Re: [PATCH 3/3] Limit E820 map when a user-defined memory map is specified

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Tue, Jun 24, 2008 at 7:35 AM, Bernhard Walle <bwalle@suse.de> 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@suse.de>
> ---
>  arch/x86/kernel/e820.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 7d1109b..19b7f05 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -979,6 +979,8 @@ 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, E820_RAM, E820_RESERVED);
==>
+       e820_update_range(mem_size, ULLONG_MAX - mem_size, E820_RAM,
E820_RESERVED);
> +
>        return 0;
>  }
>  early_param("mem", parse_memopt);
> @@ -1023,6 +1025,7 @@ 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, E820_RAM, E820_RESERVED);
==>
+       e820_update_range(mem_size, ULLONG_MAX - mem_size, E820_RAM,
E820_RESERVED);

YH