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-rw-r--r--arch/s390/kernel/process.c240
1 files changed, 240 insertions, 0 deletions
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
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index 0000000000..2580004177
--- /dev/null
+++ b/arch/s390/kernel/process.c
@@ -0,0 +1,240 @@
+// 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 <linux/entry-common.h>
+#include <linux/io.h>
+#include <asm/cpu_mf.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/stacktrace.h>
+#include <asm/switch_to.h>
+#include <asm/runtime_instr.h>
+#include <asm/unwind.h>
+#include "entry.h"
+
+void ret_from_fork(void) asm("ret_from_fork");
+
+void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs)
+{
+ void (*func)(void *arg);
+
+ schedule_tail(prev);
+
+ if (!user_mode(regs)) {
+ /* Kernel thread */
+ func = (void *)regs->gprs[9];
+ func((void *)regs->gprs[10]);
+ }
+ clear_pt_regs_flag(regs, PIF_SYSCALL);
+ syscall_exit_to_user_mode(regs);
+}
+
+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;
+
+ /*
+ * Don't transfer over the runtime instrumentation or the guarded
+ * storage control block pointers. These fields are cleared here instead
+ * of in copy_thread() to avoid premature freeing of associated memory
+ * on fork() failure. Wait to clear the RI flag because ->stack still
+ * refers to the source thread.
+ */
+ dst->thread.ri_cb = NULL;
+ dst->thread.gs_cb = NULL;
+ dst->thread.gs_bc_cb = NULL;
+
+ return 0;
+}
+
+int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
+{
+ unsigned long clone_flags = args->flags;
+ unsigned long new_stackp = args->stack;
+ unsigned long tls = args->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 */
+ /* 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;
+ p->thread.last_break = 1;
+
+ frame->sf.back_chain = 0;
+ frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs;
+ frame->sf.gprs[12 - 6] = (unsigned long)p;
+ /* new return point is ret_from_fork */
+ frame->sf.gprs[14 - 6] = (unsigned long)ret_from_fork;
+ /* fake return stack for resume(), don't go back to schedule */
+ frame->sf.gprs[15 - 6] = (unsigned long)frame;
+
+ /* Store access registers to kernel stack of new process. */
+ if (unlikely(args->fn)) {
+ /* kernel thread */
+ memset(&frame->childregs, 0, sizeof(struct pt_regs));
+ frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO |
+ PSW_MASK_EXT | PSW_MASK_MCHECK;
+ frame->childregs.gprs[9] = (unsigned long)args->fn;
+ frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
+ frame->childregs.orig_gpr2 = -1;
+ frame->childregs.last_break = 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;
+ /*
+ * Clear the runtime instrumentation flag after the above childregs
+ * copy. The CB pointer was already cleared in arch_dup_task_struct().
+ */
+ frame->childregs.psw.mask &= ~PSW_MASK_RI;
+
+ /* 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;
+ }
+ }
+ /*
+ * s390 stores the svc return address in arch_data when calling
+ * sigreturn()/restart_syscall() via vdso. 1 means no valid address
+ * stored.
+ */
+ p->restart_block.arch_data = 1;
+ return 0;
+}
+
+void execve_tail(void)
+{
+ current->thread.fpu.fpc = 0;
+ asm volatile("sfpc %0" : : "d" (0));
+}
+
+unsigned long __get_wchan(struct task_struct *p)
+{
+ struct unwind_state state;
+ unsigned long ip = 0;
+
+ if (!task_stack_page(p))
+ return 0;
+
+ if (!try_get_task_stack(p))
+ return 0;
+
+ unwind_for_each_frame(&state, p, NULL, 0) {
+ if (state.stack_info.type != STACK_TYPE_TASK) {
+ ip = 0;
+ break;
+ }
+
+ ip = unwind_get_return_address(&state);
+ if (!ip)
+ break;
+
+ if (!in_sched_functions(ip))
+ break;
+ }
+
+ put_task_stack(p);
+ return ip;
+}
+
+unsigned long arch_align_stack(unsigned long sp)
+{
+ if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+ sp -= get_random_u32_below(PAGE_SIZE);
+ return sp & ~0xf;
+}
+
+static inline unsigned long brk_rnd(void)
+{
+ return (get_random_u16() & 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;
+}