[PATCH 2/4] module, arm64: force sh_addr=0 for arch-specific sections

[Petr Pavlu <petr.pavlu@suse.com>]

When linking modules with 'ld.bfd -r', sections defined without an address
inherit the location counter, resulting in non-zero sh_addr values in the
resulting .ko files. Relocatable objects are expected to have sh_addr=0 for
all sections. Non-zero addresses are confusing in this context, typically
worse compressible, and may cause tools to misbehave [1].

Force sh_addr=0 for all arm64-specific module sections.

Link: https://sourceware.org/bugzilla/show_bug.cgi?id=33958 [1]
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
---
Note that the definition of .text.hot hasn't matched any input sections
since commit 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and
related macros"), and even before that with CONFIG_LTO_CLANG=y.

The preceding comment also explains that the directive is necessary to
merge section groups. However, this approach seems suboptimal. A better
method would be to link modules using --force-group-allocation to retain
only one copy of each group.

I plan to look at this separately.
---
 arch/arm64/include/asm/module.lds.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h
index fb944b46846d..0b3aacd22c59 100644
--- a/arch/arm64/include/asm/module.lds.h
+++ b/arch/arm64/include/asm/module.lds.h
@@ -14,7 +14,7 @@ SECTIONS {
 	 * directive to force them into a single section and silence the
 	 * warning.
 	 */
-	.text.hot : { *(.text.hot) }
+	.text.hot 0 : { *(.text.hot) }
 #endif
 
 #ifdef CONFIG_UNWIND_TABLES
@@ -22,6 +22,6 @@ SECTIONS {
 	 * Currently, we only use unwind info at module load time, so we can
 	 * put it into the .init allocation.
 	 */
-	.init.eh_frame : { *(.eh_frame) }
+	.init.eh_frame 0 : { *(.eh_frame) }
 #endif
 }
-- 
2.53.0