Re: [RFC PATCH 2/7] osdump: reuse some code from crash_core to get vmcoreinfo
Hi Qi,
first, most people, including me, prefer to be in Cc for the entire patchset.
It helps to get the whole picture.
This mail is even worse because the other patches are not in the same
thread. As a result, I can't find the other patches even via lore,
see https://lore.kernel.org/all/20231221132522.547-1-ruipeng...@gmail.com/
On Thu 2023-12-21 21:25:22, Ruipeng Qi wrote:
> From: qiruipeng
>
> Osdump is a new crash dumping solution like crash. It is interested in
> vmcoreinfo,too. Reuse some data and function from crash_core, but not full
> of them. So pick some code to get vmcoreinfo as needed.
> diff --git a/kernel/crash_core_mini.c b/kernel/crash_core_mini.c
> new file mode 100644
> index ..a0f8d0c79bba
> --- /dev/null
> +++ b/kernel/crash_core_mini.c
> @@ -0,0 +1,275 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * crash.c - kernel crash support code.
> + * Copyright (C) 2002-2004 Eric Biederman
> + */
> +
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +#include
> +#include
> +
> +#include
> +
> +#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;
> +u32 *vmcoreinfo_note;
> +
> +/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
> +static unsigned char *vmcoreinfo_data_safecopy;
> +
> +
> +Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
> + void *data, size_t data_len)
> +{
> + struct elf_note *note = (struct elf_note *)buf;
> +
> + note->n_namesz = strlen(name) + 1;
> + note->n_descsz = data_len;
> + note->n_type = type;
> + buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
> + memcpy(buf, name, note->n_namesz);
> + buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
> + memcpy(buf, data, data_len);
> + buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
> +
> + return buf;
> +}
> +
> +void final_note(Elf_Word *buf)
> +{
> + memset(buf, 0, sizeof(struct elf_note));
> +}
> +
> +static void update_vmcoreinfo_note(void)
> +{
> + u32 *buf = vmcoreinfo_note;
> +
> + if (!vmcoreinfo_size)
> + return;
> + buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
> + vmcoreinfo_size);
> + final_note(buf);
> +}
> +
> +void crash_update_vmcoreinfo_safecopy(void *ptr)
> +{
> + if (ptr)
> + memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
> +
> + vmcoreinfo_data_safecopy = ptr;
> +}
> +
> +void crash_save_vmcoreinfo(void)
> +{
> + if (!vmcoreinfo_note)
> + return;
> +
> + /* Use the safe copy to generate vmcoreinfo note if have */
> + if (vmcoreinfo_data_safecopy)
> + vmcoreinfo_data = vmcoreinfo_data_safecopy;
> +
> + vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
> + update_vmcoreinfo_note();
> +}
> +
> +void vmcoreinfo_append_str(const char *fmt, ...)
> +{
> + va_list args;
> + char buf[0x50];
> + size_t r;
> +
> + va_start(args, fmt);
> + r = vscnprintf(buf, sizeof(buf), fmt, args);
> + va_end(args);
> +
> + r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
> +
> + memcpy(_data[vmcoreinfo_size], buf, r);
> +
> + vmcoreinfo_size += r;
> +
> + WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
> + "vmcoreinfo data exceeds allocated size, truncating");
> +}
> +
> +/*
> + * provide an empty default implementation here -- architecture
> + * code may override this
> + */
> +void __weak arch_crash_save_vmcoreinfo(void)
> +{}
> +
> +phys_addr_t __weak paddr_vmcoreinfo_note(void)
> +{
> + return __pa(vmcoreinfo_note);
> +}
> +EXPORT_SYMBOL(paddr_vmcoreinfo_note);
> +
> +int get_note_size(void)
> +{
> + return VMCOREINFO_NOTE_SIZE;
> +}
> +
> +static int __init crash_save_vmcoreinfo_init(void)
> +{
> + vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
> + if (!vmcoreinfo_data) {
> + pr_warn("Memory allocation for vmcoreinfo_data failed\n");
> + return -ENOMEM;
> + }
> +
> + vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
> + GFP_KERNEL | __GFP_ZERO);
> + if (!vmcoreinfo_note) {
> + free_page((unsigned long)vmcoreinfo_data);
> + vmcoreinfo_data = NULL;
> + pr_warn("Memory allocation for vmcoreinfo_note failed\n");
> + return -ENOMEM;
> + }
> +
> + VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
> + VMCOREINFO_BUILD_ID();
> + VMCOREINFO_PAGESIZE(PAGE_SIZE);
> +
> + VMCOREINFO_SYMBOL(init_uts_ns);
> + VMCOREINFO_OFFSET(uts_namespace, name);
> +
[RFC PATCH 2/7] osdump: reuse some code from crash_core to get vmcoreinfo
From: qiruipeng
Osdump is a new crash dumping solution like crash. It is interested in
vmcoreinfo,too. Reuse some data and function from crash_core, but not full
of them. So pick some code to get vmcoreinfo as needed.
Signed-off-by: qiruipeng
---
arch/arm64/kernel/Makefile | 1 +
include/linux/buildid.h| 3 +-
kernel/Makefile| 1 +
kernel/crash_core_mini.c | 275 +
kernel/printk/printk.c | 2 +-
lib/buildid.c | 3 +-
6 files changed, 282 insertions(+), 3 deletions(-)
create mode 100644 kernel/crash_core_mini.c
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index d95b3d6b471a..fd6d06e44ae2 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_ARM64_RELOC_TEST)+=
arm64-reloc-test.o
arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_CRASH_CORE) += crash_core.o
+obj-$(CONFIG_OS_MINIDUMP) += crash_core.o
obj-$(CONFIG_ARM_SDE_INTERFACE)+= sdei.o
obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o
obj-$(CONFIG_ARM64_MTE)+= mte.o
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index 8a582d242f06..157edba44068 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -11,7 +11,8 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char
*build_id,
__u32 *size);
int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
-#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_CRASH_CORE)
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_CRASH_CORE) \
+ || IS_ENABLED(CONFIG_OS_MINIDUMP)
extern unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX];
void init_vmlinux_build_id(void);
#else
diff --git a/kernel/Makefile b/kernel/Makefile
index dc2b4ba5c953..14b7002f3279 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_KALLSYMS_SELFTEST) += kallsyms_selftest.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_CRASH_CORE) += crash_core.o
+obj-$(CONFIG_OS_MINIDUMP) += crash_core_mini.o
obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
diff --git a/kernel/crash_core_mini.c b/kernel/crash_core_mini.c
new file mode 100644
index ..a0f8d0c79bba
--- /dev/null
+++ b/kernel/crash_core_mini.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * crash.c - kernel crash support code.
+ * Copyright (C) 2002-2004 Eric Biederman
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#include
+#include
+
+#include
+
+#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;
+u32 *vmcoreinfo_note;
+
+/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
+static unsigned char *vmcoreinfo_data_safecopy;
+
+
+Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
+ void *data, size_t data_len)
+{
+ struct elf_note *note = (struct elf_note *)buf;
+
+ note->n_namesz = strlen(name) + 1;
+ note->n_descsz = data_len;
+ note->n_type = type;
+ buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
+ memcpy(buf, name, note->n_namesz);
+ buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
+ memcpy(buf, data, data_len);
+ buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
+
+ return buf;
+}
+
+void final_note(Elf_Word *buf)
+{
+ memset(buf, 0, sizeof(struct elf_note));
+}
+
+static void update_vmcoreinfo_note(void)
+{
+ u32 *buf = vmcoreinfo_note;
+
+ if (!vmcoreinfo_size)
+ return;
+ buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
+ vmcoreinfo_size);
+ final_note(buf);
+}
+
+void crash_update_vmcoreinfo_safecopy(void *ptr)
+{
+ if (ptr)
+ memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
+
+ vmcoreinfo_data_safecopy = ptr;
+}
+
+void crash_save_vmcoreinfo(void)
+{
+ if (!vmcoreinfo_note)
+ return;
+
+ /* Use the safe copy to generate vmcoreinfo note if have */
+ if (vmcoreinfo_data_safecopy)
+ vmcoreinfo_data = vmcoreinfo_data_safecopy;
+
+ vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
+ update_vmcoreinfo_note();
+}
+
+void vmcoreinfo_append_str(const char *fmt, ...)
+{
+ va_list args;
+ char buf[0x50];
+ size_t r;
+
+ va_start(args, fmt);
+ r =
