[uml-devel] 03_implement_ipis.diff

[Lennert B. <bu...@gn...>]

I know it's somewhat ugly right now.  I promise to clean it up in the
morning, honest :)


--- linux-2.4.17-3um-jeff/arch/um/kernel/irq_user.c	Thu Jan  3 02:24:46 2002
+++ linux-2.4.17-3um/arch/um/kernel/irq_user.c	Thu Jan  3 02:26:39 2002
@@ -41,6 +41,8 @@
 	struct irq_fd *irq_fd, *next;
 	int i, n;
 
+	IPI_handler(hard_smp_processor_id());
+
 	while(1){
 		if((n = poll(pollfds, pollfds_num, 0)) < 0){
 			if(errno == EINTR) continue;
@@ -65,6 +67,26 @@
 	}
 }
 
+int activate_ipi(int fd, int pid)
+{
+	int retval;
+
+	if((retval = fcntl(fd, F_SETFL, O_ASYNC | O_NONBLOCK)) < 0){
+		printk("Failed to set O_ASYNC and O_NONBLOCK on fd # %d, "
+			errno = %d\n", fd, errno);
+		return(-retval);
+	}
+
+	if(((retval = fcntl(fd, F_SETSIG, 0)) < 0) ||
+	   ((retval = fcntl(fd, F_SETOWN, pid)) < 0)){
+		printk("Failed to fcntl F_SETOWN (or F_SETSIG) "
+			fd %d to pid %d, errno = %d\n", fd, pid, errno);
+		return(-retval);
+	}
+
+	return(0);
+}
+
 int activate_fd(int irq, int fd, void *dev_id)
 {
 	struct irq_fd *new_fd;
@@ -204,6 +226,11 @@
 	irq = find_irq_by_fd(fd, &i);
 	if(irq == NULL) return;
 	pollfds[i].events = irq->events;
+}
+
+void forward_ipi(int fd, int pid)
+{
+	fcntl(fd, F_SETOWN, pid);
 }
 
 void forward_interrupts(int pid)
--- linux-2.4.17-3um-jeff/arch/um/kernel/process_kern.c	Thu Jan  3 01:55:25 2002
+++ linux-2.4.17-3um/arch/um/kernel/process_kern.c	Thu Jan  3 00:49:48 2002
@@ -238,6 +238,7 @@
 
 	to->thread.prev_sched = from;
 
+	forward_ipi(cpu_data[from->processor].ipi_pipe[0], to->thread.extern_pid);
 	forward_interrupts(to->thread.extern_pid);
 	block_signals();
 
--- linux-2.4.17-3um-jeff/arch/um/kernel/smp.c	Thu Jan  3 02:03:35 2002
+++ linux-2.4.17-3um/arch/um/kernel/smp.c	Thu Jan  3 02:08:21 2002
@@ -44,6 +44,7 @@
 
 void smp_send_reschedule(int cpu)
 {
+	write(cpu_data[cpu].ipi_pipe[1], "R", 1);
 	num_reschedules_sent++;
 }
 
@@ -101,15 +102,24 @@
 
 static int idle_proc(void *unused)
 {
+	int cpu;
+
 	set_current(current);
 	del_from_runqueue(current);
+	unhash_process(current);
+
+	cpu = current->processor;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, cpu_data[cpu].ipi_pipe) < 0)
+		panic("CPU#%d failed to create IPI pipe", cpu);
+
+	activate_ipi(cpu_data[cpu].ipi_pipe[0], current->thread.extern_pid);
 
+	wmb();
 	if (test_and_set_bit(current->processor, &smp_callin_map)) {
 		printk("huh, CPU#%d already present??\n", current->processor);
 		BUG();
 	}
 
-	printk("CPU#%d booting..\n", current->processor);
 	while (!atomic_read(&smp_commenced))
 		cpu_relax();
 
@@ -127,6 +137,10 @@
 	current->mm = &init_mm;
 	current->active_mm = &init_mm;
 
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, cpu_data[0].ipi_pipe) < 0)
+		panic("CPU#0 failed to create IPI pipe");
+	activate_ipi(cpu_data[0].ipi_pipe[0], current->thread.extern_pid);
+
 	if(ncpus < 1){
 		printk(KERN_INFO "ncpus set to 1\n");
 		ncpus = 1;
@@ -174,12 +188,83 @@
 	return(0);
 }
 
-int inited_cpus = 1;
 
 
+#include <sys/poll.h>
+
+void smp_call_function_slave(int cpu);
+
+void IPI_handler(int cpu)
+{
+	struct pollfd fd;
+
+	fd.fd = cpu_data[cpu].ipi_pipe[0];
+	fd.events = POLLIN;
+	while (poll(&fd, 1, 0)) {
+		unsigned char c;
+
+		if (read(fd.fd, &c, 1) != 1) {
+			printk("Failed to read from IPI pipe on CPU#%d\n", cpu);
+			return;
+		}
+
+		switch (c) {
+		case 'C':
+			smp_call_function_slave(cpu);
+			break;
+
+		case 'R':
+			current->need_resched = 1;
+			break;
+
+		default:
+			printk("CPU#%d received unknown IPI [%c]!\n", cpu, c);
+			break;
+		}
+	}
+}
+
+
+int inited_cpus = 1;
+
 int hard_smp_processor_id(void)
 {
 	return(pid_to_processor_id(getpid()));
+}
+
+
+/*****/
+static void (*func)(void *info);
+static void *info;
+static unsigned long smp_call_function_callin_map;
+
+void smp_call_function_slave(int cpu)
+{
+	(*func)(info);
+	clear_bit(cpu, &smp_call_function_callin_map);
+}
+
+int smp_call_function(void (*_func)(void *info), void *_info, int nonatomic, in
+t wait)
+{
+	int me = current->processor;
+	int i;
+
+	/* @@@@ need locking here */
+	func = _func;
+	info = _info;
+
+	smp_call_function_callin_map = cpu_online_map;
+	clear_bit(me, &smp_call_function_callin_map);
+
+	for (i=0;i<NR_CPUS;i++)
+		if (test_bit(i, &smp_call_function_callin_map))
+			write(cpu_data[i].ipi_pipe[1], "C", 1);
+
+	while (smp_call_function_callin_map)
+		cpu_relax();
+
+	return 0;
 }
 #endif
 
--- linux-2.4.17-3um-jeff/include/asm-um/processor-generic.h	Thu Jan  3 02:18:00 2002
+++ linux-2.4.17-3um/include/asm-um/processor-generic.h	Wed Jan  2 23:21:36 2002
@@ -162,6 +162,7 @@
 	unsigned long *pmd_quick;
 	unsigned long *pte_quick;
 	unsigned long pgtable_cache_sz;  
+	int ipi_pipe[2];
 };
 
 extern struct cpuinfo_um boot_cpu_data;