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From:   Arvind Sankar <nivedita@alum.mit.edu>
Date:   Tue, 25 Feb 2020 12:49:53 -0500
To:     Kristen Carlson Accardi <kristen@linux.intel.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
        arjan@linux.intel.com, keescook@chromium.org,
        rick.p.edgecombe@intel.com, x86@kernel.org,
        linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com
Subject: Re: [RFC PATCH 08/11] x86: Add support for finer grained KASLR
Message-ID: <20200225174951.GA1373392@rani.riverdale.lan>
References: <20200205223950.1212394-1-kristen@linux.intel.com>
 <20200205223950.1212394-9-kristen@linux.intel.com>
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On Wed, Feb 05, 2020 at 02:39:47PM -0800, Kristen Carlson Accardi wrote:
> At boot time, find all the function sections that have separate .text
> sections, shuffle them, and then copy them to new locations. Adjust
> any relocations accordingly.
> 
> Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
> ---
>  arch/x86/boot/compressed/Makefile        |   1 +
>  arch/x86/boot/compressed/fgkaslr.c       | 751 +++++++++++++++++++++++
>  arch/x86/boot/compressed/misc.c          | 106 +++-
>  arch/x86/boot/compressed/misc.h          |  26 +
>  arch/x86/boot/compressed/vmlinux.symbols |  15 +
>  arch/x86/include/asm/boot.h              |  15 +-
>  arch/x86/include/asm/kaslr.h             |   1 +
>  arch/x86/lib/kaslr.c                     |  15 +
>  scripts/kallsyms.c                       |  14 +-
>  scripts/link-vmlinux.sh                  |   4 +
>  10 files changed, 939 insertions(+), 9 deletions(-)
>  create mode 100644 arch/x86/boot/compressed/fgkaslr.c
>  create mode 100644 arch/x86/boot/compressed/vmlinux.symbols
> 
> diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
> index b7e5ea757ef4..60d4c4e59c05 100644
> --- a/arch/x86/boot/compressed/Makefile
> +++ b/arch/x86/boot/compressed/Makefile
> @@ -122,6 +122,7 @@ OBJCOPYFLAGS_vmlinux.bin :=  -R .comment -S
>  
>  ifdef CONFIG_FG_KASLR
>  	RELOCS_ARGS += --fg-kaslr
> +	OBJCOPYFLAGS += --keep-symbols=$(obj)/vmlinux.symbols

I think this should be $(srctree)/$(src) rather than $(obj)? Using a
separate build directory fails currently.