[U-Boot] [PATCH] arm: lds: Remove libgcc eabi exception handling tables

[Michal Simek]

Remove ARM eabi exception handling tables (for frame unwinding).
AFAICT, u-boot stubs away the frame unwiding routines, so the tables will
more or less just consume space. It should be OK to remove them.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias at xilinx.com>
Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---
This patch was sent to ML as RFC (May 9)

Here is the origin response in connection to this patch.

Ok, so Michal and I just did some fiddling with zynq builds and
*exidx* sections.

By default the *exidx* sections are between rodata and data, so
removing them causes many apparent changes at the binary level.
However, builds of zynq based on ARM master with the patch above vs
master with a patch mapping *exidx* sections after BSS gives identical
binaries. Thus the RFC has no functional effect.

Also, ARM EHABI states that [exception] Tables are not required for ABI
compliance at the C/Assembler level but are required for C++.

http://infocenter.arm.com/help/topic/com.arm.doc.ihi0038a/IHI0038A_ehabi.pdf

So as long as we don't put any C++ code in U-Boot (a prospect that I
don't see happening any time soon), this RFC is safe and either is a
no-op or removes useless bytes from the binary.

---
 arch/arm/cpu/u-boot.lds | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
index 3037885..8894c8a 100644
--- a/arch/arm/cpu/u-boot.lds
+++ b/arch/arm/cpu/u-boot.lds
@@ -113,4 +113,6 @@ SECTIONS
 	/DISCARD/ : { *(.plt*) }
 	/DISCARD/ : { *(.interp*) }
 	/DISCARD/ : { *(.gnu*) }
+	/DISCARD/ : { *(.ARM.exidx*) }
+	/DISCARD/ : { *(.gnu.linkonce.armexidx.*) }
 }
--
1.8.2.3

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