mm/ptdump: split note_page() into level specific callbacks

Patch series "mm/ptdump: Drop assumption that pxd_val() is u64", v2.

Last argument passed down in note_page() is u64 assuming pxd_val()
returned value (all page table levels) is 64 bit - which might not be the
case going ahead when D128 page tables is enabled on arm64 platform. 
Besides pxd_val() is very platform specific and its type should not be
assumed in generic MM.  A similar problem exists for effective_prot(),
although it is restricted to x86 platform.

This series splits note_page() and effective_prot() into individual page
table level specific callbacks which accepts corresponding pxd_t page
table entry as an argument instead and later on all subscribing platforms
could derive pxd_val() from the table entries as required and proceed as
before.

Define ptdesc_t type which describes the basic page table descriptor
layout on arm64 platform.  Subsequently all level specific pxxval_t
descriptors are derived from ptdesc_t thus establishing a common original
format, which can also be appropriate for page table entries, masks and
protection values etc which are used at all page table levels.


This patch (of 3):

Last argument passed down in note_page() is u64 assuming pxd_val()
returned value (all page table levels) is 64 bit - which might not be the
case going ahead when D128 page tables is enabled on arm64 platform. 
Besides pxd_val() is very platform specific and its type should not be
assumed in generic MM.

Split note_page() into individual page table level specific callbacks
which accepts corresponding pxd_t argument instead and then subscribing
platforms just derive pxd_val() from the entries as required and proceed
as earlier.

Also add a note_page_flush() callback for flushing the last page table
page that was being handled earlier via level = -1.

Link: https://lkml.kernel.org/r/20250407053113.746295-1-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/20250407053113.746295-2-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h
index 8dbd51ea8626..1c1eb1fae199 100644
--- a/include/linux/ptdump.h
+++ b/include/linux/ptdump.h
@@ -11,9 +11,12 @@ struct ptdump_range {
 };
 
 struct ptdump_state {
-	/* level is 0:PGD to 4:PTE, or -1 if unknown */
-	void (*note_page)(struct ptdump_state *st, unsigned long addr,
-			  int level, u64 val);
+	void (*note_page_pte)(struct ptdump_state *st, unsigned long addr, pte_t pte);
+	void (*note_page_pmd)(struct ptdump_state *st, unsigned long addr, pmd_t pmd);
+	void (*note_page_pud)(struct ptdump_state *st, unsigned long addr, pud_t pud);
+	void (*note_page_p4d)(struct ptdump_state *st, unsigned long addr, p4d_t p4d);
+	void (*note_page_pgd)(struct ptdump_state *st, unsigned long addr, pgd_t pgd);
+	void (*note_page_flush)(struct ptdump_state *st);
 	void (*effective_prot)(struct ptdump_state *st, int level, u64 val);
 	const struct ptdump_range *range;
 };