1 files changed, 721 insertions, 0 deletions

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
new file mode 100644
index 000000000..f316a833b
--- /dev/null
+++ b/arch/ia64/mm/init.c
@@ -0,0 +1,721 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Initialize MMU support.
+ *
+ * Copyright (C) 1998-2003 Hewlett-Packard Co
+ *	David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+#include <linux/dma-map-ops.h>
+#include <linux/dmar.h>
+#include <linux/efi.h>
+#include <linux/elf.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/mmzone.h>
+#include <linux/module.h>
+#include <linux/personality.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/proc_fs.h>
+#include <linux/bitops.h>
+#include <linux/kexec.h>
+#include <linux/swiotlb.h>
+
+#include <asm/dma.h>
+#include <asm/io.h>
+#include <asm/numa.h>
+#include <asm/patch.h>
+#include <asm/pgalloc.h>
+#include <asm/sal.h>
+#include <asm/sections.h>
+#include <asm/tlb.h>
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/mca.h>
+
+extern void ia64_tlb_init (void);
+
+unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;
+
+#ifdef CONFIG_VIRTUAL_MEM_MAP
+unsigned long VMALLOC_END = VMALLOC_END_INIT;
+EXPORT_SYMBOL(VMALLOC_END);
+struct page *vmem_map;
+EXPORT_SYMBOL(vmem_map);
+#endif
+
+struct page *zero_page_memmap_ptr;	/* map entry for zero page */
+EXPORT_SYMBOL(zero_page_memmap_ptr);
+
+void
+__ia64_sync_icache_dcache (pte_t pte)
+{
+	unsigned long addr;
+	struct page *page;
+
+	page = pte_page(pte);
+	addr = (unsigned long) page_address(page);
+
+	if (test_bit(PG_arch_1, &page->flags))
+		return;				/* i-cache is already coherent with d-cache */
+
+	flush_icache_range(addr, addr + page_size(page));
+	set_bit(PG_arch_1, &page->flags);	/* mark page as clean */
+}
+
+/*
+ * Since DMA is i-cache coherent, any (complete) pages that were written via
+ * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
+ * flush them when they get mapped into an executable vm-area.
+ */
+void arch_dma_mark_clean(phys_addr_t paddr, size_t size)
+{
+	unsigned long pfn = PHYS_PFN(paddr);
+
+	do {
+		set_bit(PG_arch_1, &pfn_to_page(pfn)->flags);
+	} while (++pfn <= PHYS_PFN(paddr + size - 1));
+}
+
+inline void
+ia64_set_rbs_bot (void)
+{
+	unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;
+
+	if (stack_size > MAX_USER_STACK_SIZE)
+		stack_size = MAX_USER_STACK_SIZE;
+	current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
+}
+
+/*
+ * This performs some platform-dependent address space initialization.
+ * On IA-64, we want to setup the VM area for the register backing
+ * store (which grows upwards) and install the gateway page which is
+ * used for signal trampolines, etc.
+ */
+void
+ia64_init_addr_space (void)
+{
+	struct vm_area_struct *vma;
+
+	ia64_set_rbs_bot();
+
+	/*
+	 * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
+	 * the problem.  When the process attempts to write to the register backing store
+	 * for the first time, it will get a SEGFAULT in this case.
+	 */
+	vma = vm_area_alloc(current->mm);
+	if (vma) {
+		vma_set_anonymous(vma);
+		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
+		vma->vm_end = vma->vm_start + PAGE_SIZE;
+		vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
+		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+		mmap_write_lock(current->mm);
+		if (insert_vm_struct(current->mm, vma)) {
+			mmap_write_unlock(current->mm);
+			vm_area_free(vma);
+			return;
+		}
+		mmap_write_unlock(current->mm);
+	}
+
+	/* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
+	if (!(current->personality & MMAP_PAGE_ZERO)) {
+		vma = vm_area_alloc(current->mm);
+		if (vma) {
+			vma_set_anonymous(vma);
+			vma->vm_end = PAGE_SIZE;
+			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
+			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
+					VM_DONTEXPAND | VM_DONTDUMP;
+			mmap_write_lock(current->mm);
+			if (insert_vm_struct(current->mm, vma)) {
+				mmap_write_unlock(current->mm);
+				vm_area_free(vma);
+				return;
+			}
+			mmap_write_unlock(current->mm);
+		}
+	}
+}
+
+void
+free_initmem (void)
+{
+	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
+			   -1, "unused kernel");
+}
+
+void __init
+free_initrd_mem (unsigned long start, unsigned long end)
+{
+	/*
+	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
+	 * Thus EFI and the kernel may have different page sizes. It is
+	 * therefore possible to have the initrd share the same page as
+	 * the end of the kernel (given current setup).
+	 *
+	 * To avoid freeing/using the wrong page (kernel sized) we:
+	 *	- align up the beginning of initrd
+	 *	- align down the end of initrd
+	 *
+	 *  |             |
+	 *  |=============| a000
+	 *  |             |
+	 *  |             |
+	 *  |             | 9000
+	 *  |/////////////|
+	 *  |/////////////|
+	 *  |=============| 8000
+	 *  |///INITRD////|
+	 *  |/////////////|
+	 *  |/////////////| 7000
+	 *  |             |
+	 *  |KKKKKKKKKKKKK|
+	 *  |=============| 6000
+	 *  |KKKKKKKKKKKKK|
+	 *  |KKKKKKKKKKKKK|
+	 *  K=kernel using 8KB pages
+	 *
+	 * In this example, we must free page 8000 ONLY. So we must align up
+	 * initrd_start and keep initrd_end as is.
+	 */
+	start = PAGE_ALIGN(start);
+	end = end & PAGE_MASK;
+
+	if (start < end)
+		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);
+
+	for (; start < end; start += PAGE_SIZE) {
+		if (!virt_addr_valid(start))
+			continue;
+		free_reserved_page(virt_to_page(start));
+	}
+}
+
+/*
+ * This installs a clean page in the kernel's page table.
+ */
+static struct page * __init
+put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
+{
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pgd = pgd_offset_k(address);		/* note: this is NOT pgd_offset()! */
+
+	{
+		p4d = p4d_alloc(&init_mm, pgd, address);
+		if (!p4d)
+			goto out;
+		pud = pud_alloc(&init_mm, p4d, address);
+		if (!pud)
+			goto out;
+		pmd = pmd_alloc(&init_mm, pud, address);
+		if (!pmd)
+			goto out;
+		pte = pte_alloc_kernel(pmd, address);
+		if (!pte)
+			goto out;
+		if (!pte_none(*pte))
+			goto out;
+		set_pte(pte, mk_pte(page, pgprot));
+	}
+  out:
+	/* no need for flush_tlb */
+	return page;
+}
+
+static void __init
+setup_gate (void)
+{
+	struct page *page;
+
+	/*
+	 * Map the gate page twice: once read-only to export the ELF
+	 * headers etc. and once execute-only page to enable
+	 * privilege-promotion via "epc":
+	 */
+	page = virt_to_page(ia64_imva(__start_gate_section));
+	put_kernel_page(page, GATE_ADDR, PAGE_READONLY);
+#ifdef HAVE_BUGGY_SEGREL
+	page = virt_to_page(ia64_imva(__start_gate_section + PAGE_SIZE));
+	put_kernel_page(page, GATE_ADDR + PAGE_SIZE, PAGE_GATE);
+#else
+	put_kernel_page(page, GATE_ADDR + PERCPU_PAGE_SIZE, PAGE_GATE);
+	/* Fill in the holes (if any) with read-only zero pages: */
+	{
+		unsigned long addr;
+
+		for (addr = GATE_ADDR + PAGE_SIZE;
+		     addr < GATE_ADDR + PERCPU_PAGE_SIZE;
+		     addr += PAGE_SIZE)
+		{
+			put_kernel_page(ZERO_PAGE(0), addr,
+					PAGE_READONLY);
+			put_kernel_page(ZERO_PAGE(0), addr + PERCPU_PAGE_SIZE,
+					PAGE_READONLY);
+		}
+	}
+#endif
+	ia64_patch_gate();
+}
+
+static struct vm_area_struct gate_vma;
+
+static int __init gate_vma_init(void)
+{
+	vma_init(&gate_vma, NULL);
+	gate_vma.vm_start = FIXADDR_USER_START;
+	gate_vma.vm_end = FIXADDR_USER_END;
+	gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
+	gate_vma.vm_page_prot = __P101;
+
+	return 0;
+}
+__initcall(gate_vma_init);
+
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
+{
+	return &gate_vma;
+}
+
+int in_gate_area_no_mm(unsigned long addr)
+{
+	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
+		return 1;
+	return 0;
+}
+
+int in_gate_area(struct mm_struct *mm, unsigned long addr)
+{
+	return in_gate_area_no_mm(addr);
+}
+
+void ia64_mmu_init(void *my_cpu_data)
+{
+	unsigned long pta, impl_va_bits;
+	extern void tlb_init(void);
+
+#ifdef CONFIG_DISABLE_VHPT
+#	define VHPT_ENABLE_BIT	0
+#else
+#	define VHPT_ENABLE_BIT	1
+#endif
+
+	/*
+	 * Check if the virtually mapped linear page table (VMLPT) overlaps with a mapped
+	 * address space.  The IA-64 architecture guarantees that at least 50 bits of
+	 * virtual address space are implemented but if we pick a large enough page size
+	 * (e.g., 64KB), the mapped address space is big enough that it will overlap with
+	 * VMLPT.  I assume that once we run on machines big enough to warrant 64KB pages,
+	 * IMPL_VA_MSB will be significantly bigger, so this is unlikely to become a
+	 * problem in practice.  Alternatively, we could truncate the top of the mapped
+	 * address space to not permit mappings that would overlap with the VMLPT.
+	 * --davidm 00/12/06
+	 */
+#	define pte_bits			3
+#	define mapped_space_bits	(3*(PAGE_SHIFT - pte_bits) + PAGE_SHIFT)
+	/*
+	 * The virtual page table has to cover the entire implemented address space within
+	 * a region even though not all of this space may be mappable.  The reason for
+	 * this is that the Access bit and Dirty bit fault handlers perform
+	 * non-speculative accesses to the virtual page table, so the address range of the
+	 * virtual page table itself needs to be covered by virtual page table.
+	 */
+#	define vmlpt_bits		(impl_va_bits - PAGE_SHIFT + pte_bits)
+#	define POW2(n)			(1ULL << (n))
+
+	impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61)));
+
+	if (impl_va_bits < 51 || impl_va_bits > 61)
+		panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
+	/*
+	 * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
+	 * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
+	 * the test makes sure that our mapped space doesn't overlap the
+	 * unimplemented hole in the middle of the region.
+	 */
+	if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
+	    (mapped_space_bits > impl_va_bits - 1))
+		panic("Cannot build a big enough virtual-linear page table"
+		      " to cover mapped address space.\n"
+		      " Try using a smaller page size.\n");
+
+
+	/* place the VMLPT at the end of each page-table mapped region: */
+	pta = POW2(61) - POW2(vmlpt_bits);
+
+	/*
+	 * Set the (virtually mapped linear) page table address.  Bit
+	 * 8 selects between the short and long format, bits 2-7 the
+	 * size of the table, and bit 0 whether the VHPT walker is
+	 * enabled.
+	 */
+	ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | VHPT_ENABLE_BIT);
+
+	ia64_tlb_init();
+
+#ifdef	CONFIG_HUGETLB_PAGE
+	ia64_set_rr(HPAGE_REGION_BASE, HPAGE_SHIFT << 2);
+	ia64_srlz_d();
+#endif
+}
+
+#ifdef CONFIG_VIRTUAL_MEM_MAP
+int vmemmap_find_next_valid_pfn(int node, int i)
+{
+	unsigned long end_address, hole_next_pfn;
+	unsigned long stop_address;
+	pg_data_t *pgdat = NODE_DATA(node);
+
+	end_address = (unsigned long) &vmem_map[pgdat->node_start_pfn + i];
+	end_address = PAGE_ALIGN(end_address);
+	stop_address = (unsigned long) &vmem_map[pgdat_end_pfn(pgdat)];
+
+	do {
+		pgd_t *pgd;
+		p4d_t *p4d;
+		pud_t *pud;
+		pmd_t *pmd;
+		pte_t *pte;
+
+		pgd = pgd_offset_k(end_address);
+		if (pgd_none(*pgd)) {
+			end_address += PGDIR_SIZE;
+			continue;
+		}
+
+		p4d = p4d_offset(pgd, end_address);
+		if (p4d_none(*p4d)) {
+			end_address += P4D_SIZE;
+			continue;
+		}
+
+		pud = pud_offset(p4d, end_address);
+		if (pud_none(*pud)) {
+			end_address += PUD_SIZE;
+			continue;
+		}
+
+		pmd = pmd_offset(pud, end_address);
+		if (pmd_none(*pmd)) {
+			end_address += PMD_SIZE;
+			continue;
+		}
+
+		pte = pte_offset_kernel(pmd, end_address);
+retry_pte:
+		if (pte_none(*pte)) {
+			end_address += PAGE_SIZE;
+			pte++;
+			if ((end_address < stop_address) &&
+			    (end_address != ALIGN(end_address, 1UL << PMD_SHIFT)))
+				goto retry_pte;
+			continue;
+		}
+		/* Found next valid vmem_map page */
+		break;
+	} while (end_address < stop_address);
+
+	end_address = min(end_address, stop_address);
+	end_address = end_address - (unsigned long) vmem_map + sizeof(struct page) - 1;
+	hole_next_pfn = end_address / sizeof(struct page);
+	return hole_next_pfn - pgdat->node_start_pfn;
+}
+
+int __init create_mem_map_page_table(u64 start, u64 end, void *arg)
+{
+	unsigned long address, start_page, end_page;
+	struct page *map_start, *map_end;
+	int node;
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
+	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
+
+	start_page = (unsigned long) map_start & PAGE_MASK;
+	end_page = PAGE_ALIGN((unsigned long) map_end);
+	node = paddr_to_nid(__pa(start));
+
+	for (address = start_page; address < end_page; address += PAGE_SIZE) {
+		pgd = pgd_offset_k(address);
+		if (pgd_none(*pgd)) {
+			p4d = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
+			if (!p4d)
+				goto err_alloc;
+			pgd_populate(&init_mm, pgd, p4d);
+		}
+		p4d = p4d_offset(pgd, address);
+
+		if (p4d_none(*p4d)) {
+			pud = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
+			if (!pud)
+				goto err_alloc;
+			p4d_populate(&init_mm, p4d, pud);
+		}
+		pud = pud_offset(p4d, address);
+
+		if (pud_none(*pud)) {
+			pmd = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
+			if (!pmd)
+				goto err_alloc;
+			pud_populate(&init_mm, pud, pmd);
+		}
+		pmd = pmd_offset(pud, address);
+
+		if (pmd_none(*pmd)) {
+			pte = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE, node);
+			if (!pte)
+				goto err_alloc;
+			pmd_populate_kernel(&init_mm, pmd, pte);
+		}
+		pte = pte_offset_kernel(pmd, address);
+
+		if (pte_none(*pte)) {
+			void *page = memblock_alloc_node(PAGE_SIZE, PAGE_SIZE,
+							 node);
+			if (!page)
+				goto err_alloc;
+			set_pte(pte, pfn_pte(__pa(page) >> PAGE_SHIFT,
+					     PAGE_KERNEL));
+		}
+	}
+	return 0;
+
+err_alloc:
+	panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d\n",
+	      __func__, PAGE_SIZE, PAGE_SIZE, node);
+	return -ENOMEM;
+}
+
+struct memmap_init_callback_data {
+	struct page *start;
+	struct page *end;
+	int nid;
+	unsigned long zone;
+};
+
+static int __meminit
+virtual_memmap_init(u64 start, u64 end, void *arg)
+{
+	struct memmap_init_callback_data *args;
+	struct page *map_start, *map_end;
+
+	args = (struct memmap_init_callback_data *) arg;
+	map_start = vmem_map + (__pa(start) >> PAGE_SHIFT);
+	map_end   = vmem_map + (__pa(end) >> PAGE_SHIFT);
+
+	if (map_start < args->start)
+		map_start = args->start;
+	if (map_end > args->end)
+		map_end = args->end;
+
+	/*
+	 * We have to initialize "out of bounds" struct page elements that fit completely
+	 * on the same pages that were allocated for the "in bounds" elements because they
+	 * may be referenced later (and found to be "reserved").
+	 */
+	map_start -= ((unsigned long) map_start & (PAGE_SIZE - 1)) / sizeof(struct page);
+	map_end += ((PAGE_ALIGN((unsigned long) map_end) - (unsigned long) map_end)
+		    / sizeof(struct page));
+
+	if (map_start < map_end)
+		memmap_init_zone((unsigned long)(map_end - map_start),
+				 args->nid, args->zone, page_to_pfn(map_start), page_to_pfn(map_end),
+				 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
+	return 0;
+}
+
+void __meminit
+arch_memmap_init (unsigned long size, int nid, unsigned long zone,
+	     unsigned long start_pfn)
+{
+	if (!vmem_map) {
+		memmap_init_zone(size, nid, zone, start_pfn, start_pfn + size,
+				 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
+	} else {
+		struct page *start;
+		struct memmap_init_callback_data args;
+
+		start = pfn_to_page(start_pfn);
+		args.start = start;
+		args.end = start + size;
+		args.nid = nid;
+		args.zone = zone;
+
+		efi_memmap_walk(virtual_memmap_init, &args);
+	}
+}
+
+void __init memmap_init(void)
+{
+}
+
+int
+ia64_pfn_valid (unsigned long pfn)
+{
+	char byte;
+	struct page *pg = pfn_to_page(pfn);
+
+	return     (__get_user(byte, (char __user *) pg) == 0)
+		&& ((((u64)pg & PAGE_MASK) == (((u64)(pg + 1) - 1) & PAGE_MASK))
+			|| (__get_user(byte, (char __user *) (pg + 1) - 1) == 0));
+}
+EXPORT_SYMBOL(ia64_pfn_valid);
+
+int __init find_largest_hole(u64 start, u64 end, void *arg)
+{
+	u64 *max_gap = arg;
+
+	static u64 last_end = PAGE_OFFSET;
+
+	/* NOTE: this algorithm assumes efi memmap table is ordered */
+
+	if (*max_gap < (start - last_end))
+		*max_gap = start - last_end;
+	last_end = end;
+	return 0;
+}
+
+#endif /* CONFIG_VIRTUAL_MEM_MAP */
+
+int __init register_active_ranges(u64 start, u64 len, int nid)
+{
+	u64 end = start + len;
+
+#ifdef CONFIG_KEXEC
+	if (start > crashk_res.start && start < crashk_res.end)
+		start = crashk_res.end;
+	if (end > crashk_res.start && end < crashk_res.end)
+		end = crashk_res.start;
+#endif
+
+	if (start < end)
+		memblock_add_node(__pa(start), end - start, nid);
+	return 0;
+}
+
+int
+find_max_min_low_pfn (u64 start, u64 end, void *arg)
+{
+	unsigned long pfn_start, pfn_end;
+#ifdef CONFIG_FLATMEM
+	pfn_start = (PAGE_ALIGN(__pa(start))) >> PAGE_SHIFT;
+	pfn_end = (PAGE_ALIGN(__pa(end - 1))) >> PAGE_SHIFT;
+#else
+	pfn_start = GRANULEROUNDDOWN(__pa(start)) >> PAGE_SHIFT;
+	pfn_end = GRANULEROUNDUP(__pa(end - 1)) >> PAGE_SHIFT;
+#endif
+	min_low_pfn = min(min_low_pfn, pfn_start);
+	max_low_pfn = max(max_low_pfn, pfn_end);
+	return 0;
+}
+
+/*
+ * Boot command-line option "nolwsys" can be used to disable the use of any light-weight
+ * system call handler.  When this option is in effect, all fsyscalls will end up bubbling
+ * down into the kernel and calling the normal (heavy-weight) syscall handler.  This is
+ * useful for performance testing, but conceivably could also come in handy for debugging
+ * purposes.
+ */
+
+static int nolwsys __initdata;
+
+static int __init
+nolwsys_setup (char *s)
+{
+	nolwsys = 1;
+	return 1;
+}
+
+__setup("nolwsys", nolwsys_setup);
+
+void __init
+mem_init (void)
+{
+	int i;
+
+	BUG_ON(PTRS_PER_PGD * sizeof(pgd_t) != PAGE_SIZE);
+	BUG_ON(PTRS_PER_PMD * sizeof(pmd_t) != PAGE_SIZE);
+	BUG_ON(PTRS_PER_PTE * sizeof(pte_t) != PAGE_SIZE);
+
+	/*
+	 * This needs to be called _after_ the command line has been parsed but
+	 * _before_ any drivers that may need the PCI DMA interface are
+	 * initialized or bootmem has been freed.
+	 */
+#ifdef CONFIG_INTEL_IOMMU
+	detect_intel_iommu();
+	if (!iommu_detected)
+#endif
+#ifdef CONFIG_SWIOTLB
+		swiotlb_init(1);
+#endif
+
+#ifdef CONFIG_FLATMEM
+	BUG_ON(!mem_map);
+#endif
+
+	set_max_mapnr(max_low_pfn);
+	high_memory = __va(max_low_pfn * PAGE_SIZE);
+	memblock_free_all();
+	mem_init_print_info(NULL);
+
+	/*
+	 * For fsyscall entrpoints with no light-weight handler, use the ordinary
+	 * (heavy-weight) handler, but mark it by setting bit 0, so the fsyscall entry
+	 * code can tell them apart.
+	 */
+	for (i = 0; i < NR_syscalls; ++i) {
+		extern unsigned long fsyscall_table[NR_syscalls];
+		extern unsigned long sys_call_table[NR_syscalls];
+
+		if (!fsyscall_table[i] || nolwsys)
+			fsyscall_table[i] = sys_call_table[i] | 1;
+	}
+	setup_gate();
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int arch_add_memory(int nid, u64 start, u64 size,
+		    struct mhp_params *params)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	int ret;
+
+	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
+		return -EINVAL;
+
+	ret = __add_pages(nid, start_pfn, nr_pages, params);
+	if (ret)
+		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
+		       __func__,  ret);
+
+	return ret;
+}
+
+void arch_remove_memory(int nid, u64 start, u64 size,
+			struct vmem_altmap *altmap)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+
+	__remove_pages(start_pfn, nr_pages, altmap);
+}
+#endif