Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / arch / mips / kernel / process.c

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 69b17a920049c53a49aec6b0d66597e48709b551..a11c6f9fdd5e0f2e05b306936cb98464f88a130d 100644 (file)
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -82,6 +82,7 @@ void __noreturn cpu_idle(void)
 }
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
 {
@@ -111,10 +112,10 @@ void flush_thread(void)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-       unsigned long unused, struct task_struct *p, struct pt_regs *regs)
+       unsigned long arg, struct task_struct *p)
 {
        struct thread_info *ti = task_thread_info(p);
-       struct pt_regs *childregs;
+       struct pt_regs *childregs, *regs = current_pt_regs();
        unsigned long childksp;
        p->set_child_tid = p->clear_child_tid = NULL;
 
@@ -134,19 +135,30 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
        childregs = (struct pt_regs *) childksp - 1;
        /*  Put the stack after the struct pt_regs.  */
        childksp = (unsigned long) childregs;
+       p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
+       if (unlikely(p->flags & PF_KTHREAD)) {
+               unsigned long status = p->thread.cp0_status;
+               memset(childregs, 0, sizeof(struct pt_regs));
+               ti->addr_limit = KERNEL_DS;
+               p->thread.reg16 = usp; /* fn */
+               p->thread.reg17 = arg;
+               p->thread.reg29 = childksp;
+               p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+               status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
+                        ((status & (ST0_KUC | ST0_IEC)) << 2);
+#else
+               status |= ST0_EXL;
+#endif
+               childregs->cp0_status = status;
+               return 0;
+       }
        *childregs = *regs;
        childregs->regs[7] = 0; /* Clear error flag */
-
        childregs->regs[2] = 0; /* Child gets zero as return value */
+       childregs->regs[29] = usp;
+       ti->addr_limit = USER_DS;
 
-       if (childregs->cp0_status & ST0_CU0) {
-               childregs->regs[28] = (unsigned long) ti;
-               childregs->regs[29] = childksp;
-               ti->addr_limit = KERNEL_DS;
-       } else {
-               childregs->regs[29] = usp;
-               ti->addr_limit = USER_DS;
-       }
        p->thread.reg29 = (unsigned long) childregs;
        p->thread.reg31 = (unsigned long) ret_from_fork;
 
@@ -154,7 +166,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
         * New tasks lose permission to use the fpu. This accelerates context
         * switching for most programs since they don't use the fpu.
         */
-       p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
        childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
 
 #ifdef CONFIG_MIPS_MT_SMTC
@@ -219,35 +230,6 @@ int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
        return 1;
 }
 
-/*
- * Create a kernel thread
- */
-static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-       do_exit(fn(arg));
-}
-
-long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-       struct pt_regs regs;
-
-       memset(&regs, 0, sizeof(regs));
-
-       regs.regs[4] = (unsigned long) arg;
-       regs.regs[5] = (unsigned long) fn;
-       regs.cp0_epc = (unsigned long) kernel_thread_helper;
-       regs.cp0_status = read_c0_status();
-#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
-       regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
-                         ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);
-#else
-       regs.cp0_status |= ST0_EXL;
-#endif
-
-       /* Ok, create the new process.. */
-       return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-
 /*
  *
  */