[PATCH 4/4] s390/kernel: vmlinux.lds.S: handle orphan .rela sections

[Sumanth Korikkar <sumanthk@linux.ibm.com>]

When kernel is built with CONFIG_LD_ORPHAN_WARN and -fno-PIE, there are
several warnings:

ld: warning: orphan section `.rela.iplt' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
ld: warning: orphan section `.rela.head.text' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
ld: warning: orphan section `.rela.init.text' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
ld: warning: orphan section `.rela.rodata.cst8' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'

Orphan sections are sections that exist in an object file but don't have
a corresponding output section in the final executable. ld raises a
warning when it identifies such sections.

Eliminate the warning by placing all .rela orphan sections in .rela.dyn
and raise an error when size of .rela.dyn is greater than zero. i.e.
Dont just neglect orphan sections.

This is similar to adjustment performed in x86, where kernel is built
with -fno-PIE.
commit 5354e84598f2 ("x86/build: Add asserts for unwanted sections")

Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
---
 arch/s390/kernel/vmlinux.lds.S | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index cb052ce302bd..c6e534704304 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -280,6 +280,12 @@ SECTIONS
 		*(.igot .igot.plt)
 	}
 	ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
+#ifndef CONFIG_PIE_BUILD
+	.rela.dyn : {
+		*(.rela.*) *(.rela_*)
+	}
+	ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!")
+#endif
 
 	/* Sections to be discarded */
 	DISCARDS
-- 
2.40.1