Re: [PATCH] of: Fix memory block alignment in early_init_dt_add_memory_arch()

From: Grant Likely
Date: Wed Aug 27 2014 - 06:31:06 EST


On Wed, 20 Aug 2014 17:10:31 +0200, Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote:
> If a memory block is not aligned to PAGE_SIZE, its base address must be
> rounded up, not down, and its size must be reduced.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Looks reasonable. What is the situation that exposed this problem?
Should size be checked for page alignment also?

g.

> ---
> drivers/of/fdt.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index f46a24ffa3fe..95fa81b8ca19 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -928,7 +928,11 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
> void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
> {
> const u64 phys_offset = __pa(PAGE_OFFSET);
> - base &= PAGE_MASK;
> +
> + if (!PAGE_ALIGNED(base)) {
> + size -= PAGE_SIZE - (base & ~PAGE_MASK);
> + base = PAGE_ALIGN(base);
> + }
> size &= PAGE_MASK;
>
> if (base > MAX_PHYS_ADDR) {
> --
> 1.9.1
>

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