linux-kernel - Re: [PATCH v4 05/13] m68k: mm: use pgtable-nopXd instead of 4level-fixup

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Date:   Fri, 8 Nov 2019 09:35:31 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Mike Rapoport <rppt@...nel.org>
Cc:     Linux MM <linux-mm@...ck.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Anton Ivanov <anton.ivanov@...bridgegreys.com>,
        Arnd Bergmann <arnd@...db.de>,
        "David S. Miller" <davem@...emloft.net>,
        Greentime Hu <green.hu@...il.com>,
        Greg Ungerer <gerg@...ux-m68k.org>,
        Helge Deller <deller@....de>,
        "James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
        Jeff Dike <jdike@...toit.com>,
        "Kirill A. Shutemov" <kirill@...temov.name>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mark Salter <msalter@...hat.com>,
        Matt Turner <mattst88@...il.com>,
        Michal Simek <monstr@...str.eu>, Peter Rosin <peda@...ntia.se>,
        Richard Weinberger <richard@....at>,
        Rolf Eike Beer <eike-kernel@...tec.de>,
        Russell King <linux@...linux.org.uk>,
        Sam Creasey <sammy@...my.net>,
        Vincent Chen <deanbo422@...il.com>,
        Vineet Gupta <Vineet.Gupta1@...opsys.com>,
        alpha <linux-alpha@...r.kernel.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-c6x-dev@...ux-c6x.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-m68k <linux-m68k@...ts.linux-m68k.org>,
        Parisc List <linux-parisc@...r.kernel.org>,
        linux-um@...ts.infradead.org,
        sparclinux <sparclinux@...r.kernel.org>,
        Mike Rapoport <rppt@...ux.ibm.com>
Subject: Re: [PATCH v4 05/13] m68k: mm: use pgtable-nopXd instead of 4level-fixup

Hi Mike,

On Tue, Nov 5, 2019 at 8:16 AM Mike Rapoport <rppt@...nel.org> wrote:
> From: Mike Rapoport <rppt@...ux.ibm.com>
>
> m68k has two or three levels of page tables and can use appropriate
> pgtable-nopXd and folding of the upper layers.
>
> Replace usage of include/asm-generic/4level-fixup.h and explicit
> definitions of __PAGETABLE_PxD_FOLDED in m68k with
> include/asm-generic/pgtable-nopmd.h for two-level configurations and with
> include/asm-generic/pgtable-nopud.h for three-lelve configurations and
> adjust page table manipulation macros and functions accordingly.
>
> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
> Acked-by: Greg Ungerer <gerg@...ux-m68k.org>

Acked-by: Geert Uytterhoeven <geert@...ux-m68k.org>

One forgotten error message update below.

> --- a/arch/m68k/mm/kmap.c
> +++ b/arch/m68k/mm/kmap.c
> @@ -258,18 +265,23 @@ void __iounmap(void *addr, unsigned long size)
>  {
>         unsigned long virtaddr = (unsigned long)addr;
>         pgd_t *pgd_dir;
> +       p4d_t *p4d_dir;
> +       pud_t *pud_dir;
>         pmd_t *pmd_dir;
>         pte_t *pte_dir;
>
>         while ((long)size > 0) {
>                 pgd_dir = pgd_offset_k(virtaddr);
> -               if (pgd_bad(*pgd_dir)) {
> -                       printk("iounmap: bad pgd(%08lx)\n", pgd_val(*pgd_dir));
> -                       pgd_clear(pgd_dir);
> +               p4d_dir = p4d_offset(pgd_dir, virtaddr);
> +               pud_dir = pud_offset(p4d_dir, virtaddr);
> +               if (pud_bad(*pud_dir)) {
> +                       printk("iounmap: bad pgd(%08lx)\n", pud_val(*pud_dir));

bad pud

> +                       pud_clear(pud_dir);
>                         return;
>                 }
> -               pmd_dir = pmd_offset(pgd_dir, virtaddr);
> +               pmd_dir = pmd_offset(pud_dir, virtaddr);
>
> +#if CONFIG_PGTABLE_LEVELS == 3
>                 if (CPU_IS_020_OR_030) {
>                         int pmd_off = (virtaddr/PTRTREESIZE) & 15;
>                         int pmd_type = pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK;

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