powerpc/vmlinux.lds: Don't discard .rela* for relocatable builds

commit 8da5d5380d3d970e7ba28491abe361b0b2581f53 upstream.

Relocatable kernels must not discard relocations, they need to be
processed at runtime. As such they are included for CONFIG_RELOCATABLE
builds in the powerpc linker script (line 340).

However they are also unconditionally discarded later in the
script (line 414). Previously that worked because the earlier inclusion
superseded the discard.

However commit fe15ce495a51 ("arch: fix broken BuildID for arm64 and
riscv") introduced an earlier use of DISCARD as part of the RO_DATA
macro (line 137). With binutils < 2.36 that causes the DISCARD
directives later in the script to be applied earlier, causing .rela* to
actually be discarded at link time, leading to build warnings and a
kernel that doesn't boot:

  ld: warning: discarding dynamic section .rela.init.rodata

Fix it by conditionally discarding .rela* only when CONFIG_RELOCATABLE
is disabled.

Fixes: fe15ce495a51 ("arch: fix broken BuildID for arm64 and riscv")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230105132349.384666-2-mpe@ellerman.id.au
Signed-off-by: Tom Saeger <tom.saeger@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 4d5e1662a0ba4b714e2dfb3de8ecf0fecc6c7a9f..46dfb3701c6eae90a48d82bcb464baf0b9f87872 100644 (file)
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -395,9 +395,12 @@ SECTIONS
        DISCARDS
        /DISCARD/ : {
                *(*.EMB.apuinfo)
-               *(.glink .iplt .plt .rela* .comment)
+               *(.glink .iplt .plt .comment)
                *(.gnu.version*)
                *(.gnu.attributes)
                *(.eh_frame)
+#ifndef CONFIG_RELOCATABLE
+               *(.rela*)
+#endif
        }
 }