Merge tag 'v3.7-rc5' into execve

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / arm64 / kernel / process.c

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index e04cebd..a430b5c 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -240,27 +240,35 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
        struct pt_regs *childregs = task_pt_regs(p);
        unsigned long tls = p->thread.tp_value;
 
-       *childregs = *regs;
-       childregs->regs[0] = 0;
+       memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 
-       if (is_compat_thread(task_thread_info(p)))
-               childregs->compat_sp = stack_start;
-       else {
+       if (likely(regs)) {
+               *childregs = *regs;
+               childregs->regs[0] = 0;
+               if (is_compat_thread(task_thread_info(p))) {
+                       childregs->compat_sp = stack_start;
+               } else {
+                       /*
+                        * Read the current TLS pointer from tpidr_el0 as it may be
+                        * out-of-sync with the saved value.
+                        */
+                       asm("mrs %0, tpidr_el0" : "=r" (tls));
+                       childregs->sp = stack_start;
+               }
                /*
-                * Read the current TLS pointer from tpidr_el0 as it may be
-                * out-of-sync with the saved value.
+                * If a TLS pointer was passed to clone (4th argument), use it
+                * for the new thread.
                 */
-               asm("mrs %0, tpidr_el0" : "=r" (tls));
-               childregs->sp = stack_start;
+               if (clone_flags & CLONE_SETTLS)
+                       tls = regs->regs[3];
+       } else {
+               memset(childregs, 0, sizeof(struct pt_regs));
+               childregs->pstate = PSR_MODE_EL1h;
+               p->thread.cpu_context.x19 = stack_start;
+               p->thread.cpu_context.x20 = stk_sz;
        }
-
-       memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
-       p->thread.cpu_context.sp = (unsigned long)childregs;
        p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
-
-       /* If a TLS pointer was passed to clone, use that for the new thread. */
-       if (clone_flags & CLONE_SETTLS)
-               tls = regs->regs[3];
+       p->thread.cpu_context.sp = (unsigned long)childregs;
        p->thread.tp_value = tls;
 
        ptrace_hw_copy_thread(p);
@@ -309,43 +317,6 @@ struct task_struct *__switch_to(struct task_struct *prev,
        return last;
 }
 
-/*
- * Shuffle the argument into the correct register before calling the
- * thread function.  x1 is the thread argument, x2 is the pointer to
- * the thread function, and x3 points to the exit function.
- */
-extern void kernel_thread_helper(void);
-asm(   ".section .text\n"
-"      .align\n"
-"      .type   kernel_thread_helper, #function\n"
-"kernel_thread_helper:\n"
-"      mov     x0, x1\n"
-"      mov     x30, x3\n"
-"      br      x2\n"
-"      .size   kernel_thread_helper, . - kernel_thread_helper\n"
-"      .previous");
-
-#define kernel_thread_exit     do_exit
-
-/*
- * Create a kernel thread.
- */
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-       struct pt_regs regs;
-
-       memset(&regs, 0, sizeof(regs));
-
-       regs.regs[1] = (unsigned long)arg;
-       regs.regs[2] = (unsigned long)fn;
-       regs.regs[3] = (unsigned long)kernel_thread_exit;
-       regs.pc = (unsigned long)kernel_thread_helper;
-       regs.pstate = PSR_MODE_EL1h;
-
-       return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
 unsigned long get_wchan(struct task_struct *p)
 {
        struct stackframe frame;