Re: [PATCH V4 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support
From: Xianting Tian
Date: Thu Oct 20 2022 - 00:40:39 EST
在 2022/10/20 上午11:05, Baoquan He 写道:
On 10/20/22 at 10:17am, Xianting Tian wrote:
在 2022/10/20 上午10:08, Baoquan He 写道:
On 10/19/22 at 06:36pm, Xianting Tian wrote:
Add arch_crash_save_vmcoreinfo(), which exports VM layout(MODULES, VMALLOC,
VMEMMAP ranges and KERNEL_LINK_ADDR), va bits and ram base for vmcore.
Default pagetable levels and PAGE_OFFSET aren't same for different kernel
version as below. For pagetable levels, it sets sv57 by default and falls
back to setting sv48 at boot time if sv57 is not supported by the hardware.
For ram base, the default value is 0x80200000 for qemu riscv64 env and,
for example, is 0x200000 on the XuanTie 910 CPU.
* Linux Kernel 5.18 ~
* PGTABLE_LEVELS = 5
* PAGE_OFFSET = 0xff60000000000000
* Linux Kernel 5.17 ~
* PGTABLE_LEVELS = 4
* PAGE_OFFSET = 0xffffaf8000000000
* Linux Kernel 4.19 ~
* PGTABLE_LEVELS = 3
* PAGE_OFFSET = 0xffffffe000000000
Since these configurations change from time to time and version to version,
it is preferable to export them via vmcoreinfo than to change the crash's
code frequently, it can simplify the development of crash tool.
Signed-off-by: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx>
---
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/crash_core.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+)
create mode 100644 arch/riscv/kernel/crash_core.c
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index db6e4b1294ba..4cf303a779ab 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KEXEC_CORE) += kexec_relocate.o crash_save_regs.o machine_kexec.o
obj-$(CONFIG_KEXEC_FILE) += elf_kexec.o machine_kexec_file.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
+obj-$(CONFIG_CRASH_CORE) += crash_core.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
diff --git a/arch/riscv/kernel/crash_core.c b/arch/riscv/kernel/crash_core.c
new file mode 100644
index 000000000000..3e889d0ed7bd
--- /dev/null
+++ b/arch/riscv/kernel/crash_core.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/crash_core.h>
+#include <linux/pagemap.h>
+
+void arch_crash_save_vmcoreinfo(void)
+{
+ VMCOREINFO_NUMBER(VA_BITS);
+ VMCOREINFO_NUMBER(phys_ram_base);
+
+ vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET);
+ vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
+ vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END);
+ vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START);
+ vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END);
+#ifdef CONFIG_64BIT
+ vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR);
+ vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END);
+#endif
+
+ if (IS_ENABLED(CONFIG_64BIT))
+ vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR);
Wondering why you don't put KERNEL_LINK_ADDR exporting into the above
ifdeffery scope, with that you can save one line of "IS_ENABLED(CONFIG_64BIT)".
I followed the rule in print_vm_layout() of arch/riscv/mm/init.c, which used
IS_ENABLED when print the value of KERNEL_LINK_ADDR.
I see. There's PAGE_OFFSET in the middle. Thanks.
print_ml("lowmem", (unsigned long)PAGE_OFFSET,
(unsigned long)high_memory)
So now, do you think if it's necessary to have another
IS_ENABLED(CONFIG_64BIT) in the current arch_crash_save_vmcoreinfo()?
For which MACRO? I think current code for PAGE_OFFSET is OK.