linux-kernel - [PATCH 2/2] vmlinux.lds.h: Fix linker warnings about orphan .LPBX sections

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Message-Id: <20180913110000.63934-3-oberpar@linux.ibm.com>
Date:   Thu, 13 Sep 2018 13:00:00 +0200
From:   Peter Oberparleiter <oberpar@...ux.ibm.com>
To:     arnd@...db.de
Cc:     Peter Oberparleiter <oberpar@...ux.ibm.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Steven Rostedt <rostedt@...dmis.org>,
        Greentime Hu <green.hu@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] vmlinux.lds.h: Fix linker warnings about orphan .LPBX sections

Enabling both CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y and
CONFIG_GCOV_PROFILE_ALL=y results in linker warnings:

  warning: orphan section `.data..LPBX1' being placed in
  section `.data..LPBX1'.

LD_DEAD_CODE_DATA_ELIMINATION adds compiler flag -fdata-sections. This
option causes GCC to create separate data sections for data objects,
including those generated by GCC internally for gcov profiling. The
names of these objects start with a dot (.LPBX0, .LPBX1), resulting in
section names starting with 'data..'.

As section names starting with 'data..' are used for specific purposes
in the Linux kernel, the linker script does not automatically include
them in the output data section, resulting in the "orphan section"
linker warnings.

Fix this by specifically including sections named "data..LPBX*" in the
data section.

Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
Tested-by: Stephen Rothwell <sfr@...b.auug.org.au>
Signed-off-by: Peter Oberparleiter <oberpar@...ux.ibm.com>
---
 include/asm-generic/vmlinux.lds.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index b4d74b1c1e1d..d7701d466b60 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -68,7 +68,7 @@
  */
 #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
 #define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
-#define DATA_MAIN .data .data.[0-9a-zA-Z_]*
+#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..LPBX*
 #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
 #define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]*
 #define BSS_MAIN .bss .bss.[0-9a-zA-Z_]*
-- 
2.17.0