From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper
Date: Fri, 9 Oct 2015 10:10:37 +0100 [thread overview]
Message-ID: <20151009091037.GC26278@arm.com> (raw)
In-Reply-To: <CAPAsAGz7Tp6Z87tPq_NNh_mcwPF_DOaXzu0po5f6AQxPAcsALQ@mail.gmail.com>
On Fri, Oct 09, 2015 at 11:12:24AM +0300, Andrey Ryabinin wrote:
> 2015-10-08 22:02 GMT+03:00 Ard Biesheuvel <ard.biesheuvel@linaro•org>:
> > --- a/arch/arm64/kernel/image.h
> > +++ b/arch/arm64/kernel/image.h
> > @@ -59,4 +59,31 @@
> > _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \
> > _kernel_flags_le = DATA_LE64(__HEAD_FLAGS);
> >
> > +#ifdef CONFIG_EFI
> > +
> > +/*
> > + * The EFI stub has its own symbol namespace prefixed by __efistub_, to
> > + * isolate it from the kernel proper. The following symbols are legally
> > + * accessed by the stub, so provide some aliases to make them accessible.
> > + * Only include data symbols here, or text symbols of functions that are
> > + * guaranteed to be safe when executed at another offset than they were
> > + * linked at. The routines below are all implemented in assembler in a
> > + * position independent manner
> > + */
> > +__efistub_memcmp = __pi_memcmp;
> > +__efistub_memchr = __pi_memchr;
> > +__efistub_memcpy = __pi_memcpy;
> > +__efistub_memmove = __pi_memmove;
> > +__efistub_memset = __pi_memset;
> > +__efistub_strlen = __pi_strlen;
> > +__efistub_strcmp = __pi_strcmp;
> > +__efistub_strncmp = __pi_strncmp;
> > +__efistub___flush_dcache_area = __pi___flush_dcache_area;
>
> So why we need these __pi_* aliases?
> We could just do __efistub_memcmp = memcmp; Right?
We *could*, but that defeats the whole purpose of tagging
position-independent functions explicitly in the kernel text.
Will
next prev parent reply other threads:[~2015-10-09 9:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-08 19:02 [PATCH v4 0/3] arm64: EFI stub isolation Ard Biesheuvel
2015-10-08 19:02 ` [PATCH v4 1/3] arm64/efi: remove /chosen/linux, uefi-stub-kern-ver DT property Ard Biesheuvel
2015-10-10 22:31 ` [PATCH v4 1/3] arm64/efi: remove /chosen/linux,uefi-stub-kern-ver " Matt Fleming
2015-10-08 19:02 ` [PATCH v4 2/3] arm64: use ENDPIPROC() to annotate position independent assembler routines Ard Biesheuvel
2015-10-08 19:02 ` [PATCH v4 3/3] arm64/efi: isolate EFI stub from the kernel proper Ard Biesheuvel
2015-10-09 8:12 ` Andrey Ryabinin
2015-10-09 9:10 ` Will Deacon [this message]
2015-10-09 9:40 ` Andrey Ryabinin
2015-10-09 9:43 ` Will Deacon
2015-10-09 9:48 ` Andrey Ryabinin
2015-10-10 22:40 ` Matt Fleming
2015-10-26 22:26 ` Jeremy Linton
2015-10-26 22:33 ` Jeremy Linton
2015-10-27 2:20 ` Ard Biesheuvel
2015-10-27 14:44 ` Jeremy Linton
2015-10-30 12:17 ` Ard Biesheuvel
2015-10-30 14:35 ` Mark Rutland
2015-10-30 16:01 ` Catalin Marinas
2015-11-02 12:49 ` Matt Fleming
2015-11-24 9:34 ` Robert Richter
2015-11-24 9:38 ` Ard Biesheuvel
2015-10-10 22:40 ` [PATCH v4 0/3] arm64: EFI stub isolation Matt Fleming
2015-10-12 15:30 ` Catalin Marinas
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