From: Will Deacon <will.deacon@arm.com>
Date: Fri, 22 Jun 2018 09:25:25 +0000 (+0100)
Subject: arm64: kpti: Use early_param for kpti= command-line option
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=b5b7dd647f2d21b93f734ce890671cd908e69b0a;p=openwrt%2Fstaging%2Fblogic.git

arm64: kpti: Use early_param for kpti= command-line option

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@vger.kernel.org> # 4.16.x-
Reported-by: Wei Xu <xuwei5@hisilicon.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index d2856b129097..f24892a40d2c 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -937,7 +937,7 @@ 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 */
 
 #ifdef CONFIG_ARM64_HW_AFDBM