On Aug 16, 2006, at 10:00 PM, Tony Breeds wrote:
On Wed, Aug 16, 2006 at 08:10:20AM -0400, Jimi Xenidis wrote:
Thanks for getting to the bottom of this Tony.
As it's empty the linker decides to start a
3rd segment rather than waste disk space.
Hmm, what is "empty"?
By empty I mean "filled with 0s", which I believe is because all the
per_cpu variables are initialised at runtime.
so why does LONG(0) (from option (2)) fix this?
Initially the linker guessed
it would need 2 segments, but due to this decision it actually
uses 3,
causeing the abort.
Aparently the newer (read current CVS) tools don't abort here but do
the right thing.
What _is_ the "right thing"?
Use 3 PHDRS.
Ok.
Perhaps, this is just mythology/warm-n-fuzzy for me, but I really
like having 1 PHDR.
Lemmy collect my thoughts and come up with a rational reason.
Sure. Wouldn't that mean that everything will end up being in a
read/write/execute PHDR. Do we care about that?
Not really its not like we protect any of it :) and the section
separation still exits
after-all we all (kernels/xen) link with -N/--omagic, which does not
page align the data sections which has always implied a single PHDR.
Besides, the more I do this the less I trust FW and bootloaders so a
single segment is just cleaner.
Placing everything in one PHDR would look like:
---
diff -r 279843441136 xen/arch/powerpc/xen.lds.S
--- a/xen/arch/powerpc/xen.lds.S Wed Aug 16 17:19:38 2006 -0500
+++ b/xen/arch/powerpc/xen.lds.S Thu Aug 17 11:30:50 2006 +1000
@@ -10,11 +10,15 @@ SEARCH_DIR("=/usr/local/lib64"); SEARCH_
SEARCH_DIR("=/usr/local/lib64"); SEARCH_DIR("=/lib64"); SEARCH_DIR
("=/usr/lib64"); SEARCH_DIR("=/usr/local/lib"); SEARCH_DIR("=/
lib"); SEARCH_DIR("=/usr/lib");
/* Do we need any of these for elf?
__DYNAMIC = 0; */
+PHDRS
+{
+ text PT_LOAD FILEHDR PHDRS;
+}
I think this is all we need, not other changes are required.
SECTIONS
{
/* Read-only sections, merged into text segment: */
PROVIDE (__executable_start = 0x10000000); . = 0x10000000 +
SIZEOF_HEADERS;
Actually the above line should just be:
PROVIDE (__executable_start = .);
We always specific the link address on the command line and not that
we define PHDRS there is no need for SIZEOF_HEADERS (as the linker
docs indicate)
I'm pretty sure the rest of the changes are unnecessary.
-JX
- .interp : { *(.interp) }
+ .interp : { *(.interp) } :text
.hash : { *(.hash) }
.dynsym : { *(.dynsym) }
.dynstr : { *(.dynstr) }
@@ -121,7 +125,7 @@ SECTIONS
__inithcall_end = .;
__per_cpu_start = .;
- .data.percpu : { *(.data.percpu) } :text
+ .data.percpu : { *(.data.percpu) }
__per_cpu_data_end = .;
. = __per_cpu_start + (NR_CPUS << PERCPU_SHIFT);
. = ALIGN(STACK_SIZE);
Yours Tony
linux.conf.au http://linux.conf.au/ || http://
lca2007.linux.org.au/
Jan 15-20 2007 The Australian Linux Technical Conference!
_______________________________________________
Xen-ppc-devel mailing list
Xen-ppc-devel@lists.xensource.com
http://lists.xensource.com/xen-ppc-devel
_______________________________________________
Xen-ppc-devel mailing list
Xen-ppc-devel@lists.xensource.com
http://lists.xensource.com/xen-ppc-devel
