2020-01-24 21:00:16

by H.J. Lu

Subject: [PATCH] x86: Don't clare __force_order in kaslr_64.c

GCC 10 changed the default to -fno-common, which leads to

LD arch/x86/boot/compressed/vmlinux
ld: arch/x86/boot/compressed/pgtable_64.o:(.bss+0x0): multiple definition of `__force_order'; arch/x86/boot/compressed/kaslr_64.o:(.bss+0x0): first defined here
make[2]: *** [arch/x86/boot/compressed/Makefile:119: arch/x86/boot/compressed/vmlinux] Error 1

Since __force_order is already provided in pgtable_64.c, there is no
need to declare __force_order in kaslr_64.c.

Signed-off-by: H.J. Lu <[email protected]>
Signed-off-by: Yu-cheng Yu <[email protected]>
---
arch/x86/boot/compressed/kaslr_64.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c
index 748456c365f4..9557c5a15b91 100644
--- a/arch/x86/boot/compressed/kaslr_64.c
+++ b/arch/x86/boot/compressed/kaslr_64.c
@@ -29,9 +29,6 @@
#define __PAGE_OFFSET __PAGE_OFFSET_BASE
#include "../../mm/ident_map.c"

-/* Used by pgtable.h asm code to force instruction serialization. */
-unsigned long __force_order;
-
/* Used to track our page table allocation area. */
struct alloc_pgt_data {
unsigned char *pgt_buf;
--
2.24.1

2020-01-24 21:00:24

by Andy Lutomirski

Subject: Re: [PATCH] x86: Don't clare __force_order in kaslr_64.c

> On Jan 24, 2020, at 10:18 AM, H.J. Lu <[email protected]> wrote:
>
> GCC 10 changed the default to -fno-common, which leads to
>
> LD arch/x86/boot/compressed/vmlinux
> ld: arch/x86/boot/compressed/pgtable_64.o:(.bss+0x0): multiple definition of `__force_order'; arch/x86/boot/compressed/kaslr_64.o:(.bss+0x0): first defined here
> make[2]: *** [arch/x86/boot/compressed/Makefile:119: arch/x86/boot/compressed/vmlinux] Error 1
>
> Since __force_order is already provided in pgtable_64.c, there is no
> need to declare __force_order in kaslr_64.c.

Why does anything actually define that variable? Surely any actual references are just an outright bug. Is it needed for LTO?

2020-02-17 22:28:08

by Borislav Petkov

Subject: Re: [PATCH] x86: Don't clare __force_order in kaslr_64.c

On Fri, Jan 24, 2020 at 10:24:19AM -0800, Andy Lutomirski wrote:
> Why does anything actually define that variable? Surely any actual
> references are just an outright bug. Is it needed for LTO?

I think the answer to your question is at the top of
arch/x86/include/asm/special_insns.h


--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

2020-02-18 15:09:07

by tip-bot2 for Jacob Pan

Subject: [tip: x86/boot] x86/boot/compressed: Don't declare __force_order in kaslr_64.c

The following commit has been merged into the x86/boot branch of tip:

Commit-ID: 970b41399925e34fdf5783a53fe8cc73f04fec37
Gitweb: https://git.kernel.org/tip/970b41399925e34fdf5783a53fe8cc73f04fec37
Author: H.J. Lu <[email protected]>
AuthorDate: Thu, 16 Jan 2020 12:46:51 -08:00
Committer: Borislav Petkov <[email protected]>
CommitterDate: Tue, 18 Feb 2020 14:40:53 +01:00

x86/boot/compressed: Don't declare __force_order in kaslr_64.c

GCC 10 changed the default to -fno-common, which leads to

LD arch/x86/boot/compressed/vmlinux
ld: arch/x86/boot/compressed/pgtable_64.o:(.bss+0x0): multiple definition of `__force_order'; \
arch/x86/boot/compressed/kaslr_64.o:(.bss+0x0): first defined here
make[2]: *** [arch/x86/boot/compressed/Makefile:119: arch/x86/boot/compressed/vmlinux] Error 1

Since __force_order is already provided in pgtable_64.c, there is no
need to declare __force_order in kaslr_64.c.

Signed-off-by: H.J. Lu <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/boot/compressed/kaslr_64.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c
index 748456c..9557c5a 100644
--- a/arch/x86/boot/compressed/kaslr_64.c
+++ b/arch/x86/boot/compressed/kaslr_64.c
@@ -29,9 +29,6 @@
#define __PAGE_OFFSET __PAGE_OFFSET_BASE
#include "../../mm/ident_map.c"

-/* Used by pgtable.h asm code to force instruction serialization. */
-unsigned long __force_order;
-
/* Used to track our page table allocation area. */
struct alloc_pgt_data {
unsigned char *pgt_buf;

2020-02-19 16:33:25

by tip-bot2 for Jacob Pan

Subject: [tip: x86/urgent] x86/boot/compressed: Don't declare __force_order in kaslr_64.c

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: df6d4f9db79c1a5d6f48b59db35ccd1e9ff9adfc
Gitweb: https://git.kernel.org/tip/df6d4f9db79c1a5d6f48b59db35ccd1e9ff9adfc
Author: H.J. Lu <[email protected]>
AuthorDate: Thu, 16 Jan 2020 12:46:51 -08:00
Committer: Borislav Petkov <[email protected]>
CommitterDate: Wed, 19 Feb 2020 17:23:59 +01:00

x86/boot/compressed: Don't declare __force_order in kaslr_64.c

GCC 10 changed the default to -fno-common, which leads to

LD arch/x86/boot/compressed/vmlinux
ld: arch/x86/boot/compressed/pgtable_64.o:(.bss+0x0): multiple definition of `__force_order'; \
arch/x86/boot/compressed/kaslr_64.o:(.bss+0x0): first defined here
make[2]: *** [arch/x86/boot/compressed/Makefile:119: arch/x86/boot/compressed/vmlinux] Error 1

Since __force_order is already provided in pgtable_64.c, there is no
need to declare __force_order in kaslr_64.c.

Signed-off-by: H.J. Lu <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/boot/compressed/kaslr_64.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c
index 748456c..9557c5a 100644
--- a/arch/x86/boot/compressed/kaslr_64.c
+++ b/arch/x86/boot/compressed/kaslr_64.c
@@ -29,9 +29,6 @@
#define __PAGE_OFFSET __PAGE_OFFSET_BASE
#include "../../mm/ident_map.c"

-/* Used by pgtable.h asm code to force instruction serialization. */
-unsigned long __force_order;
-
/* Used to track our page table allocation area. */
struct alloc_pgt_data {
unsigned char *pgt_buf;