Re: [PATCH v3 06/60] arm64: ptdump: Allow VMALLOC_END to be defined at boot

Ryan Roberts
2023-03-07T17:04:14Z

On 07/03/2023 14:04, Ard Biesheuvel wrote:
> Extend the existing pattern for populating ptdump marker entries at
> boot, and add handling of VMALLOC_END, which will cease to be a compile
> time constant for configurations that support 52-bit virtual addressing.
>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
> arch/arm64/mm/ptdump.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> index 76d28056bd14920a..910b35f02280cbdb 100644
> --- a/arch/arm64/mm/ptdump.c
> +++ b/arch/arm64/mm/ptdump.c
> @@ -31,7 +31,12 @@ enum address_markers_idx {
> PAGE_END_NR,
> #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> KASAN_START_NR,
> + KASAN_END_NR,
> #endif
> + MODULES_NR,
> + MODULES_END_NR,
> + VMALLOC_START_NR,
> + VMALLOC_END_NR,
> };
>
> static struct addr_marker address_markers[] = {
> @@ -44,7 +49,7 @@ static struct addr_marker address_markers[] = {
> { MODULES_VADDR, "Modules start" },
> { MODULES_END, "Modules end" },
> { VMALLOC_START, "vmalloc() area" },
> - { VMALLOC_END, "vmalloc() end" },
> + { 0, "vmalloc() end" },
> { VMEMMAP_START, "vmemmap start" },
> { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" },
> { PCI_IO_START, "PCI I/O start" },

With all the VA layout changes, and the addition of 52-bit PA/VA for 4KB and
16KB pages, Documentation/arm64/memory.rst now looks very wrong. Suggest
updating it to reflect reality?

> @@ -379,6 +384,7 @@ static int __init ptdump_init(void)
> #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> address_markers[KASAN_START_NR].start_address = KASAN_SHADOW_START;
> #endif
> + address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
> ptdump_initialize();
> ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables");
> return 0;