2022-07-14 11:34:46

by Xianting Tian

[permalink] [raw]
Subject: [PATCH V3 0/2] Improve vmcoreinfo and memory layout dump

This patch series are the improvements for vmcoreinfo and memory
layout dump.

The first patch(1/2) is to add VM layout to vmcoreinfo, which can
simlify the development of crash tool as ARM64 already did
(arch/arm64/kernel/crash_core.c).

The second patch(2/2) is to add MODULES to memory layout dump.

Changes v1 -> v2:
patch 1: add VA_BITS to vmcoreinfo as ARM64 does, not satp_mode.
crash tool can read VA_BITS to determin the pagetable
levels.
patch 1,2: As MODULES area is only defined when CONFIG_64BIT=y for
riscv64, so only use MODULES area when CONFIG_64BIT=y.
Changes v2 -> v3:
patch 1,2: use "#ifdef CONFIG_64BIT" instead of "IS_ENABLED(CONFIG_64BIT)"
when check whether MODULES area is available.

Xianting Tian (2):
RISC-V: Add arch_crash_save_vmcoreinfo support
riscv: Add modules to virtual kernel memory layout dump

arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/crash_core.c | 29 +++++++++++++++++++++++++++++
arch/riscv/mm/init.c | 4 ++++
3 files changed, 34 insertions(+)
create mode 100644 arch/riscv/kernel/crash_core.c

--
2.17.1


2022-07-14 12:07:20

by Xianting Tian

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Subject: [PATCH V3 2/2] riscv: Add modules to virtual kernel memory layout dump

Modules always live before the kernel, MODULES_END is fixed but
MODULES_VADDR isn't fixed, it depends on the kernel size.
Let's add it to virtual kernel memory layout dump.

As MODULES is only defined for CONFIG_64BIT, so we dump it when
CONFIG_64BIT=y.

eg,
MODULES_VADDR - MODULES_END
0xffffffff01133000 - 0xffffffff80000000

Signed-off-by: Xianting Tian <[email protected]>
---
arch/riscv/mm/init.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index d466ec670e1f..2c4a64e97aec 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -135,6 +135,10 @@ static void __init print_vm_layout(void)
(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)) {
--
2.17.1

2022-07-14 12:07:40

by Xianting Tian

[permalink] [raw]
Subject: [PATCH V3 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support

Add arch_crash_save_vmcoreinfo(), which exports VM layout(MODULES, VMALLOC,
VMEMMAP and KERNEL_LINK_ADDR ranges), satp mode and ram base to vmcore.

Default pagetable levels and PAGE_OFFSET aren't same for different kernel
version as below. For default pagetable levels, it sets sv57 on defaultly
in latest kernel and do fallback to try to set sv48 on boot time if sv57
is not supported in current hardware.

For ram base, the default value is 0x80200000 for qemu riscv64 env, 0x200000
for riscv64 SoC platform(eg, SoC platform of RISC-V 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 <[email protected]>
---
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 c71d6591d539..54e4183db080 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KEXEC) += 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)) {
+#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