v4.19.13 snapshot.
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
new file mode 100644
index 0000000..6e758bb
--- /dev/null
+++ b/arch/s390/kernel/process.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file handles the architecture dependent parts of process handling.
+ *
+ * Copyright IBM Corp. 1999, 2009
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ * Hartmut Penner <hp@de.ibm.com>,
+ * Denis Joseph Barrow,
+ */
+
+#include <linux/elf-randomize.h>
+#include <linux/compiler.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/elfcore.h>
+#include <linux/smp.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/tick.h>
+#include <linux/personality.h>
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <linux/kprobes.h>
+#include <linux/random.h>
+#include <linux/export.h>
+#include <linux/init_task.h>
+#include <asm/cpu_mf.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/vtimer.h>
+#include <asm/exec.h>
+#include <asm/irq.h>
+#include <asm/nmi.h>
+#include <asm/smp.h>
+#include <asm/switch_to.h>
+#include <asm/runtime_instr.h>
+#include "entry.h"
+
+asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
+
+extern void kernel_thread_starter(void);
+
+void flush_thread(void)
+{
+}
+
+void arch_setup_new_exec(void)
+{
+ if (S390_lowcore.current_pid != current->pid) {
+ S390_lowcore.current_pid = current->pid;
+ if (test_facility(40))
+ lpp(&S390_lowcore.lpp);
+ }
+}
+
+void arch_release_task_struct(struct task_struct *tsk)
+{
+ runtime_instr_release(tsk);
+ guarded_storage_release(tsk);
+}
+
+int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
+{
+ /*
+ * Save the floating-point or vector register state of the current
+ * task and set the CIF_FPU flag to lazy restore the FPU register
+ * state when returning to user space.
+ */
+ save_fpu_regs();
+
+ memcpy(dst, src, arch_task_struct_size);
+ dst->thread.fpu.regs = dst->thread.fpu.fprs;
+ return 0;
+}
+
+int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp,
+ unsigned long arg, struct task_struct *p, unsigned long tls)
+{
+ struct fake_frame
+ {
+ struct stack_frame sf;
+ struct pt_regs childregs;
+ } *frame;
+
+ frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
+ p->thread.ksp = (unsigned long) frame;
+ /* Save access registers to new thread structure. */
+ save_access_regs(&p->thread.acrs[0]);
+ /* start new process with ar4 pointing to the correct address space */
+ p->thread.mm_segment = get_fs();
+ /* Don't copy debug registers */
+ memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
+ memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
+ clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
+ p->thread.per_flags = 0;
+ /* Initialize per thread user and system timer values */
+ p->thread.user_timer = 0;
+ p->thread.guest_timer = 0;
+ p->thread.system_timer = 0;
+ p->thread.hardirq_timer = 0;
+ p->thread.softirq_timer = 0;
+
+ frame->sf.back_chain = 0;
+ /* new return point is ret_from_fork */
+ frame->sf.gprs[8] = (unsigned long) ret_from_fork;
+ /* fake return stack for resume(), don't go back to schedule */
+ frame->sf.gprs[9] = (unsigned long) frame;
+
+ /* Store access registers to kernel stack of new process. */
+ if (unlikely(p->flags & PF_KTHREAD)) {
+ /* kernel thread */
+ memset(&frame->childregs, 0, sizeof(struct pt_regs));
+ frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
+ PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
+ frame->childregs.psw.addr =
+ (unsigned long) kernel_thread_starter;
+ frame->childregs.gprs[9] = new_stackp; /* function */
+ frame->childregs.gprs[10] = arg;
+ frame->childregs.gprs[11] = (unsigned long) do_exit;
+ frame->childregs.orig_gpr2 = -1;
+
+ return 0;
+ }
+ frame->childregs = *current_pt_regs();
+ frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
+ frame->childregs.flags = 0;
+ if (new_stackp)
+ frame->childregs.gprs[15] = new_stackp;
+
+ /* Don't copy runtime instrumentation info */
+ p->thread.ri_cb = NULL;
+ frame->childregs.psw.mask &= ~PSW_MASK_RI;
+ /* Don't copy guarded storage control block */
+ p->thread.gs_cb = NULL;
+ p->thread.gs_bc_cb = NULL;
+
+ /* Set a new TLS ? */
+ if (clone_flags & CLONE_SETTLS) {
+ if (is_compat_task()) {
+ p->thread.acrs[0] = (unsigned int)tls;
+ } else {
+ p->thread.acrs[0] = (unsigned int)(tls >> 32);
+ p->thread.acrs[1] = (unsigned int)tls;
+ }
+ }
+ return 0;
+}
+
+asmlinkage void execve_tail(void)
+{
+ current->thread.fpu.fpc = 0;
+ asm volatile("sfpc %0" : : "d" (0));
+}
+
+/*
+ * fill in the FPU structure for a core dump.
+ */
+int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
+{
+ save_fpu_regs();
+ fpregs->fpc = current->thread.fpu.fpc;
+ fpregs->pad = 0;
+ if (MACHINE_HAS_VX)
+ convert_vx_to_fp((freg_t *)&fpregs->fprs,
+ current->thread.fpu.vxrs);
+ else
+ memcpy(&fpregs->fprs, current->thread.fpu.fprs,
+ sizeof(fpregs->fprs));
+ return 1;
+}
+EXPORT_SYMBOL(dump_fpu);
+
+unsigned long get_wchan(struct task_struct *p)
+{
+ struct stack_frame *sf, *low, *high;
+ unsigned long return_address;
+ int count;
+
+ if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
+ return 0;
+ low = task_stack_page(p);
+ high = (struct stack_frame *) task_pt_regs(p);
+ sf = (struct stack_frame *) p->thread.ksp;
+ if (sf <= low || sf > high)
+ return 0;
+ for (count = 0; count < 16; count++) {
+ sf = (struct stack_frame *) sf->back_chain;
+ if (sf <= low || sf > high)
+ return 0;
+ return_address = sf->gprs[8];
+ if (!in_sched_functions(return_address))
+ return return_address;
+ }
+ return 0;
+}
+
+unsigned long arch_align_stack(unsigned long sp)
+{
+ if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+ sp -= get_random_int() & ~PAGE_MASK;
+ return sp & ~0xf;
+}
+
+static inline unsigned long brk_rnd(void)
+{
+ return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+ unsigned long ret;
+
+ ret = PAGE_ALIGN(mm->brk + brk_rnd());
+ return (ret > mm->brk) ? ret : mm->brk;
+}
+
+void set_fs_fixup(void)
+{
+ struct pt_regs *regs = current_pt_regs();
+ static bool warned;
+
+ set_fs(USER_DS);
+ if (warned)
+ return;
+ WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
+ show_registers(regs);
+ warned = true;
+}