[PATCH 4.13 127/160] arm64: Ensure the instruction emulation is ready for userspace

From: Greg Kroah-Hartman
Date: Tue Oct 10 2017 - 16:07:45 EST


4.13-stable review patch. If anyone has any objections, please let me know.

------------------

From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>

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@xxxxxxx>
Cc: Matthias Brugger <mbrugger@xxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Reported-by: Matwey V. Kornilov <matwey.kornilov@xxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/arm64/kernel/armv8_deprecated.c | 2 +-
arch/arm64/kernel/cpufeature.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -649,4 +649,4 @@ static int __init armv8_deprecated_init(
return 0;
}

-late_initcall(armv8_deprecated_init);
+core_initcall(armv8_deprecated_init);
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(v
return 0;
}

-late_initcall(enable_mrs_emulation);
+core_initcall(enable_mrs_emulation);