/2)
-#define ARCH_PRNG_SEED_SIZE 32
-#define ARCH_RNG_BUF_SIZE 2048
-
-static DEFINE_SPINLOCK(arch_rng_lock);
-static u8 *arch_rng_buf;
-static unsigned int arch_rng_buf_idx;
-
-static void arch_rng_refill_buffer(struct work_struct *);
-static DECLARE_DELAYED_WORK(arch_rng_work, arch_rng_refill_buffer);
-
-bool s390_arch_random_generate(u8 *buf, unsigned int nbytes)
-{
-	/* max hunk is ARCH_RNG_BUF_SIZE */
-	if (nbytes > ARCH_RNG_BUF_SIZE)
-		return false;
-
-	/* lock rng buffer */
-	if (!spin_trylock(&arch_rng_lock))
-		return false;
-
-	/* try to resolve the requested amount of bytes from the buffer */
-	arch_rng_buf_idx -= nbytes;
-	if (arch_rng_buf_idx < ARCH_RNG_BUF_SIZE) {
-		memcpy(buf, arch_rng_buf + arch_rng_buf_idx, nbytes);
-		atomic64_add(nbytes, &s390_arch_random_counter);
-		spin_unlock(&arch_rng_lock);
-		return true;
-	}
-
-	/* not enough bytes in rng buffer, refill is done asynchronously */
-	spin_unlock(&arch_rng_lock);
-
-	return false;
-}
-EXPORT_SYMBOL(s390_arch_random_generate);
-
-static void arch_rng_refill_buffer(struct work_struct *unused)
-{
-	unsigned int delay = ARCH_REFILL_TICKS;
-
-	spin_lock(&arch_rng_lock);
-	if (arch_rng_buf_idx > ARCH_RNG_BUF_SIZE) {
-		/* buffer is exhausted and needs refill */
-		u8 seed[ARCH_PRNG_SEED_SIZE];
-		u8 prng_wa[240];
-		/* fetch ARCH_PRNG_SEED_SIZE bytes of entropy */
-		cpacf_trng(NULL, 0, seed, sizeof(seed));
-		/* blow this entropy up to ARCH_RNG_BUF_SIZE with PRNG */
-		memset(prng_wa, 0, sizeof(prng_wa));
-		cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
-			   &prng_wa, NULL, 0, seed, sizeof(seed));
-		cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN,
-			   &prng_wa, arch_rng_buf, ARCH_RNG_BUF_SIZE, NULL, 0);
-		arch_rng_buf_idx = ARCH_RNG_BUF_SIZE;
-	}
-	delay += (ARCH_REFILL_TICKS * arch_rng_buf_idx) / ARCH_RNG_BUF_SIZE;
-	spin_unlock(&arch_rng_lock);
-
-	/* kick next check */
-	queue_delayed_work(system_long_wq, &arch_rng_work, delay);
-}
-
-/*
- * Here follows the implementation of s390_arch_get_random_long().
- *
- * The random longs to be pulled by arch_get_random_long() are
- * prepared in an 4K buffer which is filled from the NIST 800-90
- * compliant s390 drbg. By default the random long buffer is refilled
- * 256 times before the drbg itself needs a reseed. The reseed of the
- * drbg is done with 32 bytes fetched from the high quality (but slow)
- * trng which is assumed to deliver 100% entropy. So the 32 * 8 = 256
- * bits of entropy are spread over 256 * 4KB = 1MB serving 131072
- * arch_get_random_long() invocations before reseeded.
- *
- * How often the 4K random long buffer is refilled with the drbg
- * before the drbg is reseeded can be adjusted. There is a module
- * parameter 's390_arch_rnd_long_drbg_reseed' accessible via
- *   /sys/module/arch_random/parameters/rndlong_drbg_reseed
- * or as kernel command line parameter
- *   arch_random.rndlong_drbg_reseed=<value>
- * This parameter tells how often the drbg fills the 4K buffer before
- * it is re-seeded by fresh entropy from the trng.
- * A value of 16 results in reseeding the drbg at every 16 * 4 KB = 64
- * KB with 32 bytes of fresh entropy pulled from the trng. So a value
- * of 16 would result in 256 bits entropy per 64 KB.
- * A value of 256 results in 1MB of drbg output before a reseed of the
- * drbg is done. So this would spread the 256 bits of entropy among 1MB.
- * Setting this parameter to 0 forces the reseed to take place every
- * time the 4K buffer is depleted, so the entropy rises to 256 bits
- * entropy per 4K or 0.5 bit entropy per arch_get_random_long().  With
- * setting this parameter to negative values all this effort is
- * disabled, arch_get_random long() returns false and thus indicating
- * that the arch_get_random_long() feature is disabled at all.
- */
-
-static unsigned long rndlong_buf[512];
-static DEFINE_SPINLOCK(rndlong_lock);
-static int rndlong_buf_index;
-
-static int rndlong_drbg_reseed = 256;
-module_param_named(rndlong_drbg_reseed, rndlong_drbg_reseed, int, 0600);
-MODULE_PARM_DESC(rndlong_drbg_reseed, "s390 arch_get_random_long() drbg reseed");
-
-static inline void refill_rndlong_buf(void)
-{
-	static u8 prng_ws[240];
-	static int drbg_counter;
-
-	if (--drbg_counter < 0) {
-		/* need to re-seed the drbg */
-		u8 seed[32];
-
-		/* fetch seed from trng */
-		cpacf_trng(NULL, 0, seed, sizeof(seed));
-		/* seed drbg */
-		memset(prng_ws, 0, sizeof(prng_ws));
-		cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED,
-			   &prng_ws, NULL, 0, seed, sizeof(seed));
-		/* re-init counter for drbg */
-		drbg_counter = rndlong_drbg_reseed;
-	}
-
-	/* fill the arch_get_random_long buffer from drbg */
-	cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, &prng_ws,
-		   (u8 *) rndlong_buf, sizeof(rndlong_buf),
-		   NULL, 0);
-}
-
-bool s390_arch_get_random_long(unsigned long *v)
-{
-	bool rc = false;
-	unsigned long flags;
-
-	/* arch_get_random_long() disabled ? */
-	if (rndlong_drbg_reseed < 0)
-		return false;
-
-	/* try to lock the random long lock */
-	if (!spin_trylock_irqsave(&rndlong_lock, flags))
-		return false;
-
-	if (--rndlong_buf_index >= 0) {
-		/* deliver next long value from the buffer */
-		*v = rndlong_buf[rndlong_buf_index];
-		rc = true;
-		goto out;
-	}
-
-	/* buffer is depleted and needs refill */
-	if (in_interrupt()) {
-		/* delay refill in interrupt context to next caller */
-		rndlong_buf_index = 0;
-		goto out;
-	}
-
-	/* refill random long buffer */
-	refill_rndlong_buf();
-	rndlong_buf_index = ARRAY_SIZE(rndlong_buf);
-
-	/* and provide one random long */
-	*v = rndlong_buf[--rndlong_buf_index];
-	rc = true;
-
-out:
-	spin_unlock_irqrestore(&rndlong_lock, flags);
-	return rc;
-}
-EXPORT_SYMBOL(s390_arch_get_random_long);
-
-static int __init s390_arch_random_init(void)
-{
-	/* all the needed PRNO subfunctions available ? */
-	if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG) &&
-	    cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN)) {
-
-		/* alloc arch random working buffer */
-		arch_rng_buf = kmalloc(ARCH_RNG_BUF_SIZE, GFP_KERNEL);
-		if (!arch_rng_buf)
-			return -ENOMEM;
-
-		/* kick worker queue job to fill the random buffer */
-		queue_delayed_work(system_long_wq,
-				   &arch_rng_work, ARCH_REFILL_TICKS);
-
-		/* enable arch random to the outside world */
-		static_branch_enable(&s390_arch_random_available);
-	}
-
-	return 0;
-}
-arch_initcall(s390_arch_random_init);

arch/s390/include/asm/archrandom.h

@@ -15,17 +15,13 @@
 
 #include <linux/static_key.h>
 #include <linux/atomic.h>
+#include <asm/cpacf.h>
 
 DECLARE_STATIC_KEY_FALSE(s390_arch_random_available);
 extern atomic64_t s390_arch_random_counter;
 
-bool s390_arch_get_random_long(unsigned long *v);
-bool s390_arch_random_generate(u8 *buf, unsigned int nbytes);
-
 static inline bool __must_check arch_get_random_long(unsigned long *v)
 {
-	if (static_branch_likely(&s390_arch_random_available))
-		return s390_arch_get_random_long(v);
 	return false;
 }
 
@@ -37,15 +33,19 @@ static inline bool __must_check arch_get_random_int(unsigned int *v)
 static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
 {
 	if (static_branch_likely(&s390_arch_random_available)) {
-		return s390_arch_random_generate((u8 *)v, sizeof(*v));
+		cpacf_trng(NULL, 0, (u8 *)v, sizeof(*v));
+		atomic64_add(sizeof(*v), &s390_arch_random_counter);
+		return true;
 	}
 	return false;
 }
 
 static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
 {
 	if (static_branch_likely(&s390_arch_random_available)) {
-		return s390_arch_random_generate((u8 *)v, sizeof(*v));
+		cpacf_trng(NULL, 0, (u8 *)v, sizeof(*v));
+		atomic64_add(sizeof(*v), &s390_arch_random_counter);
+		return true;
 	}
 	return false;
 }

arch/s390/include/asm/qdio.h

@@ -133,9 +133,9 @@ struct slibe {
  * @sb_count: number of storage blocks
  * @sba: storage block element addresses
  * @dcount: size of storage block elements
- * @user0: user defineable value
- * @res4: reserved paramater
- * @user1: user defineable value
+ * @user0: user definable value
+ * @res4: reserved parameter
+ * @user1: user definable value
  */
 struct qaob {
 	u64 res0[6];

arch/s390/kernel/setup.c

@@ -875,6 +875,11 @@ static void __init setup_randomness(void)
 	if (stsi(vmms, 3, 2, 2) == 0 && vmms->count)
 		add_device_randomness(&vmms->vm, sizeof(vmms->vm[0]) * vmms->count);
 	memblock_free(vmms, PAGE_SIZE);
+
+#ifdef CONFIG_ARCH_RANDOM
+	if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
+		static_branch_enable(&s390_arch_random_available);
+#endif
 }
 
 /*

arch/s390/purgatory/Makefile

@@ -48,7 +48,6 @@ OBJCOPYFLAGS_purgatory.ro += --remove-section='.note.*'
 $(obj)/purgatory.ro: $(obj)/purgatory $(obj)/purgatory.chk FORCE
 		$(call if_changed,objcopy)
 
-$(obj)/kexec-purgatory.o: $(obj)/kexec-purgatory.S $(obj)/purgatory.ro FORCE
-	$(call if_changed_rule,as_o_S)
+$(obj)/kexec-purgatory.o: $(obj)/purgatory.ro
 
-obj-$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) += kexec-purgatory.o
+obj-y += kexec-purgatory.o

drivers/s390/char/sclp.c

@@ -60,7 +60,7 @@ static LIST_HEAD(sclp_reg_list);
 /* List of queued requests. */
 static LIST_HEAD(sclp_req_queue);
 
-/* Data for read and and init requests. */
+/* Data for read and init requests. */
 static struct sclp_req sclp_read_req;
 static struct sclp_req sclp_init_req;
 static void *sclp_read_sccb;