Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 7be0647..1864a8b 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -16,6 +16,7 @@
#include <linux/cpu.h>
#include <asm/ctl_reg.h>
#include <asm/io.h>
+#include <asm/stacktrace.h>
static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t size)
{
@@ -51,21 +52,22 @@
* Therefore we have a read-modify-write sequence: the function reads eight
* bytes from destination at an eight byte boundary, modifies the bytes
* requested and writes the result back in a loop.
- *
- * Note: this means that this function may not be called concurrently on
- * several cpus with overlapping words, since this may potentially
- * cause data corruption.
*/
+static DEFINE_SPINLOCK(s390_kernel_write_lock);
+
void notrace s390_kernel_write(void *dst, const void *src, size_t size)
{
+ unsigned long flags;
long copied;
+ spin_lock_irqsave(&s390_kernel_write_lock, flags);
while (size) {
copied = s390_kernel_write_odd(dst, src, size);
dst += copied;
src += copied;
size -= copied;
}
+ spin_unlock_irqrestore(&s390_kernel_write_lock, flags);
}
static int __memcpy_real(void *dest, void *src, size_t count)
@@ -89,10 +91,8 @@
return rc;
}
-/*
- * Copy memory in real mode (kernel to kernel)
- */
-int memcpy_real(void *dest, void *src, size_t count)
+static unsigned long _memcpy_real(unsigned long dest, unsigned long src,
+ unsigned long count)
{
int irqs_disabled, rc;
unsigned long flags;
@@ -103,7 +103,7 @@
irqs_disabled = arch_irqs_disabled_flags(flags);
if (!irqs_disabled)
trace_hardirqs_off();
- rc = __memcpy_real(dest, src, count);
+ rc = __memcpy_real((void *) dest, (void *) src, (size_t) count);
if (!irqs_disabled)
trace_hardirqs_on();
__arch_local_irq_ssm(flags);
@@ -111,6 +111,23 @@
}
/*
+ * Copy memory in real mode (kernel to kernel)
+ */
+int memcpy_real(void *dest, void *src, size_t count)
+{
+ if (S390_lowcore.nodat_stack != 0)
+ return CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack,
+ 3, dest, src, count);
+ /*
+ * This is a really early memcpy_real call, the stacks are
+ * not set up yet. Just call _memcpy_real on the early boot
+ * stack
+ */
+ return _memcpy_real((unsigned long) dest,(unsigned long) src,
+ (unsigned long) count);
+}
+
+/*
* Copy memory in absolute mode (kernel to kernel)
*/
void memcpy_absolute(void *dest, void *src, size_t count)