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d07a980c1b
On s390 __ro_after_init is currently mapped to __read_mostly which means that data marked as __ro_after_init will not be protected. Reason for this is that the common code __ro_after_init implementation is x86 centric: the ro_after_init data section was added to rodata, since x86 enables write protection to kernel text and rodata very late. On s390 we have write protection for these sections enabled with the initial page tables. So adding the ro_after_init data section to rodata does not work on s390. In order to make __ro_after_init work properly on s390 move the ro_after_init data, right behind rodata. Unlike the rodata section it will be marked read-only later after all init calls happened. This s390 specific implementation adds new __start_ro_after_init and __end_ro_after_init labels. Everything in between will be marked read-only after the init calls happened. In addition to the __ro_after_init data move also the exception table there, since from a practical point of view it fits the __ro_after_init requirements. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
211 lines
5.4 KiB
C
211 lines
5.4 KiB
C
/*
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* S390 version
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* Copyright IBM Corp. 1999
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* Author(s): Hartmut Penner (hp@de.ibm.com)
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1995 Linus Torvalds
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*/
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/bootmem.h>
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#include <linux/memory.h>
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#include <linux/pfn.h>
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#include <linux/poison.h>
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#include <linux/initrd.h>
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#include <linux/export.h>
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#include <linux/gfp.h>
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#include <linux/memblock.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/dma.h>
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#include <asm/lowcore.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/sections.h>
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#include <asm/ctl_reg.h>
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#include <asm/sclp.h>
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pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
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unsigned long empty_zero_page, zero_page_mask;
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EXPORT_SYMBOL(empty_zero_page);
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EXPORT_SYMBOL(zero_page_mask);
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static void __init setup_zero_pages(void)
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{
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unsigned int order;
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struct page *page;
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int i;
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/* Latest machines require a mapping granularity of 512KB */
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order = 7;
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/* Limit number of empty zero pages for small memory sizes */
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while (order > 2 && (totalram_pages >> 10) < (1UL << order))
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order--;
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empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
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if (!empty_zero_page)
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panic("Out of memory in setup_zero_pages");
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page = virt_to_page((void *) empty_zero_page);
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split_page(page, order);
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for (i = 1 << order; i > 0; i--) {
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mark_page_reserved(page);
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page++;
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}
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zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
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}
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/*
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* paging_init() sets up the page tables
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*/
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void __init paging_init(void)
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{
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unsigned long max_zone_pfns[MAX_NR_ZONES];
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unsigned long pgd_type, asce_bits;
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init_mm.pgd = swapper_pg_dir;
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if (VMALLOC_END > (1UL << 42)) {
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asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
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pgd_type = _REGION2_ENTRY_EMPTY;
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} else {
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asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
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pgd_type = _REGION3_ENTRY_EMPTY;
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}
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init_mm.context.asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
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S390_lowcore.kernel_asce = init_mm.context.asce;
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clear_table((unsigned long *) init_mm.pgd, pgd_type,
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sizeof(unsigned long)*2048);
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vmem_map_init();
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/* enable virtual mapping in kernel mode */
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__ctl_load(S390_lowcore.kernel_asce, 1, 1);
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__ctl_load(S390_lowcore.kernel_asce, 7, 7);
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__ctl_load(S390_lowcore.kernel_asce, 13, 13);
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__arch_local_irq_stosm(0x04);
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sparse_memory_present_with_active_regions(MAX_NUMNODES);
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sparse_init();
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memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
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max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
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max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
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free_area_init_nodes(max_zone_pfns);
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}
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void mark_rodata_ro(void)
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{
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unsigned long size = __end_ro_after_init - __start_ro_after_init;
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set_memory_ro((unsigned long)__start_ro_after_init, size >> PAGE_SHIFT);
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pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);
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}
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void __init mem_init(void)
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{
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cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
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cpumask_set_cpu(0, mm_cpumask(&init_mm));
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set_max_mapnr(max_low_pfn);
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high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
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/* Setup guest page hinting */
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cmma_init();
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/* this will put all low memory onto the freelists */
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free_all_bootmem();
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setup_zero_pages(); /* Setup zeroed pages. */
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mem_init_print_info(NULL);
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}
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void free_initmem(void)
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{
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free_initmem_default(POISON_FREE_INITMEM);
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}
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#ifdef CONFIG_BLK_DEV_INITRD
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void __init free_initrd_mem(unsigned long start, unsigned long end)
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{
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free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
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"initrd");
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}
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#endif
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#ifdef CONFIG_MEMORY_HOTPLUG
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int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
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{
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unsigned long normal_end_pfn = PFN_DOWN(memblock_end_of_DRAM());
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unsigned long dma_end_pfn = PFN_DOWN(MAX_DMA_ADDRESS);
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unsigned long start_pfn = PFN_DOWN(start);
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unsigned long size_pages = PFN_DOWN(size);
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unsigned long nr_pages;
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int rc, zone_enum;
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rc = vmem_add_mapping(start, size);
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if (rc)
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return rc;
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while (size_pages > 0) {
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if (start_pfn < dma_end_pfn) {
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nr_pages = (start_pfn + size_pages > dma_end_pfn) ?
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dma_end_pfn - start_pfn : size_pages;
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zone_enum = ZONE_DMA;
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} else if (start_pfn < normal_end_pfn) {
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nr_pages = (start_pfn + size_pages > normal_end_pfn) ?
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normal_end_pfn - start_pfn : size_pages;
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zone_enum = ZONE_NORMAL;
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} else {
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nr_pages = size_pages;
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zone_enum = ZONE_MOVABLE;
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}
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rc = __add_pages(nid, NODE_DATA(nid)->node_zones + zone_enum,
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start_pfn, size_pages);
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if (rc)
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break;
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start_pfn += nr_pages;
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size_pages -= nr_pages;
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}
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if (rc)
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vmem_remove_mapping(start, size);
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return rc;
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}
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unsigned long memory_block_size_bytes(void)
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{
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/*
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* Make sure the memory block size is always greater
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* or equal than the memory increment size.
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*/
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return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
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}
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#ifdef CONFIG_MEMORY_HOTREMOVE
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int arch_remove_memory(u64 start, u64 size)
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{
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/*
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* There is no hardware or firmware interface which could trigger a
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* hot memory remove on s390. So there is nothing that needs to be
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* implemented.
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*/
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return -EBUSY;
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}
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#endif
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#endif /* CONFIG_MEMORY_HOTPLUG */
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