Patch "x86/mm: Abstract switching CR3" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

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

    x86/mm: Abstract switching CR3

to the 4.14-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:
     x86-mm-abstract-switching-cr3.patch
and it can be found in the queue-4.14 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 48e111982cda033fec832c6b0592c2acedd85d04 Mon Sep 17 00:00:00 2001
From: Dave Hansen <dave.hansen@linux.intel.com>
Date: Mon, 4 Dec 2017 15:07:58 +0100
Subject: x86/mm: Abstract switching CR3

From: Dave Hansen <dave.hansen@linux.intel.com>

commit 48e111982cda033fec832c6b0592c2acedd85d04 upstream.

In preparation to adding additional PCID flushing, abstract the
loading of a new ASID into CR3.

[ PeterZ: Split out from big combo patch ]

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/mm/tlb.c |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -100,6 +100,24 @@ static void choose_new_asid(struct mm_st
 	*need_flush = true;
 }
 
+static void load_new_mm_cr3(pgd_t *pgdir, u16 new_asid, bool need_flush)
+{
+	unsigned long new_mm_cr3;
+
+	if (need_flush) {
+		new_mm_cr3 = build_cr3(pgdir, new_asid);
+	} else {
+		new_mm_cr3 = build_cr3_noflush(pgdir, new_asid);
+	}
+
+	/*
+	 * Caution: many callers of this function expect
+	 * that load_cr3() is serializing and orders TLB
+	 * fills with respect to the mm_cpumask writes.
+	 */
+	write_cr3(new_mm_cr3);
+}
+
 void leave_mm(int cpu)
 {
 	struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm);
@@ -230,7 +248,7 @@ void switch_mm_irqs_off(struct mm_struct
 		if (need_flush) {
 			this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id);
 			this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen);
-			write_cr3(build_cr3(next->pgd, new_asid));
+			load_new_mm_cr3(next->pgd, new_asid, true);
 
 			/*
 			 * NB: This gets called via leave_mm() in the idle path
@@ -243,7 +261,7 @@ void switch_mm_irqs_off(struct mm_struct
 			trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
 		} else {
 			/* The new ASID is already up to date. */
-			write_cr3(build_cr3_noflush(next->pgd, new_asid));
+			load_new_mm_cr3(next->pgd, new_asid, false);
 
 			/* See above wrt _rcuidle. */
 			trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0);


Patches currently in stable-queue which might be from dave.hansen@linux.intel.com are

queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch
queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch
queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch
queue-4.14/x86-mm-abstract-switching-cr3.patch
queue-4.14/x86-mm-optimize-restore_cr3.patch
queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch
queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch
queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch
queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch
queue-4.14/x86-mm-pti-share-entry-text-pmd.patch
queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch
queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch
queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch
queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch
queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch
queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch
queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch
queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch
queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch
queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch
queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch
queue-4.14/x86-mm-pti-add-kconfig.patch
queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch
queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch
queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch
queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch
queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch
queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch
queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch
queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch
queue-4.14/x86-mm-pti-populate-user-pgd.patch
queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch