Re: [PATCH 1/5] x86: Move enabling of PSE and PGE out of init_memory_mapping

From: Yinghai Lu
Date: Fri Aug 24 2012 - 21:25:34 EST


On Fri, Aug 24, 2012 at 4:55 PM, Jacob Shin <jacob.shin@xxxxxxx> wrote:
> Depending on the platform, init_memory_mapping() may be called multiple
> times. Move it out to setup_arch() to avoid writing to cr4 on every call.
>
> Signed-off-by: Jacob Shin <jacob.shin@xxxxxxx>
> ---
> arch/x86/kernel/setup.c | 10 ++++++++++
> arch/x86/mm/init.c | 10 ----------
> 2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index f4b9b80..751e020 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -913,6 +913,16 @@ void __init setup_arch(char **cmdline_p)
>
> init_gbpages();
>
> + /* Enable PSE if available */
> + if (cpu_has_pse)
> + set_in_cr4(X86_CR4_PSE);
> +
> + /* Enable PGE if available */
> + if (cpu_has_pge) {
> + set_in_cr4(X86_CR4_PGE);
> + __supported_pte_mask |= _PAGE_GLOBAL;
> + }
> +

please don't put it directly in setup_arch().

and another function.

Thanks

Yinghai

> /* max_pfn_mapped is updated here */
> max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
> max_pfn_mapped = max_low_pfn_mapped;
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index e0e6990..2f07e09 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -149,16 +149,6 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> use_gbpages = direct_gbpages;
> #endif
>
> - /* Enable PSE if available */
> - if (cpu_has_pse)
> - set_in_cr4(X86_CR4_PSE);
> -
> - /* Enable PGE if available */
> - if (cpu_has_pge) {
> - set_in_cr4(X86_CR4_PGE);
> - __supported_pte_mask |= _PAGE_GLOBAL;
> - }
> -
> if (use_gbpages)
> page_size_mask |= 1 << PG_LEVEL_1G;
> if (use_pse)
> --
> 1.7.9.5
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/