Merge with ../linux-2.6-smp

arch/arm/kernel/head.S

@@ -2,6 +2,8 @@
  *  linux/arch/arm/kernel/head.S
  *
  *  Copyright (C) 1994-2002 Russell King
+ *  Copyright (c) 2003 ARM Limited
+ *  All Rights Reserved
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -165,6 +167,48 @@ __mmap_switched:
 	stmia	r6, {r0, r4}			@ Save control register values
 	b	start_kernel
 
+#if defined(CONFIG_SMP)
+	.type   secondary_startup, #function
+ENTRY(secondary_startup)
+	/*
+	 * Common entry point for secondary CPUs.
+	 *
+	 * Ensure that we're in SVC mode, and IRQs are disabled.  Lookup
+	 * the processor type - there is no need to check the machine type
+	 * as it has already been validated by the primary processor.
+	 */
+	msr	cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC
+	bl	__lookup_processor_type
+	movs	r10, r5				@ invalid processor?
+	moveq	r0, #'p'			@ yes, error 'p'
+	beq	__error
+
+	/*
+	 * Use the page tables supplied from  __cpu_up.
+	 */
+	adr	r4, __secondary_data
+	ldmia	r4, {r5, r6, r13}		@ address to jump to after
+	sub	r4, r4, r5			@ mmu has been enabled
+	ldr	r4, [r6, r4]			@ get secondary_data.pgdir
+	adr	lr, __enable_mmu		@ return address
+	add	pc, r10, #12			@ initialise processor
+						@ (return control reg)
+
+	/*
+	 * r6  = &secondary_data
+	 */
+ENTRY(__secondary_switched)
+	ldr	sp, [r6, #4]			@ get secondary_data.stack
+	mov	fp, #0
+	b	secondary_start_kernel
+
+	.type	__secondary_data, %object
+__secondary_data:
+	.long	.
+	.long	secondary_data
+	.long	__secondary_switched
+#endif /* defined(CONFIG_SMP) */
+
 
 
 /*

arch/arm/kernel/smp.c

@@ -24,6 +24,9 @@
 #include <asm/atomic.h>
 #include <asm/cacheflush.h>
 #include <asm/cpu.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
 #include <asm/ptrace.h>
@@ -36,6 +39,13 @@
 cpumask_t cpu_present_mask;
 cpumask_t cpu_online_map;
 
+/*
+ * as from 2.5, kernels no longer have an init_tasks structure
+ * so we need some other way of telling a new secondary core
+ * where to place its SVC stack
+ */
+struct secondary_data secondary_data;
+
 /*
  * structures for inter-processor calls
  * - A collection of single bit ipi messages.
@@ -71,6 +81,8 @@ static DEFINE_SPINLOCK(smp_call_function_lock);
 int __init __cpu_up(unsigned int cpu)
 {
 	struct task_struct *idle;
+	pgd_t *pgd;
+	pmd_t *pmd;
 	int ret;
 
 	/*
@@ -83,10 +95,55 @@ int __init __cpu_up(unsigned int cpu)
 		return PTR_ERR(idle);
 	}
 
+	/*
+	 * Allocate initial page tables to allow the new CPU to
+	 * enable the MMU safely.  This essentially means a set
+	 * of our "standard" page tables, with the addition of
+	 * a 1:1 mapping for the physical address of the kernel.
+	 */
+	pgd = pgd_alloc(&init_mm);
+	pmd = pmd_offset(pgd, PHYS_OFFSET);
+	*pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) |
+		     PMD_TYPE_SECT | PMD_SECT_AP_WRITE);
+
+	/*
+	 * We need to tell the secondary core where to find
+	 * its stack and the page tables.
+	 */
+	secondary_data.stack = (void *)idle->thread_info + THREAD_SIZE - 8;
+	secondary_data.pgdir = virt_to_phys(pgd);
+	wmb();
+
 	/*
 	 * Now bring the CPU into our world.
 	 */
 	ret = boot_secondary(cpu, idle);
+	if (ret == 0) {
+		unsigned long timeout;
+
+		/*
+		 * CPU was successfully started, wait for it
+		 * to come online or time out.
+		 */
+		timeout = jiffies + HZ;
+		while (time_before(jiffies, timeout)) {
+			if (cpu_online(cpu))
+				break;
+
+			udelay(10);
+			barrier();
+		}
+
+		if (!cpu_online(cpu))
+			ret = -EIO;
+	}
+
+	secondary_data.stack = 0;
+	secondary_data.pgdir = 0;
+
+	*pmd_offset(pgd, PHYS_OFFSET) = __pmd(0);
+	pgd_free(pgd);
+
 	if (ret) {
 		printk(KERN_CRIT "cpu_up: processor %d failed to boot\n", cpu);
 		/*
@@ -97,6 +154,56 @@ int __init __cpu_up(unsigned int cpu)
 	return ret;
 }
 
+/*
+ * This is the secondary CPU boot entry.  We're using this CPUs
+ * idle thread stack, but a set of temporary page tables.
+ */
+asmlinkage void __init secondary_start_kernel(void)
+{
+	struct mm_struct *mm = &init_mm;
+	unsigned int cpu = smp_processor_id();
+
+	printk("CPU%u: Booted secondary processor\n", cpu);
+
+	/*
+	 * All kernel threads share the same mm context; grab a
+	 * reference and switch to it.
+	 */
+	atomic_inc(&mm->mm_users);
+	atomic_inc(&mm->mm_count);
+	current->active_mm = mm;
+	cpu_set(cpu, mm->cpu_vm_mask);
+	cpu_switch_mm(mm->pgd, mm);
+	enter_lazy_tlb(mm, current);
+
+	cpu_init();
+
+	/*
+	 * Give the platform a chance to do its own initialisation.
+	 */
+	platform_secondary_init(cpu);
+
+	/*
+	 * Enable local interrupts.
+	 */
+	local_irq_enable();
+	local_fiq_enable();
+
+	calibrate_delay();
+
+	smp_store_cpu_info(cpu);
+
+	/*
+	 * OK, now it's safe to let the boot CPU continue
+	 */
+	cpu_set(cpu, cpu_online_map);
+
+	/*
+	 * OK, it's off to the idle thread for us
+	 */
+	cpu_idle();
+}
+
 /*
  * Called by both boot and secondaries to move global data into
  * per-processor storage.

arch/arm/mach-integrator/Makefile

@@ -12,3 +12,4 @@ obj-$(CONFIG_LEDS)			+= leds.o
 obj-$(CONFIG_PCI)			+= pci_v3.o pci.o
 obj-$(CONFIG_CPU_FREQ_INTEGRATOR)	+= cpu.o
 obj-$(CONFIG_INTEGRATOR_IMPD1)		+= impd1.o
+obj-$(CONFIG_SMP)			+= platsmp.o headsmp.o

arch/arm/mach-integrator/core.c

@@ -14,6 +14,7 @@
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/sched.h>
+#include <linux/smp.h>
 
 #include <asm/hardware.h>
 #include <asm/irq.h>
@@ -221,7 +222,24 @@ integrator_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	 */
 	timer1->TimerClear = 1;
 
-	timer_tick(regs);
+	/*
+	 * the clock tick routines are only processed on the
+	 * primary CPU
+	 */
+	if (hard_smp_processor_id() == 0) {
+		nmi_tick();
+		timer_tick(regs);
+#ifdef CONFIG_SMP
+		smp_send_timer();
+#endif
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * this is the ARM equivalent of the APIC timer interrupt
+	 */
+	update_process_times(user_mode(regs));
+#endif /* CONFIG_SMP */
 
 	write_sequnlock(&xtime_lock);
 

arch/arm/mach-integrator/headsmp.S

+/*
+ *  linux/arch/arm/mach-integrator/headsmp.S
+ *
+ *  Copyright (c) 2003 ARM Limited
+ *  All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+	__INIT
+
+/*
+ * Integrator specific entry point for secondary CPUs.  This provides
+ * a "holding pen" into which all secondary cores are held until we're
+ * ready for them to initialise.
+ */
+ENTRY(integrator_secondary_startup)
+	adr	r4, 1f
+	ldmia	r4, {r5, r6}
+	sub	r4, r4, r5
+	ldr	r6, [r6, r4]
+pen:	ldr	r7, [r6]
+	cmp	r7, r0
+	bne	pen
+
+	/*
+	 * we've been released from the holding pen: secondary_stack
+	 * should now contain the SVC stack for this core
+	 */
+	b	secondary_startup
+
+1:	.long	.
+	.long	phys_pen_release

arch/arm/mach-integrator/leds.c

@@ -22,6 +22,8 @@
  */
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
 
 #include <asm/hardware.h>
 #include <asm/io.h>
@@ -85,4 +87,4 @@ static int __init leds_init(void)
 	return 0;
 }
 
-__initcall(leds_init);
+core_initcall(leds_init);

arch/arm/mach-integrator/platsmp.c

+/*
+ *  linux/arch/arm/mach-cintegrator/platsmp.c
+ *
+ *  Copyright (C) 2002 ARM Ltd.
+ *  All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+
+#include <asm/atomic.h>
+#include <asm/delay.h>
+#include <asm/mmu_context.h>
+#include <asm/procinfo.h>
+#include <asm/ptrace.h>
+#include <asm/smp.h>
+
+extern void integrator_secondary_startup(void);
+
+/*
+ * control for which core is the next to come out of the secondary
+ * boot "holding pen"
+ */
+volatile int __initdata pen_release = -1;
+unsigned long __initdata phys_pen_release = 0;
+
+static DEFINE_SPINLOCK(boot_lock);
+
+void __init platform_secondary_init(unsigned int cpu)
+{
+	/*
+	 * the primary core may have used a "cross call" soft interrupt
+	 * to get this processor out of WFI in the BootMonitor - make
+	 * sure that we are no longer being sent this soft interrupt
+	 */
+	smp_cross_call_done(cpumask_of_cpu(cpu));
+
+	/*
+	 * if any interrupts are already enabled for the primary
+	 * core (e.g. timer irq), then they will not have been enabled
+	 * for us: do so
+	 */
+	secondary_scan_irqs();
+
+	/*
+	 * let the primary processor know we're out of the
+	 * pen, then head off into the C entry point
+	 */
+	pen_release = -1;
+
+	/*
+	 * Synchronise with the boot thread.
+	 */
+	spin_lock(&boot_lock);
+	spin_unlock(&boot_lock);
+}
+
+int __init boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	unsigned long timeout;
+
+	/*
+	 * set synchronisation state between this boot processor
+	 * and the secondary one
+	 */
+	spin_lock(&boot_lock);
+
+	/*
+	 * The secondary processor is waiting to be released from
+	 * the holding pen - release it, then wait for it to flag
+	 * that it has been released by resetting pen_release.
+	 *
+	 * Note that "pen_release" is the hardware CPU ID, whereas
+	 * "cpu" is Linux's internal ID.
+	 */
+	pen_release = cpu;
+
+	/*
+	 * XXX
+	 *
+	 * This is a later addition to the booting protocol: the
+	 * bootMonitor now puts secondary cores into WFI, so
+	 * poke_milo() no longer gets the cores moving; we need
+	 * to send a soft interrupt to wake the secondary core.
+	 * Use smp_cross_call() for this, since there's little
+	 * point duplicating the code here
+	 */
+	smp_cross_call(cpumask_of_cpu(cpu));
+
+	timeout = jiffies + (1 * HZ);
+	while (time_before(jiffies, timeout)) {
+		if (pen_release == -1)
+			break;
+
+		udelay(10);
+	}
+
+	/*
+	 * now the secondary core is starting up let it run its
+	 * calibrations, then wait for it to finish
+	 */
+	spin_unlock(&boot_lock);
+
+	return pen_release != -1 ? -ENOSYS : 0;
+}
+
+static void __init poke_milo(void)
+{
+	extern void secondary_startup(void);
+
+	/* nobody is to be released from the pen yet */
+	pen_release = -1;
+
+	phys_pen_release = virt_to_phys(&pen_release);
+
+	/*
+	 * write the address of secondary startup into the system-wide
+	 * flags register, then clear the bottom two bits, which is what
+	 * BootMonitor is waiting for
+	 */
+#if 1
+#define CINTEGRATOR_HDR_FLAGSS_OFFSET 0x30
+	__raw_writel(virt_to_phys(integrator_secondary_startup),
+		     (IO_ADDRESS(INTEGRATOR_HDR_BASE) +
+		      CINTEGRATOR_HDR_FLAGSS_OFFSET));
+#define CINTEGRATOR_HDR_FLAGSC_OFFSET 0x34
+	__raw_writel(3,
+		     (IO_ADDRESS(INTEGRATOR_HDR_BASE) +
+		      CINTEGRATOR_HDR_FLAGSC_OFFSET));
+#endif
+
+	mb();
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned int ncores = get_core_count();
+	unsigned int cpu = smp_processor_id();
+	int i;
+
+	/* sanity check */
+	if (ncores == 0) {
+		printk(KERN_ERR
+		       "Integrator/CP: strange CM count of 0? Default to 1\n");
+
+		ncores = 1;
+	}
+
+	if (ncores > NR_CPUS) {
+		printk(KERN_WARNING
+		       "Integrator/CP: no. of cores (%d) greater than configured "
+		       "maximum of %d - clipping\n",
+		       ncores, NR_CPUS);
+		ncores = NR_CPUS;
+	}
+
+	/*
+	 * start with some more config for the Boot CPU, now that
+	 * the world is a bit more alive (which was not the case
+	 * when smp_prepare_boot_cpu() was called)
+	 */
+	smp_store_cpu_info(cpu);
+
+	/*
+	 * are we trying to boot more cores than exist?
+	 */
+	if (max_cpus > ncores)
+		max_cpus = ncores;
+
+	/*
+	 * Initialise the present mask - this tells us which CPUs should
+	 * be present.
+	 */
+	for (i = 0; i < max_cpus; i++) {
+		cpu_set(i, cpu_present_mask);
+	}
+
+	/*
+	 * Do we need any more CPUs? If so, then let them know where
+	 * to start. Note that, on modern versions of MILO, the "poke"
+	 * doesn't actually do anything until each individual core is
+	 * sent a soft interrupt to get it out of WFI
+	 */
+	if (max_cpus > 1)
+		poke_milo();
+}

include/asm-arm/arch-integrator/smp.h

+#ifndef ASMARM_ARCH_SMP_H
+#define ASMARM_ARCH_SMP_H
+
+#include <linux/config.h>
+
+#include <asm/arch/hardware.h>
+#include <asm/io.h>
+
+#define hard_smp_processor_id()				\
+	({						\
+		unsigned int cpunum;			\
+		__asm__("mrc p15, 0, %0, c0, c0, 5"	\
+			: "=r" (cpunum));		\
+		cpunum &= 0x0F;				\
+	})
+
+extern void secondary_scan_irqs(void);
+
+#endif

include/asm-arm/smp.h

@@ -55,4 +55,18 @@ extern void smp_cross_call(cpumask_t callmap);
  */
 extern int boot_secondary(unsigned int cpu, struct task_struct *);
 
+/*
+ * Perform platform specific initialisation of the specified CPU.
+ */
+extern void platform_secondary_init(unsigned int cpu);
+
+/*
+ * Initial data for bringing up a secondary CPU.
+ */
+struct secondary_data {
+	unsigned long pgdir;
+	void *stack;
+};
+extern struct secondary_data secondary_data;
+
 #endif /* ifndef __ASM_ARM_SMP_H */