[Buildroot] [PATCH] Fix musl-based builds on ARMhf platforms.

[Buildroot] [PATCH] Fix musl-based builds on ARMhf platforms.

[Vicente Bergas]

When ARCH is arm and the hard-floating-point option is on executables
expect to find the dynamic linker at /lib/ld-musl-armhf.so.1 and not
/lib/ld-musl-arm.so.1
There are two ways of fixing this:
 1) Changing the actual location of the dynamic linker.
 2) Changing the expected location of the dynamic linker.
This patch uses option 1.
I don't know how to do option 2 and also don't know which option is better.

Signed-off-by: Vicente Bergas <vicencb@gmail.com>
---
 toolchain/toolchain-external/toolchain-external.mk | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/toolchain/toolchain-external/toolchain-external.mk b/toolchain/toolchain-external/toolchain-external.mk
index 61a5dba..79afdaa 100644
--- a/toolchain/toolchain-external/toolchain-external.mk
+++ b/toolchain/toolchain-external/toolchain-external.mk
@@ -524,6 +524,8 @@ endef
 ifeq ($(BR2_TOOLCHAIN_EXTERNAL_MUSL),y)
 ifeq ($(BR2_i386),y)
 MUSL_ARCH = i386
+else ifeq ($(BR2_ARM_EABIHF),y)
+MUSL_ARCH = armhf
 else
 MUSL_ARCH = $(ARCH)
 endif
-- 
2.5.3

[Buildroot] [PATCH] Fix musl-based builds on ARMhf platforms.

[Thomas Petazzoni]

Dear Vicente Bergas,

On Sun, 27 Sep 2015 14:48:22 +0100, Vicente Bergas wrote:
> When ARCH is arm and the hard-floating-point option is on executables
> expect to find the dynamic linker at /lib/ld-musl-armhf.so.1 and not
> /lib/ld-musl-arm.so.1
> There are two ways of fixing this:
>  1) Changing the actual location of the dynamic linker.
>  2) Changing the expected location of the dynamic linker.
> This patch uses option 1.
> I don't know how to do option 2 and also don't know which option is better.
> 
> Signed-off-by: Vicente Bergas <vicencb@gmail.com>
> ---
>  toolchain/toolchain-external/toolchain-external.mk | 2 ++
>  1 file changed, 2 insertions(+)

I've slightly tweaked the commit log and applied. In fact your
explanation about "two ways of fixing this" is not completely correct:
the dynamic linker in musl is part of the C library itself. So all what
Buildroot is doing is create a symbolic link with the name of the
dynamic linker encoded into the executables, which points to the musl C
library. So all what your patch is doing is adjusting the logic that
calculates the name of this symbolic link.

Thanks for this contribution!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com