On Mon, May 21, 2018 at 08:21:58PM -0700, Florian Fainelli wrote:

On 05/21/2018 04:44 AM, Russell King wrote:

quoted

Harden the branch predictor against Spectre v2 attacks on context
switches for ARMv7 and later CPUs.  We do this by:

Cortex A9, A12, A17, A73, A75: invalidating the BTB.
Cortex A15, Brahma B15: invalidating the instruction cache.

Cortex A57 and Cortex A72 are not addressed in this patch.

Cortex R7 and Cortex R8 are also not addressed as we do not enforce
memory protection on these cores.

Signed-off-by: Russell King <redacted>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

It does need this additional patch to avoid some build errors - I'm
surprised that my autobuilder found it before the 0-day builder...

diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index 0c37e6a2830d..526d07ab6b7a 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c

@@ -127,4 +127,8 @@ void cpu_v7_bugs_init(void)
 		pr_info("CPU: Spectre v2: using %s workaround\n",
 			spectre_v2_method);
 }
+#else
+void cpu_v7_bugs_init(void)
+{
+}
 #endif

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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