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-rw-r--r--arch/s390/kernel/process.c416
1 files changed, 416 insertions, 0 deletions
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
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+/*
+ * arch/s390/kernel/process.c
+ *
+ * S390 version
+ * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ * Hartmut Penner (hp@de.ibm.com),
+ * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ *
+ * Derived from "arch/i386/kernel/process.c"
+ * Copyright (C) 1995, Linus Torvalds
+ */
+
+/*
+ * This file handles the architecture-dependent parts of process handling..
+ */
+
+#include <linux/config.h>
+#include <linux/compiler.h>
+#include <linux/cpu.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/user.h>
+#include <linux/a.out.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/irq.h>
+#include <asm/timer.h>
+
+asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+
+/*
+ * Return saved PC of a blocked thread. used in kernel/sched.
+ * resume in entry.S does not create a new stack frame, it
+ * just stores the registers %r6-%r15 to the frame given by
+ * schedule. We want to return the address of the caller of
+ * schedule, so we have to walk the backchain one time to
+ * find the frame schedule() store its return address.
+ */
+unsigned long thread_saved_pc(struct task_struct *tsk)
+{
+ struct stack_frame *sf;
+
+ sf = (struct stack_frame *) tsk->thread.ksp;
+ sf = (struct stack_frame *) sf->back_chain;
+ return sf->gprs[8];
+}
+
+/*
+ * Need to know about CPUs going idle?
+ */
+static struct notifier_block *idle_chain;
+
+int register_idle_notifier(struct notifier_block *nb)
+{
+ return notifier_chain_register(&idle_chain, nb);
+}
+EXPORT_SYMBOL(register_idle_notifier);
+
+int unregister_idle_notifier(struct notifier_block *nb)
+{
+ return notifier_chain_unregister(&idle_chain, nb);
+}
+EXPORT_SYMBOL(unregister_idle_notifier);
+
+void do_monitor_call(struct pt_regs *regs, long interruption_code)
+{
+ /* disable monitor call class 0 */
+ __ctl_clear_bit(8, 15);
+
+ notifier_call_chain(&idle_chain, CPU_NOT_IDLE,
+ (void *)(long) smp_processor_id());
+}
+
+/*
+ * The idle loop on a S390...
+ */
+void default_idle(void)
+{
+ psw_t wait_psw;
+ unsigned long reg;
+ int cpu, rc;
+
+ local_irq_disable();
+ if (need_resched()) {
+ local_irq_enable();
+ schedule();
+ return;
+ }
+
+ /* CPU is going idle. */
+ cpu = smp_processor_id();
+ rc = notifier_call_chain(&idle_chain, CPU_IDLE, (void *)(long) cpu);
+ if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
+ BUG();
+ if (rc != NOTIFY_OK) {
+ local_irq_enable();
+ return;
+ }
+
+ /* enable monitor call class 0 */
+ __ctl_set_bit(8, 15);
+
+#ifdef CONFIG_HOTPLUG_CPU
+ if (cpu_is_offline(smp_processor_id()))
+ cpu_die();
+#endif
+
+ /*
+ * Wait for external, I/O or machine check interrupt and
+ * switch off machine check bit after the wait has ended.
+ */
+ wait_psw.mask = PSW_KERNEL_BITS | PSW_MASK_MCHECK | PSW_MASK_WAIT |
+ PSW_MASK_IO | PSW_MASK_EXT;
+#ifndef CONFIG_ARCH_S390X
+ asm volatile (
+ " basr %0,0\n"
+ "0: la %0,1f-0b(%0)\n"
+ " st %0,4(%1)\n"
+ " oi 4(%1),0x80\n"
+ " lpsw 0(%1)\n"
+ "1: la %0,2f-1b(%0)\n"
+ " st %0,4(%1)\n"
+ " oi 4(%1),0x80\n"
+ " ni 1(%1),0xf9\n"
+ " lpsw 0(%1)\n"
+ "2:"
+ : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
+#else /* CONFIG_ARCH_S390X */
+ asm volatile (
+ " larl %0,0f\n"
+ " stg %0,8(%1)\n"
+ " lpswe 0(%1)\n"
+ "0: larl %0,1f\n"
+ " stg %0,8(%1)\n"
+ " ni 1(%1),0xf9\n"
+ " lpswe 0(%1)\n"
+ "1:"
+ : "=&a" (reg) : "a" (&wait_psw) : "memory", "cc" );
+#endif /* CONFIG_ARCH_S390X */
+}
+
+void cpu_idle(void)
+{
+ for (;;)
+ default_idle();
+}
+
+void show_regs(struct pt_regs *regs)
+{
+ struct task_struct *tsk = current;
+
+ printk("CPU: %d %s\n", tsk->thread_info->cpu, print_tainted());
+ printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
+ current->comm, current->pid, (void *) tsk,
+ (void *) tsk->thread.ksp);
+
+ show_registers(regs);
+ /* Show stack backtrace if pt_regs is from kernel mode */
+ if (!(regs->psw.mask & PSW_MASK_PSTATE))
+ show_trace(0,(unsigned long *) regs->gprs[15]);
+}
+
+extern void kernel_thread_starter(void);
+
+__asm__(".align 4\n"
+ "kernel_thread_starter:\n"
+ " la 2,0(10)\n"
+ " basr 14,9\n"
+ " la 2,0\n"
+ " br 11\n");
+
+int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
+{
+ struct pt_regs regs;
+
+ memset(&regs, 0, sizeof(regs));
+ regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
+ regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
+ regs.gprs[9] = (unsigned long) fn;
+ regs.gprs[10] = (unsigned long) arg;
+ regs.gprs[11] = (unsigned long) do_exit;
+ regs.orig_gpr2 = -1;
+
+ /* Ok, create the new process.. */
+ return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
+ 0, &regs, 0, NULL, NULL);
+}
+
+/*
+ * Free current thread data structures etc..
+ */
+void exit_thread(void)
+{
+}
+
+void flush_thread(void)
+{
+ clear_used_math();
+ clear_tsk_thread_flag(current, TIF_USEDFPU);
+}
+
+void release_thread(struct task_struct *dead_task)
+{
+}
+
+int copy_thread(int nr, unsigned long clone_flags, unsigned long new_stackp,
+ unsigned long unused,
+ struct task_struct * p, struct pt_regs * regs)
+{
+ struct fake_frame
+ {
+ struct stack_frame sf;
+ struct pt_regs childregs;
+ } *frame;
+
+ frame = ((struct fake_frame *)
+ (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
+ p->thread.ksp = (unsigned long) frame;
+ /* Store access registers to kernel stack of new process. */
+ frame->childregs = *regs;
+ frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
+ frame->childregs.gprs[15] = new_stackp;
+ 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;
+
+ /* Save access registers to new thread structure. */
+ save_access_regs(&p->thread.acrs[0]);
+
+#ifndef CONFIG_ARCH_S390X
+ /*
+ * save fprs to current->thread.fp_regs to merge them with
+ * the emulated registers and then copy the result to the child.
+ */
+ save_fp_regs(&current->thread.fp_regs);
+ memcpy(&p->thread.fp_regs, &current->thread.fp_regs,
+ sizeof(s390_fp_regs));
+ p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _SEGMENT_TABLE;
+ /* Set a new TLS ? */
+ if (clone_flags & CLONE_SETTLS)
+ p->thread.acrs[0] = regs->gprs[6];
+#else /* CONFIG_ARCH_S390X */
+ /* Save the fpu registers to new thread structure. */
+ save_fp_regs(&p->thread.fp_regs);
+ p->thread.user_seg = __pa((unsigned long) p->mm->pgd) | _REGION_TABLE;
+ /* Set a new TLS ? */
+ if (clone_flags & CLONE_SETTLS) {
+ if (test_thread_flag(TIF_31BIT)) {
+ p->thread.acrs[0] = (unsigned int) regs->gprs[6];
+ } else {
+ p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
+ p->thread.acrs[1] = (unsigned int) regs->gprs[6];
+ }
+ }
+#endif /* CONFIG_ARCH_S390X */
+ /* 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_info,0,sizeof(p->thread.per_info));
+
+ return 0;
+}
+
+asmlinkage long sys_fork(struct pt_regs regs)
+{
+ return do_fork(SIGCHLD, regs.gprs[15], &regs, 0, NULL, NULL);
+}
+
+asmlinkage long sys_clone(struct pt_regs regs)
+{
+ unsigned long clone_flags;
+ unsigned long newsp;
+ int __user *parent_tidptr, *child_tidptr;
+
+ clone_flags = regs.gprs[3];
+ newsp = regs.orig_gpr2;
+ parent_tidptr = (int __user *) regs.gprs[4];
+ child_tidptr = (int __user *) regs.gprs[5];
+ if (!newsp)
+ newsp = regs.gprs[15];
+ return do_fork(clone_flags, newsp, &regs, 0,
+ parent_tidptr, child_tidptr);
+}
+
+/*
+ * This is trivial, and on the face of it looks like it
+ * could equally well be done in user mode.
+ *
+ * Not so, for quite unobvious reasons - register pressure.
+ * In user mode vfork() cannot have a stack frame, and if
+ * done by calling the "clone()" system call directly, you
+ * do not have enough call-clobbered registers to hold all
+ * the information you need.
+ */
+asmlinkage long sys_vfork(struct pt_regs regs)
+{
+ return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
+ regs.gprs[15], &regs, 0, NULL, NULL);
+}
+
+/*
+ * sys_execve() executes a new program.
+ */
+asmlinkage long sys_execve(struct pt_regs regs)
+{
+ int error;
+ char * filename;
+
+ filename = getname((char __user *) regs.orig_gpr2);
+ error = PTR_ERR(filename);
+ if (IS_ERR(filename))
+ goto out;
+ error = do_execve(filename, (char __user * __user *) regs.gprs[3],
+ (char __user * __user *) regs.gprs[4], &regs);
+ if (error == 0) {
+ task_lock(current);
+ current->ptrace &= ~PT_DTRACE;
+ task_unlock(current);
+ current->thread.fp_regs.fpc = 0;
+ if (MACHINE_HAS_IEEE)
+ asm volatile("sfpc %0,%0" : : "d" (0));
+ }
+ putname(filename);
+out:
+ return error;
+}
+
+
+/*
+ * fill in the FPU structure for a core dump.
+ */
+int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
+{
+#ifndef CONFIG_ARCH_S390X
+ /*
+ * save fprs to current->thread.fp_regs to merge them with
+ * the emulated registers and then copy the result to the dump.
+ */
+ save_fp_regs(&current->thread.fp_regs);
+ memcpy(fpregs, &current->thread.fp_regs, sizeof(s390_fp_regs));
+#else /* CONFIG_ARCH_S390X */
+ save_fp_regs(fpregs);
+#endif /* CONFIG_ARCH_S390X */
+ return 1;
+}
+
+/*
+ * fill in the user structure for a core dump..
+ */
+void dump_thread(struct pt_regs * regs, struct user * dump)
+{
+
+/* changed the size calculations - should hopefully work better. lbt */
+ dump->magic = CMAGIC;
+ dump->start_code = 0;
+ dump->start_stack = regs->gprs[15] & ~(PAGE_SIZE - 1);
+ dump->u_tsize = current->mm->end_code >> PAGE_SHIFT;
+ dump->u_dsize = (current->mm->brk + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ dump->u_dsize -= dump->u_tsize;
+ dump->u_ssize = 0;
+ if (dump->start_stack < TASK_SIZE)
+ dump->u_ssize = (TASK_SIZE - dump->start_stack) >> PAGE_SHIFT;
+ memcpy(&dump->regs, regs, sizeof(s390_regs));
+ dump_fpu (regs, &dump->regs.fp_regs);
+ dump->regs.per_info = current->thread.per_info;
+}
+
+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 || !p->thread_info)
+ return 0;
+ low = (struct stack_frame *) p->thread_info;
+ high = (struct stack_frame *)
+ ((unsigned long) p->thread_info + THREAD_SIZE) - 1;
+ sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
+ if (sf <= low || sf > high)
+ return 0;
+ for (count = 0; count < 16; count++) {
+ sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
+ if (sf <= low || sf > high)
+ return 0;
+ return_address = sf->gprs[8] & PSW_ADDR_INSN;
+ if (!in_sched_functions(return_address))
+ return return_address;
+ }
+ return 0;
+}
+
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