MIPS: make setup_zero_pages() use memblock

Allocating the zero pages from memblock is simpler because the memory is
already reserved.

This will also help with pulling out memblock_free_all() to the generic
code and reducing code duplication in arch::mem_init().

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Mike Rapoport (Microsoft) <[e-mail]>
Cc: Alexander Gordeev <[e-mail]>
Cc: Andreas Larsson <[e-mail]>
Cc: Andy Lutomirski <[e-mail]>
Cc: Ard Biesheuvel <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Borislav Betkov <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Dinh Nguyen <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Guo Ren (csky) <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Helge Deller <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiaxun Yang <[e-mail]>
Cc: Johannes Berg <[e-mail]>
Cc: John Paul Adrian Glaubitz <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Mark Brown <[e-mail]>
Cc: Matt Turner <[e-mail]>
Cc: Max Filippov <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Michal Simek <[e-mail]>
Cc: Palmer Dabbelt <[e-mail]>
Cc: Richard Weinberger <[e-mail]>
Cc: Russel King <[e-mail]>
Cc: Stafford Horne <[e-mail]>
Cc: Thomas Bogendoerfer <[e-mail]>
Cc: Thomas Gleinxer <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

arch/mips/include/asm/mmzone.h

···
 #define nid_to_addrbase(nid) 0
 #endif
 
-extern void setup_zero_pages(void);
-
 #endif /* _ASM_MMZONE_H_ */

arch/mips/mm/init.c

···
 /*
  * Not static inline because used by IP27 special magic initialization code
  */
-void setup_zero_pages(void)
+static void __init setup_zero_pages(void)
 {
-	unsigned int order, i;
-	struct page *page;
+	unsigned int order;
 
 	if (cpu_has_vce)
 		order = 3;
 	else
 		order = 0;
 
-	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
-	if (!empty_zero_page)
-		panic("Oh boy, that early out of memory?");
-
-	page = virt_to_page((void *)empty_zero_page);
-	split_page(page, order);
-	for (i = 0; i < (1 << order); i++, page++)
-		mark_page_reserved(page);
+	empty_zero_page = (unsigned long)memblock_alloc_or_panic(PAGE_SIZE << order, PAGE_SIZE);
 
 	zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
 }
···
 	BUILD_BUG_ON(IS_ENABLED(CONFIG_32BIT) && (PFN_PTE_SHIFT > PAGE_SHIFT));
 
 	maar_init();
-	memblock_free_all();
 	setup_zero_pages();	/* Setup zeroed pages.  */
 	mem_init_free_highmem();
+	memblock_free_all();
 
 #ifdef CONFIG_64BIT
 	if ((unsigned long) &_text > (unsigned long) CKSEG0)
···
 void __init mem_init(void)
 {
 	high_memory = (void *) __va(get_num_physpages() << PAGE_SHIFT);
-	memblock_free_all();
 	setup_zero_pages();	/* This comes from node 0 */
+	memblock_free_all();
 }
 #endif /* !CONFIG_NUMA */