mm: Remove arch_remap() and mm-arch-hooks.h

powerpc was the last provider of arch_remap() and the last
user of mm-arch-hooks.h.

Since commit 526a9c4a ("powerpc/vdso: Provide vdso_remap()"),
arch_remap() hence mm-arch-hooks.h are not used anymore.

Remove them.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/asm/Kbuild

@@ -14,7 +14,6 @@ generic-y += irq_regs.h
 generic-y += irq_work.h
 generic-y += kdebug.h
 generic-y += mcs_spinlock.h
-generic-y += mm-arch-hooks.h
 generic-y += mmiowb.h
 generic-y += module.lds.h
 generic-y += param.h

include/asm-generic/Kbuild

@@ -35,7 +35,6 @@ mandatory-y += kprobes.h
 mandatory-y += linkage.h
 mandatory-y += local.h
 mandatory-y += local64.h
-mandatory-y += mm-arch-hooks.h
 mandatory-y += mmiowb.h
 mandatory-y += mmu.h
 mandatory-y += mmu_context.h

include/asm-generic/mm-arch-hooks.h

-/*
- * Architecture specific mm hooks
- */
-
-#ifndef _ASM_GENERIC_MM_ARCH_HOOKS_H
-#define _ASM_GENERIC_MM_ARCH_HOOKS_H
-
-/*
- * This file should be included through arch/../include/asm/Kbuild for
- * the architecture which doesn't need specific mm hooks.
- *
- * In that case, the generic hooks defined in include/linux/mm-arch-hooks.h
- * are used.
- */
-
-#endif /* _ASM_GENERIC_MM_ARCH_HOOKS_H */

include/linux/mm-arch-hooks.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Generic mm no-op hooks.
- *
- * Copyright (C) 2015, IBM Corporation
- * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
- */
-#ifndef _LINUX_MM_ARCH_HOOKS_H
-#define _LINUX_MM_ARCH_HOOKS_H
-
-#include <asm/mm-arch-hooks.h>
-
-#ifndef arch_remap
-static inline void arch_remap(struct mm_struct *mm,
-			      unsigned long old_start, unsigned long old_end,
-			      unsigned long new_start, unsigned long new_end)
-{
-}
-#define arch_remap arch_remap
-#endif
-
-#endif /* _LINUX_MM_ARCH_HOOKS_H */

mm/mremap.c

@@ -22,7 +22,6 @@
 #include <linux/syscalls.h>
 #include <linux/mmu_notifier.h>
 #include <linux/uaccess.h>
-#include <linux/mm-arch-hooks.h>
 #include <linux/userfaultfd_k.h>
 
 #include <asm/cacheflush.h>
@@ -562,8 +561,6 @@ static unsigned long move_vma(struct vm_area_struct *vma,
 		new_addr = err;
 	} else {
 		mremap_userfaultfd_prep(new_vma, uf);
-		arch_remap(mm, old_addr, old_addr + old_len,
-			   new_addr, new_addr + new_len);
 	}
 
 	/* Conceal VM_ACCOUNT so old reservation is not undone */