releases/4.13.6/arm64-ensure-the-instruction-emulation-is-ready-for-userspace.patch

   1 From c0d8832e78cbfd4a64b7112e34920af4b0b0e60e Mon Sep 17 00:00:00 2001
   2 From: Suzuki K Poulose <suzuki.poulose@arm.com>
   3 Date: Fri, 6 Oct 2017 14:16:52 +0100
   4 Subject: arm64: Ensure the instruction emulation is ready for userspace
   5
   6 From: Suzuki K Poulose <suzuki.poulose@arm.com>
   7
   8 commit c0d8832e78cbfd4a64b7112e34920af4b0b0e60e upstream.
   9
  10 We trap and emulate some instructions (e.g, mrs, deprecated instructions)
  11 for the userspace. However the handlers for these are registered as
  12 late_initcalls and the userspace could be up and running from the initramfs
  13 by that time (with populate_rootfs, which is a rootfs_initcall()). This
  14 could cause problems for the early applications ending up in failure
  15 like :
  16
  17 [   11.152061] modprobe[93]: undefined instruction: pc=0000ffff8ca48ff4
  18
  19 This patch promotes the specific calls to core_initcalls, which are
  20 guaranteed to be completed before we hit userspace.
  21
  22 Cc: Dave Martin <dave.martin@arm.com>
  23 Cc: Matthias Brugger <mbrugger@suse.com>
  24 Cc: James Morse <james.morse@arm.com>
  25 Reported-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
  26 Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
  27 Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
  28 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  29
  30 ---
  31  arch/arm64/kernel/armv8_deprecated.c |    2 +-
  32  arch/arm64/kernel/cpufeature.c       |    2 +-
  33  2 files changed, 2 insertions(+), 2 deletions(-)
  34
  35 --- a/arch/arm64/kernel/armv8_deprecated.c
  36 +++ b/arch/arm64/kernel/armv8_deprecated.c
  37 @@ -649,4 +649,4 @@ static int __init armv8_deprecated_init(
  38         return 0;
  39  }
  40
  41 -late_initcall(armv8_deprecated_init);
  42 +core_initcall(armv8_deprecated_init);
  43 --- a/arch/arm64/kernel/cpufeature.c
  44 +++ b/arch/arm64/kernel/cpufeature.c
  45 @@ -1294,4 +1294,4 @@ static int __init enable_mrs_emulation(v
  46         return 0;
  47  }
  48
  49 -late_initcall(enable_mrs_emulation);
  50 +core_initcall(enable_mrs_emulation);