Re: [PATCH] x86: Limit E820 map when a user-defined memory map is specified

From: Yinghai Lu
Date: Wed Jun 25 2008 - 15:59:27 EST


On Wed, Jun 25, 2008 at 12:39 PM, Bernhard Walle <bwalle@xxxxxxx> wrote:
> This patch brings back limiting of the E820 map when a user-defined
> E820 map is specified. While the behaviour of i386 (32 bit) was to limit
> the E820 map (and /proc/iomem), the behaviour of x86-64 (64 bit) was not to
> limit.
>
> That patch limits the E820 map again for both x86 architectures.
>
> Code was tested for compilation and booting on a 32 bit and 64 bit system.
>
>
> Signed-off-by: Bernhard Walle <bwalle@xxxxxxx>

Acked-by: Yinghai Lu <yhlu.kernel@xxxxxxxxx>

> ---
> arch/x86/kernel/e820.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index a1b0548..3771386 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -988,6 +988,9 @@ static int __init parse_memopt(char *p)
>
> mem_size = memparse(p, &p);
> end_user_pfn = mem_size>>PAGE_SHIFT;
> + e820_update_range(mem_size, ULLONG_MAX - mem_size,
> + E820_RAM, E820_RESERVED);
> +
> return 0;
> }
> early_param("mem", parse_memopt);
> @@ -1032,6 +1035,8 @@ static int __init parse_memmap_opt(char *p)
> e820_add_region(start_at, mem_size, E820_RESERVED);
> } else {
> end_user_pfn = (mem_size >> PAGE_SHIFT);
> + e820_update_range(mem_size, ULLONG_MAX - mem_size,
> + E820_RAM, E820_RESERVED);
> }
> return *p == '\0' ? 0 : -EINVAL;
> }
> --
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