Re: [PATCH v7u1 07/31] x86, realmode: Separate real_mode reserve andsetup

From: Borislav Petkov
Date: Mon Jan 07 2013 - 10:54:48 EST


On Thu, Jan 03, 2013 at 04:48:27PM -0800, Yinghai Lu wrote:
> After we switch to use #PF handler help to set page table, init_level4_pgt
> will only have entries set after init_mem_mapping.
> We need to move copying init_level4_pgt to trampoline_pgd after that.
>
> So split reserve and setup, and move the setup after init_mem_mapping()
>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxx>
> ---
> arch/x86/include/asm/realmode.h | 3 ++-
> arch/x86/kernel/setup.c | 4 +++-
> arch/x86/realmode/init.c | 30 +++++++++++++++++++-----------
> 3 files changed, 24 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
> index fe1ec5b..9c6b890 100644
> --- a/arch/x86/include/asm/realmode.h
> +++ b/arch/x86/include/asm/realmode.h
> @@ -58,6 +58,7 @@ extern unsigned char boot_gdt[];
> extern unsigned char secondary_startup_64[];
> #endif
>
> -extern void __init setup_real_mode(void);
> +void reserve_real_mode(void);
> +void setup_real_mode(void);
>
> #endif /* _ARCH_X86_REALMODE_H */
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 81ea5a5..01b22d0 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -913,10 +913,12 @@ void __init setup_arch(char **cmdline_p)
> printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
> (max_pfn_mapped<<PAGE_SHIFT) - 1);
>
> - setup_real_mode();
> + reserve_real_mode();
>
> init_mem_mapping();
>
> + setup_real_mode();
> +
> memblock.current_limit = get_max_mapped();
> dma_contiguous_reserve(0);
>
> diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
> index 384b3f4..3baae96 100644
> --- a/arch/x86/realmode/init.c
> +++ b/arch/x86/realmode/init.c
> @@ -8,9 +8,26 @@
> struct real_mode_header *real_mode_header;
> u32 *trampoline_cr4_features;
>
> -void __init setup_real_mode(void)
> +void __init reserve_real_mode(void)
> {
> phys_addr_t mem;
> + unsigned char *base;
> + size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
> +
> + /* Has to be in very low memory so we can execute real-mode AP code. */

While we're at it, can we change the comment to say "has to be in the
first megabyte..." to be more precise. "very low" is not very telling
:-).

Thanks.

--
Regards/Gruss,
Boris.
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