Re: [PATCH V2 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support
From: Xianting Tian
Date: Tue Oct 18 2022 - 04:01:53 EST
在 2022/10/18 下午3:19, Conor.Dooley@xxxxxxxxxxxxx 写道:
On 18/10/2022 03:28, Xianting Tian wrote:
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在 2022/10/18 上午3:54, Conor Dooley 写道:
On Fri, Oct 14, 2022 at 09:41:38PM +0800, Xianting Tian wrote:
* 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 | 29 +++++++++++++++++++++++++++++
2 files changed, 30 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..8d7f5ff108da
--- /dev/null
+++ b/arch/riscv/kernel/crash_core.c
@@ -0,0 +1,29 @@
+// 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)) {
You've already got a #ifdef CONFIG_64BIT above, is there a reason why
you'd use the IS_ENABLED here rather than merge this with the above
section? I'm a big fan of IS_ENABLED but I'm not sure what it adds here,
maybe you can show me the light :)
The IS_ENABLED() check prevents the line from getting executed, but
unlike an #ifdef it relies on it to be parsable.
Hey Xianting,
Firstly, neither this nor the other version of this message made it to
the mailing list - and since I usually use lei to get my mails that is
a bit of a problem :(
Sorry, I don't know why, I just reply via Thunderbird.
But git send-mail is right, I will send V3 soon.
Yeah, I know that that is what IS_ENABLED() does, it's just in this
situation it does not look very intentional & more like disjoint bits
of copy-paste. It's fine though, leave it as it is.
OK, thanks
Thanks,
Conor.
I wrote this arch_crash_save_vmcoreinfo() func with reference to this: static void __init print_vm_layout(void) // arch/riscv/mm/init.c
{
pr_notice("Virtual kernel memory layout:\n");
print_ml("fixmap", (unsigned long)FIXADDR_START,
(unsigned long)FIXADDR_TOP);
print_ml("pci io", (unsigned long)PCI_IO_START,
(unsigned long)PCI_IO_END);
print_ml("vmemmap", (unsigned long)VMEMMAP_START,
(unsigned long)VMEMMAP_END);
print_ml("vmalloc", (unsigned long)VMALLOC_START,
(unsigned long)VMALLOC_END);
#ifdef CONFIG_64BIT
print_ml("modules", (unsigned long)MODULES_VADDR,
(unsigned long)MODULES_END);
#endif
print_ml("lowmem", (unsigned long)PAGE_OFFSET,
(unsigned long)high_memory);
if (IS_ENABLED(CONFIG_64BIT)) {
#ifdef CONFIG_KASAN
print_ml("kasan", KASAN_SHADOW_START, KASAN_SHADOW_END);
#endif
print_ml("kernel", (unsigned long)KERNEL_LINK_ADDR,
(unsigned long)ADDRESS_SPACE_END);
}
}
Thanks,
Conor.
+#ifdef CONFIG_KASAN
+ vmcoreinfo_append_str("NUMBER(KASAN_SHADOW_START)=0x%lx\n", KASAN_SHADOW_START);
+ vmcoreinfo_append_str("NUMBER(KASAN_SHADOW_END)=0x%lx\n", KASAN_SHADOW_END);
+#endif
+ vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR);
+ vmcoreinfo_append_str("NUMBER(ADDRESS_SPACE_END)=0x%lx\n", ADDRESS_SPACE_END);
+ }
+}
--
2.17.1