[PATCH 1/5] kexec_core: move kdump related codes from crash_core.c to kexec_core.c

Baoquan He
2024-01-05T10:33:50Z

In commit 6f991cc363a3 ("crash: move a few code bits to setup support
of crash hotplug"), some elfcorehdr processing codes were moved to
kernel/crash_core.c so that they can be shared by kexec_load and
kexec_file_load interface. And later in commit 247262756121 ("crash: add
generic infrastructure for crash hotplug support"), generic code for
crash hotplug support codes were added into kernel/crash_core.c.

In fact, these codes should be put in kernel/kexec_core.c because
both kexec_load and kexec_file_load need them.

So move them from kernel/crash_core.c to kernel/kexec_core.c. No
functionality change is introduced.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
include/linux/crash_core.h | 26 ---
include/linux/kexec.h | 24 +++
kernel/crash_core.c | 404 ------------------------------------
kernel/kexec_core.c | 408 +++++++++++++++++++++++++++++++++++++
4 files changed, 432 insertions(+), 430 deletions(-)

diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 5126a4fecb44..af304259afa3 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -124,30 +124,4 @@ static inline void __init reserve_crashkernel_generic(char *cmdline,
bool high)
{}
#endif
-
-/* Alignment required for elf header segment */
-#define ELF_CORE_HEADER_ALIGN 4096
-
-struct crash_mem {
- unsigned int max_nr_ranges;
- unsigned int nr_ranges;
- struct range ranges[] __counted_by(max_nr_ranges);
-};
-
-extern int crash_exclude_mem_range(struct crash_mem *mem,
- unsigned long long mstart,
- unsigned long long mend);
-extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
- void **addr, unsigned long *sz);
-
-struct kimage;
-struct kexec_segment;
-
-#define KEXEC_CRASH_HP_NONE 0
-#define KEXEC_CRASH_HP_ADD_CPU 1
-#define KEXEC_CRASH_HP_REMOVE_CPU 2
-#define KEXEC_CRASH_HP_ADD_MEMORY 3
-#define KEXEC_CRASH_HP_REMOVE_MEMORY 4
-#define KEXEC_CRASH_HP_INVALID_CPU -1U
-
#endif /* LINUX_CRASH_CORE_H */
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 8227455192b7..6705812f07f5 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -227,6 +227,21 @@ static inline int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
}
#endif

+/* Alignment required for elf header segment */
+#define ELF_CORE_HEADER_ALIGN 4096
+
+struct crash_mem {
+ unsigned int max_nr_ranges;
+ unsigned int nr_ranges;
+ struct range ranges[] __counted_by(max_nr_ranges);
+};
+
+extern int crash_exclude_mem_range(struct crash_mem *mem,
+ unsigned long long mstart,
+ unsigned long long mend);
+extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
+ void **addr, unsigned long *sz);
+
#ifndef arch_kexec_apply_relocations_add
/*
* arch_kexec_apply_relocations_add - apply relocations of type RELA
@@ -500,6 +515,15 @@ static inline int crash_hotplug_memory_support(void) { return 0; }
static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
#endif

+#ifdef CONFIG_CRASH_HOTPLUG
+#define KEXEC_CRASH_HP_NONE 0
+#define KEXEC_CRASH_HP_ADD_CPU 1
+#define KEXEC_CRASH_HP_REMOVE_CPU 2
+#define KEXEC_CRASH_HP_ADD_MEMORY 3
+#define KEXEC_CRASH_HP_REMOVE_MEMORY 4
+#define KEXEC_CRASH_HP_INVALID_CPU -1U
+#endif
+
#else /* !CONFIG_KEXEC_CORE */
struct pt_regs;
struct task_struct;
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index d4313b53837e..b4f3fdecbe26 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -24,9 +24,6 @@
#include "kallsyms_internal.h"
#include "kexec_internal.h"

-/* Per cpu memory for storing cpu states in case of system crash. */
-note_buf_t __percpu *crash_notes;
-
/* vmcoreinfo stuff */
unsigned char *vmcoreinfo_data;
size_t vmcoreinfo_size;
@@ -463,187 +460,6 @@ void __init reserve_crashkernel_generic(char *cmdline,
}
#endif

-int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
- void **addr, unsigned long *sz)
-{
- Elf64_Ehdr *ehdr;
- Elf64_Phdr *phdr;
- unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
- unsigned char *buf;
- unsigned int cpu, i;
- unsigned long long notes_addr;
- unsigned long mstart, mend;
-
- /* extra phdr for vmcoreinfo ELF note */
- nr_phdr = nr_cpus + 1;
- nr_phdr += mem->nr_ranges;
-
- /*
- * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
- * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
- * I think this is required by tools like gdb. So same physical
- * memory will be mapped in two ELF headers. One will contain kernel
- * text virtual addresses and other will have __va(physical) addresses.
- */
-
- nr_phdr++;
- elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
- elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
-
- buf = vzalloc(elf_sz);
- if (!buf)
- return -ENOMEM;
-
- ehdr = (Elf64_Ehdr *)buf;
- phdr = (Elf64_Phdr *)(ehdr + 1);
- memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
- ehdr->e_ident[EI_CLASS] = ELFCLASS64;
- ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
- ehdr->e_ident[EI_VERSION] = EV_CURRENT;
- ehdr->e_ident[EI_OSABI] = ELF_OSABI;
- memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
- ehdr->e_type = ET_CORE;
- ehdr->e_machine = ELF_ARCH;
- ehdr->e_version = EV_CURRENT;
- ehdr->e_phoff = sizeof(Elf64_Ehdr);
- ehdr->e_ehsize = sizeof(Elf64_Ehdr);
- ehdr->e_phentsize = sizeof(Elf64_Phdr);
-
- /* Prepare one phdr of type PT_NOTE for each possible CPU */
- for_each_possible_cpu(cpu) {
- phdr->p_type = PT_NOTE;
- notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
- phdr->p_offset = phdr->p_paddr = notes_addr;
- phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
- (ehdr->e_phnum)++;
- phdr++;
- }
-
- /* Prepare one PT_NOTE header for vmcoreinfo */
- phdr->p_type = PT_NOTE;
- phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
- phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
- (ehdr->e_phnum)++;
- phdr++;
-
- /* Prepare PT_LOAD type program header for kernel text region */
- if (need_kernel_map) {
- phdr->p_type = PT_LOAD;
- phdr->p_flags = PF_R|PF_W|PF_X;
- phdr->p_vaddr = (unsigned long) _text;
- phdr->p_filesz = phdr->p_memsz = _end - _text;
- phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
- ehdr->e_phnum++;
- phdr++;
- }
-
- /* Go through all the ranges in mem->ranges[] and prepare phdr */
- for (i = 0; i < mem->nr_ranges; i++) {
- mstart = mem->ranges[i].start;
- mend = mem->ranges[i].end;
-
- phdr->p_type = PT_LOAD;
- phdr->p_flags = PF_R|PF_W|PF_X;
- phdr->p_offset = mstart;
-
- phdr->p_paddr = mstart;
- phdr->p_vaddr = (unsigned long) __va(mstart);
- phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
- phdr->p_align = 0;
- ehdr->e_phnum++;
- pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
- phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
- ehdr->e_phnum, phdr->p_offset);
- phdr++;
- }
-
- *addr = buf;
- *sz = elf_sz;
- return 0;
-}
-
-int crash_exclude_mem_range(struct crash_mem *mem,
- unsigned long long mstart, unsigned long long mend)
-{
- int i, j;
- unsigned long long start, end, p_start, p_end;
- struct range temp_range = {0, 0};
-
- for (i = 0; i < mem->nr_ranges; i++) {
- start = mem->ranges[i].start;
- end = mem->ranges[i].end;
- p_start = mstart;
- p_end = mend;
-
- if (mstart > end || mend < start)
- continue;
-
- /* Truncate any area outside of range */
- if (mstart < start)
- p_start = start;
- if (mend > end)
- p_end = end;
-
- /* Found completely overlapping range */
- if (p_start == start && p_end == end) {
- mem->ranges[i].start = 0;
- mem->ranges[i].end = 0;
- if (i < mem->nr_ranges - 1) {
- /* Shift rest of the ranges to left */
- for (j = i; j < mem->nr_ranges - 1; j++) {
- mem->ranges[j].start =
- mem->ranges[j+1].start;
- mem->ranges[j].end =
- mem->ranges[j+1].end;
- }
-
- /*
- * Continue to check if there are another overlapping ranges
- * from the current position because of shifting the above
- * mem ranges.
- */
- i--;
- mem->nr_ranges--;
- continue;
- }
- mem->nr_ranges--;
- return 0;
- }
-
- if (p_start > start && p_end < end) {
- /* Split original range */
- mem->ranges[i].end = p_start - 1;
- temp_range.start = p_end + 1;
- temp_range.end = end;
- } else if (p_start != start)
- mem->ranges[i].end = p_start - 1;
- else
- mem->ranges[i].start = p_end + 1;
- break;
- }
-
- /* If a split happened, add the split to array */
- if (!temp_range.end)
- return 0;
-
- /* Split happened */
- if (i == mem->max_nr_ranges - 1)
- return -ENOMEM;
-
- /* Location where new range should go */
- j = i + 1;
- if (j < mem->nr_ranges) {
- /* Move over all ranges one slot towards the end */
- for (i = mem->nr_ranges - 1; i >= j; i--)
- mem->ranges[i + 1] = mem->ranges[i];
- }
-
- mem->ranges[j].start = temp_range.start;
- mem->ranges[j].end = temp_range.end;
- mem->nr_ranges++;
- return 0;
-}
-
Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len)
{
@@ -843,223 +659,3 @@ static int __init crash_save_vmcoreinfo_init(void)
}

subsys_initcall(crash_save_vmcoreinfo_init);
-
-static int __init crash_notes_memory_init(void)
-{
- /* Allocate memory for saving cpu registers. */
- size_t size, align;
-
- /*
- * crash_notes could be allocated across 2 vmalloc pages when percpu
- * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
- * pages are also on 2 continuous physical pages. In this case the
- * 2nd part of crash_notes in 2nd page could be lost since only the
- * starting address and size of crash_notes are exported through sysfs.
- * Here round up the size of crash_notes to the nearest power of two
- * and pass it to __alloc_percpu as align value. This can make sure
- * crash_notes is allocated inside one physical page.
- */
- size = sizeof(note_buf_t);
- align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
-
- /*
- * Break compile if size is bigger than PAGE_SIZE since crash_notes
- * definitely will be in 2 pages with that.
- */
- BUILD_BUG_ON(size > PAGE_SIZE);
-
- crash_notes = __alloc_percpu(size, align);
- if (!crash_notes) {
- pr_warn("Memory allocation for saving cpu register states failed\n");
- return -ENOMEM;
- }
- return 0;
-}
-subsys_initcall(crash_notes_memory_init);
-
-#ifdef CONFIG_CRASH_HOTPLUG
-#undef pr_fmt
-#define pr_fmt(fmt) "crash hp: " fmt
-
-/*
- * Different than kexec/kdump loading/unloading/jumping/shrinking which
- * usually rarely happen, there will be many crash hotplug events notified
- * during one short period, e.g one memory board is hot added and memory
- * regions are online. So mutex lock __crash_hotplug_lock is used to
- * serialize the crash hotplug handling specifically.
- */
-DEFINE_MUTEX(__crash_hotplug_lock);
-#define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
-#define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)
-
-/*
- * This routine utilized when the crash_hotplug sysfs node is read.
- * It reflects the kernel's ability/permission to update the crash
- * elfcorehdr directly.
- */
-int crash_check_update_elfcorehdr(void)
-{
- int rc = 0;
-
- crash_hotplug_lock();
- /* Obtain lock while reading crash information */
- if (!kexec_trylock()) {
- pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
- crash_hotplug_unlock();
- return 0;
- }
- if (kexec_crash_image) {
- if (kexec_crash_image->file_mode)
- rc = 1;
- else
- rc = kexec_crash_image->update_elfcorehdr;
- }
- /* Release lock now that update complete */
- kexec_unlock();
- crash_hotplug_unlock();
-
- return rc;
-}
-
-/*
- * To accurately reflect hot un/plug changes of cpu and memory resources
- * (including onling and offlining of those resources), the elfcorehdr
- * (which is passed to the crash kernel via the elfcorehdr= parameter)
- * must be updated with the new list of CPUs and memories.
- *
- * In order to make changes to elfcorehdr, two conditions are needed:
- * First, the segment containing the elfcorehdr must be large enough
- * to permit a growing number of resources; the elfcorehdr memory size
- * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
- * Second, purgatory must explicitly exclude the elfcorehdr from the
- * list of segments it checks (since the elfcorehdr changes and thus
- * would require an update to purgatory itself to update the digest).
- */
-static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
-{
- struct kimage *image;
-
- crash_hotplug_lock();
- /* Obtain lock while changing crash information */
- if (!kexec_trylock()) {
- pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
- crash_hotplug_unlock();
- return;
- }
-
- /* Check kdump is not loaded */
- if (!kexec_crash_image)
- goto out;
-
- image = kexec_crash_image;
-
- /* Check that updating elfcorehdr is permitted */
- if (!(image->file_mode || image->update_elfcorehdr))
- goto out;
-
- if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
- hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
- pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
- else
- pr_debug("hp_action %u\n", hp_action);
-
- /*
- * The elfcorehdr_index is set to -1 when the struct kimage
- * is allocated. Find the segment containing the elfcorehdr,
- * if not already found.
- */
- if (image->elfcorehdr_index < 0) {
- unsigned long mem;
- unsigned char *ptr;
- unsigned int n;
-
- for (n = 0; n < image->nr_segments; n++) {
- mem = image->segment[n].mem;
- ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
- if (ptr) {
- /* The segment containing elfcorehdr */
- if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
- image->elfcorehdr_index = (int)n;
- kunmap_local(ptr);
- }
- }
- }
-
- if (image->elfcorehdr_index < 0) {
- pr_err("unable to locate elfcorehdr segment");
- goto out;
- }
-
- /* Needed in order for the segments to be updated */
- arch_kexec_unprotect_crashkres();
-
- /* Differentiate between normal load and hotplug update */
- image->hp_action = hp_action;
-
- /* Now invoke arch-specific update handler */
- arch_crash_handle_hotplug_event(image);
-
- /* No longer handling a hotplug event */
- image->hp_action = KEXEC_CRASH_HP_NONE;
- image->elfcorehdr_updated = true;
-
- /* Change back to read-only */
- arch_kexec_protect_crashkres();
-
- /* Errors in the callback is not a reason to rollback state */
-out:
- /* Release lock now that update complete */
- kexec_unlock();
- crash_hotplug_unlock();
-}
-
-static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
-{
- switch (val) {
- case MEM_ONLINE:
- crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
- KEXEC_CRASH_HP_INVALID_CPU);
- break;
-
- case MEM_OFFLINE:
- crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
- KEXEC_CRASH_HP_INVALID_CPU);
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block crash_memhp_nb = {
- .notifier_call = crash_memhp_notifier,
- .priority = 0
-};
-
-static int crash_cpuhp_online(unsigned int cpu)
-{
- crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
- return 0;
-}
-
-static int crash_cpuhp_offline(unsigned int cpu)
-{
- crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
- return 0;
-}
-
-static int __init crash_hotplug_init(void)
-{
- int result = 0;
-
- if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
- register_memory_notifier(&crash_memhp_nb);
-
- if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
- result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
- "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
- }
-
- return result;
-}
-
-subsys_initcall(crash_hotplug_init);
-#endif
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index be5642a4ec49..ec481e5a9330 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -40,6 +40,8 @@
#include <linux/hugetlb.h>
#include <linux/objtool.h>
#include <linux/kmsg_dump.h>
+#include <linux/memory.h>
+#include <linux/cpuhotplug.h>

#include <asm/page.h>
#include <asm/sections.h>
@@ -49,6 +51,9 @@

atomic_t __kexec_lock = ATOMIC_INIT(0);

+/* Per cpu memory for storing cpu states in case of system crash. */
+note_buf_t __percpu *crash_notes;
+
/* Flag to indicate we are going to kexec a new kernel */
bool kexec_in_progress = false;

@@ -1082,6 +1087,189 @@ static inline resource_size_t crash_resource_size(const struct resource *res)
return !res->end ? 0 : resource_size(res);
}

+int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
+ void **addr, unsigned long *sz)
+{
+ Elf64_Ehdr *ehdr;
+ Elf64_Phdr *phdr;
+ unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
+ unsigned char *buf;
+ unsigned int cpu, i;
+ unsigned long long notes_addr;
+ unsigned long mstart, mend;
+
+ /* extra phdr for vmcoreinfo ELF note */
+ nr_phdr = nr_cpus + 1;
+ nr_phdr += mem->nr_ranges;
+
+ /*
+ * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
+ * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
+ * I think this is required by tools like gdb. So same physical
+ * memory will be mapped in two ELF headers. One will contain kernel
+ * text virtual addresses and other will have __va(physical) addresses.
+ */
+
+ nr_phdr++;
+ elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
+ elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
+
+ buf = vzalloc(elf_sz);
+ if (!buf)
+ return -ENOMEM;
+
+ ehdr = (Elf64_Ehdr *)buf;
+ phdr = (Elf64_Phdr *)(ehdr + 1);
+ memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+ ehdr->e_ident[EI_CLASS] = ELFCLASS64;
+ ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
+ ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+ ehdr->e_ident[EI_OSABI] = ELF_OSABI;
+ memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
+ ehdr->e_type = ET_CORE;
+ ehdr->e_machine = ELF_ARCH;
+ ehdr->e_version = EV_CURRENT;
+ ehdr->e_phoff = sizeof(Elf64_Ehdr);
+ ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+ ehdr->e_phentsize = sizeof(Elf64_Phdr);
+
+ /* Prepare one phdr of type PT_NOTE for each possible CPU */
+ for_each_possible_cpu(cpu) {
+ phdr->p_type = PT_NOTE;
+ notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
+ phdr->p_offset = phdr->p_paddr = notes_addr;
+ phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
+ (ehdr->e_phnum)++;
+ phdr++;
+ }
+
+ /* Prepare one PT_NOTE header for vmcoreinfo */
+ phdr->p_type = PT_NOTE;
+ phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
+ phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
+ (ehdr->e_phnum)++;
+ phdr++;
+
+ /* Prepare PT_LOAD type program header for kernel text region */
+ if (need_kernel_map) {
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R|PF_W|PF_X;
+ phdr->p_vaddr = (unsigned long) _text;
+ phdr->p_filesz = phdr->p_memsz = _end - _text;
+ phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
+ ehdr->e_phnum++;
+ phdr++;
+ }
+
+ /* Go through all the ranges in mem->ranges[] and prepare phdr */
+ for (i = 0; i < mem->nr_ranges; i++) {
+ mstart = mem->ranges[i].start;
+ mend = mem->ranges[i].end;
+
+ phdr->p_type = PT_LOAD;
+ phdr->p_flags = PF_R|PF_W|PF_X;
+ phdr->p_offset = mstart;
+
+ phdr->p_paddr = mstart;
+ phdr->p_vaddr = (unsigned long) __va(mstart);
+ phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
+ phdr->p_align = 0;
+ ehdr->e_phnum++;
+ pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
+ phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
+ ehdr->e_phnum, phdr->p_offset);
+ phdr++;
+ }
+
+ *addr = buf;
+ *sz = elf_sz;
+ return 0;
+}
+
+int crash_exclude_mem_range(struct crash_mem *mem,
+ unsigned long long mstart, unsigned long long mend)
+{
+ int i, j;
+ unsigned long long start, end, p_start, p_end;
+ struct range temp_range = {0, 0};
+
+ for (i = 0; i < mem->nr_ranges; i++) {
+ start = mem->ranges[i].start;
+ end = mem->ranges[i].end;
+ p_start = mstart;
+ p_end = mend;
+
+ if (mstart > end || mend < start)
+ continue;
+
+ /* Truncate any area outside of range */
+ if (mstart < start)
+ p_start = start;
+ if (mend > end)
+ p_end = end;
+
+ /* Found completely overlapping range */
+ if (p_start == start && p_end == end) {
+ mem->ranges[i].start = 0;
+ mem->ranges[i].end = 0;
+ if (i < mem->nr_ranges - 1) {
+ /* Shift rest of the ranges to left */
+ for (j = i; j < mem->nr_ranges - 1; j++) {
+ mem->ranges[j].start =
+ mem->ranges[j+1].start;
+ mem->ranges[j].end =
+ mem->ranges[j+1].end;
+ }
+
+ /*
+ * Continue to check if there are another overlapping ranges
+ * from the current position because of shifting the above
+ * mem ranges.
+ */
+ i--;
+ mem->nr_ranges--;
+ continue;
+ }
+ mem->nr_ranges--;
+ return 0;
+ }
+
+ if (p_start > start && p_end < end) {
+ /* Split original range */
+ mem->ranges[i].end = p_start - 1;
+ temp_range.start = p_end + 1;
+ temp_range.end = end;
+ } else if (p_start != start)
+ mem->ranges[i].end = p_start - 1;
+ else
+ mem->ranges[i].start = p_end + 1;
+ break;
+ }
+
+ /* If a split happened, add the split to array */
+ if (!temp_range.end)
+ return 0;
+
+ /* Split happened */
+ if (i == mem->max_nr_ranges - 1)
+ return -ENOMEM;
+
+ /* Location where new range should go */
+ j = i + 1;
+ if (j < mem->nr_ranges) {
+ /* Move over all ranges one slot towards the end */
+ for (i = mem->nr_ranges - 1; i >= j; i--)
+ mem->ranges[i + 1] = mem->ranges[i];
+ }
+
+ mem->ranges[j].start = temp_range.start;
+ mem->ranges[j].end = temp_range.end;
+ mem->nr_ranges++;
+ return 0;
+}
+
+
+
ssize_t crash_get_memory_size(void)
{
ssize_t size = 0;
@@ -1204,6 +1392,226 @@ void crash_save_cpu(struct pt_regs *regs, int cpu)
final_note(buf);
}

+static int __init crash_notes_memory_init(void)
+{
+ /* Allocate memory for saving cpu registers. */
+ size_t size, align;
+
+ /*
+ * crash_notes could be allocated across 2 vmalloc pages when percpu
+ * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
+ * pages are also on 2 continuous physical pages. In this case the
+ * 2nd part of crash_notes in 2nd page could be lost since only the
+ * starting address and size of crash_notes are exported through sysfs.
+ * Here round up the size of crash_notes to the nearest power of two
+ * and pass it to __alloc_percpu as align value. This can make sure
+ * crash_notes is allocated inside one physical page.
+ */
+ size = sizeof(note_buf_t);
+ align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
+
+ /*
+ * Break compile if size is bigger than PAGE_SIZE since crash_notes
+ * definitely will be in 2 pages with that.
+ */
+ BUILD_BUG_ON(size > PAGE_SIZE);
+
+ crash_notes = __alloc_percpu(size, align);
+ if (!crash_notes) {
+ pr_warn("Memory allocation for saving cpu register states failed\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+subsys_initcall(crash_notes_memory_init);
+
+#ifdef CONFIG_CRASH_HOTPLUG
+#undef pr_fmt
+#define pr_fmt(fmt) "crash hp: " fmt
+
+/*
+ * Different than kexec/kdump loading/unloading/jumping/shrinking which
+ * usually rarely happen, there will be many crash hotplug events notified
+ * during one short period, e.g one memory board is hot added and memory
+ * regions are online. So mutex lock __crash_hotplug_lock is used to
+ * serialize the crash hotplug handling specifically.
+ */
+DEFINE_MUTEX(__crash_hotplug_lock);
+#define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
+#define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)
+
+/*
+ * This routine utilized when the crash_hotplug sysfs node is read.
+ * It reflects the kernel's ability/permission to update the crash
+ * elfcorehdr directly.
+ */
+int crash_check_update_elfcorehdr(void)
+{
+ int rc = 0;
+
+ crash_hotplug_lock();
+ /* Obtain lock while reading crash information */
+ if (!kexec_trylock()) {
+ pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
+ crash_hotplug_unlock();
+ return 0;
+ }
+ if (kexec_crash_image) {
+ if (kexec_crash_image->file_mode)
+ rc = 1;
+ else
+ rc = kexec_crash_image->update_elfcorehdr;
+ }
+ /* Release lock now that update complete */
+ kexec_unlock();
+ crash_hotplug_unlock();
+
+ return rc;
+}
+
+/*
+ * To accurately reflect hot un/plug changes of cpu and memory resources
+ * (including onling and offlining of those resources), the elfcorehdr
+ * (which is passed to the crash kernel via the elfcorehdr= parameter)
+ * must be updated with the new list of CPUs and memories.
+ *
+ * In order to make changes to elfcorehdr, two conditions are needed:
+ * First, the segment containing the elfcorehdr must be large enough
+ * to permit a growing number of resources; the elfcorehdr memory size
+ * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
+ * Second, purgatory must explicitly exclude the elfcorehdr from the
+ * list of segments it checks (since the elfcorehdr changes and thus
+ * would require an update to purgatory itself to update the digest).
+ */
+static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
+{
+ struct kimage *image;
+
+ crash_hotplug_lock();
+ /* Obtain lock while changing crash information */
+ if (!kexec_trylock()) {
+ pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
+ crash_hotplug_unlock();
+ return;
+ }
+
+ /* Check kdump is not loaded */
+ if (!kexec_crash_image)
+ goto out;
+
+ image = kexec_crash_image;
+
+ /* Check that updating elfcorehdr is permitted */
+ if (!(image->file_mode || image->update_elfcorehdr))
+ goto out;
+
+ if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
+ hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
+ pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
+ else
+ pr_debug("hp_action %u\n", hp_action);
+
+ /*
+ * The elfcorehdr_index is set to -1 when the struct kimage
+ * is allocated. Find the segment containing the elfcorehdr,
+ * if not already found.
+ */
+ if (image->elfcorehdr_index < 0) {
+ unsigned long mem;
+ unsigned char *ptr;
+ unsigned int n;
+
+ for (n = 0; n < image->nr_segments; n++) {
+ mem = image->segment[n].mem;
+ ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
+ if (ptr) {
+ /* The segment containing elfcorehdr */
+ if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
+ image->elfcorehdr_index = (int)n;
+ kunmap_local(ptr);
+ }
+ }
+ }
+
+ if (image->elfcorehdr_index < 0) {
+ pr_err("unable to locate elfcorehdr segment");
+ goto out;
+ }
+
+ /* Needed in order for the segments to be updated */
+ arch_kexec_unprotect_crashkres();
+
+ /* Differentiate between normal load and hotplug update */
+ image->hp_action = hp_action;
+
+ /* Now invoke arch-specific update handler */
+ arch_crash_handle_hotplug_event(image);
+
+ /* No longer handling a hotplug event */
+ image->hp_action = KEXEC_CRASH_HP_NONE;
+ image->elfcorehdr_updated = true;
+
+ /* Change back to read-only */
+ arch_kexec_protect_crashkres();
+
+ /* Errors in the callback is not a reason to rollback state */
+out:
+ /* Release lock now that update complete */
+ kexec_unlock();
+ crash_hotplug_unlock();
+}
+
+static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
+{
+ switch (val) {
+ case MEM_ONLINE:
+ crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
+ KEXEC_CRASH_HP_INVALID_CPU);
+ break;
+
+ case MEM_OFFLINE:
+ crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
+ KEXEC_CRASH_HP_INVALID_CPU);
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block crash_memhp_nb = {
+ .notifier_call = crash_memhp_notifier,
+ .priority = 0
+};
+
+static int crash_cpuhp_online(unsigned int cpu)
+{
+ crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
+ return 0;
+}
+
+static int crash_cpuhp_offline(unsigned int cpu)
+{
+ crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
+ return 0;
+}
+
+static int __init crash_hotplug_init(void)
+{
+ int result = 0;
+
+ if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+ register_memory_notifier(&crash_memhp_nb);
+
+ if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
+ result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
+ "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
+ }
+
+ return result;
+}
+
+subsys_initcall(crash_hotplug_init);
+#endif
+
/*
* Move into place and start executing a preloaded standalone
* executable. If nothing was preloaded return an error.