[PATCH][2.6.19-rc5-mm1] i386: Convert more absolute symbols to section relative

[PATCH][2.6.19-rc5-mm1] i386: Convert more absolute symbols to section relative

[Vivek Goyal]

o Convert more absolute symbols to section relative to keep the theme in
  vmlinux.lds.S file and to avoid problem if kernel is relocated.

o Also put a message so that in future people can be aware of it and 
  avoid introducing absolute symbols.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
---

 arch/i386/kernel/vmlinux.lds.S |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff -puN arch/i386/kernel/vmlinux.lds.S~i386-reloc-convert-more-abs-syms-to-section-relative arch/i386/kernel/vmlinux.lds.S
--- linux-2.6.19-rc5-mm1-reloc/arch/i386/kernel/vmlinux.lds.S~i386-reloc-convert-more-abs-syms-to-section-relative	2006-11-08 16:24:31.000000000 -0500
+++ linux-2.6.19-rc5-mm1-reloc-root/arch/i386/kernel/vmlinux.lds.S	2006-11-08 16:29:51.000000000 -0500
@@ -2,6 +2,12 @@
  * Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>;
  */
 
+/* Don't define absolute symbols until and unless you know that symbol
+ * value is should remain constant even if kernel image is relocated
+ * at run time. Absolute symbols are not relocated. If symbol value should
+ * change if kernel is relocated, make the symbol section relative and
+ * put it inside the section definition.
+ */
 #define LOAD_OFFSET __PAGE_OFFSET
 
 #include <asm-generic/vmlinux.lds.h>
@@ -63,11 +69,11 @@ SECTIONS
 	CONSTRUCTORS
 	} :data
 
-  __start_paravirtprobe = .;
   .paravirtprobe : AT(ADDR(.paravirtprobe) - LOAD_OFFSET) {
+  	__start_paravirtprobe = .;
 	*(.paravirtprobe)
+  	__stop_paravirtprobe = .;
   }
-  __stop_paravirtprobe = .;
 
   . = ALIGN(4096);
   .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
@@ -163,11 +169,11 @@ SECTIONS
 	*(.altinstr_replacement)
   }
   . = ALIGN(4);
-  __start_parainstructions = .;
   .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
+  	__start_parainstructions = .;
 	*(.parainstructions)
+  	__stop_parainstructions = .;
   }
-  __stop_parainstructions = .;
   /* .exit.text is discard at runtime, not link time, to deal with references
      from .altinstructions and .eh_frame */
   .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { *(.exit.text) }
_

Re: [PATCH][2.6.19-rc5-mm1] i386: Convert more absolute symbols to section relative

[Andi Kleen]

On Wed, Nov 08, 2006 at 05:16:21PM -0500, Vivek Goyal wrote:
> 
> 
> o Convert more absolute symbols to section relative to keep the theme in
>   vmlinux.lds.S file and to avoid problem if kernel is relocated.
> 
> o Also put a message so that in future people can be aware of it and 
>   avoid introducing absolute symbols.

Added thanks

-Andi