Patch "powerpc/vmlinux.lds: Don't discard .rela* for relocatable builds" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-vmlinux.lds-don-t-discard-.rela-for-relocata.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5b4a7c35df5825ef9383bd378172a24a199cb61b
Author: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Date:   Tue Jan 24 14:14:21 2023 -0700

    powerpc/vmlinux.lds: Don't discard .rela* for relocatable builds
    
    commit 07b050f9290ee012a407a0f64151db902a1520f5 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    superseded the discard.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 99cb0d917ffa ("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: 99cb0d917ffa ("arch: fix broken BuildID for arm64 and riscv")
    Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
    
    Link: https://lore.kernel.org/r/20230105132349.384666-2-mpe@xxxxxxxxxxxxxx
    Signed-off-by: Tom Saeger <tom.saeger@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 4d5e1662a0ba..46dfb3701c6e 100644
--- 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
 	}
 }