The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
unless you really know what this hack does.
-config SMP
- bool "Symmetric multi-processing support"
- default n
- depends on BROKEN
- help
- This option enables UML SMP support.
- It is NOT related to having a real SMP box. Not directly, at least.
-
- UML implements virtual SMP by allowing as many processes to run
- simultaneously on the host as there are virtual processors configured.
-
- Obviously, if the host is a uniprocessor, those processes will
- timeshare, but, inside UML, will appear to be running simultaneously.
- If the host is a multiprocessor, then UML processes may run
- simultaneously, depending on the host scheduler.
-
- This, however, is supported only in TT mode. So, if you use the SKAS
- patch on your host, switching to TT mode and enabling SMP usually
- gives you worse performances.
- Also, since the support for SMP has been under-developed, there could
- be some bugs being exposed by enabling SMP.
-
- If you don't know what to do, say N.
-
-config NR_CPUS
- int "Maximum number of CPUs (2-32)"
- range 2 32
- depends on SMP
- default "32"
-
config HIGHMEM
bool "Highmem support"
depends on !64BIT && BROKEN
+++ /dev/null
-/*
- * 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
{
int index = 0;
-#ifdef CONFIG_SMP
- index = (struct cpuinfo_um *) v - cpu_data;
- if (!cpu_online(index))
- return 0;
-#endif
-
seq_printf(m, "processor\t: %d\n", index);
seq_printf(m, "vendor_id\t: User Mode Linux\n");
seq_printf(m, "model name\t: UML\n");
" this flag is not needed to run gdb on UML in skas mode\n\n"
);
-#ifdef CONFIG_SMP
-static int __init uml_ncpus_setup(char *line, int *add)
-{
- if (!sscanf(line, "%d", &ncpus)) {
- printf("Couldn't parse [%s]\n", line);
- return -1;
- }
-
- return 0;
-}
-
-__uml_setup("ncpus=", uml_ncpus_setup,
-"ncpus=<# of desired CPUs>\n"
-" This tells an SMP kernel how many virtual processors to start.\n\n"
-);
-#endif
-
static int __init Usage(char *line, int *add)
{
const char **p;
void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
{
}
-
-#ifdef CONFIG_SMP
-void alternatives_smp_module_add(struct module *mod, char *name,
- void *locks, void *locks_end,
- void *text, void *text_end)
-{
-}
-
-void alternatives_smp_module_del(struct module *mod)
-{
-}
-#endif
projects / karo-tx-linux.git / commitdiff