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Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface

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From Ingo Molnar <mingo@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface
Date Wed, 11 May 2016 08:30:01 +0200
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* Kees Cook <keescook@chromium.org> wrote:

> +/*
> + * Mapping information structure passed to kernel_ident_mapping_init().
> + * Due to relocation, pointers must be assigned at run time not build time.
> + */
> +static struct x86_mapping_info mapping_info = {
> +	.pmd_flag       = __PAGE_KERNEL_LARGE_EXEC,
> +};

> +void initialize_identity_maps(void)
>  {
> +	/* Init mapping_info with run-time function/buffer pointers. */
> +	mapping_info.alloc_pgt_page = alloc_pgt_page;
> +	mapping_info.context = &pgt_data;

Could you please outline the precise failure mode? What gets executed when, which 
pointer gets relocated and which not, and exactly when does it pose a problem, 
etc.

Thanks,

	Ingo

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Thread

[PATCH v8 1/4] x86/KASLR: Clarify identity map interface Kees Cook <keescook@chromium.org> - 2016-05-10 19:20 +0200
  Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface Borislav Petkov <bp@suse.de> - 2016-05-10 19:50 +0200
  Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface Ingo Molnar <mingo@kernel.org> - 2016-05-11 08:30 +0200
    Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface Kees Cook <keescook@chromium.org> - 2016-05-11 17:30 +0200
      Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface Ingo Molnar <mingo@kernel.org> - 2016-05-12 10:40 +0200
      Re: [PATCH v8 1/4] x86/KASLR: Clarify identity map interface Ingo Molnar <mingo@kernel.org> - 2016-05-12 10:40 +0200

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