Patch "ARM: 9209/1: Spectre-BHB: avoid pr_info() every time a CPU comes out of idle" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ARM: 9209/1: Spectre-BHB: avoid pr_info() every time a CPU comes out of idle

to the 5.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm-9209-1-spectre-bhb-avoid-pr_info-every-time-a-cp.patch
and it can be found in the queue-5.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 2c6afffb43b463a1b06b0ed222f5c69913f2fc26
Author: Ard Biesheuvel <ardb@xxxxxxxxxx>
Date:   Tue May 31 09:53:42 2022 +0100

    ARM: 9209/1: Spectre-BHB: avoid pr_info() every time a CPU comes out of idle
    
    [ Upstream commit 0609e200246bfd3b7516091c491bec4308349055 ]
    
    Jon reports that the Spectre-BHB init code is filling up the kernel log
    with spurious notifications about which mitigation has been enabled,
    every time any CPU comes out of a low power state.
    
    Given that Spectre-BHB mitigations are system wide, only a single
    mitigation can be enabled, and we already print an error if two types of
    CPUs coexist in a single system that require different Spectre-BHB
    mitigations.
    
    This means that the pr_info() that describes the selected mitigation
    does not need to be emitted for each CPU anyway, and so we can simply
    emit it only once.
    
    In order to clarify the above in the log message, update it to describe
    that the selected mitigation will be enabled on all CPUs, including ones
    that are unaffected. If another CPU comes up later that is affected and
    requires a different mitigation, we report an error as before.
    
    Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround")
    Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>
    Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
    Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index f9730eba0632..8bc7a2d6d6c7 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -208,10 +208,10 @@ static int spectre_bhb_install_workaround(int method)
 			return SPECTRE_VULNERABLE;
 
 		spectre_bhb_method = method;
-	}
 
-	pr_info("CPU%u: Spectre BHB: using %s workaround\n",
-		smp_processor_id(), spectre_bhb_method_name(method));
+		pr_info("CPU%u: Spectre BHB: enabling %s workaround for all CPUs\n",
+			smp_processor_id(), spectre_bhb_method_name(method));
+	}
 
 	return SPECTRE_MITIGATED;
 }