• B
    x86/fpu: Always restore_xinit_state() when use_eager_cpu() · c88d4748
    Bobby Powers 提交于
    The following commit:
    
      f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
    
    removed drop_init_fpu() usage from flush_thread(). This seems to break
    things for me - the Go 1.4 test suite fails all over the place with
    floating point comparision errors (offending commit found through
    bisection).
    
    The functional change was that flush_thread() after this commit
    only calls restore_init_xstate() when both use_eager_fpu() and
    !used_math() are true. drop_init_fpu() (now fpu_reset_state()) calls
    restore_init_xstate() regardless of whether current used_math() - apply
    the same logic here.
    
    Switch used_math() -> tsk_used_math(tsk) to consistently use the grabbed
    tsk instead of current, like in the rest of flush_thread().
    Tested-by: NDave Hansen <dave.hansen@intel.com>
    Signed-off-by: NBobby Powers <bobbypowers@gmail.com>
    Signed-off-by: NBorislav Petkov <bp@suse.de>
    Acked-by: NOleg Nesterov <oleg@redhat.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Fenghua Yu <fenghua.yu@intel.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Pekka Riikonen <priikone@iki.fi>
    Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Suresh Siddha <sbsiddha@gmail.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Fixes: f893959b ("x86/fpu: Don't abuse drop_init_fpu() in flush_thread()")
    Link: http://lkml.kernel.org/r/1430147441-9820-1-git-send-email-bobbypowers@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
    c88d4748
process.c 12.2 KB