Re: [PATCH v3 2/5] arm/config: Declare ELFSIZE_[32|64] respectively.

[Konrad Rzeszutek Wilk <konrad@kernel.org>]

On Wed, Mar 16, 2016 at 03:21:51PM -0400, Konrad Rzeszutek Wilk wrote:
> On Wed, Mar 16, 2016 at 06:08:06PM +0000, Julien Grall wrote:
> > Hi Konrad
> > 
> > On 16/03/2016 17:52, Konrad Rzeszutek Wilk wrote:
> > >On Wed, Mar 16, 2016 at 05:32:09PM +0000, Julien Grall wrote:
> > >>Sorry for the late answer on this patch. I noticed the problem while I was
> > >>reviewing your xSplice patch series.
> > >>
> > >>On 12/02/2016 15:56, Konrad Rzeszutek Wilk wrote:
> > >>> From 32a062c119091f2f3f6a4c540a8098e97c273dd2 Mon Sep 17 00:00:00 2001
> > >>>From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > >>>Date: Fri, 5 Feb 2016 10:44:45 -0500
> > >>>Subject: [PATCH] arm/config: Declare ELFSIZE_64.
> > >>>
> > >>>Otherwise any code that tries to use Elf_* macros would
> > >>>require us to use Elf64_* types instead of the more
> > >>>friendly Elf_ one.
> > >>>
> > >>>This is OK to do since 32-bit ARM uses LPAE mode.
> > >>
> > >>That's not true. Some of structures have a different layout based on the
> > >>file class (i.e ELFSIZE in Xen).
> > >>
> > >>For 32-bit ARM, ELFCLASS32 (i.e 32-bit data types) will always be used. So
> > >>we need to set ELFSIZE to 32.
> > >
> > >OK. Let me send out a patch to fix that. Thanks for the heads up!
> > 
> > With this change, do you need to revise the answer to the question Jan
> > raised in the design document about ARM32 and the ELF payload declaring the
> > ELF only 64-bit syntax?
> 
> Yes I will. Thank you for raising that as I completly forgot it!
> 
> I think we can still keep the same structure and size. But instead of
> using ELF types in the design (and in the code) I will swap them to
> proper uintXX_t types.

And here is the patch. The change for uintXX_t type worked out - same
size and offset as on 64-bit. Thought I am tempted to add some
more BUILD_BUG checks.

From 7007f1a3fa3a77a725f529420c7aea0e8ebdc9fa Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Wed, 16 Mar 2016 16:08:25 -0400
Subject: [PATCH v4 01/35] arm/config: Declare ELFSIZE_[32|64]

The commit bcfaea685d38c08e5eb90797512ab80f0bc69d0c
"arm/config: Declare ELFSIZE_64" was not correct.

For 32-bit ARM, ELFCLASS32 (i.e. 32-bit data types) will always
be used so we need to set ELFSIZE to 32.

Reported-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

---
Cc: Stefano Stabellini <stefano.stabellini@citrix.com>
Cc: Julien Grall <julien.grall@arm.com>
--
---
 xen/include/asm-arm/config.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index 7ceb5c5..2d11b62 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -9,8 +9,10 @@
 
 #if defined(CONFIG_ARM_64)
 # define LONG_BYTEORDER 3
+# define ELFSIZE 64
 #else
 # define LONG_BYTEORDER 2
+# define ELFSIZE 32
 #endif
 
 #define BYTES_PER_LONG (1 << LONG_BYTEORDER)
@@ -20,9 +22,6 @@
 /* xen_ulong_t is always 64 bits */
 #define BITS_PER_XEN_ULONG 64
 
-/* And ELF files are also 64-bit. */
-#define ELFSIZE 64
-
 #define CONFIG_PAGING_ASSISTANCE 1
 
 #define CONFIG_PAGING_LEVELS 3
-- 
2.5.0

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