4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon <will.deacon@xxxxxxx>
commit b5b7dd647f2d21b93f734ce890671cd908e69b0a upstream.
We inspect __kpti_forced early on as part of the cpufeature enable
callback which remaps the swapper page table using non-global entries.
Ensure that __kpti_forced has been updated to reflect the kpti=
command-line option before we start using it.
Fixes: ea1e3de85e94 ("arm64: entry: Add fake CPU feature for unmapping the kernel at EL0")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.16.x-
Reported-by: Wei Xu <xuwei5@xxxxxxxxxxxxx>
Tested-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Tested-by: Wei Xu <xuwei5@xxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/cpufeature.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -826,7 +826,7 @@ static int __init parse_kpti(char *str)
__kpti_forced = enabled ? 1 : -1;
return 0;
}
-__setup("kpti=", parse_kpti);
+early_param("kpti", parse_kpti);
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
static const struct arm64_cpu_capabilities arm64_features[] = {
