linux-kernel - [tip:x86/urgent] x86/boot: Avoid warning for zero-filling .bss

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Message-ID: <tip-553bbc11aa6c1f9e0f529a06aeeca15fbe4a3985@git.kernel.org>
Date:   Wed, 16 Nov 2016 23:19:11 -0800
From:   tip-bot for Arnd Bergmann <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     peterz@...radead.org, jpoimboe@...hat.com, dvlasenk@...hat.com,
        bp@...en8.de, linux-kernel@...r.kernel.org,
        torvalds@...ux-foundation.org, luto@...nel.org, tglx@...utronix.de,
        brgerst@...il.com, hpa@...or.com, mingo@...nel.org, arnd@...db.de
Subject: [tip:x86/urgent] x86/boot: Avoid warning for zero-filling .bss

Commit-ID:  553bbc11aa6c1f9e0f529a06aeeca15fbe4a3985
Gitweb:     http://git.kernel.org/tip/553bbc11aa6c1f9e0f529a06aeeca15fbe4a3985
Author:     Arnd Bergmann <arnd@...db.de>
AuthorDate: Wed, 16 Nov 2016 15:17:09 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 17 Nov 2016 07:34:58 +0100

x86/boot: Avoid warning for zero-filling .bss

The latest binutils are warning about a .fill directive with an explicit
value in a .bss section:

  arch/x86/kernel/head_32.S: Assembler messages:
  arch/x86/kernel/head_32.S:677: Warning: ignoring fill value in section `.bss..page_aligned'
  arch/x86/kernel/head_32.S:679: Warning: ignoring fill value in section `.bss..page_aligned'

This comes from the 'ENTRY()' macro padding the space between the symbols
with 'nop' via:

  .align 4,0x90

Open-coding the .globl directive without the padding avoids that warning,
as all the symbols are already page aligned.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20161116141726.2013389-1-arnd@arndb.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/head_32.S | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index b6b2f02..2dabea4 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -665,14 +665,17 @@ __PAGE_ALIGNED_BSS
 initial_pg_pmd:
 	.fill 1024*KPMDS,4,0
 #else
-ENTRY(initial_page_table)
+.globl initial_page_table
+initial_page_table:
 	.fill 1024,4,0
 #endif
 initial_pg_fixmap:
 	.fill 1024,4,0
-ENTRY(empty_zero_page)
+.globl empty_zero_page
+empty_zero_page:
 	.fill 4096,1,0
-ENTRY(swapper_pg_dir)
+.globl swapper_pg_dir
+swapper_pg_dir:
 	.fill 1024,4,0
 EXPORT_SYMBOL(empty_zero_page)