Re: [PATCH v14 21/22] arm64: mm: Convert mm/dump.c to use walk_page_range()

Catalin Marinas
2019-10-31T14:00:46Z

On Thu, Oct 31, 2019 at 01:32:34PM +0000, Steven Price wrote:
> On 30/10/2019 16:45, Catalin Marinas wrote:
> > On Mon, Oct 28, 2019 at 01:59:09PM +0000, Steven Price wrote:
> >> diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
> >> index 93f9f77582ae..9d9b740a86d2 100644
> >> --- a/arch/arm64/mm/dump.c
> >> +++ b/arch/arm64/mm/dump.c
> >> @@ -15,6 +15,7 @@
> >> #include <linux/io.h>
> >> #include <linux/init.h>
> >> #include <linux/mm.h>
> >> +#include <linux/ptdump.h>
> >> #include <linux/sched.h>
> >> #include <linux/seq_file.h>
> >>
> >> @@ -75,10 +76,11 @@ static struct addr_marker address_markers[] = {
> >> * dumps out a description of the range.
> >> */
> >> struct pg_state {
> >> + struct ptdump_state ptdump;
> >> struct seq_file *seq;
> >> const struct addr_marker *marker;
> >> unsigned long start_address;
> >> - unsigned level;
> >> + int level;
> >> u64 current_prot;
> >> bool check_wx;
> >> unsigned long wx_pages;
> >> @@ -178,6 +180,10 @@ static struct pg_level pg_level[] = {
> >> .name = "PGD",
> >> .bits = pte_bits,
> >> .num = ARRAY_SIZE(pte_bits),
> >> + }, { /* p4d */
> >> + .name = "P4D",
> >> + .bits = pte_bits,
> >> + .num = ARRAY_SIZE(pte_bits),
> >> }, { /* pud */
> >> .name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
> >> .bits = pte_bits,
> >
> > We could use "PGD" for the p4d entry since we don't have five levels.
> > This patches the "PGD" name used for pud/pmd when these levels are
> > folded.
>
> Good point, although I'd actually be more tempted to do the opposite -
> remove the special casing for PUD/PMD as the generic code should now
> never provide those levels if they are folded. What do you think?

I agree, it makes sense.

--
Catalin