Fixed MTP to work with TWRP

arch/um/kernel/smp.c

@@ -0,0 +1,238 @@
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/percpu.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+
+#ifdef CONFIG_SMP
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/threads.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/hardirq.h>
+#include <asm/smp.h>
+#include <asm/processor.h>
+#include <asm/spinlock.h>
+#include <kern.h>
+#include <irq_user.h>
+#include <os.h>
+
+/* Per CPU bogomips and other parameters
+ * The only piece used here is the ipi pipe, which is set before SMP is
+ * started and never changed.
+ */
+struct cpuinfo_um cpu_data[NR_CPUS];
+
+/* A statistic, can be a little off */
+int num_reschedules_sent = 0;
+
+/* Not changed after boot */
+struct task_struct *idle_threads[NR_CPUS];
+
+void smp_send_reschedule(int cpu)
+{
+	os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
+	num_reschedules_sent++;
+}
+
+void smp_send_stop(void)
+{
+	int i;
+
+	printk(KERN_INFO "Stopping all CPUs...");
+	for (i = 0; i < num_online_cpus(); i++) {
+		if (i == current_thread->cpu)
+			continue;
+		os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
+	}
+	printk(KERN_CONT "done\n");
+}
+
+static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
+static cpumask_t cpu_callin_map = CPU_MASK_NONE;
+
+static int idle_proc(void *cpup)
+{
+	int cpu = (int) cpup, err;
+
+	err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
+	if (err < 0)
+		panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
+
+	os_set_fd_async(cpu_data[cpu].ipi_pipe[0]);
+
+	wmb();
+	if (cpu_test_and_set(cpu, cpu_callin_map)) {
+		printk(KERN_ERR "huh, CPU#%d already present??\n", cpu);
+		BUG();
+	}
+
+	while (!cpu_isset(cpu, smp_commenced_mask))
+		cpu_relax();
+
+	notify_cpu_starting(cpu);
+	set_cpu_online(cpu, true);
+	default_idle();
+	return 0;
+}
+
+static struct task_struct *idle_thread(int cpu)
+{
+	struct task_struct *new_task;
+
+	current->thread.request.u.thread.proc = idle_proc;
+	current->thread.request.u.thread.arg = (void *) cpu;
+	new_task = fork_idle(cpu);
+	if (IS_ERR(new_task))
+		panic("copy_process failed in idle_thread, error = %ld",
+		      PTR_ERR(new_task));
+
+	cpu_tasks[cpu] = ((struct cpu_task)
+		          { .pid = 	new_task->thread.mode.tt.extern_pid,
+			    .task = 	new_task } );
+	idle_threads[cpu] = new_task;
+	panic("skas mode doesn't support SMP");
+	return new_task;
+}
+
+void smp_prepare_cpus(unsigned int maxcpus)
+{
+	struct task_struct *idle;
+	unsigned long waittime;
+	int err, cpu, me = smp_processor_id();
+	int i;
+
+	for (i = 0; i < ncpus; ++i)
+		set_cpu_possible(i, true);
+
+	set_cpu_online(me, true);
+	cpu_set(me, cpu_callin_map);
+
+	err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
+	if (err < 0)
+		panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
+
+	os_set_fd_async(cpu_data[me].ipi_pipe[0]);
+
+	for (cpu = 1; cpu < ncpus; cpu++) {
+		printk(KERN_INFO "Booting processor %d...\n", cpu);
+
+		idle = idle_thread(cpu);
+
+		init_idle(idle, cpu);
+
+		waittime = 200000000;
+		while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
+			cpu_relax();
+
+		printk(KERN_INFO "%s\n",
+		       cpu_isset(cpu, cpu_calling_map) ? "done" : "failed");
+	}
+}
+
+void smp_prepare_boot_cpu(void)
+{
+	set_cpu_online(smp_processor_id(), true);
+}
+
+int __cpu_up(unsigned int cpu, struct task_struct *tidle)
+{
+	cpu_set(cpu, smp_commenced_mask);
+	while (!cpu_online(cpu))
+		mb();
+	return 0;
+}
+
+int setup_profiling_timer(unsigned int multiplier)
+{
+	printk(KERN_INFO "setup_profiling_timer\n");
+	return 0;
+}
+
+void smp_call_function_slave(int cpu);
+
+void IPI_handler(int cpu)
+{
+	unsigned char c;
+	int fd;
+
+	fd = cpu_data[cpu].ipi_pipe[0];
+	while (os_read_file(fd, &c, 1) == 1) {
+		switch (c) {
+		case 'C':
+			smp_call_function_slave(cpu);
+			break;
+
+		case 'R':
+			scheduler_ipi();
+			break;
+
+		case 'S':
+			printk(KERN_INFO "CPU#%d stopping\n", cpu);
+			while (1)
+				pause();
+			break;
+
+		default:
+			printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n",
+			       cpu, c);
+			break;
+		}
+	}
+}
+
+int hard_smp_processor_id(void)
+{
+	return pid_to_processor_id(os_getpid());
+}
+
+static DEFINE_SPINLOCK(call_lock);
+static atomic_t scf_started;
+static atomic_t scf_finished;
+static void (*func)(void *info);
+static void *info;
+
+void smp_call_function_slave(int cpu)
+{
+	atomic_inc(&scf_started);
+	(*func)(info);
+	atomic_inc(&scf_finished);
+}
+
+int smp_call_function(void (*_func)(void *info), void *_info, int wait)
+{
+	int cpus = num_online_cpus() - 1;
+	int i;
+
+	if (!cpus)
+		return 0;
+
+	/* Can deadlock when called with interrupts disabled */
+	WARN_ON(irqs_disabled());
+
+	spin_lock_bh(&call_lock);
+	atomic_set(&scf_started, 0);
+	atomic_set(&scf_finished, 0);
+	func = _func;
+	info = _info;
+
+	for_each_online_cpu(i)
+		os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
+
+	while (atomic_read(&scf_started) != cpus)
+		barrier();
+
+	if (wait)
+		while (atomic_read(&scf_finished) != cpus)
+			barrier();
+
+	spin_unlock_bh(&call_lock);
+	return 0;
+}
+
+#endif