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authorDave Hansen <dave.hansen@linux.intel.com>2018-04-06 23:55:15 +0300
committerIngo Molnar <mingo@kernel.org>2018-04-12 10:05:59 +0300
commit0f561fce4d6979a50415616896512f87a6d1d5c8 (patch)
treec65424a590f9a405e617cf042275443b53349e75 /arch/x86/mm/cpu_entry_area.c
parent639d6aafe437a7464399d2a77d006049053df06f (diff)
downloadlinux-0f561fce4d6979a50415616896512f87a6d1d5c8.tar.xz
x86/pti: Enable global pages for shared areas
The entry/exit text and cpu_entry_area are mapped into userspace and the kernel. But, they are not _PAGE_GLOBAL. This creates unnecessary TLB misses. Add the _PAGE_GLOBAL flag for these areas. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205515.2977EE7D@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/cpu_entry_area.c')
-rw-r--r--arch/x86/mm/cpu_entry_area.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 476d810639a8..b45f5aaefd74 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -27,8 +27,20 @@ EXPORT_SYMBOL(get_cpu_entry_area);
void cea_set_pte(void *cea_vaddr, phys_addr_t pa, pgprot_t flags)
{
unsigned long va = (unsigned long) cea_vaddr;
+ pte_t pte = pfn_pte(pa >> PAGE_SHIFT, flags);
- set_pte_vaddr(va, pfn_pte(pa >> PAGE_SHIFT, flags));
+ /*
+ * The cpu_entry_area is shared between the user and kernel
+ * page tables. All of its ptes can safely be global.
+ * _PAGE_GLOBAL gets reused to help indicate PROT_NONE for
+ * non-present PTEs, so be careful not to set it in that
+ * case to avoid confusion.
+ */
+ if (boot_cpu_has(X86_FEATURE_PGE) &&
+ (pgprot_val(flags) & _PAGE_PRESENT))
+ pte = pte_set_flags(pte, _PAGE_GLOBAL);
+
+ set_pte_vaddr(va, pte);
}
static void __init