Commit 0f561fce authored by Dave Hansen's avatar Dave Hansen Committed by Ingo Molnar
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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: default avatarDave Hansen <>
Cc: Andrea Arcangeli <>
Cc: Andy Lutomirski <>
Cc: Arjan van de Ven <>
Cc: Borislav Petkov <>
Cc: Dan Williams <>
Cc: David Woodhouse <>
Cc: Greg Kroah-Hartman <>
Cc: Hugh Dickins <>
Cc: Josh Poimboeuf <>
Cc: Juergen Gross <>
Cc: Kees Cook <>
Cc: Linus Torvalds <>
Cc: Nadav Amit <>
Cc: Peter Zijlstra <>
Cc: Thomas Gleixner <>

Signed-off-by: default avatarIngo Molnar <>
parent 639d6aaf
......@@ -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
......@@ -299,6 +299,27 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear)
if (WARN_ON(!target_pmd))
* Only clone present PMDs. This ensures only setting
* _PAGE_GLOBAL on present PMDs. This should only be
* called on well-known addresses anyway, so a non-
* present PMD would be a surprise.
if (WARN_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT)))
* Setting 'target_pmd' below creates a mapping in both
* the user and kernel page tables. It is effectively
* global, so set it as global in both copies. Note:
* the X86_FEATURE_PGE check is not _required_ because
* the CPU ignores _PAGE_GLOBAL when PGE is not
* supported. The check keeps consistentency with
* code that only set this bit when supported.
if (boot_cpu_has(X86_FEATURE_PGE))
*pmd = pmd_set_flags(*pmd, _PAGE_GLOBAL);
* Copy the PMD. That is, the kernelmode and usermode
* tables will share the last-level page tables of this
......@@ -348,7 +369,7 @@ static void __init pti_clone_entry_text(void)
pti_clone_pmds((unsigned long) __entry_text_start,
(unsigned long) __irqentry_text_end,
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