2016-03-16 12:19:56

by Borislav Petkov

Subject: [PATCH] x86/cpu: Do the feature test first in enable_sep_cpu()

From: Borislav Petkov <[email protected]>

... before assigning local vars. Kill out label too and simplify.

No functionality change.

Signed-off-by: Borislav Petkov <[email protected]>
---
arch/x86/kernel/cpu/common.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 249461f95851..63658d23d3dd 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1030,12 +1030,12 @@ void enable_sep_cpu(void)
struct tss_struct *tss;
int cpu;

+ if (!boot_cpu_has(X86_FEATURE_SEP))
+ return;
+
cpu = get_cpu();
tss = &per_cpu(cpu_tss, cpu);

- if (!boot_cpu_has(X86_FEATURE_SEP))
- goto out;
-
/*
* We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
* see the big comment in struct x86_hw_tss's definition.
@@ -1050,7 +1050,6 @@ void enable_sep_cpu(void)

wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);

-out:
put_cpu();
}
#endif
--
2.7.3

2016-03-18 01:44:19

by Andy Lutomirski

Subject: Re: [PATCH] x86/cpu: Do the feature test first in enable_sep_cpu()

On Wed, Mar 16, 2016 at 5:19 AM, Borislav Petkov <[email protected]> wrote:
> From: Borislav Petkov <[email protected]>
>
> ... before assigning local vars. Kill out label too and simplify.
>
> No functionality change.

Acked-by: Andy Lutomirski <[email protected]>

>
> Signed-off-by: Borislav Petkov <[email protected]>
> ---
> arch/x86/kernel/cpu/common.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 249461f95851..63658d23d3dd 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1030,12 +1030,12 @@ void enable_sep_cpu(void)
> struct tss_struct *tss;
> int cpu;
>
> + if (!boot_cpu_has(X86_FEATURE_SEP))
> + return;
> +
> cpu = get_cpu();
> tss = &per_cpu(cpu_tss, cpu);
>
> - if (!boot_cpu_has(X86_FEATURE_SEP))
> - goto out;
> -
> /*
> * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
> * see the big comment in struct x86_hw_tss's definition.
> @@ -1050,7 +1050,6 @@ void enable_sep_cpu(void)
>
> wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
>
> -out:
> put_cpu();
> }
> #endif
> --
> 2.7.3
>



--
Andy Lutomirski
AMA Capital Management, LLC

2016-03-29 12:28:46

by tip-bot for Vasyl Gomonovych

Subject: [tip:x86/asm] x86/cpu: Do the feature test first in enable_sep_cpu()

Commit-ID: b3edfda4382ffaef5e5c1cffb25a33b3b9ef4546
Gitweb: http://git.kernel.org/tip/b3edfda4382ffaef5e5c1cffb25a33b3b9ef4546
Author: Borislav Petkov <[email protected]>
AuthorDate: Wed, 16 Mar 2016 13:19:29 +0100
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 29 Mar 2016 12:57:12 +0200

x86/cpu: Do the feature test first in enable_sep_cpu()

... before assigning local vars. Kill out label too and simplify.

No functionality change.

Signed-off-by: Borislav Petkov <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/cpu/common.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8394b3d..7fea407 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1076,12 +1076,12 @@ void enable_sep_cpu(void)
struct tss_struct *tss;
int cpu;

+ if (!boot_cpu_has(X86_FEATURE_SEP))
+ return;
+
cpu = get_cpu();
tss = &per_cpu(cpu_tss, cpu);

- if (!boot_cpu_has(X86_FEATURE_SEP))
- goto out;
-
/*
* We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
* see the big comment in struct x86_hw_tss's definition.
@@ -1096,7 +1096,6 @@ void enable_sep_cpu(void)

wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);

-out:
put_cpu();
}
#endif