patches/kernel/0234-x86-tlb-Drop-the-_GPL-from-the-cpu_tlbstate-export.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Thomas Gleixner <tglx@linutronix.de>
   3 Date: Thu, 4 Jan 2018 22:19:04 +0100
   4 Subject: [PATCH] x86/tlb: Drop the _GPL from the cpu_tlbstate export
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 commit 1e5476815fd7f98b888e01a0f9522b63085f96c9 upstream.
  10
  11 The recent changes for PTI touch cpu_tlbstate from various tlb_flush
  12 inlines. cpu_tlbstate is exported as GPL symbol, so this causes a
  13 regression when building out of tree drivers for certain graphics cards.
  14
  15 Aside of that the export was wrong since it was introduced as it should
  16 have been EXPORT_PER_CPU_SYMBOL_GPL().
  17
  18 Use the correct PER_CPU export and drop the _GPL to restore the previous
  19 state which allows users to utilize the cards they payed for.
  20
  21 As always I'm really thrilled to make this kind of change to support the
  22 #friends (or however the hot hashtag of today is spelled) from that closet
  23 sauce graphics corp.
  24
  25 Fixes: 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4")
  26 Fixes: 6fd166aae78c ("x86/mm: Use/Fix PCID to optimize user/kernel switches")
  27 Reported-by: Kees Cook <keescook@google.com>
  28 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  29 Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  30 Cc: Peter Zijlstra <peterz@infradead.org>
  31 Cc: Andy Lutomirski <luto@kernel.org>
  32 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  33 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  34 ---
  35  arch/x86/mm/init.c | 2 +-
  36  1 file changed, 1 insertion(+), 1 deletion(-)
  37
  38 diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
  39 index 80259ad8c386..6b462a472a7b 100644
  40 --- a/arch/x86/mm/init.c
  41 +++ b/arch/x86/mm/init.c
  42 @@ -870,7 +870,7 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
  43         .next_asid = 1,
  44         .cr4 = ~0UL,    /* fail hard if we screw up cr4 shadow initialization */
  45  };
  46 -EXPORT_SYMBOL_GPL(cpu_tlbstate);
  47 +EXPORT_PER_CPU_SYMBOL(cpu_tlbstate);
  48
  49  void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
  50  {
  51 --
  52 2.14.2
  53