Re: [PATCH 08/11] x86: Move uaccess_err and sig_on_uaccess_err to thread_struct

[Ingo Molnar]

* Andy Lutomirski <l...@kernel.org> wrote:

> thread_info is a legacy mess.  To prepare for its partial removal,
> move the uaccess control fields out -- they're straightforward.
> 
> Signed-off-by: Andy Lutomirski <l...@kernel.org>
> ---
>  arch/x86/entry/vsyscall/vsyscall_64.c | 6 +++---
>  arch/x86/include/asm/processor.h      | 3 +++
>  arch/x86/include/asm/thread_info.h    | 2 --
>  arch/x86/include/asm/uaccess.h        | 4 ++--
>  arch/x86/mm/extable.c                 | 2 +-
>  arch/x86/mm/fault.c                   | 2 +-
>  6 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c 
> b/arch/x86/entry/vsyscall/vsyscall_64.c
> index 174c2549939d..3aba2b043050 100644
> --- a/arch/x86/entry/vsyscall/vsyscall_64.c
> +++ b/arch/x86/entry/vsyscall/vsyscall_64.c
> @@ -221,8 +221,8 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long 
> address)
>        * With a real vsyscall, page faults cause SIGSEGV.  We want to
>        * preserve that behavior to make writing exploits harder.
>        */
> -     prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
> -     current_thread_info()->sig_on_uaccess_error = 1;
> +     prev_sig_on_uaccess_error = current->thread.sig_on_uaccess_error;
> +     current->thread.sig_on_uaccess_error = 1;
>  
>       ret = -EFAULT;
>       switch (vsyscall_nr) {
> @@ -243,7 +243,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long 
> address)
>               break;
>       }
>  
> -     current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
> +     current->thread.sig_on_uaccess_error = prev_sig_on_uaccess_error;
>  
>  check_fault:
>       if (ret == -EFAULT) {
> diff --git a/arch/x86/include/asm/processor.h 
> b/arch/x86/include/asm/processor.h
> index 62c6cc3cc5d3..f53ae57bd985 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -419,6 +419,9 @@ struct thread_struct {
>       /* Max allowed port in the bitmap, in bytes: */
>       unsigned                io_bitmap_max;
>  
> +     unsigned int            sig_on_uaccess_error:1;
> +     unsigned int            uaccess_err:1;  /* uaccess failed */

Btw., while at it I've renamed 'sig_on_uaccess_error' to 'sig_on_uaccess_err' 
to 
make the two names consistent.

Thanks,

        Ingo