Patch "arm64: Ensure the instruction emulation is ready for userspace" has been added to the 4.13-stable tree

Patch "arm64: Ensure the instruction emulation is ready for userspace" has been added to the 4.13-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    arm64: Ensure the instruction emulation is ready for userspace

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm64-ensure-the-instruction-emulation-is-ready-for-userspace.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c0d8832e78cbfd4a64b7112e34920af4b0b0e60e Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Fri, 6 Oct 2017 14:16:52 +0100
Subject: arm64: Ensure the instruction emulation is ready for userspace

From: Suzuki K Poulose <suzuki.poulose@arm.com>

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>

---
 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);


Patches currently in stable-queue which might be from suzuki.poulose@arm.com are

queue-4.13/arm64-ensure-the-instruction-emulation-is-ready-for-userspace.patch