From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Fri, 6 Oct 2017 13:16:52 +0000 (+0100)
Subject: arm64: Ensure the instruction emulation is ready for userspace
X-Git-Tag: v4.13.6~34
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07f9d7905eaab778e17d23ec1ea3c7f39f6bc152;p=thirdparty%2Fkernel%2Fstable.git

arm64: Ensure the instruction emulation is ready for userspace

commit c0d8832e78cbfd4a64b7112e34920af4b0b0e60e upstream.

We trap and emulate some instructions (e.g, mrs, deprecated instructions)
for the userspace. However the handlers for these are registered as
late_initcalls and the userspace could be up and running from the initramfs
by that time (with populate_rootfs, which is a rootfs_initcall()). This
could cause problems for the early applications ending up in failure
like :

[   11.152061] modprobe[93]: undefined instruction: pc=0000ffff8ca48ff4

This patch promotes the specific calls to core_initcalls, which are
guaranteed to be completed before we hit userspace.

Cc: Dave Martin <dave.martin@arm.com>
Cc: Matthias Brugger <mbrugger@suse.com>
Cc: James Morse <james.morse@arm.com>
Reported-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index f0e6d717885b1..d06fbe4cd38d7 100644
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -649,4 +649,4 @@ static int __init armv8_deprecated_init(void)
 	return 0;
 }
 
-late_initcall(armv8_deprecated_init);
+core_initcall(armv8_deprecated_init);
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9f9e0064c8c15..276eecab6cea5 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(void)
 	return 0;
 }
 
-late_initcall(enable_mrs_emulation);
+core_initcall(enable_mrs_emulation);