linux-kernel - Re: [PATCH 16/22] arm64: Add function to create identity mappings

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Message-ID: <20140214174256.GC12304@arm.com>
Date:	Fri, 14 Feb 2014 17:42:56 +0000
From:	Catalin Marinas <catalin.marinas@....com>
To:	Leif Lindholm <leif.lindholm@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-efi@...r.kernel.org, patches@...aro.org,
	Mark Salter <msalter@...hat.com>
Subject: Re: [PATCH 16/22] arm64: Add function to create identity mappings

On Wed, Feb 05, 2014 at 05:04:07PM +0000, Leif Lindholm wrote:
> +void __init create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io)
> +{
> +	pgd_t *pgd = &idmap_pg_dir[pgd_index(addr)];
> +
> +	if (pgd >= &idmap_pg_dir[ARRAY_SIZE(idmap_pg_dir)]) {
> +		pr_warn("BUG: not creating id mapping for 0x%016llx\n", addr);
> +		return;
> +	}
> +	__create_mapping(pgd, addr, addr, size, map_io);
> +}

I'm a bit worried because I gave some feedback in the past but it didn't
make to this patch.

What I said on 22nd of January:

  The condition above is always false since pgd_index() already ands the
  index with (PTRS_PER_PGD - 1). Better check addr against something like
  (PTRS_PER_PGD * PGDIR_SIZE) (for clarity, you could do other shifts,
  doesn't really matter).

-- 
Catalin
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