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    Subject[PATCH v7 01/26] ptrace,x86: Make user_64bit_mode() available to 32-bit builds
    Date
    In its current form, user_64bit_mode() can only be used when CONFIG_X86_64
    is selected. This implies that code built with CONFIG_X86_64=n cannot use
    it. If a piece of code needs to be built for both CONFIG_X86_64=y and
    CONFIG_X86_64=n and wants to use this function, it needs to wrap it in
    an #ifdef/#endif; potentially, in multiple places.

    This can be easily avoided with a single #ifdef/#endif pair within
    user_64bit_mode() itself.

    Suggested-by: Borislav Petkov <bp@suse.de>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
    Cc: Colin Ian King <colin.king@canonical.com>
    Cc: Lorenzo Stoakes <lstoakes@gmail.com>
    Cc: Qiaowei Ren <qiaowei.ren@intel.com>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Thomas Garnier <thgarnie@google.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
    Cc: x86@kernel.org
    Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
    ---
    arch/x86/include/asm/ptrace.h | 6 +++++-
    1 file changed, 5 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
    index 2b5d686..ea78a84 100644
    --- a/arch/x86/include/asm/ptrace.h
    +++ b/arch/x86/include/asm/ptrace.h
    @@ -115,9 +115,9 @@ static inline int v8086_mode(struct pt_regs *regs)
    #endif
    }

    -#ifdef CONFIG_X86_64
    static inline bool user_64bit_mode(struct pt_regs *regs)
    {
    +#ifdef CONFIG_X86_64
    #ifndef CONFIG_PARAVIRT
    /*
    * On non-paravirt systems, this is the only long mode CPL 3
    @@ -128,8 +128,12 @@ static inline bool user_64bit_mode(struct pt_regs *regs)
    /* Headers are too twisted for this to go in paravirt.h. */
    return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
    #endif
    +#else /* !CONFIG_X86_64 */
    + return false;
    +#endif
    }

    +#ifdef CONFIG_X86_64
    #define current_user_stack_pointer() current_pt_regs()->sp
    #define compat_user_stack_pointer() current_pt_regs()->sp
    #endif
    --
    2.9.3
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