// SPDX-License-Identifier: GPL-2.0-only
/*
* Architecture specific (i386/x86_64) functions for kexec based crash dumps.
*
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
*
* Copyright (C) IBM Corporation, 2004. All rights reserved.
* Copyright (C) Red Hat Inc., 2014. All rights reserved.
* Authors:
* Vivek Goyal <vgoyal@redhat.com>
*
*/
#define pr_fmt(fmt) "kexec: " fmt
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/reboot.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
#include <asm/nmi.h>
#include <asm/hw_irq.h>
#include <asm/apic.h>
#include <asm/e820/types.h>
#include <asm/io_apic.h>
#include <asm/hpet.h>
#include <linux/kdebug.h>
#include <asm/cpu.h>
#include <asm/reboot.h>
#include <asm/virtext.h>
#include <asm/intel_pt.h>
#include <asm/crash.h>
/* Used while preparing memory map entries for second kernel */
struct crash_memmap_data {
struct boot_params *params;
/* Type of memory */
unsigned int type;
};
/*
* This is used to VMCLEAR all VMCSs loaded on the
* processor. And when loading kvm_intel module, the
* callback function pointer will be assigned.
*
* protected by rcu.
*/
crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
static inline void cpu_crash_vmclear_loaded_vmcss(void)
{
crash_vmclear_fn *do_vmclear_operation = NULL;
rcu_read_lock();
do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
if (do_vmclear_operation)
do_vmclear_operation();
rcu_read_unlock();
}
#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
{
crash_save_cpu(regs, cpu);
/*
* VMCLEAR VMCSs loaded on all cpus if needed.
*/
cpu_crash_vmclear_loaded_vmcss();
/* Disable VMX or SVM if needed.
*
* We need to disable virtualization on all CPUs.
* Having VMX or SVM enabled on any CPU may break rebooting
* after the kdump kernel has finished its task.
*/
cpu_emergency_vmxoff();
cpu_emergency_svm_disable();
/*
* Disable Intel PT to stop its logging
*/
cpu_emergency_stop_pt();
disable_local_APIC();
}
void kdump_nmi_shootdown_cpus(void)
{
nmi_shootdown_cpus(kdump_nmi_callback);
disable_local_APIC();
}
/* Override the weak function in kernel/panic.c */
void crash_smp_send_stop(void)
{
static int cpus_stopped;
if (cpus_stopped)
return;
if (smp_ops.crash_stop_other_cpus)
smp_ops.crash_stop_other_cpus();
else
smp_send_stop();
cpus_stopped = 1;
}
#else
void crash_smp_send_stop(void)
{
/* There are no cpus to shootdown */
}
#endif
void native_machine_crash_shutdown(struct pt_regs *regs)
{
/* This function is only called after the system
* has panicked or is otherwise in a critical state.
* The minimum amount of code to allow a kexec'd kernel
* to run successfully needs to happen here.
*
* In practice this means shooting down the other cpus in
* an SMP system.
*/
/* The kernel is broken so disable interrupts */
local_irq_disable();
crash_smp_send_stop();
/*
* VMCLEAR VMCSs loaded on this cpu if needed.
*/
cpu_crash_vmclear_loaded_vmcss();
/* Booting kdump kernel with VMX or SVM enabled won't work,
* because (among other limitations) we can't disable paging
* with the virt flags.
*/
cpu_emergency_vmxoff();
cpu_emergency_svm_disable();
/*
* Disable Intel PT to stop its logging
*/
cpu_emergency_stop_pt();
#ifdef CONFIG_X86_IO_APIC
/* Prevent crash_kexec() from deadlocking on ioapic_lock. */
ioapic_zap_locks();
clear_IO_APIC();
#endif
lapic_shutdown();
restore_boot_irq_mode();
#ifdef CONFIG_HPET_TIMER
hpet_disable();
#endif
crash_save_cpu(regs, safe_smp_processor_id());
}
#ifdef CONFIG_KEXEC_FILE
static unsigned long crash_zero_bytes;
static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
{
unsigned int *nr_ranges = arg;
(*nr_ranges)++;
return 0;
}
/* Gather all the required information to prepare elf headers for ram regions */
static struct crash_mem *fill_up_crash_elf_data(void)
{
unsigned int nr_ranges = 0;
struct crash_mem *cmem;
walk_system_ram_res(0, -1, &nr_ranges,
get_nr_ram_ranges_callback);
if (!nr_ranges)
return NULL;
/*
* Exclusion of crash region and/or crashk_low_res may cause
* another range split. So add extra two slots here.
*/
nr_ranges += 2;
cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
if (!cmem)
return NULL;
cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
return cmem;
}
/*
* Look for any unwanted ranges between mstart, mend and remove them. This
* might lead to split and split ranges are put in cmem->ranges[] array
*/
static int elf_header_exclude_ranges(struct crash_mem *cmem)
{
int ret = 0;
/* Exclude crashkernel region */
ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
if (ret)
return ret;
if (crashk_low_res.end) {
ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
crashk_low_res.end);
if (ret)
return ret;
}
return ret;
}
static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
{
struct crash_mem *cmem = arg;
cmem->ranges[cmem->nr_ranges].start = res->start;
cmem->ranges[cmem->nr_ranges].end = res->end;
cmem->nr_ranges++;
return 0;
}
/* Prepare elf headers. Return addr and size */
static int prepare_elf_headers(struct kimage *image, void **addr,
unsigned long *sz)
{
struct crash_mem *cmem;
Elf64_Ehdr *ehdr;
Elf64_Phdr *phdr;
int ret, i;
cmem = fill_up_crash_elf_data();
if (!cmem)
return -ENOMEM;
ret = walk_system_ram_res(0, -1, cmem,
prepare_elf64_ram_headers_callback);
if (ret)
goto out;
/* Exclude unwanted mem ranges */
ret = elf_header_exclude_ranges(cmem);
if (ret)
goto out;
/* By default prepare 64bit headers */
ret = crash_prepare_elf64_headers(cmem,
IS_ENABLED(CONFIG_X86_64), addr, sz);
if (ret)
goto out;
/*
* If a range matches backup region, adjust offset to backup
* segment.
*/
ehdr = (Elf64_Ehdr *)*addr;
phdr = (Elf64_Phdr *)(ehdr + 1);
for (i = 0; i < ehdr->e_phnum; phdr++, i++)
if (phdr->p_type == PT_LOAD &&
phdr->p_paddr == image->arch.backup_src_start &&
phdr->p_memsz == image->arch.backup_src_sz) {
phdr->p_offset = image->arch.backup_load_addr;
break;
}
out:
vfree(cmem);
return ret;
}
static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
{
unsigned int nr_e820_entries;
nr_e820_entries = params->e820_entries;
if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
return 1;
memcpy(¶ms->e820_table[nr_e820_entries], entry,
sizeof(struct e820_entry));
params->e820_entries++;
return 0;
}
static int memmap_entry_callback(struct resource *res, void *arg)
{
struct crash_memmap_data *cmd = arg;
struct boot_params *params = cmd->params;
struct e820_entry ei;
ei.addr = res->start;
ei.size = resource_size(res);
ei.type = cmd->type;
add_e820_entry(params, &ei);
return 0;
}
static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
unsigned long long mstart,
unsigned long long mend)
{
unsigned long start, end;
int ret = 0;
cmem->ranges[0].start = mstart;
cmem->ranges[0].end = mend;
cmem->nr_ranges = 1;
/* Exclude Backup region */
start = image->arch.backup_load_addr;
end = start + image->arch.backup_src_sz - 1;
ret = crash_exclude_mem_range(cmem, start, end);
if (ret)
return ret;
/* Exclude elf header region */
start = image->arch.elf_load_addr;
end = start + image->arch.elf_headers_sz - 1;
return crash_exclude_mem_range(cmem, start, end);
}
/* Prepare memory map for crash dump kernel */
int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
{
int i, ret = 0;
unsigned long flags;
struct e820_entry ei;
struct crash_memmap_data cmd;
struct crash_mem *cmem;
cmem = vzalloc(sizeof(struct crash_mem));
if (!cmem)
return -ENOMEM;
memset(&cmd, 0, sizeof(struct crash_memmap_data));
cmd.params = params;
/* Add first 640K segment */
ei.addr = image->arch.backup_src_start;
ei.size = image->arch.backup_src_sz;
ei.type = E820_TYPE_RAM;
add_e820_entry(params, &ei);
/* Add ACPI tables */
cmd.type = E820_TYPE_ACPI;
flags = IORESOURCE_MEM | IORESOURCE_BUSY;
walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
memmap_entry_callback);
/* Add ACPI Non-volatile Storage */
cmd.type = E820_TYPE_NVS;
walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
memmap_entry_callback);
/* Add e820 reserved ranges */
cmd.type = E820_TYPE_RESERVED;
flags = IORESOURCE_MEM;
walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd,
memmap_entry_callback);
/* Add crashk_low_res region */
if (crashk_low_res.end) {
ei.addr = crashk_low_res.start;
ei.size = crashk_low_res.end - crashk_low_res.start + 1;
ei.type = E820_TYPE_RAM;
add_e820_entry(params, &ei);
}
/* Exclude some ranges from crashk_res and add rest to memmap */
ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
crashk_res.end);
if (ret)
goto out;
for (i = 0; i < cmem->nr_ranges; i++) {
ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
/* If entry is less than a page, skip it */
if (ei.size < PAGE_SIZE)
continue;
ei.addr = cmem->ranges[i].start;
ei.type = E820_TYPE_RAM;
add_e820_entry(params, &ei);
}
out:
vfree(cmem);
return ret;
}
static int determine_backup_region(struct resource *res, void *arg)
{
struct kimage *image = arg;
image->arch.backup_src_start = res->start;
image->arch.backup_src_sz = resource_size(res);
/* Expecting only one range for backup region */
return 1;
}
int crash_load_segments(struct kimage *image)
{
int ret;
struct kexec_buf kbuf = { .image = image, .buf_min = 0,
.buf_max = ULONG_MAX, .top_down = false };
/*
* Determine and load a segment for backup area. First 640K RAM
* region is backup source
*/
ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
image, determine_backup_region);
/* Zero or postive return values are ok */
if (ret < 0)
return ret;
/* Add backup segment. */
if (image->arch.backup_src_sz) {
kbuf.buffer = &crash_zero_bytes;
kbuf.bufsz = sizeof(crash_zero_bytes);
kbuf.memsz = image->arch.backup_src_sz;
kbuf.buf_align = PAGE_SIZE;
/*
* Ideally there is no source for backup segment. This is
* copied in purgatory after crash. Just add a zero filled
* segment for now to make sure checksum logic works fine.
*/
ret = kexec_add_buffer(&kbuf);
if (ret)
return ret;
image->arch.backup_load_addr = kbuf.mem;
pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
image->arch.backup_load_addr,
image->arch.backup_src_start, kbuf.memsz);
}
/* Prepare elf headers and add a segment */
ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
if (ret)
return ret;
image->arch.elf_headers = kbuf.buffer;
image->arch.elf_headers_sz = kbuf.bufsz;
kbuf.memsz = kbuf.bufsz;
kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
ret = kexec_add_buffer(&kbuf);
if (ret) {
vfree((void *)image->arch.elf_headers);
return ret;
}
image->arch.elf_load_addr = kbuf.mem;
pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
return ret;
}
#endif /* CONFIG_KEXEC_FILE */
