sh: switch to copy_thread_tls()

Use the copy_thread_tls() calling convention which passes tls through a
register. This is required so we can remove the copy_thread{_tls}() split
and remove the HAVE_COPY_THREAD_TLS macro.

Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-sh@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

arch/sh/Kconfig

@@ -70,6 +70,7 @@ config SUPERH
 	select ARCH_HIBERNATION_POSSIBLE if MMU
 	select SPARSE_IRQ
 	select HAVE_STACKPROTECTOR
+	select HAVE_COPY_THREAD_TLS
 	help
 	  The SuperH is a RISC processor targeted for use in embedded systems
 	  and consumer electronics; it was also used in the Sega Dreamcast

arch/sh/kernel/process_32.c

@@ -115,8 +115,8 @@ EXPORT_SYMBOL(dump_fpu);
 asmlinkage void ret_from_fork(void);
 asmlinkage void ret_from_kernel_thread(void);
 
-int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long arg, struct task_struct *p)
+int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
+		    unsigned long arg, struct task_struct *p, unsigned long tls)
 {
 	struct thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs;
@@ -158,7 +158,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	ti->addr_limit = USER_DS;
 
 	if (clone_flags & CLONE_SETTLS)
-		childregs->gbr = childregs->regs[0];
+		childregs->gbr = tls;
 
 	childregs->regs[0] = 0; /* Set return value for child */
 	p->thread.pc = (unsigned long) ret_from_fork;