linux-kernel - Re: [PATCH][EFI] Run EFI in physical mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <AANLkTimM0H0ryre3pXsXQ6c0e3=v_36-h0TsXzriMWXe@mail.gmail.com>
Date:	Mon, 16 Aug 2010 09:43:56 +0800
From:	huang ying <huang.ying.caritas@...il.com>
To:	Takao Indoh <indou.takao@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
	ebiederm@...ssion.com, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, vgoyal@...hat.com, nhorman@...driver.com
Subject: Re: [PATCH][EFI] Run EFI in physical mode

On Sat, Aug 14, 2010 at 3:18 AM, Takao Indoh <indou.takao@...fujitsu.com> wrote:
> diff -Nurp linux-2.6.35.org/arch/x86/kernel/efi_64.c linux-2.6.35/arch/x86/kernel/efi_64.c
> --- linux-2.6.35.org/arch/x86/kernel/efi_64.c   2010-08-01 18:11:14.000000000 -0400
> +++ linux-2.6.35/arch/x86/kernel/efi_64.c       2010-08-13 14:39:25.819105004 -0400
> @@ -39,7 +39,9 @@
>  #include <asm/fixmap.h>
>
>  static pgd_t save_pgd __initdata;
> -static unsigned long efi_flags __initdata;
> +static unsigned long efi_flags;
> +static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;
> +static unsigned long save_cr3;
>
>  static void __init early_mapping_set_exec(unsigned long start,
>                                          unsigned long end,
> @@ -98,6 +100,19 @@ void __init efi_call_phys_epilog(void)
>        early_runtime_code_mapping_set_exec(0);
>  }
>
> +void efi_call_phys_prelog_in_physmode(void)
> +{
> +       local_irq_save(efi_flags);
> +       save_cr3 = read_cr3();
> +       write_cr3(virt_to_phys(efi_pgd));
> +}
> +
> +void efi_call_phys_epilog_in_physmode(void)
> +{
> +       write_cr3(save_cr3);
> +       local_irq_restore(efi_flags);
> +}

efi_flags and save_cr3 should be per-CPU, because they now will be
used after SMP is enabled.

efi_pgd should be dynamically allocated instead of statically
allocated, because EFI may be not enabled on some platform.

And I think it is better to unify early physical mode with run-time
physical mode. Just allocate the page table with early page allocator
(lmb?).

Best Regards,
Huang Ying
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/