Re: [RFC 5/8] powerpc/ptdump: Dump PXX level info for kernel_page_tables

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 30/08/2025 à 05:51, Ritesh Harjani (IBM) a écrit :
> This patch adds PGD/PUD/PMD/PTE level information while dumping kernel
> page tables. Before this patch it was hard to identify which entries
> belongs to which page table level e.g.
> 
> ~ # dmesg |grep -i radix
> [0.000000] radix-mmu: Mapped 0x0000000000000000-0x0000000005400000 with 2.00 MiB pages (exec)
> [0.000000] radix-mmu: Mapped 0x0000000005400000-0x0000000040000000 with 2.00 MiB pages
> [0.000000] radix-mmu: Mapped 0x0000000040000000-0x0000000100000000 with 1.00 GiB pages
> [0.000000] radix-mmu: Initializing Radix MMU
> 
> Before:
> ---[ Start of kernel VM ]---
> 0xc000000000000000-0xc000000003ffffff  XXX   64M   r      X   pte  valid  present  dirty  accessed
> 0xc000000004000000-0xc00000003fffffff  XXX  960M   r  w       pte  valid  present  dirty  accessed
> 0xc000000040000000-0xc0000000ffffffff  XXX    3G   r  w       pte  valid  present  dirty  accessed
> ...
> ---[ vmemmap start ]---
> 0xc00c000000000000-0xc00c0000003fffff  XXX    4M   r  w       pte  valid  present  dirty  accessed
> 
> After:
> ---[ Start of kernel VM ]---
> 0xc000000000000000-0xc000000003ffffff  XXX   64M PMD  r      X   pte  valid  present  dirty  accessed
> 0xc000000004000000-0xc00000003fffffff  XXX  960M PMD  r  w       pte  valid  present  dirty  accessed
> 0xc000000040000000-0xc0000000ffffffff  XXX    3G PUD  r  w       pte  valid  present  dirty  accessed
> ...
> ---[ vmemmap start ]---
> 0xc00c000000000000-0xc00c0000003fffff  XXX    4M PMD  r  w       pte  valid  present  dirty  accessed
> 
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
> Cc: Paul Mackerras <paulus@ozlabs.org>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
> Cc: Donet Tom <donettom@linux.ibm.com>
> Cc: linuxppc-dev@lists.ozlabs.org
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> ---
>   arch/powerpc/mm/ptdump/8xx.c      | 5 +++++
>   arch/powerpc/mm/ptdump/book3s64.c | 5 +++++
>   arch/powerpc/mm/ptdump/ptdump.c   | 1 +
>   arch/powerpc/mm/ptdump/ptdump.h   | 1 +
>   arch/powerpc/mm/ptdump/shared.c   | 5 +++++
>   5 files changed, 17 insertions(+)
> 
> diff --git a/arch/powerpc/mm/ptdump/8xx.c b/arch/powerpc/mm/ptdump/8xx.c
> index b5c79b11ea3c..1dc0f2438a73 100644
> --- a/arch/powerpc/mm/ptdump/8xx.c
> +++ b/arch/powerpc/mm/ptdump/8xx.c
> @@ -71,18 +71,23 @@ static const struct flag_info flag_array[] = {
> 
>   struct pgtable_level pg_level[5] = {
>   	{ /* pgd */
> +		.name	= "PGD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* p4d */
> +		.name	= "P4D",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pud */
> +		.name	= "PUD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pmd */
> +		.name	= "PMD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pte */
> +		.name	= "PTX",

Why PTX not PTE ?

>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	},
> diff --git a/arch/powerpc/mm/ptdump/book3s64.c b/arch/powerpc/mm/ptdump/book3s64.c
> index 5ad92d9dc5d1..79c9a8391042 100644
> --- a/arch/powerpc/mm/ptdump/book3s64.c
> +++ b/arch/powerpc/mm/ptdump/book3s64.c
> @@ -104,18 +104,23 @@ static const struct flag_info flag_array[] = {
> 
>   struct pgtable_level pg_level[5] = {
>   	{ /* pgd */
> +		.name	= "PGD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* p4d */
> +		.name	= "P4D",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pud */
> +		.name	= "PUD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pmd */
> +		.name	= "PMD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pte */
> +		.name	= "PTE",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	},
> diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
> index b2358d794855..0d499aebee72 100644
> --- a/arch/powerpc/mm/ptdump/ptdump.c
> +++ b/arch/powerpc/mm/ptdump/ptdump.c
> @@ -178,6 +178,7 @@ static void dump_addr(struct pg_state *st, unsigned long addr)
>   	pt_dump_seq_printf(st->seq, REG "-" REG " ", st->start_address, addr - 1);
>   	pt_dump_seq_printf(st->seq, " " REG " ", st->start_pa);
>   	pt_dump_size(st->seq, addr - st->start_address);
> +	pt_dump_seq_printf(st->seq, "%s ", pg_level[st->level].name);
>   }
> 
>   static void note_prot_wx(struct pg_state *st, unsigned long addr)
> diff --git a/arch/powerpc/mm/ptdump/ptdump.h b/arch/powerpc/mm/ptdump/ptdump.h
> index 154efae96ae0..88cf28c4138e 100644
> --- a/arch/powerpc/mm/ptdump/ptdump.h
> +++ b/arch/powerpc/mm/ptdump/ptdump.h
> @@ -13,6 +13,7 @@ struct flag_info {
> 
>   struct pgtable_level {
>   	const struct flag_info *flag;
> +	char name[4];
>   	size_t num;
>   	u64 mask;
>   };
> diff --git a/arch/powerpc/mm/ptdump/shared.c b/arch/powerpc/mm/ptdump/shared.c
> index 39c30c62b7ea..92d77f3e5155 100644
> --- a/arch/powerpc/mm/ptdump/shared.c
> +++ b/arch/powerpc/mm/ptdump/shared.c
> @@ -69,18 +69,23 @@ static const struct flag_info flag_array[] = {
> 
>   struct pgtable_level pg_level[5] = {
>   	{ /* pgd */
> +		.name	= "PGD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* p4d */
> +		.name	= "P4D",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pud */
> +		.name	= "PUD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pmd */
> +		.name	= "PMD",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	}, { /* pte */
> +		.name	= "PTE",
>   		.flag	= flag_array,
>   		.num	= ARRAY_SIZE(flag_array),
>   	},
> --
> 2.50.1
>