summaryrefslogtreecommitdiff
path: root/kernel/crash_core.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/crash_core.c')
-rw-r--r--kernel/crash_core.c256
1 files changed, 256 insertions, 0 deletions
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