Merge tag 's390-5.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Alexander Gordeev:

 - Rework copy_oldmem_page() callback to take an iov_iter.

   This includes a few prerequisite updates and fixes to the oldmem
   reading code.

 - Rework cpufeature implementation to allow for various CPU feature
   indications, which is not only limited to hardware capabilities, but
   also allows CPU facilities.

 - Use the cpufeature rework to autoload Ultravisor module when CPU
   facility 158 is available.

 - Add ELF note type for encrypted CPU state of a protected virtual CPU.
   The zgetdump tool from s390-tools package will decrypt the CPU state
   using a Customer Communication Key and overwrite respective notes to
   make the data accessible for crash and other debugging tools.

 - Use vzalloc() instead of vmalloc() + memset() in ChaCha20 crypto
   test.

 - Fix incorrect recovery of kretprobe modified return address in
   stacktrace.

 - Switch the NMI handler to use generic irqentry_nmi_enter() and
   irqentry_nmi_exit() helper functions.

 - Rework the cryptographic Adjunct Processors (AP) pass-through design
   to support dynamic changes to the AP matrix of a running guest as
   well as to implement more of the AP architecture.

 - Minor boot code cleanups.

 - Grammar and typo fixes to hmcdrv and tape drivers.

* tag 's390-5.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits)
  Revert "s390/smp: enforce lowcore protection on CPU restart"
  Revert "s390/smp: rework absolute lowcore access"
  Revert "s390/smp,ptdump: add absolute lowcore markers"
  s390/unwind: fix fgraph return address recovery
  s390/nmi: use irqentry_nmi_enter()/irqentry_nmi_exit()
  s390: add ELF note type for encrypted CPU state of a PV VCPU
  s390/smp,ptdump: add absolute lowcore markers
  s390/smp: rework absolute lowcore access
  s390/setup: rearrange absolute lowcore initialization
  s390/boot: cleanup adjust_to_uv_max() function
  s390/smp: enforce lowcore protection on CPU restart
  s390/tape: fix comment typo
  s390/hmcdrv: fix Kconfig "its" grammar
  s390/docs: fix warnings for vfio_ap driver doc
  s390/docs: fix warnings for vfio_ap driver lock usage doc
  s390/crash: support multi-segment iterators
  s390/crash: use static swap buffer for copy_to_user_real()
  s390/crash: move copy_to_user_real() to crash_dump.c
  s390/zcore: fix race when reading from hardware system area
  s390/crash: fix incorrect number of bytes to copy to user space
  ...

1 files changed, 26 insertions, 29 deletions

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 516783ba950f..f6da215ccf9f 100644
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -17,6 +17,7 @@
 #include <linux/debugfs.h>
 #include <linux/panic_notifier.h>
 #include <linux/reboot.h>
+#include <linux/uio.h>
 
 #include <asm/asm-offsets.h>
 #include <asm/ipl.h>
@@ -50,36 +51,41 @@ static struct dentry *zcore_reipl_file;
 static struct dentry *zcore_hsa_file;
 static struct ipl_parameter_block *zcore_ipl_block;
 
+static DEFINE_MUTEX(hsa_buf_mutex);
 static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
 
 /*
- * Copy memory from HSA to user memory (not reentrant):
+ * Copy memory from HSA to iterator (not reentrant):
  *
- * @dest:  User buffer where memory should be copied to
+ * @iter:  Iterator where memory should be copied to
  * @src:   Start address within HSA where data should be copied
  * @count: Size of buffer, which should be copied
  */
-int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
+size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count)
 {
-	unsigned long offset, bytes;
+	size_t bytes, copied, res = 0;
+	unsigned long offset;
 
 	if (!hsa_available)
-		return -ENODATA;
+		return 0;
 
+	mutex_lock(&hsa_buf_mutex);
 	while (count) {
 		if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
 			TRACE("sclp_sdias_copy() failed\n");
-			return -EIO;
+			break;
 		}
 		offset = src % PAGE_SIZE;
 		bytes = min(PAGE_SIZE - offset, count);
-		if (copy_to_user(dest, hsa_buf + offset, bytes))
-			return -EFAULT;
-		src += bytes;
-		dest += bytes;
-		count -= bytes;
+		copied = copy_to_iter(hsa_buf + offset, bytes, iter);
+		count -= copied;
+		src += copied;
+		res += copied;
+		if (copied < bytes)
+			break;
 	}
-	return 0;
+	mutex_unlock(&hsa_buf_mutex);
+	return res;
 }
 
 /*
@@ -89,25 +95,16 @@ int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
  * @src:   Start address within HSA where data should be copied
  * @count: Size of buffer, which should be copied
  */
-int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
+static inline int memcpy_hsa_kernel(void *dst, unsigned long src, size_t count)
 {
-	unsigned long offset, bytes;
+	struct iov_iter iter;
+	struct kvec kvec;
 
-	if (!hsa_available)
-		return -ENODATA;
-
-	while (count) {
-		if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
-			TRACE("sclp_sdias_copy() failed\n");
-			return -EIO;
-		}
-		offset = src % PAGE_SIZE;
-		bytes = min(PAGE_SIZE - offset, count);
-		memcpy(dest, hsa_buf + offset, bytes);
-		src += bytes;
-		dest += bytes;
-		count -= bytes;
-	}
+	kvec.iov_base = dst;
+	kvec.iov_len = count;
+	iov_iter_kvec(&iter, WRITE, &kvec, 1, count);
+	if (memcpy_hsa_iter(&iter, src, count) < count)
+		return -EIO;
 	return 0;
 }