[PATCH] powerpc/mm: Fix page table dump to work on Radix

[PATCH] powerpc/mm: Fix page table dump to work on Radix

[Michael Ellerman]

When we're running on Book3S with the Radix MMU enabled the page table
dump currently prints the wrong addresses because it uses the wrong
start address.

Fix it to use PAGE_OFFSET rather than KERN_VIRT_START.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/mm/dump_linuxpagetables.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c
index e60aa6d7456d..2b74f8adf4d0 100644
--- a/arch/powerpc/mm/dump_linuxpagetables.c
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -267,12 +267,13 @@ static void walk_pagetables(struct pg_state *st)
 	unsigned int i;
 	unsigned long addr;
 
+	addr = st->start_address;
+
 	/*
 	 * Traverse the linux pagetable structure and dump pages that are in
 	 * the hash pagetable.
 	 */
-	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
-		addr = KERN_VIRT_START + i * PGDIR_SIZE;
+	for (i = 0; i < PTRS_PER_PGD; i++, pgd++, addr += PGDIR_SIZE) {
 		if (!pgd_none(*pgd) && !pgd_huge(*pgd))
 			/* pgd exists */
 			walk_pud(st, pgd, addr);
@@ -321,9 +322,14 @@ static int ptdump_show(struct seq_file *m, void *v)
 {
 	struct pg_state st = {
 		.seq = m,
-		.start_address = KERN_VIRT_START,
 		.marker = address_markers,
 	};
+
+	if (radix_enabled())
+		st.start_address = PAGE_OFFSET;
+	else
+		st.start_address = KERN_VIRT_START;
+
 	/* Traverse kernel page tables */
 	walk_pagetables(&st);
 	note_page(&st, 0, 0, 0);
-- 
2.17.2

Re: powerpc/mm: Fix page table dump to work on Radix

[Michael Ellerman]

On Fri, 2018-10-19 at 04:12:50 UTC, Michael Ellerman wrote:
> When we're running on Book3S with the Radix MMU enabled the page table
> dump currently prints the wrong addresses because it uses the wrong
> start address.
> 
> Fix it to use PAGE_OFFSET rather than KERN_VIRT_START.
> 
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/0d923962ab69c27cca664a2d535e90

cheers