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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2018-04-06 23:55:15 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-04-12 10:05:59 +0300 |
| commit | 0f561fce4d6979a50415616896512f87a6d1d5c8 (patch) | |
| tree | c65424a590f9a405e617cf042275443b53349e75 /arch/x86/mm/cpu_entry_area.c | |
| parent | 639d6aafe437a7464399d2a77d006049053df06f (diff) | |
| download | linux-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.c | 14 |
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 |