Patchwork [211/270] arch/tile: avoid generating .eh_frame information in modules

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Submitter Herton Ronaldo Krzesinski
Date Nov. 26, 2012, 4:58 p.m.
Message ID <1353949160-26803-212-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/201943/
State New
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Herton Ronaldo Krzesinski - Nov. 26, 2012, 4:58 p.m.
3.5.7u1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Metcalf <cmetcalf@tilera.com>

commit 627072b06c362bbe7dc256f618aaa63351f0cfe6 upstream.

The tile tool chain uses the .eh_frame information for backtracing.
The vmlinux build drops any .eh_frame sections at link time, but when
present in kernel modules, it causes a module load failure due to the
presence of unsupported pc-relative relocations.  When compiling to
use compiler feedback support, the compiler by default omits .eh_frame
information, so we don't see this problem.  But when not using feedback,
we need to explicitly suppress the .eh_frame.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 arch/tile/Makefile |    4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/arch/tile/Makefile b/arch/tile/Makefile
index e20b0a0..7da1015 100644
--- a/arch/tile/Makefile
+++ b/arch/tile/Makefile
@@ -26,6 +26,10 @@  $(error Set TILERA_ROOT or CROSS_COMPILE when building $(ARCH) on $(HOST_ARCH))
   endif
 endif
 
+# The tile compiler may emit .eh_frame information for backtracing.
+# In kernel modules, this causes load failures due to unsupported relocations.
+KBUILD_CFLAGS   += -fno-asynchronous-unwind-tables
+
 ifneq ($(CONFIG_DEBUG_EXTRA_FLAGS),"")
 KBUILD_CFLAGS   += $(CONFIG_DEBUG_EXTRA_FLAGS)
 endif