powerpc/mm: make ioremap_bot common to all

Drop multiple definitions of ioremap_bot and make one common to
all subarches.

Only CONFIG_PPC_BOOK3E_64 had a global static init value for
ioremap_bot. Now ioremap_bot is set in early_init_mmu_global().
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/920eebfd9f36f14c79d1755847f5bf7c83703bdd.1566309262.git.christophe.leroy@c-s.fr

arch/powerpc/include/asm/book3s/32/pgtable.h

@@ -201,8 +201,6 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
 #include <linux/sched.h>
 #include <linux/threads.h>
 
-extern unsigned long ioremap_bot;
-
 /* Bits to mask out from a PGD to get to the PUD page */
 #define PGD_MASKED_BITS		0
 

arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -289,7 +289,6 @@ extern unsigned long __kernel_io_end;
 #define KERN_IO_END __kernel_io_end
 
 extern struct page *vmemmap;
-extern unsigned long ioremap_bot;
 extern unsigned long pci_io_base;
 #endif /* __ASSEMBLY__ */
 

arch/powerpc/include/asm/nohash/32/pgtable.h

@@ -11,8 +11,6 @@
 #include <asm/mmu.h>			/* For sub-arch specific PPC_PIN_SIZE */
 #include <asm/asm-405.h>
 
-extern unsigned long ioremap_bot;
-
 #ifdef CONFIG_44x
 extern int icache_44x_need_flush;
 #endif

arch/powerpc/include/asm/pgtable.h

@@ -68,6 +68,8 @@ extern pgd_t swapper_pg_dir[];
 
 extern void paging_init(void);
 
+extern unsigned long ioremap_bot;
+
 /*
  * kern_addr_valid is intended to indicate whether an address is a valid
  * kernel address.  Most 32-bit archs define it as always true (like this)

arch/powerpc/mm/ioremap.c

@@ -3,6 +3,9 @@
 #include <linux/io.h>
 #include <asm/io-workarounds.h>
 
+unsigned long ioremap_bot;
+EXPORT_SYMBOL(ioremap_bot);
+
 void __iomem *ioremap(phys_addr_t addr, unsigned long size)
 {
 	pgprot_t prot = pgprot_noncached(PAGE_KERNEL);

arch/powerpc/mm/mmu_decl.h

@@ -106,7 +106,6 @@ extern u8 early_hash[];
 
 #endif /* CONFIG_PPC32 */
 
-extern unsigned long ioremap_bot;
 extern unsigned long __max_low_memory;
 extern phys_addr_t __initial_memory_limit_addr;
 extern phys_addr_t total_memory;

arch/powerpc/mm/nohash/tlb.c

@@ -703,6 +703,8 @@ static void __init early_init_mmu_global(void)
 	 * for use by the TLB miss code
 	 */
 	linear_map_top = memblock_end_of_DRAM();
+
+	ioremap_bot = IOREMAP_BASE;
 }
 
 static void __init early_mmu_set_memory_limit(void)

arch/powerpc/mm/pgtable_32.c

@@ -33,9 +33,6 @@
 
 #include <mm/mmu_decl.h>
 
-unsigned long ioremap_bot;
-EXPORT_SYMBOL(ioremap_bot);	/* aka VMALLOC_END */
-
 extern char etext[], _stext[], _sinittext[], _einittext[];
 
 void __iomem *

arch/powerpc/mm/pgtable_64.c

@@ -98,9 +98,6 @@ unsigned long __pte_frag_nr;
 EXPORT_SYMBOL(__pte_frag_nr);
 unsigned long __pte_frag_size_shift;
 EXPORT_SYMBOL(__pte_frag_size_shift);
-unsigned long ioremap_bot;
-#else /* !CONFIG_PPC_BOOK3S_64 */
-unsigned long ioremap_bot = IOREMAP_BASE;
 #endif
 
 int __weak ioremap_range(unsigned long ea, phys_addr_t pa, unsigned long size, pgprot_t prot, int nid)