[PATCH v1] ARM: Silence proc-v7-bugs.c spam about disabled Spectre workarounds

[PATCH v1] ARM: Silence proc-v7-bugs.c spam about disabled Spectre workarounds

[Dmitry Osipenko]

Print message about disabled Spectre workarounds only once to stop
endless spam into KSMG each time CPU goes out from idling state.
This spam makes system unusable with CONFIG_HARDEN_BRANCH_PREDICTOR=n
for those who don't care about security and wants maximum performance.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 arch/arm/mm/proc-v7-bugs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index fb9f3eb6bf48..f9730eba0632 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -108,8 +108,7 @@ static unsigned int spectre_v2_install_workaround(unsigned int method)
 #else
 static unsigned int spectre_v2_install_workaround(unsigned int method)
 {
-	pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n",
-		smp_processor_id());
+	pr_info_once("Spectre V2: workarounds disabled by configuration\n");
 
 	return SPECTRE_VULNERABLE;
 }
-- 
2.35.3


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Re: [PATCH v1] ARM: Silence proc-v7-bugs.c spam about disabled Spectre workarounds

[Dmitry Osipenko]

On 5/19/22 19:13, Dmitry Osipenko wrote:
> Print message about disabled Spectre workarounds only once to stop
> endless spam into KSMG each time CPU goes out from idling state.
> This spam makes system unusable with CONFIG_HARDEN_BRANCH_PREDICTOR=n
> for those who don't care about security and wants maximum performance.
> 
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> ---
>  arch/arm/mm/proc-v7-bugs.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
> index fb9f3eb6bf48..f9730eba0632 100644
> --- a/arch/arm/mm/proc-v7-bugs.c
> +++ b/arch/arm/mm/proc-v7-bugs.c
> @@ -108,8 +108,7 @@ static unsigned int spectre_v2_install_workaround(unsigned int method)
>  #else
>  static unsigned int spectre_v2_install_workaround(unsigned int method)
>  {
> -	pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n",
> -		smp_processor_id());
> +	pr_info_once("Spectre V2: workarounds disabled by configuration\n");
>  
>  	return SPECTRE_VULNERABLE;
>  }

Hello Russell,

Could you please apply this patch? I tried to use yours patch tracker
today and it doesn't allow me to recover my password (server error: MAIL
FROM command failed Detail: Space shortage).

Thanks!

-- 
Best regards,
Dmitry

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Re: [PATCH v1] ARM: Silence proc-v7-bugs.c spam about disabled Spectre workarounds

[Russell King (Oracle)]

On Tue, Jun 28, 2022 at 10:23:06AM +0300, Dmitry Osipenko wrote:
> On 5/19/22 19:13, Dmitry Osipenko wrote:
> > Print message about disabled Spectre workarounds only once to stop
> > endless spam into KSMG each time CPU goes out from idling state.
> > This spam makes system unusable with CONFIG_HARDEN_BRANCH_PREDICTOR=n
> > for those who don't care about security and wants maximum performance.
> > 
> > Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> > ---
> >  arch/arm/mm/proc-v7-bugs.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
> > index fb9f3eb6bf48..f9730eba0632 100644
> > --- a/arch/arm/mm/proc-v7-bugs.c
> > +++ b/arch/arm/mm/proc-v7-bugs.c
> > @@ -108,8 +108,7 @@ static unsigned int spectre_v2_install_workaround(unsigned int method)
> >  #else
> >  static unsigned int spectre_v2_install_workaround(unsigned int method)
> >  {
> > -	pr_info("CPU%u: Spectre V2: workarounds disabled by configuration\n",
> > -		smp_processor_id());
> > +	pr_info_once("Spectre V2: workarounds disabled by configuration\n");
> >  
> >  	return SPECTRE_VULNERABLE;
> >  }
> 
> Hello Russell,
> 
> Could you please apply this patch? I tried to use yours patch tracker
> today and it doesn't allow me to recover my password (server error: MAIL
> FROM command failed Detail: Space shortage).

That should now be working - thanks to apt needlessly consuming 200MB of
space. Please use the patch system, thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

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