This is a note to let you know that I've just added the patch titled
arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field
to the 4.9-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:
arm64-kpti-whitelist-cortex-a-cpus-that-don-t-implement-the-csv3-field.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2a355ec25729053bb9a1a89b6c1d1cdd6c3b3fb1 Mon Sep 17 00:00:00 2001
From: Will Deacon <will@xxxxxxxxxx>
Date: Thu, 13 Dec 2018 13:47:38 +0000
Subject: arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field
From: Will Deacon <will.deacon@xxxxxxx>
commit 2a355ec25729053bb9a1a89b6c1d1cdd6c3b3fb1 upstream.
While the CSV3 field of the ID_AA64_PFR0 CPU ID register can be checked
to see if a CPU is susceptible to Meltdown and therefore requires kpti
to be enabled, existing CPUs do not implement this field.
We therefore whitelist all unaffected Cortex-A CPUs that do not implement
the CSV3 field.
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
[florian: adjust whilelist location and table to stable-4.9.y]
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/cpufeature.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -789,6 +789,11 @@ static bool unmap_kernel_at_el0(const st
switch (read_cpuid_id() & MIDR_CPU_MODEL_MASK) {
case MIDR_CAVIUM_THUNDERX2:
case MIDR_BRCM_VULCAN:
+ case MIDR_CORTEX_A53:
+ case MIDR_CORTEX_A55:
+ case MIDR_CORTEX_A57:
+ case MIDR_CORTEX_A72:
+ case MIDR_CORTEX_A73:
return false;
}
Patches currently in stable-queue which might be from will@xxxxxxxxxx are
queue-4.9/arm64-kpti-whitelist-cortex-a-cpus-that-don-t-implement-the-csv3-field.patch
queue-4.9/partially-revert-kfifo-fix-kfifo_alloc-and-kfifo_ini.patch
