mm/ARM64: kill poison_init_mem()

Use free_reserved_area() to poison initmem memory pages and kill
poison_init_mem() on ARM64.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm64/mm/init.c

@@ -197,14 +197,6 @@ void __init bootmem_init(void)
 	max_pfn = max_low_pfn = max;
 }
 
-/*
- * Poison init memory with an undefined instruction (0x0).
- */
-static inline void poison_init_mem(void *s, size_t count)
-{
-	memset(s, 0, count);
-}
-
 #ifndef CONFIG_SPARSEMEM_VMEMMAP
 static inline void free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 {
@@ -386,8 +378,7 @@ void __init mem_init(void)
 
 void free_initmem(void)
 {
-	poison_init_mem(__init_begin, __init_end - __init_begin);
-	free_initmem_default(-1);
+	free_initmem_default(0);
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -396,10 +387,8 @@ static int keep_initrd;
 
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-	if (!keep_initrd) {
-		poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
-		free_reserved_area((void *)start, (void *)end, -1, "initrd");
-	}
+	if (!keep_initrd)
+		free_reserved_area((void *)start, (void *)end, 0, "initrd");
 }
 
 static int __init keepinitrd_setup(char *__unused)