400 lines
9.0 KiB
C
400 lines
9.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Memory hotplug support via sclp
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*
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* Copyright IBM Corp. 2025
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*/
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#define KMSG_COMPONENT "sclp_mem"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/cpufeature.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/memory.h>
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#include <linux/memory_hotplug.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/slab.h>
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#include <asm/facility.h>
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#include <asm/page.h>
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#include <asm/page-states.h>
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#include <asm/sclp.h>
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#include "sclp.h"
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#define SCLP_CMDW_ASSIGN_STORAGE 0x000d0001
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#define SCLP_CMDW_UNASSIGN_STORAGE 0x000c0001
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static DEFINE_MUTEX(sclp_mem_mutex);
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static LIST_HEAD(sclp_mem_list);
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static u8 sclp_max_storage_id;
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static DECLARE_BITMAP(sclp_storage_ids, 256);
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struct memory_increment {
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struct list_head list;
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u16 rn;
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int standby;
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};
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struct assign_storage_sccb {
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struct sccb_header header;
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u16 rn;
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} __packed;
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struct attach_storage_sccb {
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struct sccb_header header;
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u16 :16;
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u16 assigned;
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u32 :32;
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u32 entries[];
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} __packed;
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int arch_get_memory_phys_device(unsigned long start_pfn)
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{
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if (!sclp.rzm)
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return 0;
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return PFN_PHYS(start_pfn) >> ilog2(sclp.rzm);
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}
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static unsigned long rn2addr(u16 rn)
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{
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return (unsigned long)(rn - 1) * sclp.rzm;
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}
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static int do_assign_storage(sclp_cmdw_t cmd, u16 rn)
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{
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struct assign_storage_sccb *sccb;
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int rc;
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sccb = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
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if (!sccb)
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return -ENOMEM;
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sccb->header.length = PAGE_SIZE;
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sccb->rn = rn;
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rc = sclp_sync_request_timeout(cmd, sccb, SCLP_QUEUE_INTERVAL);
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if (rc)
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goto out;
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switch (sccb->header.response_code) {
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case 0x0020:
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case 0x0120:
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break;
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default:
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pr_warn("assign storage failed (cmd=0x%08x, response=0x%04x, rn=0x%04x)\n",
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cmd, sccb->header.response_code, rn);
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rc = -EIO;
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break;
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}
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out:
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free_page((unsigned long)sccb);
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return rc;
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}
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static int sclp_assign_storage(u16 rn)
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{
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unsigned long start;
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int rc;
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rc = do_assign_storage(SCLP_CMDW_ASSIGN_STORAGE, rn);
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if (rc)
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return rc;
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start = rn2addr(rn);
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storage_key_init_range(start, start + sclp.rzm);
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return 0;
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}
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static int sclp_unassign_storage(u16 rn)
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{
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return do_assign_storage(SCLP_CMDW_UNASSIGN_STORAGE, rn);
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}
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static int sclp_attach_storage(u8 id)
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{
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struct attach_storage_sccb *sccb;
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int rc, i;
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sccb = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
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if (!sccb)
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return -ENOMEM;
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sccb->header.length = PAGE_SIZE;
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sccb->header.function_code = 0x40;
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rc = sclp_sync_request_timeout(0x00080001 | id << 8, sccb,
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SCLP_QUEUE_INTERVAL);
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if (rc)
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goto out;
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switch (sccb->header.response_code) {
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case 0x0020:
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set_bit(id, sclp_storage_ids);
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for (i = 0; i < sccb->assigned; i++) {
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if (sccb->entries[i])
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sclp_unassign_storage(sccb->entries[i] >> 16);
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}
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break;
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default:
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rc = -EIO;
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break;
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}
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out:
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free_page((unsigned long)sccb);
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return rc;
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}
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static int sclp_mem_change_state(unsigned long start, unsigned long size,
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int online)
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{
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struct memory_increment *incr;
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unsigned long istart;
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int rc = 0;
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list_for_each_entry(incr, &sclp_mem_list, list) {
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istart = rn2addr(incr->rn);
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if (start + size - 1 < istart)
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break;
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if (start > istart + sclp.rzm - 1)
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continue;
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if (online)
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rc |= sclp_assign_storage(incr->rn);
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else
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sclp_unassign_storage(incr->rn);
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if (rc == 0)
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incr->standby = online ? 0 : 1;
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}
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return rc ? -EIO : 0;
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}
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static bool contains_standby_increment(unsigned long start, unsigned long end)
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{
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struct memory_increment *incr;
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unsigned long istart;
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list_for_each_entry(incr, &sclp_mem_list, list) {
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istart = rn2addr(incr->rn);
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if (end - 1 < istart)
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continue;
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if (start > istart + sclp.rzm - 1)
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continue;
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if (incr->standby)
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return true;
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}
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return false;
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}
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static int sclp_mem_notifier(struct notifier_block *nb,
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unsigned long action, void *data)
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{
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unsigned long start, size;
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struct memory_notify *arg;
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unsigned char id;
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int rc = 0;
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arg = data;
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start = arg->start_pfn << PAGE_SHIFT;
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size = arg->nr_pages << PAGE_SHIFT;
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mutex_lock(&sclp_mem_mutex);
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for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1)
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sclp_attach_storage(id);
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switch (action) {
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case MEM_GOING_OFFLINE:
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/*
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* Do not allow to set memory blocks offline that contain
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* standby memory. This is done to simplify the "memory online"
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* case.
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*/
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if (contains_standby_increment(start, start + size))
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rc = -EPERM;
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break;
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case MEM_PREPARE_ONLINE:
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/*
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* Access the altmap_start_pfn and altmap_nr_pages fields
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* within the struct memory_notify specifically when dealing
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* with only MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers.
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*
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* When altmap is in use, take the specified memory range
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* online, which includes the altmap.
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*/
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if (arg->altmap_nr_pages) {
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start = PFN_PHYS(arg->altmap_start_pfn);
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size += PFN_PHYS(arg->altmap_nr_pages);
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}
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rc = sclp_mem_change_state(start, size, 1);
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if (rc || !arg->altmap_nr_pages)
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break;
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/*
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* Set CMMA state to nodat here, since the struct page memory
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* at the beginning of the memory block will not go through the
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* buddy allocator later.
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*/
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__arch_set_page_nodat((void *)__va(start), arg->altmap_nr_pages);
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break;
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case MEM_FINISH_OFFLINE:
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/*
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* When altmap is in use, take the specified memory range
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* offline, which includes the altmap.
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*/
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if (arg->altmap_nr_pages) {
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start = PFN_PHYS(arg->altmap_start_pfn);
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size += PFN_PHYS(arg->altmap_nr_pages);
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}
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sclp_mem_change_state(start, size, 0);
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break;
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default:
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break;
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}
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mutex_unlock(&sclp_mem_mutex);
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return rc ? NOTIFY_BAD : NOTIFY_OK;
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}
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static struct notifier_block sclp_mem_nb = {
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.notifier_call = sclp_mem_notifier,
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};
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static void __init align_to_block_size(unsigned long *start,
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unsigned long *size,
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unsigned long alignment)
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{
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unsigned long start_align, size_align;
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start_align = roundup(*start, alignment);
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size_align = rounddown(*start + *size, alignment) - start_align;
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pr_info("Standby memory at 0x%lx (%luM of %luM usable)\n",
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*start, size_align >> 20, *size >> 20);
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*start = start_align;
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*size = size_align;
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}
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static void __init add_memory_merged(u16 rn)
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{
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unsigned long start, size, addr, block_size;
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static u16 first_rn, num;
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if (rn && first_rn && (first_rn + num == rn)) {
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num++;
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return;
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}
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if (!first_rn)
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goto skip_add;
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start = rn2addr(first_rn);
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size = (unsigned long)num * sclp.rzm;
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if (start >= ident_map_size)
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goto skip_add;
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if (start + size > ident_map_size)
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size = ident_map_size - start;
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block_size = memory_block_size_bytes();
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align_to_block_size(&start, &size, block_size);
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if (!size)
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goto skip_add;
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for (addr = start; addr < start + size; addr += block_size) {
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add_memory(0, addr, block_size,
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cpu_has_edat1() ?
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MHP_MEMMAP_ON_MEMORY | MHP_OFFLINE_INACCESSIBLE : MHP_NONE);
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}
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skip_add:
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first_rn = rn;
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num = 1;
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}
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static void __init sclp_add_standby_memory(void)
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{
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struct memory_increment *incr;
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list_for_each_entry(incr, &sclp_mem_list, list) {
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if (incr->standby)
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add_memory_merged(incr->rn);
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}
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add_memory_merged(0);
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}
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static void __init insert_increment(u16 rn, int standby, int assigned)
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{
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struct memory_increment *incr, *new_incr;
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struct list_head *prev;
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u16 last_rn;
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new_incr = kzalloc(sizeof(*new_incr), GFP_KERNEL);
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if (!new_incr)
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return;
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new_incr->rn = rn;
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new_incr->standby = standby;
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last_rn = 0;
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prev = &sclp_mem_list;
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list_for_each_entry(incr, &sclp_mem_list, list) {
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if (assigned && incr->rn > rn)
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break;
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if (!assigned && incr->rn - last_rn > 1)
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break;
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last_rn = incr->rn;
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prev = &incr->list;
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}
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if (!assigned)
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new_incr->rn = last_rn + 1;
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if (new_incr->rn > sclp.rnmax) {
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kfree(new_incr);
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return;
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}
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list_add(&new_incr->list, prev);
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}
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static int __init sclp_detect_standby_memory(void)
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{
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struct read_storage_sccb *sccb;
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int i, id, assigned, rc;
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/* No standby memory in kdump mode */
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if (oldmem_data.start)
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return 0;
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if ((sclp.facilities & 0xe00000000000UL) != 0xe00000000000UL)
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return 0;
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rc = -ENOMEM;
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sccb = (void *)__get_free_page(GFP_KERNEL | GFP_DMA);
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if (!sccb)
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goto out;
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assigned = 0;
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for (id = 0; id <= sclp_max_storage_id; id++) {
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memset(sccb, 0, PAGE_SIZE);
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sccb->header.length = PAGE_SIZE;
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rc = sclp_sync_request(SCLP_CMDW_READ_STORAGE_INFO | id << 8, sccb);
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if (rc)
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goto out;
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switch (sccb->header.response_code) {
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case 0x0010:
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set_bit(id, sclp_storage_ids);
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for (i = 0; i < sccb->assigned; i++) {
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if (!sccb->entries[i])
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continue;
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assigned++;
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insert_increment(sccb->entries[i] >> 16, 0, 1);
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}
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break;
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case 0x0310:
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break;
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case 0x0410:
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for (i = 0; i < sccb->assigned; i++) {
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if (!sccb->entries[i])
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continue;
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assigned++;
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insert_increment(sccb->entries[i] >> 16, 1, 1);
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}
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break;
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default:
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rc = -EIO;
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break;
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}
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if (!rc)
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sclp_max_storage_id = sccb->max_id;
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}
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if (rc || list_empty(&sclp_mem_list))
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goto out;
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for (i = 1; i <= sclp.rnmax - assigned; i++)
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insert_increment(0, 1, 0);
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rc = register_memory_notifier(&sclp_mem_nb);
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if (rc)
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goto out;
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sclp_add_standby_memory();
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out:
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free_page((unsigned long)sccb);
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return rc;
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}
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__initcall(sclp_detect_standby_memory);
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