| // 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(); |
| |
| *dst = *src; |
| 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; |
| } |