[RFC 3/3] arm64/ptdump: Add ARM64_PTDUMP_CONSOLE
From: Anshuman Khandual <hidden>
Date: 2025-08-18 09:14:53
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Enable early kernel page table dump for debug purpose when required via new config ARM64_PDUMP_CONSOLE. This calls existing ptdump_walk() early on just after ptdump has been initialized with ptdump_init(). Suggested-by: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Anshuman Khandual <redacted> --- arch/arm64/Kconfig.debug | 12 ++++++++++++ arch/arm64/include/asm/ptdump.h | 7 +++++++ arch/arm64/kernel/setup.c | 1 + arch/arm64/mm/ptdump.c | 7 +++++++ 4 files changed, 27 insertions(+)
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index 265c4461031f..0f8af0dd0f4c 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug@@ -20,4 +20,16 @@ config ARM64_RELOC_TEST depends on m tristate "Relocation testing module" +config ARM64_PTDUMP_CONSOLE + bool "Dump early kernel page table" + depends on DEBUG_KERNEL + depends on ARCH_HAS_PTDUMP + select PTDUMP + help + Enable this option to dump early kernel page table entries during + boot using the PTDUMP framework. This helps in examining kernel's + page table mapping entries and their attributes etc. + + If in doubt, say N. + source "drivers/hwtracing/coresight/Kconfig"
diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
index 27e774134e7f..81dc53ca9643 100644
--- a/arch/arm64/include/asm/ptdump.h
+++ b/arch/arm64/include/asm/ptdump.h@@ -74,8 +74,15 @@ void __init ptdump_debugfs_register(struct ptdump_info *info, const char *name); static inline void ptdump_debugfs_register(struct ptdump_info *info, const char *name) { } #endif /* CONFIG_PTDUMP_DEBUGFS */ + +#ifdef CONFIG_ARM64_PTDUMP_CONSOLE +void __init arm64_kernel_pgtable_dump(void); +#else +static inline void __init arm64_kernel_pgtable_dump(void) { } +#endif /* CONFIG_ARM64_PTDUMP_CONSOLE */ #else static inline void __init ptdump_init(void) { } +static inline void __init arm64_kernel_pgtable_dump(void) { } static inline void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, pteval_t val) { } static inline void note_page_pte(struct ptdump_state *st, unsigned long addr, pte_t pte) { }
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 0a3812c8e177..86bf7607d304 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c@@ -361,6 +361,7 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p) init_bootcpu_ops(); smp_init_cpus(); smp_build_mpidr_hash(); + arm64_kernel_pgtable_dump(); #ifdef CONFIG_ARM64_SW_TTBR0_PAN /*
diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
index c78e6b496dea..f6d22462add6 100644
--- a/arch/arm64/mm/ptdump.c
+++ b/arch/arm64/mm/ptdump.c@@ -407,6 +407,13 @@ void __init ptdump_init(void) ptdump_initialize(); } +#ifdef CONFIG_ARM64_PTDUMP_CONSOLE +void __init arm64_kernel_pgtable_dump(void) +{ + ptdump_walk(CONSOLE, &kernel_ptdump_info); +} +#endif + static int __init ptdump_debugfs_init(void) { ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables");
--
2.25.1