[PATCH v2 04/14] crash: split crash dumping code out from kexec_core.c

Baoquan He
2024-01-19T14:53:30Z

Currently, KEXEC_CORE select CRASH_CORE automatically because crash codes
need be built in to avoid compiling error when building kexec code even
though the crash dumping functionality is not enabled. E.g
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------

After splitting out crashkernel reservation code and vmcoreinfo exporting
code, there's only crash related code left in kernel/crash_core.c. Now
move crash related codes from kexec_core.c to crash_core.c and only build it
in when CONFIG_CRASH_DUMP=y.

And also wrap up crash codes inside CONFIG_CRASH_DUMP ifdeffery scope,
or replace inappropriate CONFIG_KEXEC_CORE ifdef with CONFIG_CRASH_DUMP
ifdef in generic kernel files.

With these changes, crash_core codes are abstracted from kexec codes and
can be disabled at all if only kexec reboot feature is wanted.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
drivers/base/cpu.c | 6 +-
include/linux/crash_core.h | 61 +++++++++
include/linux/kexec.h | 45 +------
init/initramfs.c | 2 +-
kernel/Makefile | 3 +-
kernel/crash_core.c | 256 +++++++++++++++++++++++++++++++++++++
kernel/kexec.c | 11 +-
kernel/kexec_core.c | 250 ++----------------------------------
kernel/kexec_file.c | 13 +-
kernel/ksysfs.c | 4 +
10 files changed, 359 insertions(+), 292 deletions(-)

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 47de0f140ba6..b621a0fc75e1 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -144,7 +144,7 @@ static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
#endif /* CONFIG_HOTPLUG_CPU */

-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_DUMP
#include <linux/kexec.h>

static ssize_t crash_notes_show(struct device *dev,
@@ -189,14 +189,14 @@ static const struct attribute_group crash_note_cpu_attr_group = {
#endif

static const struct attribute_group *common_cpu_attr_groups[] = {
-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_DUMP
&crash_note_cpu_attr_group,
#endif
NULL
};

static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_DUMP
&crash_note_cpu_attr_group,
#endif
NULL
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 7f19f62018ef..23270b16e1db 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -6,6 +6,48 @@
#include <linux/elfcore.h>
#include <linux/elf.h>

+struct kimage;
+
+#ifdef CONFIG_CRASH_DUMP
+
+int crash_shrink_memory(unsigned long new_size);
+ssize_t crash_get_memory_size(void);
+
+#ifndef arch_kexec_protect_crashkres
+/*
+ * Protection mechanism for crashkernel reserved memory after
+ * the kdump kernel is loaded.
+ *
+ * Provide an empty default implementation here -- architecture
+ * code may override this
+ */
+static inline void arch_kexec_protect_crashkres(void) { }
+#endif
+
+#ifndef arch_kexec_unprotect_crashkres
+static inline void arch_kexec_unprotect_crashkres(void) { }
+#endif
+
+
+
+#ifndef arch_crash_handle_hotplug_event
+static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }
+#endif
+
+int crash_check_update_elfcorehdr(void);
+
+#ifndef crash_hotplug_cpu_support
+static inline int crash_hotplug_cpu_support(void) { return 0; }
+#endif
+
+#ifndef crash_hotplug_memory_support
+static inline int crash_hotplug_memory_support(void) { return 0; }
+#endif
+
+#ifndef crash_get_elfcorehdr_size
+static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
+#endif
+
/* Alignment required for elf header segment */
#define ELF_CORE_HEADER_ALIGN 4096

@@ -31,4 +73,23 @@ struct kexec_segment;
#define KEXEC_CRASH_HP_REMOVE_MEMORY 4
#define KEXEC_CRASH_HP_INVALID_CPU -1U

+extern void __crash_kexec(struct pt_regs *regs);
+extern void crash_kexec(struct pt_regs *regs);
+int kexec_should_crash(struct task_struct *p);
+int kexec_crash_loaded(void);
+void crash_save_cpu(struct pt_regs *regs, int cpu);
+extern int kimage_crash_copy_vmcoreinfo(struct kimage *image);
+
+#else /* !CONFIG_CRASH_DUMP*/
+struct pt_regs;
+struct task_struct;
+struct kimage;
+static inline void __crash_kexec(struct pt_regs *regs) { }
+static inline void crash_kexec(struct pt_regs *regs) { }
+static inline int kexec_should_crash(struct task_struct *p) { return 0; }
+static inline int kexec_crash_loaded(void) { return 0; }
+static inline void crash_save_cpu(struct pt_regs *regs, int cpu) {};
+static inline int kimage_crash_copy_vmcoreinfo(struct kimage *image) { return 0; };
+#endif /* CONFIG_CRASH_DUMP*/
+
#endif /* LINUX_CRASH_CORE_H */
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9c7bb8b56ed6..060835bb82d5 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -15,7 +15,6 @@

#if !defined(__ASSEMBLY__)

-#include <linux/crash_core.h>
#include <linux/vmcore_info.h>
#include <linux/crash_reserve.h>
#include <asm/io.h>
@@ -33,6 +32,7 @@ extern note_buf_t __percpu *crash_notes;
#include <linux/module.h>
#include <linux/highmem.h>
#include <asm/kexec.h>
+#include <linux/crash_core.h>

/* Verify architecture specific macros are defined */

@@ -380,13 +380,6 @@ extern struct page *kimage_alloc_control_pages(struct kimage *image,
static inline int machine_kexec_post_load(struct kimage *image) { return 0; }
#endif

-extern void __crash_kexec(struct pt_regs *);
-extern void crash_kexec(struct pt_regs *);
-int kexec_should_crash(struct task_struct *);
-int kexec_crash_loaded(void);
-void crash_save_cpu(struct pt_regs *regs, int cpu);
-extern int kimage_crash_copy_vmcoreinfo(struct kimage *image);
-
extern struct kimage *kexec_image;
extern struct kimage *kexec_crash_image;

@@ -410,24 +403,6 @@ bool kexec_load_permitted(int kexec_image_type);
/* flag to track if kexec reboot is in progress */
extern bool kexec_in_progress;

-int crash_shrink_memory(unsigned long new_size);
-ssize_t crash_get_memory_size(void);
-
-#ifndef arch_kexec_protect_crashkres
-/*
- * Protection mechanism for crashkernel reserved memory after
- * the kdump kernel is loaded.
- *
- * Provide an empty default implementation here -- architecture
- * code may override this
- */
-static inline void arch_kexec_protect_crashkres(void) { }
-#endif
-
-#ifndef arch_kexec_unprotect_crashkres
-static inline void arch_kexec_unprotect_crashkres(void) { }
-#endif
-
#ifndef page_to_boot_pfn
static inline unsigned long page_to_boot_pfn(struct page *page)
{
@@ -484,24 +459,6 @@ static inline int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, g
static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) { }
#endif

-#ifndef arch_crash_handle_hotplug_event
-static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }
-#endif
-
-int crash_check_update_elfcorehdr(void);
-
-#ifndef crash_hotplug_cpu_support
-static inline int crash_hotplug_cpu_support(void) { return 0; }
-#endif
-
-#ifndef crash_hotplug_memory_support
-static inline int crash_hotplug_memory_support(void) { return 0; }
-#endif
-
-#ifndef crash_get_elfcorehdr_size
-static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
-#endif
-
extern bool kexec_file_dbg_print;

#define kexec_dprintk(fmt, ...) \
diff --git a/init/initramfs.c b/init/initramfs.c
index 76deb48c38cb..6f095f54eec9 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -642,7 +642,7 @@ void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
"initrd");
}

-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_RESERVE
static bool __init kexec_free_initrd(void)
{
unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
diff --git a/kernel/Makefile b/kernel/Makefile
index 35abc65e1f1a..3c13240dfc9f 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -70,7 +70,8 @@ obj-$(CONFIG_KALLSYMS_SELFTEST) += kallsyms_selftest.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_VMCORE_INFO) += vmcore_info.o elfcorehdr.o
obj-$(CONFIG_CRASH_RESERVE) += crash_reserve.o
-obj-$(CONFIG_KEXEC_CORE) += kexec_core.o crash_core.o
+obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
+obj-$(CONFIG_CRASH_DUMP) += crash_core.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 2f4df1fe6f7a..78b5dc7cee3a 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -11,9 +11,14 @@
#include <linux/sizes.h>
#include <linux/kexec.h>
#include <linux/memory.h>
+#include <linux/mm.h>
#include <linux/cpuhotplug.h>
#include <linux/memblock.h>
#include <linux/kmemleak.h>
+#include <linux/crash_core.h>
+#include <linux/reboot.h>
+#include <linux/btf.h>
+#include <linux/objtool.h>

#include <asm/page.h>
#include <asm/sections.h>
@@ -26,6 +31,131 @@
/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;

+#ifdef CONFIG_CRASH_DUMP
+
+int kimage_crash_copy_vmcoreinfo(struct kimage *image)
+{
+ struct page *vmcoreinfo_page;
+ void *safecopy;
+
+ if (!IS_ENABLED(CONFIG_CRASH_DUMP))
+ return 0;
+ if (image->type != KEXEC_TYPE_CRASH)
+ return 0;
+
+ /*
+ * For kdump, allocate one vmcoreinfo safe copy from the
+ * crash memory. as we have arch_kexec_protect_crashkres()
+ * after kexec syscall, we naturally protect it from write
+ * (even read) access under kernel direct mapping. But on
+ * the other hand, we still need to operate it when crash
+ * happens to generate vmcoreinfo note, hereby we rely on
+ * vmap for this purpose.
+ */
+ vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
+ if (!vmcoreinfo_page) {
+ pr_warn("Could not allocate vmcoreinfo buffer\n");
+ return -ENOMEM;
+ }
+ safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
+ if (!safecopy) {
+ pr_warn("Could not vmap vmcoreinfo buffer\n");
+ return -ENOMEM;
+ }
+
+ image->vmcoreinfo_data_copy = safecopy;
+ crash_update_vmcoreinfo_safecopy(safecopy);
+
+ return 0;
+}
+
+
+
+int kexec_should_crash(struct task_struct *p)
+{
+ /*
+ * If crash_kexec_post_notifiers is enabled, don't run
+ * crash_kexec() here yet, which must be run after panic
+ * notifiers in panic().
+ */
+ if (crash_kexec_post_notifiers)
+ return 0;
+ /*
+ * There are 4 panic() calls in make_task_dead() path, each of which
+ * corresponds to each of these 4 conditions.
+ */
+ if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
+ return 1;
+ return 0;
+}
+
+int kexec_crash_loaded(void)
+{
+ return !!kexec_crash_image;
+}
+EXPORT_SYMBOL_GPL(kexec_crash_loaded);
+
+/*
+ * No panic_cpu check version of crash_kexec(). This function is called
+ * only when panic_cpu holds the current CPU number; this is the only CPU
+ * which processes crash_kexec routines.
+ */
+void __noclone __crash_kexec(struct pt_regs *regs)
+{
+ /* Take the kexec_lock here to prevent sys_kexec_load
+ * running on one cpu from replacing the crash kernel
+ * we are using after a panic on a different cpu.
+ *
+ * If the crash kernel was not located in a fixed area
+ * of memory the xchg(&kexec_crash_image) would be
+ * sufficient. But since I reuse the memory...
+ */
+ if (kexec_trylock()) {
+ if (kexec_crash_image) {
+ struct pt_regs fixed_regs;
+
+ crash_setup_regs(&fixed_regs, regs);
+ crash_save_vmcoreinfo();
+ machine_crash_shutdown(&fixed_regs);
+ machine_kexec(kexec_crash_image);
+ }
+ kexec_unlock();
+ }
+}
+STACK_FRAME_NON_STANDARD(__crash_kexec);
+
+__bpf_kfunc void crash_kexec(struct pt_regs *regs)
+{
+ int old_cpu, this_cpu;
+
+ /*
+ * Only one CPU is allowed to execute the crash_kexec() code as with
+ * panic(). Otherwise parallel calls of panic() and crash_kexec()
+ * may stop each other. To exclude them, we use panic_cpu here too.
+ */
+ old_cpu = PANIC_CPU_INVALID;
+ this_cpu = raw_smp_processor_id();
+
+ if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) {
+ /* This is the 1st CPU which comes here, so go ahead. */
+ __crash_kexec(regs);
+
+ /*
+ * Reset panic_cpu to allow another panic()/crash_kexec()
+ * call.
+ */
+ atomic_set(&panic_cpu, PANIC_CPU_INVALID);
+ }
+}
+
+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)
{
@@ -187,6 +317,130 @@ int crash_exclude_mem_range(struct crash_mem *mem,
return 0;
}

+ssize_t crash_get_memory_size(void)
+{
+ ssize_t size = 0;
+
+ if (!kexec_trylock())
+ return -EBUSY;
+
+ size += crash_resource_size(&crashk_res);
+ size += crash_resource_size(&crashk_low_res);
+
+ kexec_unlock();
+ return size;
+}
+
+static int __crash_shrink_memory(struct resource *old_res,
+ unsigned long new_size)
+{
+ struct resource *ram_res;
+
+ ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
+ if (!ram_res)
+ return -ENOMEM;
+
+ ram_res->start = old_res->start + new_size;
+ ram_res->end = old_res->end;
+ ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
+ ram_res->name = "System RAM";
+
+ if (!new_size) {
+ release_resource(old_res);
+ old_res->start = 0;
+ old_res->end = 0;
+ } else {
+ crashk_res.end = ram_res->start - 1;
+ }
+
+ crash_free_reserved_phys_range(ram_res->start, ram_res->end);
+ insert_resource(&iomem_resource, ram_res);
+
+ return 0;
+}
+
+int crash_shrink_memory(unsigned long new_size)
+{
+ int ret = 0;
+ unsigned long old_size, low_size;
+
+ if (!kexec_trylock())
+ return -EBUSY;
+
+ if (kexec_crash_image) {
+ ret = -ENOENT;
+ goto unlock;
+ }
+
+ low_size = crash_resource_size(&crashk_low_res);
+ old_size = crash_resource_size(&crashk_res) + low_size;
+ new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
+ if (new_size >= old_size) {
+ ret = (new_size == old_size) ? 0 : -EINVAL;
+ goto unlock;
+ }
+
+ /*
+ * (low_size > new_size) implies that low_size is greater than zero.
+ * This also means that if low_size is zero, the else branch is taken.
+ *
+ * If low_size is greater than 0, (low_size > new_size) indicates that
+ * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res
+ * needs to be shrunken.
+ */
+ if (low_size > new_size) {
+ ret = __crash_shrink_memory(&crashk_res, 0);
+ if (ret)
+ goto unlock;
+
+ ret = __crash_shrink_memory(&crashk_low_res, new_size);
+ } else {
+ ret = __crash_shrink_memory(&crashk_res, new_size - low_size);
+ }
+
+ /* Swap crashk_res and crashk_low_res if needed */
+ if (!crashk_res.end && crashk_low_res.end) {
+ crashk_res.start = crashk_low_res.start;
+ crashk_res.end = crashk_low_res.end;
+ release_resource(&crashk_low_res);
+ crashk_low_res.start = 0;
+ crashk_low_res.end = 0;
+ insert_resource(&iomem_resource, &crashk_res);
+ }
+
+unlock:
+ kexec_unlock();
+ return ret;
+}
+
+void crash_save_cpu(struct pt_regs *regs, int cpu)
+{
+ struct elf_prstatus prstatus;
+ u32 *buf;
+
+ if ((cpu < 0) || (cpu >= nr_cpu_ids))
+ return;
+
+ /* Using ELF notes here is opportunistic.
+ * I need a well defined structure format
+ * for the data I pass, and I need tags
+ * on the data to indicate what information I have
+ * squirrelled away. ELF notes happen to provide
+ * all of that, so there is no need to invent something new.
+ */
+ buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
+ if (!buf)
+ return;
+ memset(&prstatus, 0, sizeof(prstatus));
+ prstatus.common.pr_pid = current->pid;
+ elf_core_copy_regs(&prstatus.pr_reg, regs);
+ buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
+ &prstatus, sizeof(prstatus));
+ final_note(buf);
+}
+
+
+
static int __init crash_notes_memory_init(void)
{
/* Allocate memory for saving cpu registers. */
@@ -220,6 +474,8 @@ static int __init crash_notes_memory_init(void)
}
subsys_initcall(crash_notes_memory_init);

+#endif /*CONFIG_CRASH_DUMP*/
+
#ifdef CONFIG_CRASH_HOTPLUG
#undef pr_fmt
#define pr_fmt(fmt) "crash hp: " fmt
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 8f35a5a42af8..bab542fc1463 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -28,12 +28,14 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
struct kimage *image;
bool kexec_on_panic = flags & KEXEC_ON_CRASH;

+#ifdef CONFIG_CRASH_DUMP
if (kexec_on_panic) {
/* Verify we have a valid entry point */
if ((entry < phys_to_boot_phys(crashk_res.start)) ||
(entry > phys_to_boot_phys(crashk_res.end)))
return -EADDRNOTAVAIL;
}
+#endif

/* Allocate and initialize a controlling structure */
image = do_kimage_alloc_init();
@@ -44,11 +46,13 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
image->nr_segments = nr_segments;
memcpy(image->segment, segments, nr_segments * sizeof(*segments));

+#ifdef CONFIG_CRASH_DUMP
if (kexec_on_panic) {
/* Enable special crash kernel control page alloc policy. */
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
}
+#endif

ret = sanity_check_segment_list(image);
if (ret)
@@ -99,13 +103,14 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
if (!kexec_trylock())
return -EBUSY;

+#ifdef CONFIG_CRASH_DUMP
if (flags & KEXEC_ON_CRASH) {
dest_image = &kexec_crash_image;
if (kexec_crash_image)
arch_kexec_unprotect_crashkres();
- } else {
+ } else
+#endif
dest_image = &kexec_image;
- }

if (nr_segments == 0) {
/* Uninstall image */
@@ -162,8 +167,10 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
image = xchg(dest_image, image);

out:
+#ifdef CONFIG_CRASH_DUMP
if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
arch_kexec_protect_crashkres();
+#endif

kimage_free(image);
out_unlock:
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index d08fc7b5db97..ce3429e7972c 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -54,30 +54,6 @@ bool kexec_in_progress = false;

bool kexec_file_dbg_print;

-int kexec_should_crash(struct task_struct *p)
-{
- /*
- * If crash_kexec_post_notifiers is enabled, don't run
- * crash_kexec() here yet, which must be run after panic
- * notifiers in panic().
- */
- if (crash_kexec_post_notifiers)
- return 0;
- /*
- * There are 4 panic() calls in make_task_dead() path, each of which
- * corresponds to each of these 4 conditions.
- */
- if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
- return 1;
- return 0;
-}
-
-int kexec_crash_loaded(void)
-{
- return !!kexec_crash_image;
-}
-EXPORT_SYMBOL_GPL(kexec_crash_loaded);
-
/*
* When kexec transitions to the new kernel there is a one-to-one
* mapping between physical and virtual addresses. On processors
@@ -209,6 +185,7 @@ int sanity_check_segment_list(struct kimage *image)
if (total_pages > nr_pages / 2)
return -EINVAL;

+#ifdef CONFIG_CRASH_DUMP
/*
* Verify we have good destination addresses. Normally
* the caller is responsible for making certain we don't
@@ -231,6 +208,7 @@ int sanity_check_segment_list(struct kimage *image)
return -EADDRNOTAVAIL;
}
}
+#endif

return 0;
}
@@ -403,6 +381,7 @@ static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
return pages;
}

+#ifdef CONFIG_CRASH_DUMP
static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
unsigned int order)
{
@@ -468,6 +447,7 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image,

return pages;
}
+#endif

struct page *kimage_alloc_control_pages(struct kimage *image,
@@ -479,48 +459,16 @@ struct page *kimage_alloc_control_pages(struct kimage *image,
case KEXEC_TYPE_DEFAULT:
pages = kimage_alloc_normal_control_pages(image, order);
break;
+#ifdef CONFIG_CRASH_DUMP
case KEXEC_TYPE_CRASH:
pages = kimage_alloc_crash_control_pages(image, order);
break;
+#endif
}

return pages;
}

-int kimage_crash_copy_vmcoreinfo(struct kimage *image)
-{
- struct page *vmcoreinfo_page;
- void *safecopy;
-
- if (image->type != KEXEC_TYPE_CRASH)
- return 0;
-
- /*
- * For kdump, allocate one vmcoreinfo safe copy from the
- * crash memory. as we have arch_kexec_protect_crashkres()
- * after kexec syscall, we naturally protect it from write
- * (even read) access under kernel direct mapping. But on
- * the other hand, we still need to operate it when crash
- * happens to generate vmcoreinfo note, hereby we rely on
- * vmap for this purpose.
- */
- vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
- if (!vmcoreinfo_page) {
- pr_warn("Could not allocate vmcoreinfo buffer\n");
- return -ENOMEM;
- }
- safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
- if (!safecopy) {
- pr_warn("Could not vmap vmcoreinfo buffer\n");
- return -ENOMEM;
- }
-
- image->vmcoreinfo_data_copy = safecopy;
- crash_update_vmcoreinfo_safecopy(safecopy);
-
- return 0;
-}
-
static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
{
if (*image->entry != 0)
@@ -603,10 +551,12 @@ void kimage_free(struct kimage *image)
if (!image)
return;

+#ifdef CONFIG_CRASH_DUMP
if (image->vmcoreinfo_data_copy) {
crash_update_vmcoreinfo_safecopy(NULL);
vunmap(image->vmcoreinfo_data_copy);
}
+#endif

kimage_free_extra_pages(image);
for_each_kimage_entry(image, ptr, entry) {
@@ -824,6 +774,7 @@ static int kimage_load_normal_segment(struct kimage *image,
return result;
}

+#ifdef CONFIG_CRASH_DUMP
static int kimage_load_crash_segment(struct kimage *image,
struct kexec_segment *segment)
{
@@ -891,6 +842,7 @@ static int kimage_load_crash_segment(struct kimage *image,
out:
return result;
}
+#endif

int kimage_load_segment(struct kimage *image,
struct kexec_segment *segment)
@@ -901,9 +853,11 @@ int kimage_load_segment(struct kimage *image,
case KEXEC_TYPE_DEFAULT:
result = kimage_load_normal_segment(image, segment);
break;
+#ifdef CONFIG_CRASH_DUMP
case KEXEC_TYPE_CRASH:
result = kimage_load_crash_segment(image, segment);
break;
+#endif
}

return result;
@@ -1027,186 +981,6 @@ bool kexec_load_permitted(int kexec_image_type)
return true;
}

-/*
- * No panic_cpu check version of crash_kexec(). This function is called
- * only when panic_cpu holds the current CPU number; this is the only CPU
- * which processes crash_kexec routines.
- */
-void __noclone __crash_kexec(struct pt_regs *regs)
-{
- /* Take the kexec_lock here to prevent sys_kexec_load
- * running on one cpu from replacing the crash kernel
- * we are using after a panic on a different cpu.
- *
- * If the crash kernel was not located in a fixed area
- * of memory the xchg(&kexec_crash_image) would be
- * sufficient. But since I reuse the memory...
- */
- if (kexec_trylock()) {
- if (kexec_crash_image) {
- struct pt_regs fixed_regs;
-
- crash_setup_regs(&fixed_regs, regs);
- crash_save_vmcoreinfo();
- machine_crash_shutdown(&fixed_regs);
- machine_kexec(kexec_crash_image);
- }
- kexec_unlock();
- }
-}
-STACK_FRAME_NON_STANDARD(__crash_kexec);
-
-__bpf_kfunc void crash_kexec(struct pt_regs *regs)
-{
- int old_cpu, this_cpu;
-
- /*
- * Only one CPU is allowed to execute the crash_kexec() code as with
- * panic(). Otherwise parallel calls of panic() and crash_kexec()
- * may stop each other. To exclude them, we use panic_cpu here too.
- */
- old_cpu = PANIC_CPU_INVALID;
- this_cpu = raw_smp_processor_id();
-
- if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) {
- /* This is the 1st CPU which comes here, so go ahead. */
- __crash_kexec(regs);
-
- /*
- * Reset panic_cpu to allow another panic()/crash_kexec()
- * call.
- */
- atomic_set(&panic_cpu, PANIC_CPU_INVALID);
- }
-}
-
-static inline resource_size_t crash_resource_size(const struct resource *res)
-{
- return !res->end ? 0 : resource_size(res);
-}
-
-ssize_t crash_get_memory_size(void)
-{
- ssize_t size = 0;
-
- if (!kexec_trylock())
- return -EBUSY;
-
- size += crash_resource_size(&crashk_res);
- size += crash_resource_size(&crashk_low_res);
-
- kexec_unlock();
- return size;
-}
-
-static int __crash_shrink_memory(struct resource *old_res,
- unsigned long new_size)
-{
- struct resource *ram_res;
-
- ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
- if (!ram_res)
- return -ENOMEM;
-
- ram_res->start = old_res->start + new_size;
- ram_res->end = old_res->end;
- ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
- ram_res->name = "System RAM";
-
- if (!new_size) {
- release_resource(old_res);
- old_res->start = 0;
- old_res->end = 0;
- } else {
- crashk_res.end = ram_res->start - 1;
- }
-
- crash_free_reserved_phys_range(ram_res->start, ram_res->end);
- insert_resource(&iomem_resource, ram_res);
-
- return 0;
-}
-
-int crash_shrink_memory(unsigned long new_size)
-{
- int ret = 0;
- unsigned long old_size, low_size;
-
- if (!kexec_trylock())
- return -EBUSY;
-
- if (kexec_crash_image) {
- ret = -ENOENT;
- goto unlock;
- }
-
- low_size = crash_resource_size(&crashk_low_res);
- old_size = crash_resource_size(&crashk_res) + low_size;
- new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
- if (new_size >= old_size) {
- ret = (new_size == old_size) ? 0 : -EINVAL;
- goto unlock;
- }
-
- /*
- * (low_size > new_size) implies that low_size is greater than zero.
- * This also means that if low_size is zero, the else branch is taken.
- *
- * If low_size is greater than 0, (low_size > new_size) indicates that
- * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res
- * needs to be shrunken.
- */
- if (low_size > new_size) {
- ret = __crash_shrink_memory(&crashk_res, 0);
- if (ret)
- goto unlock;
-
- ret = __crash_shrink_memory(&crashk_low_res, new_size);
- } else {
- ret = __crash_shrink_memory(&crashk_res, new_size - low_size);
- }
-
- /* Swap crashk_res and crashk_low_res if needed */
- if (!crashk_res.end && crashk_low_res.end) {
- crashk_res.start = crashk_low_res.start;
- crashk_res.end = crashk_low_res.end;
- release_resource(&crashk_low_res);
- crashk_low_res.start = 0;
- crashk_low_res.end = 0;
- insert_resource(&iomem_resource, &crashk_res);
- }
-
-unlock:
- kexec_unlock();
- return ret;
-}
-
-void crash_save_cpu(struct pt_regs *regs, int cpu)
-{
- struct elf_prstatus prstatus;
- u32 *buf;
-
- if ((cpu < 0) || (cpu >= nr_cpu_ids))
- return;
-
- /* Using ELF notes here is opportunistic.
- * I need a well defined structure format
- * for the data I pass, and I need tags
- * on the data to indicate what information I have
- * squirrelled away. ELF notes happen to provide
- * all of that, so there is no need to invent something new.
- */
- buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
- if (!buf)
- return;
- memset(&prstatus, 0, sizeof(prstatus));
- prstatus.common.pr_pid = current->pid;
- elf_core_copy_regs(&prstatus.pr_reg, regs);
- buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
- &prstatus, sizeof(prstatus));
- final_note(buf);
-}
-
/*
* Move into place and start executing a preloaded standalone
* executable. If nothing was preloaded return an error.
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index bef2f6f2571b..ce7ce2ae27cd 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -285,11 +285,13 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
image->file_mode = 1;

+#ifdef CONFIG_CRASH_DUMP
if (kexec_on_panic) {
/* Enable special crash kernel control page alloc policy. */
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
}
+#endif

ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
cmdline_ptr, cmdline_len, flags);
@@ -349,13 +351,14 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
if (!kexec_trylock())
return -EBUSY;

+#ifdef CONFIG_CRASH_DUMP
if (image_type == KEXEC_TYPE_CRASH) {
dest_image = &kexec_crash_image;
if (kexec_crash_image)
arch_kexec_unprotect_crashkres();
- } else {
+ } else
+#endif
dest_image = &kexec_image;
- }

if (flags & KEXEC_FILE_UNLOAD)
goto exchange;
@@ -419,8 +422,10 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
exchange:
image = xchg(dest_image, image);
out:
+#ifdef CONFIG_CRASH_DUMP
if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
arch_kexec_protect_crashkres();
+#endif

kexec_unlock();
kimage_free(image);
@@ -595,12 +600,14 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf,
static int kexec_walk_resources(struct kexec_buf *kbuf,
int (*func)(struct resource *, void *))
{
+#ifdef CONFIG_CRASH_DUMP
if (kbuf->image->type == KEXEC_TYPE_CRASH)
return walk_iomem_res_desc(crashk_res.desc,
IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
crashk_res.start, crashk_res.end,
kbuf, func);
- else if (kbuf->top_down)
+#endif
+ if (kbuf->top_down)
return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func);
else
return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 11526fc42bc2..fe7a517fc4ab 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -120,6 +120,7 @@ static ssize_t kexec_loaded_show(struct kobject *kobj,
}
KERNEL_ATTR_RO(kexec_loaded);

+#ifdef CONFIG_CRASH_DUMP
static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
@@ -152,6 +153,7 @@ static ssize_t kexec_crash_size_store(struct kobject *kobj,
}
KERNEL_ATTR_RW(kexec_crash_size);

+#endif /* CONFIG_CRASH_DUMP*/
#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_VMCORE_INFO
@@ -262,9 +264,11 @@ static struct attribute * kernel_attrs[] = {
#endif
#ifdef CONFIG_KEXEC_CORE
&kexec_loaded_attr.attr,
+#ifdef CONFIG_CRASH_DUMP
&kexec_crash_loaded_attr.attr,
&kexec_crash_size_attr.attr,
#endif
+#endif
#ifdef CONFIG_VMCORE_INFO
&vmcoreinfo_attr.attr,
#ifdef CONFIG_CRASH_HOTPLUG
--
2.41.0