[PATCH v9 03/29] ptrace,x86: Make user_64bit_mode() available to 32-bit builds

From: Ricardo Neri
Date: Tue Oct 03 2017 - 23:56:11 EST

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@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Adam Buchbinder <adam.buchbinder@xxxxxxxxx>
Cc: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Thomas Garnier <thgarnie@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Ravi V. Shankar <ravi.v.shankar@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
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 91c04c8..e2afbf6 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -135,9 +135,9 @@ static inline int v8086_mode(struct pt_regs *regs)

-#ifdef CONFIG_X86_64
static inline bool user_64bit_mode(struct pt_regs *regs)
+#ifdef CONFIG_X86_64
* On non-paravirt systems, this is the only long mode CPL 3
@@ -148,8 +148,12 @@ 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;
+#else /* !CONFIG_X86_64 */
+ return false;

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