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Diffstat (limited to '')
-rw-r--r-- | arch/um/kernel/process.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c new file mode 100644 index 000000000..010bc422a --- /dev/null +++ b/arch/um/kernel/process.c @@ -0,0 +1,402 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk}) + * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) + * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + * Copyright 2003 PathScale, Inc. + */ + +#include <linux/stddef.h> +#include <linux/err.h> +#include <linux/hardirq.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/personality.h> +#include <linux/proc_fs.h> +#include <linux/ptrace.h> +#include <linux/random.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/sched/task.h> +#include <linux/sched/task_stack.h> +#include <linux/seq_file.h> +#include <linux/tick.h> +#include <linux/threads.h> +#include <linux/resume_user_mode.h> +#include <asm/current.h> +#include <asm/mmu_context.h> +#include <linux/uaccess.h> +#include <as-layout.h> +#include <kern_util.h> +#include <os.h> +#include <skas.h> +#include <registers.h> +#include <linux/time-internal.h> + +/* + * This is a per-cpu array. A processor only modifies its entry and it only + * cares about its entry, so it's OK if another processor is modifying its + * entry. + */ +struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } }; + +static inline int external_pid(void) +{ + /* FIXME: Need to look up userspace_pid by cpu */ + return userspace_pid[0]; +} + +int pid_to_processor_id(int pid) +{ + int i; + + for (i = 0; i < ncpus; i++) { + if (cpu_tasks[i].pid == pid) + return i; + } + return -1; +} + +void free_stack(unsigned long stack, int order) +{ + free_pages(stack, order); +} + +unsigned long alloc_stack(int order, int atomic) +{ + unsigned long page; + gfp_t flags = GFP_KERNEL; + + if (atomic) + flags = GFP_ATOMIC; + page = __get_free_pages(flags, order); + + return page; +} + +static inline void set_current(struct task_struct *task) +{ + cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task) + { external_pid(), task }); +} + +extern void arch_switch_to(struct task_struct *to); + +void *__switch_to(struct task_struct *from, struct task_struct *to) +{ + to->thread.prev_sched = from; + set_current(to); + + switch_threads(&from->thread.switch_buf, &to->thread.switch_buf); + arch_switch_to(current); + + return current->thread.prev_sched; +} + +void interrupt_end(void) +{ + struct pt_regs *regs = ¤t->thread.regs; + + if (need_resched()) + schedule(); + if (test_thread_flag(TIF_SIGPENDING) || + test_thread_flag(TIF_NOTIFY_SIGNAL)) + do_signal(regs); + if (test_thread_flag(TIF_NOTIFY_RESUME)) + resume_user_mode_work(regs); +} + +int get_current_pid(void) +{ + return task_pid_nr(current); +} + +/* + * This is called magically, by its address being stuffed in a jmp_buf + * and being longjmp-d to. + */ +void new_thread_handler(void) +{ + int (*fn)(void *), n; + void *arg; + + if (current->thread.prev_sched != NULL) + schedule_tail(current->thread.prev_sched); + current->thread.prev_sched = NULL; + + fn = current->thread.request.u.thread.proc; + arg = current->thread.request.u.thread.arg; + + /* + * callback returns only if the kernel thread execs a process + */ + n = fn(arg); + userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); +} + +/* Called magically, see new_thread_handler above */ +void fork_handler(void) +{ + force_flush_all(); + + schedule_tail(current->thread.prev_sched); + + /* + * XXX: if interrupt_end() calls schedule, this call to + * arch_switch_to isn't needed. We could want to apply this to + * improve performance. -bb + */ + arch_switch_to(current); + + current->thread.prev_sched = NULL; + + userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs); +} + +int copy_thread(struct task_struct * p, const struct kernel_clone_args *args) +{ + unsigned long clone_flags = args->flags; + unsigned long sp = args->stack; + unsigned long tls = args->tls; + void (*handler)(void); + int ret = 0; + + p->thread = (struct thread_struct) INIT_THREAD; + + if (!args->fn) { + memcpy(&p->thread.regs.regs, current_pt_regs(), + sizeof(p->thread.regs.regs)); + PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0); + if (sp != 0) + REGS_SP(p->thread.regs.regs.gp) = sp; + + handler = fork_handler; + + arch_copy_thread(¤t->thread.arch, &p->thread.arch); + } else { + get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp); + p->thread.request.u.thread.proc = args->fn; + p->thread.request.u.thread.arg = args->fn_arg; + handler = new_thread_handler; + } + + new_thread(task_stack_page(p), &p->thread.switch_buf, handler); + + if (!args->fn) { + clear_flushed_tls(p); + + /* + * Set a new TLS for the child thread? + */ + if (clone_flags & CLONE_SETTLS) + ret = arch_set_tls(p, tls); + } + + return ret; +} + +void initial_thread_cb(void (*proc)(void *), void *arg) +{ + int save_kmalloc_ok = kmalloc_ok; + + kmalloc_ok = 0; + initial_thread_cb_skas(proc, arg); + kmalloc_ok = save_kmalloc_ok; +} + +void um_idle_sleep(void) +{ + if (time_travel_mode != TT_MODE_OFF) + time_travel_sleep(); + else + os_idle_sleep(); +} + +void arch_cpu_idle(void) +{ + cpu_tasks[current_thread_info()->cpu].pid = os_getpid(); + um_idle_sleep(); + raw_local_irq_enable(); +} + +int __cant_sleep(void) { + return in_atomic() || irqs_disabled() || in_interrupt(); + /* Is in_interrupt() really needed? */ +} + +int user_context(unsigned long sp) +{ + unsigned long stack; + + stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER); + return stack != (unsigned long) current_thread_info(); +} + +extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end; + +void do_uml_exitcalls(void) +{ + exitcall_t *call; + + call = &__uml_exitcall_end; + while (--call >= &__uml_exitcall_begin) + (*call)(); +} + +char *uml_strdup(const char *string) +{ + return kstrdup(string, GFP_KERNEL); +} +EXPORT_SYMBOL(uml_strdup); + +int copy_to_user_proc(void __user *to, void *from, int size) +{ + return copy_to_user(to, from, size); +} + +int copy_from_user_proc(void *to, void __user *from, int size) +{ + return copy_from_user(to, from, size); +} + +int clear_user_proc(void __user *buf, int size) +{ + return clear_user(buf, size); +} + +static atomic_t using_sysemu = ATOMIC_INIT(0); +int sysemu_supported; + +void set_using_sysemu(int value) +{ + if (value > sysemu_supported) + return; + atomic_set(&using_sysemu, value); +} + +int get_using_sysemu(void) +{ + return atomic_read(&using_sysemu); +} + +static int sysemu_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%d\n", get_using_sysemu()); + return 0; +} + +static int sysemu_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, sysemu_proc_show, NULL); +} + +static ssize_t sysemu_proc_write(struct file *file, const char __user *buf, + size_t count, loff_t *pos) +{ + char tmp[2]; + + if (copy_from_user(tmp, buf, 1)) + return -EFAULT; + + if (tmp[0] >= '0' && tmp[0] <= '2') + set_using_sysemu(tmp[0] - '0'); + /* We use the first char, but pretend to write everything */ + return count; +} + +static const struct proc_ops sysemu_proc_ops = { + .proc_open = sysemu_proc_open, + .proc_read = seq_read, + .proc_lseek = seq_lseek, + .proc_release = single_release, + .proc_write = sysemu_proc_write, +}; + +int __init make_proc_sysemu(void) +{ + struct proc_dir_entry *ent; + if (!sysemu_supported) + return 0; + + ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops); + + if (ent == NULL) + { + printk(KERN_WARNING "Failed to register /proc/sysemu\n"); + return 0; + } + + return 0; +} + +late_initcall(make_proc_sysemu); + +int singlestepping(void * t) +{ + struct task_struct *task = t ? t : current; + + if (!test_thread_flag(TIF_SINGLESTEP)) + return 0; + + if (task->thread.singlestep_syscall) + return 1; + + return 2; +} + +/* + * Only x86 and x86_64 have an arch_align_stack(). + * All other arches have "#define arch_align_stack(x) (x)" + * in their asm/exec.h + * As this is included in UML from asm-um/system-generic.h, + * we can use it to behave as the subarch does. + */ +#ifndef arch_align_stack +unsigned long arch_align_stack(unsigned long sp) +{ + if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + sp -= prandom_u32_max(8192); + return sp & ~0xf; +} +#endif + +unsigned long __get_wchan(struct task_struct *p) +{ + unsigned long stack_page, sp, ip; + bool seen_sched = 0; + + stack_page = (unsigned long) task_stack_page(p); + /* Bail if the process has no kernel stack for some reason */ + if (stack_page == 0) + return 0; + + sp = p->thread.switch_buf->JB_SP; + /* + * Bail if the stack pointer is below the bottom of the kernel + * stack for some reason + */ + if (sp < stack_page) + return 0; + + while (sp < stack_page + THREAD_SIZE) { + ip = *((unsigned long *) sp); + if (in_sched_functions(ip)) + /* Ignore everything until we're above the scheduler */ + seen_sched = 1; + else if (kernel_text_address(ip) && seen_sched) + return ip; + + sp += sizeof(unsigned long); + } + + return 0; +} + +int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu) +{ + int cpu = current_thread_info()->cpu; + + return save_i387_registers(userspace_pid[cpu], (unsigned long *) fpu); +} + |