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authorYouling Tang2022-10-12 16:36:19 +0800
committerHuacai Chen2022-10-12 16:36:19 +0800
commit4e62d1d86585e1b62b4f96ee586881dd45a443dc (patch)
tree9f2d3d290bcbca2ee14787441f1ae6d174ec1875 /arch
parent4a03b2ac06a5bcae29371866d9d11f5bfd4c9188 (diff)
LoongArch: Add kdump support
This patch adds support for kdump. In kdump case the normal kernel will reserve a region for the crash kernel and jump there on panic. Arch-specific functions are added to allow for implementing a crash dump file interface, /proc/vmcore, which can be viewed as a ELF file. A user-space tool, such as kexec-tools, is responsible for allocating a separate region for the core's ELF header within the crash kdump kernel memory and filling it in when executing kexec_load(). Then, its location will be advertised to the crash dump kernel via a command line argument "elfcorehdr=", and the crash dump kernel will preserve this region for later use with arch_reserve_vmcore() at boot time. At the same time, the crash kdump kernel is also limited within the "crashkernel" area via a command line argument "mem=", so as not to destroy the original kernel dump data. In the crash dump kernel environment, /proc/vmcore is used to access the primary kernel's memory with copy_oldmem_page(). I tested kdump on LoongArch machines (Loongson-3A5000) and it works as expected (suggested crashkernel parameter is "crashkernel=512M@2560M"), you may test it by triggering a crash through /proc/sysrq-trigger: $ sudo kexec -p /boot/vmlinux-kdump --reuse-cmdline --append="nr_cpus=1" # echo c > /proc/sysrq-trigger Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch')
-rw-r--r--arch/loongarch/Kconfig22
-rw-r--r--arch/loongarch/Makefile4
-rw-r--r--arch/loongarch/kernel/Makefile1
-rw-r--r--arch/loongarch/kernel/crash_dump.c23
-rw-r--r--arch/loongarch/kernel/machine_kexec.c98
-rw-r--r--arch/loongarch/kernel/mem.c3
-rw-r--r--arch/loongarch/kernel/relocate_kernel.S6
-rw-r--r--arch/loongarch/kernel/setup.c74
-rw-r--r--arch/loongarch/kernel/traps.c4
9 files changed, 227 insertions, 8 deletions
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index cbbb82b0c4fe..2837ac5413c0 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -437,6 +437,28 @@ config KEXEC
The name comes from the similarity to the exec system call.
+config CRASH_DUMP
+ bool "Build kdump crash kernel"
+ help
+ Generate crash dump after being started by kexec. This should
+ be normally only set in special crash dump kernels which are
+ loaded in the main kernel with kexec-tools into a specially
+ reserved region and then later executed after a crash by
+ kdump/kexec.
+
+ For more details see Documentation/admin-guide/kdump/kdump.rst
+
+config PHYSICAL_START
+ hex "Physical address where the kernel is loaded"
+ default "0x90000000a0000000"
+ depends on CRASH_DUMP
+ help
+ This gives the XKPRANGE address where the kernel is loaded.
+ If you plan to use kernel for capturing the crash dump change
+ this value to start of the reserved region (the "X" value as
+ specified in the "crashkernel=YM@XM" command line boot parameter
+ passed to the panic-ed kernel).
+
config SECCOMP
bool "Enable seccomp to safely compute untrusted bytecode"
depends on PROC_FS
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index 42352f905858..ea17e692684e 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -69,7 +69,11 @@ endif
cflags-y += -ffreestanding
cflags-y += $(call cc-option, -mno-check-zero-division)
+ifndef CONFIG_PHYSICAL_START
load-y = 0x9000000000200000
+else
+load-y = $(CONFIG_PHYSICAL_START)
+endif
bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y)
drivers-$(CONFIG_PCI) += arch/loongarch/pci/
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 0bad6272a55e..b8cca9c22a9f 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
diff --git a/arch/loongarch/kernel/crash_dump.c b/arch/loongarch/kernel/crash_dump.c
new file mode 100644
index 000000000000..e559307c1092
--- /dev/null
+++ b/arch/loongarch/kernel/crash_dump.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/crash_dump.h>
+#include <linux/io.h>
+#include <linux/uio.h>
+
+ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
+ size_t csize, unsigned long offset)
+{
+ void *vaddr;
+
+ if (!csize)
+ return 0;
+
+ vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
+ if (!vaddr)
+ return -ENOMEM;
+
+ csize = copy_to_iter(vaddr + offset, csize, iter);
+
+ memunmap(vaddr);
+
+ return csize;
+}
diff --git a/arch/loongarch/kernel/machine_kexec.c b/arch/loongarch/kernel/machine_kexec.c
index d5037573ed66..2dcb9e003657 100644
--- a/arch/loongarch/kernel/machine_kexec.c
+++ b/arch/loongarch/kernel/machine_kexec.c
@@ -7,10 +7,15 @@
#include <linux/compiler.h>
#include <linux/cpu.h>
#include <linux/kexec.h>
-#include <linux/mm.h>
+#include <linux/crash_dump.h>
#include <linux/delay.h>
+#include <linux/irq.h>
#include <linux/libfdt.h>
+#include <linux/mm.h>
#include <linux/of_fdt.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
#include <asm/bootinfo.h>
#include <asm/cacheflush.h>
@@ -21,6 +26,7 @@
#define KEXEC_CMDLINE_ADDR TO_CACHE(0x108000UL)
static unsigned long reboot_code_buffer;
+static cpumask_t cpus_in_crash = CPU_MASK_NONE;
#ifdef CONFIG_SMP
static void (*relocated_kexec_smp_wait)(void *);
@@ -78,7 +84,7 @@ int machine_kexec_prepare(struct kimage *kimage)
return -EINVAL;
}
- /* kexec need a safe page to save reboot_code_buffer */
+ /* kexec/kdump need a safe page to save reboot_code_buffer */
kimage->control_code_page = virt_to_page((void *)KEXEC_CONTROL_CODE);
reboot_code_buffer = (unsigned long)page_address(kimage->control_code_page);
@@ -102,7 +108,8 @@ void kexec_reboot(void)
/*
* We know we were online, and there will be no incoming IPIs at
- * this point.
+ * this point. Mark online again before rebooting so that the crash
+ * analysis tool will see us correctly.
*/
set_cpu_online(smp_processor_id(), true);
@@ -147,7 +154,74 @@ static void kexec_shutdown_secondary(void *regs)
kexec_reboot();
}
-#endif
+
+static void crash_shutdown_secondary(void *passed_regs)
+{
+ int cpu = smp_processor_id();
+ struct pt_regs *regs = passed_regs;
+
+ /*
+ * If we are passed registers, use those. Otherwise get the
+ * regs from the last interrupt, which should be correct, as
+ * we are in an interrupt. But if the regs are not there,
+ * pull them from the top of the stack. They are probably
+ * wrong, but we need something to keep from crashing again.
+ */
+ if (!regs)
+ regs = get_irq_regs();
+ if (!regs)
+ regs = task_pt_regs(current);
+
+ if (!cpu_online(cpu))
+ return;
+
+ /* We won't be sent IPIs any more. */
+ set_cpu_online(cpu, false);
+
+ local_irq_disable();
+ if (!cpumask_test_cpu(cpu, &cpus_in_crash))
+ crash_save_cpu(regs, cpu);
+ cpumask_set_cpu(cpu, &cpus_in_crash);
+
+ while (!atomic_read(&kexec_ready_to_reboot))
+ cpu_relax();
+
+ kexec_reboot();
+}
+
+void crash_smp_send_stop(void)
+{
+ unsigned int ncpus;
+ unsigned long timeout;
+ static int cpus_stopped;
+
+ /*
+ * This function can be called twice in panic path, but obviously
+ * we should execute this only once.
+ */
+ if (cpus_stopped)
+ return;
+
+ cpus_stopped = 1;
+
+ /* Excluding the panic cpu */
+ ncpus = num_online_cpus() - 1;
+
+ smp_call_function(crash_shutdown_secondary, NULL, 0);
+ smp_wmb();
+
+ /*
+ * The crash CPU sends an IPI and wait for other CPUs to
+ * respond. Delay of at least 10 seconds.
+ */
+ timeout = MSEC_PER_SEC * 10;
+ pr_emerg("Sending IPI to other cpus...\n");
+ while ((cpumask_weight(&cpus_in_crash) < ncpus) && timeout--) {
+ mdelay(1);
+ cpu_relax();
+ }
+}
+#endif /* defined(CONFIG_SMP) */
void machine_shutdown(void)
{
@@ -165,6 +239,19 @@ void machine_shutdown(void)
void machine_crash_shutdown(struct pt_regs *regs)
{
+ int crashing_cpu;
+
+ local_irq_disable();
+
+ crashing_cpu = smp_processor_id();
+ crash_save_cpu(regs, crashing_cpu);
+
+#ifdef CONFIG_SMP
+ crash_smp_send_stop();
+#endif
+ cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
+
+ pr_info("Starting crashdump kernel...\n");
}
void machine_kexec(struct kimage *image)
@@ -178,7 +265,8 @@ void machine_kexec(struct kimage *image)
start_addr = (unsigned long)phys_to_virt(image->start);
- first_ind_entry = (unsigned long)phys_to_virt(image->head & PAGE_MASK);
+ first_ind_entry = (image->type == KEXEC_TYPE_DEFAULT) ?
+ (unsigned long)phys_to_virt(image->head & PAGE_MASK) : 0;
/*
* The generic kexec code builds a page list with physical
diff --git a/arch/loongarch/kernel/mem.c b/arch/loongarch/kernel/mem.c
index 7423361b0ebc..4a4107a6a965 100644
--- a/arch/loongarch/kernel/mem.c
+++ b/arch/loongarch/kernel/mem.c
@@ -58,7 +58,4 @@ void __init memblock_init(void)
/* Reserve the kernel text/data/bss */
memblock_reserve(__pa_symbol(&_text),
__pa_symbol(&_end) - __pa_symbol(&_text));
-
- /* Reserve the initrd */
- reserve_initrd_mem();
}
diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S
index 48362f38c6bf..d13252553a7c 100644
--- a/arch/loongarch/kernel/relocate_kernel.S
+++ b/arch/loongarch/kernel/relocate_kernel.S
@@ -24,6 +24,12 @@ SYM_CODE_START(relocate_new_kernel)
*/
move s0, a4
+ /*
+ * In case of a kdump/crash kernel, the indirection page is not
+ * populated as the kernel is directly copied to a reserved location
+ */
+ beqz s0, done
+
process_entry:
PTR_L s1, s0, 0
PTR_ADDI s0, s0, SZREG
diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 05af1102fee7..837111292ec6 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -19,6 +19,8 @@
#include <linux/memblock.h>
#include <linux/initrd.h>
#include <linux/ioport.h>
+#include <linux/kexec.h>
+#include <linux/crash_dump.h>
#include <linux/root_dev.h>
#include <linux/console.h>
#include <linux/pfn.h>
@@ -185,8 +187,70 @@ static int __init early_parse_mem(char *p)
}
early_param("mem", early_parse_mem);
+static void __init arch_reserve_vmcore(void)
+{
+#ifdef CONFIG_PROC_VMCORE
+ u64 i;
+ phys_addr_t start, end;
+
+ if (!is_kdump_kernel())
+ return;
+
+ if (!elfcorehdr_size) {
+ for_each_mem_range(i, &start, &end) {
+ if (elfcorehdr_addr >= start && elfcorehdr_addr < end) {
+ /*
+ * Reserve from the elf core header to the end of
+ * the memory segment, that should all be kdump
+ * reserved memory.
+ */
+ elfcorehdr_size = end - elfcorehdr_addr;
+ break;
+ }
+ }
+ }
+
+ if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
+ pr_warn("elfcorehdr is overlapped\n");
+ return;
+ }
+
+ memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
+
+ pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
+ elfcorehdr_size >> 10, elfcorehdr_addr);
+#endif
+}
+
+static void __init arch_parse_crashkernel(void)
+{
+#ifdef CONFIG_KEXEC
+ int ret;
+ unsigned long long start;
+ unsigned long long total_mem;
+ unsigned long long crash_base, crash_size;
+
+ total_mem = memblock_phys_mem_size();
+ ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
+ if (ret < 0 || crash_size <= 0)
+ return;
+
+ start = memblock_phys_alloc_range(crash_size, 1, crash_base, crash_base + crash_size);
+ if (start != crash_base) {
+ pr_warn("Invalid memory region reserved for crash kernel\n");
+ return;
+ }
+
+ crashk_res.start = crash_base;
+ crashk_res.end = crash_base + crash_size - 1;
+#endif
+}
+
void __init platform_init(void)
{
+ arch_reserve_vmcore();
+ arch_parse_crashkernel();
+
#ifdef CONFIG_ACPI_TABLE_UPGRADE
acpi_table_upgrade();
#endif
@@ -289,6 +353,15 @@ static void __init resource_init(void)
request_resource(res, &data_resource);
request_resource(res, &bss_resource);
}
+
+#ifdef CONFIG_KEXEC
+ if (crashk_res.start < crashk_res.end) {
+ insert_resource(&iomem_resource, &crashk_res);
+ pr_info("Reserving %ldMB of memory at %ldMB for crashkernel\n",
+ (unsigned long)((crashk_res.end - crashk_res.start + 1) >> 20),
+ (unsigned long)(crashk_res.start >> 20));
+ }
+#endif
}
static int __init reserve_memblock_reserved_regions(void)
@@ -350,6 +423,7 @@ void __init setup_arch(char **cmdline_p)
memblock_init();
pagetable_init();
parse_early_param();
+ reserve_initrd_mem();
platform_init();
arch_mem_init(cmdline_p);
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index 66c2849b26e5..1a4dce84ebc6 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -10,6 +10,7 @@
#include <linux/entry-common.h>
#include <linux/init.h>
#include <linux/kernel.h>
+#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/extable.h>
#include <linux/mm.h>
@@ -246,6 +247,9 @@ void __noreturn die(const char *str, struct pt_regs *regs)
oops_exit();
+ if (regs && kexec_should_crash(current))
+ crash_kexec(regs);
+
if (in_interrupt())
panic("Fatal exception in interrupt");