[PATCH 4.4 083/193] x86/boot: Avoid warning for zero-filling .bss

From: Greg Kroah-Hartman
Date: Fri Feb 23 2018 - 13:36:36 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@xxxxxxxx>

commit 553bbc11aa6c1f9e0f529a06aeeca15fbe4a3985 upstream.

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@xxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20161116141726.2013389-1-arnd@xxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kernel/head_32.S | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -669,14 +669,17 @@ __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

/*