[S390] replace diag10() with diag10_range() function

Currently the diag10() function can only release one page. For exploiters
that have to call diag10 on a contiguous memory region this is suboptimal.
This patch replaces the diag10() function with diag10_range() that is
able to release multiple pages. In addition to that the new function now
allows to release memory with addresses higher than 2047 MiB. This was
due to a restriction of the diagnose implementation under z/VM prior to
release 5.2.

Signed-off-by: Michael Holzheu <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/diag.h

···
 #define _ASM_S390_DIAG_H
 
 /*
- * Diagnose 10: Release pages
+ * Diagnose 10: Release page range
  */
-extern void diag10(unsigned long addr);
+static inline void diag10_range(unsigned long start_pfn, unsigned long num_pfn)
+{
+	unsigned long start_addr, end_addr;
+
+	start_addr = start_pfn << PAGE_SHIFT;
+	end_addr = (start_pfn + num_pfn - 1) << PAGE_SHIFT;
+
+	asm volatile(
+		"0:	diag	%0,%1,0x10\n"
+		"1:\n"
+		EX_TABLE(0b, 1b)
+		EX_TABLE(1b, 1b)
+		: : "a" (start_addr), "a" (end_addr));
+}
 
 /*
  * Diagnose 14: Input spool file manipulation

arch/s390/kernel/diag.c

···
 #include <asm/diag.h>
 
 /*
- * Diagnose 10: Release pages
- */
-void diag10(unsigned long addr)
-{
-	if (addr >= 0x7ff00000)
-		return;
-	asm volatile(
-#ifdef CONFIG_64BIT
-		"	sam31\n"
-		"	diag	%0,%0,0x10\n"
-		"0:	sam64\n"
-#else
-		"	diag	%0,%0,0x10\n"
-		"0:\n"
-#endif
-		EX_TABLE(0b, 0b)
-		: : "a" (addr));
-}
-EXPORT_SYMBOL(diag10);
-
-/*
  * Diagnose 14: Input spool file manipulation
  */
 int diag14(unsigned long rx, unsigned long ry1, unsigned long subcode)

arch/s390/mm/cmm.c

···
 			} else
 				free_page((unsigned long) npa);
 		}
-		diag10(addr);
+		diag10_range(addr >> PAGE_SHIFT, 1);
 		pa->pages[pa->index++] = addr;
 		(*counter)++;
 		spin_unlock(&cmm_lock);