patches/kernel/0208-x86-mm-Abstract-switching-CR3.patch

   1 From 7cc2d98148d5b5be191f4dbf4c29d4d6da93a9f8 Mon Sep 17 00:00:00 2001
   2 From: Dave Hansen <dave.hansen@linux.intel.com>
   3 Date: Mon, 4 Dec 2017 15:07:58 +0100
   4 Subject: [PATCH 208/233] x86/mm: Abstract switching CR3
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 CVE-2017-5754
  10
  11 In preparation to adding additional PCID flushing, abstract the
  12 loading of a new ASID into CR3.
  13
  14 [ PeterZ: Split out from big combo patch ]
  15
  16 Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
  17 Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
  18 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  19 Cc: Andy Lutomirski <luto@kernel.org>
  20 Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
  21 Cc: Borislav Petkov <bp@alien8.de>
  22 Cc: Brian Gerst <brgerst@gmail.com>
  23 Cc: David Laight <David.Laight@aculab.com>
  24 Cc: Denys Vlasenko <dvlasenk@redhat.com>
  25 Cc: Eduardo Valentin <eduval@amazon.com>
  26 Cc: Greg KH <gregkh@linuxfoundation.org>
  27 Cc: H. Peter Anvin <hpa@zytor.com>
  28 Cc: Josh Poimboeuf <jpoimboe@redhat.com>
  29 Cc: Juergen Gross <jgross@suse.com>
  30 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  31 Cc: Peter Zijlstra <peterz@infradead.org>
  32 Cc: Will Deacon <will.deacon@arm.com>
  33 Cc: aliguori@amazon.com
  34 Cc: daniel.gruss@iaik.tugraz.at
  35 Cc: hughd@google.com
  36 Cc: keescook@google.com
  37 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  38 (cherry picked from commit 48e111982cda033fec832c6b0592c2acedd85d04)
  39 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  40 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  41 (cherry picked from commit 1e2affe2a79305b3a5f3ad65d3f61ad9d1f9e168)
  42 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  43 ---
  44  arch/x86/mm/tlb.c | 22 ++++++++++++++++++++--
  45  1 file changed, 20 insertions(+), 2 deletions(-)
  46
  47 diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
  48 index ce87b69fb4e0..353f2f4e1d96 100644
  49 --- a/arch/x86/mm/tlb.c
  50 +++ b/arch/x86/mm/tlb.c
  51 @@ -101,6 +101,24 @@ static void choose_new_asid(struct mm_struct *next, u64 next_tlb_gen,
  52         *need_flush = true;
  53  }
  54
  55 +static void load_new_mm_cr3(pgd_t *pgdir, u16 new_asid, bool need_flush)
  56 +{
  57 +       unsigned long new_mm_cr3;
  58 +
  59 +       if (need_flush) {
  60 +               new_mm_cr3 = build_cr3(pgdir, new_asid);
  61 +       } else {
  62 +               new_mm_cr3 = build_cr3_noflush(pgdir, new_asid);
  63 +       }
  64 +
  65 +       /*
  66 +        * Caution: many callers of this function expect
  67 +        * that load_cr3() is serializing and orders TLB
  68 +        * fills with respect to the mm_cpumask writes.
  69 +        */
  70 +       write_cr3(new_mm_cr3);
  71 +}
  72 +
  73  void leave_mm(int cpu)
  74  {
  75         struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm);
  76 @@ -228,7 +246,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
  77                 if (need_flush) {
  78                         this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id);
  79                         this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen);
  80 -                       write_cr3(build_cr3(next->pgd, new_asid));
  81 +                       load_new_mm_cr3(next->pgd, new_asid, true);
  82
  83                         /*
  84                          * NB: This gets called via leave_mm() in the idle path
  85 @@ -241,7 +259,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
  86                         trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
  87                 } else {
  88                         /* The new ASID is already up to date. */
  89 -                       write_cr3(build_cr3_noflush(next->pgd, new_asid));
  90 +                       load_new_mm_cr3(next->pgd, new_asid, false);
  91
  92                         /* See above wrt _rcuidle. */
  93                         trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0);
  94 --
  95 2.14.2
  96