Re: [PATCH v2 1/2] mm: Introduce flush_cache_vmap_early()

[Geert Uytterhoeven]

On Tue, Dec 12, 2023 at 10:36 PM Alexandre Ghiti <alexghiti@xxxxxxxxxxxx> wrote:
> The pcpu setup when using the page allocator sets up a new vmalloc
> mapping very early in the boot process, so early that it cannot use the
> flush_cache_vmap() function which may depend on structures not yet
> initialized (for example in riscv, we currently send an IPI to flush
> other cpus TLB).
>
> But on some architectures, we must call flush_cache_vmap(): for example,
> in riscv, some uarchs can cache invalid TLB entries so we need to flush
> the new established mapping to avoid taking an exception.
>
> So fix this by introducing a new function flush_cache_vmap_early() which
> is called right after setting the new page table entry and before
> accessing this new mapping. This new function implements a local flush
> tlb on riscv and is no-op for other architectures (same as today).
>
> Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>

>  arch/m68k/include/asm/cacheflush_mm.h  | 1 +

Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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