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Diffstat (limited to 'arch/s390/kernel/process.c')
| -rw-r--r-- | arch/s390/kernel/process.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c new file mode 100644 index 000000000..258000417 --- /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; +} |