• Thomas Gleixner's avatar
    x86/cpu_entry_area: Add debugstore entries to cpu_entry_area · e0eb3466
    Thomas Gleixner authored
    commit 10043e02 upstream.
    
    The Intel PEBS/BTS debug store is a design trainwreck as it expects virtual
    addresses which must be visible in any execution context.
    
    So it is required to make these mappings visible to user space when kernel
    page table isolation is active.
    
    Provide enough room for the buffer mappings in the cpu_entry_area so the
    buffers are available in the user space visible page tables.
    
    At the point where the kernel side entry area is populated there is no
    buffer available yet, but the kernel PMD must be populated. To achieve this
    set the entries for these buffers to non present.
    Signed-off-by: 's avatarThomas 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: 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: 's avatarIngo Molnar <mingo@kernel.org>
    Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    e0eb3466
cpu_entry_area.h 2.27 KB