2013-03-02 23:22:01

by Krzysztof Mazur

[permalink] [raw]
Subject: [PATCH] x86: fix 32-bit *_cpu_data initializers

The commit 27be457000211a6903968dfce06d5f73f051a217
(x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok flag)
removed the hlt_works_ok flag from struct cpuinfo_x86, but
boot_cpu_data and new_cpu_data initializers were not changed causing
setting f00f_bug flag, instead of fdiv_bug. If CONFIG_X86_F00F_BUG
is not set the f00f_bug flag is never cleared.

To avoid such problems in future C99-style initialization is now used.

Signed-off-by: Krzysztof Mazur <[email protected]>
---
$ cat < /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 1.73GHz
stepping : 8
microcode : 0x20
cpu MHz : 800.000
cache size : 2048 KB
fdiv_bug : no
f00f_bug : yes
...

By the way now in struct cpuinfo_x86 for 32-bit systems pad0
should be extended to 2 bytes or removed, because now 32-bit
specific bugs area have now 6 bytes + pad0.

arch/x86/kernel/setup.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 84d3285..90d8cc9 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -171,9 +171,15 @@ static struct resource bss_resource = {

#ifdef CONFIG_X86_32
/* cpu data as detected by the assembly code in head.S */
-struct cpuinfo_x86 new_cpu_data __cpuinitdata = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 new_cpu_data __cpuinitdata = {
+ .wp_works_ok = -1,
+ .fdiv_bug = -1,
+};
/* common cpu data for all cpus */
-struct cpuinfo_x86 boot_cpu_data __read_mostly = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 boot_cpu_data __read_mostly = {
+ .wp_works_ok = -1,
+ .fdiv_bug = -1,
+};
EXPORT_SYMBOL(boot_cpu_data);

unsigned int def_to_bigsmp;
--
1.8.2.rc1.362.gc8d5142


2013-03-02 23:46:37

by Borislav Petkov

[permalink] [raw]
Subject: Re: [PATCH] x86: fix 32-bit *_cpu_data initializers

On Sun, Mar 03, 2013 at 12:14:42AM +0100, Krzysztof Mazur wrote:
> The commit 27be457000211a6903968dfce06d5f73f051a217
> (x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok flag)
> removed the hlt_works_ok flag from struct cpuinfo_x86, but
> boot_cpu_data and new_cpu_data initializers were not changed causing
> setting f00f_bug flag, instead of fdiv_bug. If CONFIG_X86_F00F_BUG
> is not set the f00f_bug flag is never cleared.
>
> To avoid such problems in future C99-style initialization is now used.
>
> Signed-off-by: Krzysztof Mazur <[email protected]>

Good catch.

Acked-by: Borislav Petkov <[email protected]>

> ---
> $ cat < /proc/cpuinfo
> processor : 0
> vendor_id : GenuineIntel
> cpu family : 6
> model : 13
> model name : Intel(R) Pentium(R) M processor 1.73GHz
> stepping : 8
> microcode : 0x20
> cpu MHz : 800.000
> cache size : 2048 KB
> fdiv_bug : no
> f00f_bug : yes
> ...
>
> By the way now in struct cpuinfo_x86 for 32-bit systems pad0
> should be extended to 2 bytes or removed, because now 32-bit
> specific bugs area have now 6 bytes + pad0.

It's good that you bring this up - I have a patchset which removes all
those *_bug fields in cpuinfo_x86 which means the padding goes away too.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
--

Subject: [tip:x86/urgent] x86: Fix 32-bit *_cpu_data initializers

Commit-ID: 7ae184e4b97158629d657ab5c0eca2ea06d1c5a9
Gitweb: http://git.kernel.org/tip/7ae184e4b97158629d657ab5c0eca2ea06d1c5a9
Author: Krzysztof Mazur <[email protected]>
AuthorDate: Sun, 3 Mar 2013 00:14:42 +0100
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 6 Mar 2013 11:17:09 +0100

x86: Fix 32-bit *_cpu_data initializers

The commit 27be457000211a6903968dfce06d5f73f051a217
('x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok
flag') removed the hlt_works_ok flag from struct cpuinfo_x86, but
boot_cpu_data and new_cpu_data initializers were not changed
causing setting f00f_bug flag, instead of fdiv_bug.

If CONFIG_X86_F00F_BUG is not set the f00f_bug flag is never
cleared.

To avoid such problems in future C99-style initialization is now
used.

Signed-off-by: Krzysztof Mazur <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/setup.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 84d3285..90d8cc9 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -171,9 +171,15 @@ static struct resource bss_resource = {

#ifdef CONFIG_X86_32
/* cpu data as detected by the assembly code in head.S */
-struct cpuinfo_x86 new_cpu_data __cpuinitdata = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 new_cpu_data __cpuinitdata = {
+ .wp_works_ok = -1,
+ .fdiv_bug = -1,
+};
/* common cpu data for all cpus */
-struct cpuinfo_x86 boot_cpu_data __read_mostly = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 boot_cpu_data __read_mostly = {
+ .wp_works_ok = -1,
+ .fdiv_bug = -1,
+};
EXPORT_SYMBOL(boot_cpu_data);

unsigned int def_to_bigsmp;

Subject: [tip:x86/urgent] x86: Fix 32-bit *_cpu_data initializers

Commit-ID: 015221fefbc93689dd47508a66326556adf2abcd
Gitweb: http://git.kernel.org/tip/015221fefbc93689dd47508a66326556adf2abcd
Author: Krzysztof Mazur <[email protected]>
AuthorDate: Sun, 3 Mar 2013 00:14:42 +0100
Committer: H. Peter Anvin <[email protected]>
CommitDate: Wed, 6 Mar 2013 20:15:50 -0800

x86: Fix 32-bit *_cpu_data initializers

The commit 27be457000211a6903968dfce06d5f73f051a217
('x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok
flag') removed the hlt_works_ok flag from struct cpuinfo_x86, but
boot_cpu_data and new_cpu_data initializers were not changed
causing setting f00f_bug flag, instead of fdiv_bug.

If CONFIG_X86_F00F_BUG is not set the f00f_bug flag is never
cleared.

To avoid such problems in future C99-style initialization is now
used.

Signed-off-by: Krzysztof Mazur <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
---
arch/x86/kernel/setup.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 84d3285..90d8cc9 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -171,9 +171,15 @@ static struct resource bss_resource = {

#ifdef CONFIG_X86_32
/* cpu data as detected by the assembly code in head.S */
-struct cpuinfo_x86 new_cpu_data __cpuinitdata = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 new_cpu_data __cpuinitdata = {
+ .wp_works_ok = -1,
+ .fdiv_bug = -1,
+};
/* common cpu data for all cpus */
-struct cpuinfo_x86 boot_cpu_data __read_mostly = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 boot_cpu_data __read_mostly = {
+ .wp_works_ok = -1,
+ .fdiv_bug = -1,
+};
EXPORT_SYMBOL(boot_cpu_data);

unsigned int def_to_bigsmp;