LXR linux/arch/s390/kernel/machine

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright IBM Corp. 2005, 2011
   4 *
   5 * Author(s): Rolf Adelsberger,
   6 *            Heiko Carstens <heiko.carstens@de.ibm.com>
   7 *            Michael Holzheu <holzheu@linux.vnet.ibm.com>
   8 */
   9
  10#include <linux/device.h>
  11#include <linux/mm.h>
  12#include <linux/kexec.h>
  13#include <linux/delay.h>
  14#include <linux/reboot.h>
  15#include <linux/ftrace.h>
  16#include <linux/debug_locks.h>
  17#include <linux/suspend.h>
  18#include <asm/cio.h>
  19#include <asm/setup.h>
  20#include <asm/pgtable.h>
  21#include <asm/pgalloc.h>
  22#include <asm/smp.h>
  23#include <asm/ipl.h>
  24#include <asm/diag.h>
  25#include <asm/elf.h>
  26#include <asm/asm-offsets.h>
  27#include <asm/cacheflush.h>
  28#include <asm/os_info.h>
  29#include <asm/set_memory.h>
  30#include <asm/stacktrace.h>
  31#include <asm/switch_to.h>
  32#include <asm/nmi.h>
  33
  34typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
  35
  36extern const unsigned char relocate_kernel[];
  37extern const unsigned long long relocate_kernel_len;
  38
  39#ifdef CONFIG_CRASH_DUMP
  40
  41/*
  42 * PM notifier callback for kdump
  43 */
  44static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
  45                               void *ptr)
  46{
  47        switch (action) {
  48        case PM_SUSPEND_PREPARE:
  49        case PM_HIBERNATION_PREPARE:
  50                if (kexec_crash_image)
  51                        arch_kexec_unprotect_crashkres();
  52                break;
  53        case PM_POST_SUSPEND:
  54        case PM_POST_HIBERNATION:
  55                if (kexec_crash_image)
  56                        arch_kexec_protect_crashkres();
  57                break;
  58        default:
  59                return NOTIFY_DONE;
  60        }
  61        return NOTIFY_OK;
  62}
  63
  64static int __init machine_kdump_pm_init(void)
  65{
  66        pm_notifier(machine_kdump_pm_cb, 0);
  67        return 0;
  68}
  69arch_initcall(machine_kdump_pm_init);
  70
  71/*
  72 * Reset the system, copy boot CPU registers to absolute zero,
  73 * and jump to the kdump image
  74 */
  75static void __do_machine_kdump(void *image)
  76{
  77        int (*start_kdump)(int);
  78        unsigned long prefix;
  79
  80        /* store_status() saved the prefix register to lowcore */
  81        prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
  82
  83        /* Now do the reset  */
  84        s390_reset_system();
  85
  86        /*
  87         * Copy dump CPU store status info to absolute zero.
  88         * This need to be done *after* s390_reset_system set the
  89         * prefix register of this CPU to zero
  90         */
  91        memcpy((void *) __LC_FPREGS_SAVE_AREA,
  92               (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
  93
  94        __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
  95        start_kdump = (void *)((struct kimage *) image)->start;
  96        start_kdump(1);
  97
  98        /* Die if start_kdump returns */
  99        disabled_wait();
 100}
 101
 102/*
 103 * Start kdump: create a LGR log entry, store status of all CPUs and
 104 * branch to __do_machine_kdump.
 105 */
 106static noinline void __machine_kdump(void *image)
 107{
 108        struct mcesa *mcesa;
 109        union ctlreg2 cr2_old, cr2_new;
 110        int this_cpu, cpu;
 111
 112        lgr_info_log();
 113        /* Get status of the other CPUs */
 114        this_cpu = smp_find_processor_id(stap());
 115        for_each_online_cpu(cpu) {
 116                if (cpu == this_cpu)
 117                        continue;
 118                if (smp_store_status(cpu))
 119                        continue;
 120        }
 121        /* Store status of the boot CPU */
 122        mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
 123        if (MACHINE_HAS_VX)
 124                save_vx_regs((__vector128 *) mcesa->vector_save_area);
 125        if (MACHINE_HAS_GS) {
 126                __ctl_store(cr2_old.val, 2, 2);
 127                cr2_new = cr2_old;
 128                cr2_new.gse = 1;
 129                __ctl_load(cr2_new.val, 2, 2);
 130                save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area);
 131                __ctl_load(cr2_old.val, 2, 2);
 132        }
 133        /*
 134         * To create a good backchain for this CPU in the dump store_status
 135         * is passed the address of a function. The address is saved into
 136         * the PSW save area of the boot CPU and the function is invoked as
 137         * a tail call of store_status. The backchain in the dump will look
 138         * like this:
 139         *   restart_int_handler ->  __machine_kexec -> __do_machine_kdump
 140         * The call to store_status() will not return.
 141         */
 142        store_status(__do_machine_kdump, image);
 143}
 144
 145static unsigned long do_start_kdump(unsigned long addr)
 146{
 147        struct kimage *image = (struct kimage *) addr;
 148        int (*start_kdump)(int) = (void *)image->start;
 149        int rc;
 150
 151        __arch_local_irq_stnsm(0xfb); /* disable DAT */
 152        rc = start_kdump(0);
 153        __arch_local_irq_stosm(0x04); /* enable DAT */
 154        return rc;
 155}
 156
 157#endif /* CONFIG_CRASH_DUMP */
 158
 159/*
 160 * Check if kdump checksums are valid: We call purgatory with parameter "0"
 161 */
 162static bool kdump_csum_valid(struct kimage *image)
 163{
 164#ifdef CONFIG_CRASH_DUMP
 165        int rc;
 166
 167        rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image);
 168        return rc == 0;
 169#else
 170        return false;
 171#endif
 172}
 173
 174#ifdef CONFIG_CRASH_DUMP
 175
 176void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
 177{
 178        unsigned long addr, size;
 179
 180        for (addr = begin; addr < end; addr += PAGE_SIZE)
 181                free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
 182        size = begin - crashk_res.start;
 183        if (size)
 184                os_info_crashkernel_add(crashk_res.start, size);
 185        else
 186                os_info_crashkernel_add(0, 0);
 187}
 188
 189static void crash_protect_pages(int protect)
 190{
 191        unsigned long size;
 192
 193        if (!crashk_res.end)
 194                return;
 195        size = resource_size(&crashk_res);
 196        if (protect)
 197                set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
 198        else
 199                set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
 200}
 201
 202void arch_kexec_protect_crashkres(void)
 203{
 204        crash_protect_pages(1);
 205}
 206
 207void arch_kexec_unprotect_crashkres(void)
 208{
 209        crash_protect_pages(0);
 210}
 211
 212#endif
 213
 214/*
 215 * Give back memory to hypervisor before new kdump is loaded
 216 */
 217static int machine_kexec_prepare_kdump(void)
 218{
 219#ifdef CONFIG_CRASH_DUMP
 220        if (MACHINE_IS_VM)
 221                diag10_range(PFN_DOWN(crashk_res.start),
 222                             PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 223        return 0;
 224#else
 225        return -EINVAL;
 226#endif
 227}
 228
 229int machine_kexec_prepare(struct kimage *image)
 230{
 231        void *reboot_code_buffer;
 232
 233        if (image->type == KEXEC_TYPE_CRASH)
 234                return machine_kexec_prepare_kdump();
 235
 236        /* We don't support anything but the default image type for now. */
 237        if (image->type != KEXEC_TYPE_DEFAULT)
 238                return -EINVAL;
 239
 240        /* Get the destination where the assembler code should be copied to.*/
 241        reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
 242
 243        /* Then copy it */
 244        memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 245        return 0;
 246}
 247
 248void machine_kexec_cleanup(struct kimage *image)
 249{
 250}
 251
 252void arch_crash_save_vmcoreinfo(void)
 253{
 254        VMCOREINFO_SYMBOL(lowcore_ptr);
 255        VMCOREINFO_SYMBOL(high_memory);
 256        VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 257        mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 258        vmcoreinfo_append_str("SDMA=%lx\n", __sdma);
 259        vmcoreinfo_append_str("EDMA=%lx\n", __edma);
 260        vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
 261}
 262
 263void machine_shutdown(void)
 264{
 265}
 266
 267void machine_crash_shutdown(struct pt_regs *regs)
 268{
 269        set_os_info_reipl_block();
 270}
 271
 272/*
 273 * Do normal kexec
 274 */
 275static void __do_machine_kexec(void *data)
 276{
 277        relocate_kernel_t data_mover;
 278        struct kimage *image = data;
 279
 280        s390_reset_system();
 281        data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 282
 283        __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
 284        /* Call the moving routine */
 285        (*data_mover)(&image->head, image->start);
 286
 287        /* Die if kexec returns */
 288        disabled_wait();
 289}
 290
 291/*
 292 * Reset system and call either kdump or normal kexec
 293 */
 294static void __machine_kexec(void *data)
 295{
 296        __arch_local_irq_stosm(0x04); /* enable DAT */
 297        pfault_fini();
 298        tracing_off();
 299        debug_locks_off();
 300#ifdef CONFIG_CRASH_DUMP
 301        if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
 302                __machine_kdump(data);
 303#endif
 304        __do_machine_kexec(data);
 305}
 306
 307/*
 308 * Do either kdump or normal kexec. In case of kdump we first ask
 309 * purgatory, if kdump checksums are valid.
 310 */
 311void machine_kexec(struct kimage *image)
 312{
 313        if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 314                return;
 315        tracer_disable();
 316        smp_send_stop();
 317        smp_call_ipl_cpu(__machine_kexec, image);
 318}
 319