linux-kernel - Re: [PATCH 2/2] sh: add support for folded p4d page tables

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Date:   Tue, 17 Dec 2019 18:59:43 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Mike Rapoport <rppt@...nel.org>
Cc:     Linux-sh list <linux-sh@...r.kernel.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>, Linux MM <linux-mm@...ck.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Mike Rapoport <rppt@...ux.ibm.com>
Subject: Re: [PATCH 2/2] sh: add support for folded p4d page tables

Hi Mike,

On Tue, Dec 17, 2019 at 3:23 PM Mike Rapoport <rppt@...nel.org> wrote:
> From: Mike Rapoport <rppt@...ux.ibm.com>
>
> Implement primitives necessary for the 4th level folding, add walks of p4d
> level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK.
>
> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>

Thanks for your patch!

> --- a/arch/sh/mm/fault.c
> +++ b/arch/sh/mm/fault.c
> @@ -65,7 +66,20 @@ static void show_pte(struct mm_struct *mm, unsigned long addr)
>                         break;
>                 }
>
> -               pud = pud_offset(pgd, addr);
> +               p4d = p4d_offset(pgd, addr);
> +               if (PTRS_PER_P4D != 1)
> +                       printk(", *p4d=%0*Lx", (u32)(sizeof(*p4d) * 2),
> +                              (u64)p4d_val(*p4d));

This (and the prints below) is gonna cause lots of broken output lines.
You should use pr_cont() instead, and probably rebase on top of  my
"[PATCH 7/7] sh: fault: Modernize printing of kernel messages"
(https://lore.kernel.org/lkml/20191203162645.19950-8-geert+renesas@glider.be/).

> +
> +               if (p4d_none(*p4d))
> +                       break;
> +
> +               if (p4d_bad(*p4d)) {
> +                       printk("(bad)");
> +                       break;
> +               }
> +
> +               pud = pud_offset(p4d, addr);
>                 if (PTRS_PER_PUD != 1)
>                         printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2),
>                                (u64)pud_val(*pud));

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds