From: Arvind Sankar <nivedita@alum.mit.edu>
To: "Mika Penttilä" <mika.penttila@nextfour.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
Ard Biesheuvel <ardb@kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] efi/x86: Decompress at start of PE image load address
Date: Tue, 3 Mar 2020 08:45:21 -0500 [thread overview]
Message-ID: <20200303134521.GA3628638@rani.riverdale.lan> (raw)
In-Reply-To: <dce7e026-ccb2-36f0-c892-83558dcc055f@nextfour.com>
On Tue, Mar 03, 2020 at 06:28:20AM +0000, Mika Penttilä wrote:
>
>
> On 2.3.2020 1.05, Arvind Sankar wrote:
> > When booted via PE loader, define image_offset to hold the offset of
> > startup_32 from the start of the PE image, and use it as the start of
> > the decompression buffer.
> >
> > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> > ---
> > arch/x86/boot/compressed/head_32.S | 17 +++++++++++
> > arch/x86/boot/compressed/head_64.S | 38 +++++++++++++++++++++++--
> > drivers/firmware/efi/libstub/x86-stub.c | 12 ++++++--
> > 3 files changed, 61 insertions(+), 6 deletions(-)
>
> ...
> > --- a/drivers/firmware/efi/libstub/x86-stub.c
> > +++ b/drivers/firmware/efi/libstub/x86-stub.c
> > @@ -19,6 +19,7 @@
> >
> > static efi_system_table_t *sys_table;
> > extern const bool efi_is64;
> > +extern u32 image_offset;
> >
> > __pure efi_system_table_t *efi_system_table(void)
> > {
> > @@ -364,6 +365,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
> > struct boot_params *boot_params;
> > struct setup_header *hdr;
> > efi_loaded_image_t *image;
> > + void *image_base;
> > efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
> > int options_size = 0;
> > efi_status_t status;
> > @@ -384,7 +386,10 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
> > efi_exit(handle, status);
> > }
> >
> > - hdr = &((struct boot_params *)efi_table_attr(image, image_base))->hdr;
> > + image_base = efi_table_attr(image, image_base);
> > + image_offset = (void *)startup_32 - image_base;
>
> startup_32 == 0, so maybe something like
>
> leaq startup_32(%rip) - image_base
>
> should be used ?
>
That's what it already uses. All the files in this directory are
compiled to be position-independent, so it uses rip-relative addressing
on 64-bit and GOT-relative addressing on 32-bit.
next prev parent reply other threads:[~2020-03-03 13:45 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-01 23:05 [PATCH 0/5] Minimize the need to move the kernel in the EFI stub Arvind Sankar
2020-03-01 23:05 ` [PATCH 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Arvind Sankar
2020-03-03 19:10 ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 2/5] efi/x86: Decompress at start of PE image load address Arvind Sankar
2020-03-03 6:28 ` Mika Penttilä
2020-03-03 13:45 ` Arvind Sankar [this message]
2020-03-03 19:08 ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 3/5] efi/x86: Add kernel preferred address to PE header Arvind Sankar
2020-03-03 19:11 ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 4/5] efi/x86: Remove extra headroom for setup block Arvind Sankar
2020-03-02 4:21 ` Mika Penttilä
2020-03-03 4:14 ` Arvind Sankar
2020-03-01 23:05 ` [PATCH 5/5] efi/x86: Don't relocate the kernel unless necessary Arvind Sankar
2020-03-03 19:15 ` Ard Biesheuvel
2020-03-03 22:12 ` [PATCH v2 0/5] Minimize the need to move the kernel in the EFI stub Arvind Sankar
2020-03-03 22:12 ` [PATCH v2 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Arvind Sankar
2020-03-03 22:12 ` [PATCH v2 2/5] efi/x86: Decompress at start of PE image load address Arvind Sankar
2020-03-03 22:12 ` [PATCH v2 3/5] efi/x86: Add kernel preferred address to PE header Arvind Sankar
2020-03-03 22:12 ` [PATCH v2 4/5] efi/x86: Remove extra headroom for setup block Arvind Sankar
2020-05-11 17:01 ` Mike Lothian
2020-05-11 18:36 ` Arvind Sankar
2020-05-11 21:13 ` Ard Biesheuvel
2020-05-11 22:53 ` Arvind Sankar
2020-05-11 22:58 ` [PATCH] x86/boot: Mark global variables as static Arvind Sankar
2020-05-11 23:12 ` Mike Lothian
2020-05-12 11:05 ` Ard Biesheuvel
2020-03-03 22:12 ` [PATCH v2 5/5] efi/x86: Don't relocate the kernel unless necessary Arvind Sankar
2020-03-03 23:08 ` Ard Biesheuvel
2020-03-03 23:34 ` Arvind Sankar
2020-03-04 7:30 ` Ard Biesheuvel
2020-03-03 22:26 ` [PATCH v2 0/5] Minimize the need to move the kernel in the EFI stub Ard Biesheuvel
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