[PATCH] x86, vdso: Make the vdso linker script compatible with Gold

From: Andy Lutomirski
Date: Thu Apr 03 2014 - 13:54:03 EST


Gold can't parse the script due to:
https://sourceware.org/bugzilla/show_bug.cgi?id=16804

With a workaround in place for that issue, Gold 2.23 crashes due to:
https://sourceware.org/bugzilla/show_bug.cgi?id=15355

This works around the former bug and avoids the second by removing
the unnecessary vvar and hpet sections and segments. The vdso and
hpet symbols are still there, and nothing needed the sections or
segments.

Reported-by: Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
---
arch/x86/vdso/vdso-layout.lds.S | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S
index 2e263f3..9df017a 100644
--- a/arch/x86/vdso/vdso-layout.lds.S
+++ b/arch/x86/vdso/vdso-layout.lds.S
@@ -9,12 +9,9 @@ SECTIONS
#ifdef BUILD_VDSO32
#include <asm/vdso32.h>

- .hpet_sect : {
- hpet_page = . - VDSO_OFFSET(VDSO_HPET_PAGE);
- } :text :hpet_sect
+ hpet_page = . - VDSO_OFFSET(VDSO_HPET_PAGE);

- .vvar_sect : {
- vvar = . - VDSO_OFFSET(VDSO_VVAR_PAGE);
+ vvar = . - VDSO_OFFSET(VDSO_VVAR_PAGE);

/* Place all vvars at the offsets in asm/vvar.h. */
#define EMIT_VVAR(name, offset) vvar_ ## name = vvar + offset;
@@ -22,7 +19,6 @@ SECTIONS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
#undef EMIT_VVAR
- } :text :vvar_sect
#endif
. = SIZEOF_HEADERS;

@@ -61,7 +57,12 @@ SECTIONS
*/
. = ALIGN(0x100);

- .text : { *(.text*) } :text =0x90909090
+ .text : { *(.text*) } :text =0x90909090,
+
+ /*
+ * The comma above works around a bug in gold:
+ * https://sourceware.org/bugzilla/show_bug.cgi?id=16804
+ */

/DISCARD/ : {
*(.discard)
@@ -84,8 +85,4 @@ PHDRS
dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
note PT_NOTE FLAGS(4); /* PF_R */
eh_frame_hdr PT_GNU_EH_FRAME;
-#ifdef BUILD_VDSO32
- vvar_sect PT_NULL FLAGS(4); /* PF_R */
- hpet_sect PT_NULL FLAGS(4); /* PF_R */
-#endif
}
--
1.9.0

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