lkml.org 
[lkml]   [2018]   [Jan]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 015/146] x86/mm/pti: Share cpu_entry_area with user space page tables
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Andy Lutomirski <luto@kernel.org>

    commit f7cfbee91559ca7e3e961a00ffac921208a115ad upstream.

    Share the cpu entry area so the user space and kernel space page tables
    have the same P4D page.

    Signed-off-by: Andy Lutomirski <luto@kernel.org>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave.hansen@linux.intel.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/pti.c | 25 +++++++++++++++++++++++++
    1 file changed, 25 insertions(+)

    --- a/arch/x86/mm/pti.c
    +++ b/arch/x86/mm/pti.c
    @@ -265,6 +265,29 @@ pti_clone_pmds(unsigned long start, unsi
    }

    /*
    + * Clone a single p4d (i.e. a top-level entry on 4-level systems and a
    + * next-level entry on 5-level systems.
    + */
    +static void __init pti_clone_p4d(unsigned long addr)
    +{
    + p4d_t *kernel_p4d, *user_p4d;
    + pgd_t *kernel_pgd;
    +
    + user_p4d = pti_user_pagetable_walk_p4d(addr);
    + kernel_pgd = pgd_offset_k(addr);
    + kernel_p4d = p4d_offset(kernel_pgd, addr);
    + *user_p4d = *kernel_p4d;
    +}
    +
    +/*
    + * Clone the CPU_ENTRY_AREA into the user space visible page table.
    + */
    +static void __init pti_clone_user_shared(void)
    +{
    + pti_clone_p4d(CPU_ENTRY_AREA_BASE);
    +}
    +
    +/*
    * Initialize kernel page table isolation
    */
    void __init pti_init(void)
    @@ -273,4 +296,6 @@ void __init pti_init(void)
    return;

    pr_info("enabled\n");
    +
    + pti_clone_user_shared();
    }

    \
     
     \ /
      Last update: 2018-01-01 15:40    [W:4.180 / U:0.352 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site