[PATCH] m68k: Implement "current_stack_pointer"

[Kees Cook]

To follow the existing per-arch conventions, add asm "sp" as
"current_stack_pointer". This will let it be used in non-arch places
(like HARDENED_USERCOPY).

Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 arch/m68k/Kconfig               | 1 +
 arch/m68k/include/asm/current.h | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 936e1803c7c7..f0eac0e2f123 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -4,6 +4,7 @@ config M68K
 	default y
 	select ARCH_32BIT_OFF_T
 	select ARCH_HAS_BINFMT_FLAT
+	select ARCH_HAS_CURRENT_STACK_POINTER
 	select ARCH_HAS_DMA_PREP_COHERENT if HAS_DMA && MMU && !COLDFIRE
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if HAS_DMA
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
diff --git a/arch/m68k/include/asm/current.h b/arch/m68k/include/asm/current.h
index 6390ef2f7f86..0c87a7047e15 100644
--- a/arch/m68k/include/asm/current.h
+++ b/arch/m68k/include/asm/current.h
@@ -24,6 +24,8 @@ static inline struct task_struct *get_current(void)
 
 #define	current	get_current()
 
+register unsigned long current_stack_pointer __asm__("sp");
+
 #endif /* CONFNIG_MMU */
 
 #endif /* !(_M68K_CURRENT_H) */
-- 
2.30.2