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

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

[H.J. Lu]

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 <hjl.tools@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
 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

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

[Andy Lutomirski]

> On Jan 24, 2020, at 10:18 AM, H.J. Lu <hjl.tools@gmail.com> 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?

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

[H.J. Lu]

On Fri, Jan 24, 2020 at 10:24 AM Andy Lutomirski <luto@amacapital.net> wrote:
>
>
>
> > On Jan 24, 2020, at 10:18 AM, H.J. Lu <hjl.tools@gmail.com> 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?

It is needed by GCC 10 without LTO.

-- 
H.J.

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

[H.J. Lu]

[-- Attachment #1: Type: text/plain, Size: 1046 bytes --]

On Fri, Jan 24, 2020 at 10:39 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Jan 24, 2020 at 10:24 AM Andy Lutomirski <luto@amacapital.net> wrote:
> >
> >
> >
> > > On Jan 24, 2020, at 10:18 AM, H.J. Lu <hjl.tools@gmail.com> 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?
>
> It is needed by GCC 10 without LTO.
>

This updated patch fixed a typo in Subject: "care" -> "declare".


-- 
H.J.

[-- Attachment #2: 0001-x86-Don-t-declare-__force_order-in-kaslr_64.c.patch --]
[-- Type: application/x-patch, Size: 1388 bytes --]

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

[Borislav Petkov]

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

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

[Borislav Petkov]

On Fri, Jan 24, 2020 at 10:44:30AM -0800, H.J. Lu wrote:
> This updated patch fixed a typo in Subject: "care" -> "declare".
>
> From c8c26194cf5a344cd53763eaaf16c3ab609736f4 Mon Sep 17 00:00:00 2001
> From: "H.J. Lu" <hjl.tools@gmail.com>
> Date: Thu, 16 Jan 2020 12:46:51 -0800
> Subject: [PATCH] x86: 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 <hjl.tools@gmail.com>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>

What is Yu-cheng's SOB supposed to mean here?

The only case where it would make sense is if he's sending this patch
but he isn't. So what's up?

-- 
Regards/Gruss,
    Boris.

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

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

[H.J. Lu]

On Tue, Feb 18, 2020 at 2:45 AM Borislav Petkov <bp@alien8.de> wrote:
>
> On Fri, Jan 24, 2020 at 10:44:30AM -0800, H.J. Lu wrote:
> > This updated patch fixed a typo in Subject: "care" -> "declare".
> >
> > From c8c26194cf5a344cd53763eaaf16c3ab609736f4 Mon Sep 17 00:00:00 2001
> > From: "H.J. Lu" <hjl.tools@gmail.com>
> > Date: Thu, 16 Jan 2020 12:46:51 -0800
> > Subject: [PATCH] x86: 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 <hjl.tools@gmail.com>
> > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
>
> What is Yu-cheng's SOB supposed to mean here?
>
> The only case where it would make sense is if he's sending this patch
> but he isn't. So what's up?
>

I wrote this patch as the part of the previous CET patch set Yu-cheng submitted.
Since this is a standalone patch, he asked me to send it separately.  I didn't
remove Yu-cheng's SOB when I submitted this patch.

-- 
H.J.

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

[Borislav Petkov]

On Tue, Feb 18, 2020 at 03:38:54AM -0800, H.J. Lu wrote:
> I wrote this patch as the part of the previous CET patch set Yu-cheng submitted.
> Since this is a standalone patch, he asked me to send it separately.  I didn't
> remove Yu-cheng's SOB when I submitted this patch.

Ok, dropping it.

Thx.

-- 
Regards/Gruss,
    Boris.

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

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

[tip-bot2 for H.J. Lu]

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 <hjl.tools@gmail.com>
AuthorDate:    Thu, 16 Jan 2020 12:46:51 -08:00
Committer:     Borislav Petkov <bp@suse.de>
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 <hjl.tools@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200124181811.4780-1-hjl.tools@gmail.com
---
 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;

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

[tip-bot2 for H.J. Lu]

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 <hjl.tools@gmail.com>
AuthorDate:    Thu, 16 Jan 2020 12:46:51 -08:00
Committer:     Borislav Petkov <bp@suse.de>
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 <hjl.tools@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200124181811.4780-1-hjl.tools@gmail.com
---
 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;