[PATCH] swsusp: preparation for smp support & fix device suspending

It fixes levels for calling driver model, puts devices into sleep before
powering down (so that emergency parking does not happen), and actually
introduces SMP support, but its disabled for now.  Plus noone should try to
freeze_processes() when thats not implemented, we now BUG()s -- we do not
want Heisenbugs.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/suspend.c

@@ -35,40 +35,45 @@ unsigned long saved_context_r08, saved_context_r09, saved_context_r10, saved_con
 unsigned long saved_context_r12, saved_context_r13, saved_context_r14, saved_context_r15;
 unsigned long saved_context_eflags;
 
-void save_processor_state (void)
+void __save_processor_state(struct saved_context *ctxt)
 {
 	kernel_fpu_begin();
 
 	/*
 	 * descriptor tables
 	 */
-	asm volatile ("sgdt %0" : "=m" (saved_context.gdt_limit));
-	asm volatile ("sidt %0" : "=m" (saved_context.idt_limit));
-	asm volatile ("sldt %0" : "=m" (saved_context.ldt));
-	asm volatile ("str %0"  : "=m" (saved_context.tr));
+	asm volatile ("sgdt %0" : "=m" (ctxt->gdt_limit));
+	asm volatile ("sidt %0" : "=m" (ctxt->idt_limit));
+	asm volatile ("sldt %0" : "=m" (ctxt->ldt));
+	asm volatile ("str %0"  : "=m" (ctxt->tr));
 
 	/* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
 	/* EFER should be constant for kernel version, no need to handle it. */
 	/*
 	 * segment registers
 	 */
-	asm volatile ("movw %%ds, %0" : "=m" (saved_context.ds));
-	asm volatile ("movw %%es, %0" : "=m" (saved_context.es));
-	asm volatile ("movw %%fs, %0" : "=m" (saved_context.fs));
-	asm volatile ("movw %%gs, %0" : "=m" (saved_context.gs));
-	asm volatile ("movw %%ss, %0" : "=m" (saved_context.ss));
+	asm volatile ("movw %%ds, %0" : "=m" (ctxt->ds));
+	asm volatile ("movw %%es, %0" : "=m" (ctxt->es));
+	asm volatile ("movw %%fs, %0" : "=m" (ctxt->fs));
+	asm volatile ("movw %%gs, %0" : "=m" (ctxt->gs));
+	asm volatile ("movw %%ss, %0" : "=m" (ctxt->ss));
 
-	rdmsrl(MSR_FS_BASE, saved_context.fs_base);
-	rdmsrl(MSR_GS_BASE, saved_context.gs_base);
-	rdmsrl(MSR_KERNEL_GS_BASE, saved_context.gs_kernel_base);
+	rdmsrl(MSR_FS_BASE, ctxt->fs_base);
+	rdmsrl(MSR_GS_BASE, ctxt->gs_base);
+	rdmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
 
 	/*
 	 * control registers 
 	 */
-	asm volatile ("movq %%cr0, %0" : "=r" (saved_context.cr0));
-	asm volatile ("movq %%cr2, %0" : "=r" (saved_context.cr2));
-	asm volatile ("movq %%cr3, %0" : "=r" (saved_context.cr3));
-	asm volatile ("movq %%cr4, %0" : "=r" (saved_context.cr4));
+	asm volatile ("movq %%cr0, %0" : "=r" (ctxt->cr0));
+	asm volatile ("movq %%cr2, %0" : "=r" (ctxt->cr2));
+	asm volatile ("movq %%cr3, %0" : "=r" (ctxt->cr3));
+	asm volatile ("movq %%cr4, %0" : "=r" (ctxt->cr4));
+}
+
+void save_processor_state(void)
+{
+	__save_processor_state(&saved_context);
 }
 
 static void
@@ -80,42 +85,47 @@ do_fpu_end(void)
 	mxcsr_feature_mask_init();
 }
 
-void restore_processor_state(void)
+void __restore_processor_state(struct saved_context *ctxt)
 {
 	/*
 	 * control registers
 	 */
-	asm volatile ("movq %0, %%cr4" :: "r" (saved_context.cr4));
-	asm volatile ("movq %0, %%cr3" :: "r" (saved_context.cr3));
-	asm volatile ("movq %0, %%cr2" :: "r" (saved_context.cr2));
-	asm volatile ("movq %0, %%cr0" :: "r" (saved_context.cr0));
+	asm volatile ("movq %0, %%cr4" :: "r" (ctxt->cr4));
+	asm volatile ("movq %0, %%cr3" :: "r" (ctxt->cr3));
+	asm volatile ("movq %0, %%cr2" :: "r" (ctxt->cr2));
+	asm volatile ("movq %0, %%cr0" :: "r" (ctxt->cr0));
 
 	/*
 	 * segment registers
 	 */
-	asm volatile ("movw %0, %%ds" :: "r" (saved_context.ds));
-	asm volatile ("movw %0, %%es" :: "r" (saved_context.es));
-	asm volatile ("movw %0, %%fs" :: "r" (saved_context.fs));
-	load_gs_index(saved_context.gs);
-	asm volatile ("movw %0, %%ss" :: "r" (saved_context.ss));
+	asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds));
+	asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
+	asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));
+	load_gs_index(ctxt->gs);
+	asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss));
 
-	wrmsrl(MSR_FS_BASE, saved_context.fs_base);
-	wrmsrl(MSR_GS_BASE, saved_context.gs_base);
-	wrmsrl(MSR_KERNEL_GS_BASE, saved_context.gs_kernel_base);
+	wrmsrl(MSR_FS_BASE, ctxt->fs_base);
+	wrmsrl(MSR_GS_BASE, ctxt->gs_base);
+	wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
 
 	/*
 	 * now restore the descriptor tables to their proper values
 	 * ltr is done i fix_processor_context().
 	 */
-	asm volatile ("lgdt %0" :: "m" (saved_context.gdt_limit));
-	asm volatile ("lidt %0" :: "m" (saved_context.idt_limit));
-	asm volatile ("lldt %0" :: "m" (saved_context.ldt));
+	asm volatile ("lgdt %0" :: "m" (ctxt->gdt_limit));
+	asm volatile ("lidt %0" :: "m" (ctxt->idt_limit));
+	asm volatile ("lldt %0" :: "m" (ctxt->ldt));
 
 	fix_processor_context();
 
 	do_fpu_end();
 }
 
+void restore_processor_state(void)
+{
+	__restore_processor_state(&saved_context);
+}
+
 void fix_processor_context(void)
 {
 	int cpu = smp_processor_id();

include/asm-i386/suspend.h

@@ -36,9 +36,6 @@ struct saved_context {
                        : /* no output */ \
                        :"r" ((thread)->debugreg[register]))
 
-extern void save_processor_state(void);
-extern void restore_processor_state(void);
-
 #ifdef CONFIG_ACPI_SLEEP
 extern unsigned long saved_eip;
 extern unsigned long saved_esp;

include/asm-x86_64/suspend.h

@@ -38,7 +38,6 @@ extern unsigned long saved_context_r08, saved_context_r09, saved_context_r10, sa
 extern unsigned long saved_context_r12, saved_context_r13, saved_context_r14, saved_context_r15;
 extern unsigned long saved_context_eflags;
 
-
 #define loaddebug(thread,register) \
                __asm__("movq %0,%%db" #register  \
                        : /* no output */ \

include/linux/suspend.h

@@ -67,24 +67,27 @@ extern int pm_prepare_console(void);
 extern void pm_restore_console(void);
 
 #else
-static inline void refrigerator(unsigned long flag)
-{
-
-}
-static inline int freeze_processes(void)
-{
-	return 0;
-}
-static inline void thaw_processes(void)
-{
-
-}
+static inline void refrigerator(unsigned long flag) {}
 #endif	/* CONFIG_PM */
 
+#ifdef CONFIG_SMP
+extern void disable_nonboot_cpus(void);
+extern void enable_nonboot_cpus(void);
+#else
+static inline void disable_nonboot_cpus(void) {}
+static inline void enable_nonboot_cpus(void) {}
+#endif
+
 asmlinkage void do_magic(int is_resume);
 asmlinkage void do_magic_resume_1(void);
 asmlinkage void do_magic_resume_2(void);
 asmlinkage void do_magic_suspend_1(void);
 asmlinkage void do_magic_suspend_2(void);
 
+void save_processor_state(void);
+void restore_processor_state(void);
+struct saved_context;
+void __save_processor_state(struct saved_context *ctxt);
+void __restore_processor_state(struct saved_context *ctxt);
+
 #endif /* _LINUX_SWSUSP_H */

kernel/power/Makefile

 obj-y				:= main.o process.o console.o pm.o
+obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o
 obj-$(CONFIG_PM_DISK)		+= disk.o pmdisk.o
 

kernel/power/smp.c

+/*
+ * drivers/power/smp.c - Functions for stopping other CPUs.
+ *
+ * Copyright 2004 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2002-2003 Nigel Cunningham <ncunningham@clear.net.nz>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#undef DEBUG
+
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/suspend.h>
+#include <linux/module.h>
+#include <asm/atomic.h>
+#include <asm/tlbflush.h>
+
+static atomic_t cpu_counter, freeze;
+
+
+static void smp_pause(void * data)
+{
+	struct saved_context ctxt;
+	__save_processor_state(&ctxt);
+	printk("Sleeping in:\n");
+	dump_stack();
+	atomic_inc(&cpu_counter);
+	while (atomic_read(&freeze)) {
+		/* FIXME: restore takes place at random piece inside this.
+		   This should probably be written in assembly, and
+		   preserve general-purpose registers, too
+
+		   What about stack? We may need to move to new stack here.
+
+		   This should better be ran with interrupts disabled.
+		 */
+		cpu_relax();
+		barrier();
+	}
+	atomic_dec(&cpu_counter);
+	__restore_processor_state(&ctxt);
+}
+
+cpumask_t oldmask;
+
+void disable_nonboot_cpus(void)
+{
+	printk("Freezing CPUs (at %d)", smp_processor_id());
+	oldmask = current->cpus_allowed;
+	set_cpus_allowed(current, cpumask_of_cpu(0));
+	current->state = TASK_INTERRUPTIBLE;
+	schedule_timeout(HZ);
+	printk("...");
+	BUG_ON(smp_processor_id() != 0);
+
+	/* FIXME: for this to work, all the CPUs must be running
+	 * "idle" thread (or we deadlock). Is that guaranteed? */
+
+	atomic_set(&cpu_counter, 0);
+	atomic_set(&freeze, 1);
+	smp_call_function(smp_pause, NULL, 0, 0);
+	while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) {
+		cpu_relax();
+		barrier();
+	}
+	printk("ok\n");
+}
+
+void enable_nonboot_cpus(void)
+{
+	printk("Restarting CPUs");
+	atomic_set(&freeze, 0);
+	while (atomic_read(&cpu_counter)) {
+		cpu_relax();
+		barrier();
+	}
+	printk("...");
+	set_cpus_allowed(current, oldmask);
+	schedule();
+	printk("ok\n");
+
+}
+
+

kernel/power/swsusp.c

@@ -696,6 +696,7 @@ static void suspend_power_down(void)
 	else
 #endif
 	{
+		device_suspend(3);
 		device_shutdown();
 		machine_power_off();
 	}
@@ -716,7 +717,7 @@ asmlinkage void do_magic_resume_1(void)
 	mb();
 	spin_lock_irq(&suspend_pagedir_lock);	/* Done to disable interrupts */ 
 
-	device_power_down(4);
+	device_power_down(3);
 	PRINTK( "Waiting for DMAs to settle down...\n");
 	mdelay(1000);	/* We do not want some readahead with DMA to corrupt our memory, right?
 			   Do it with disabled interrupts for best effect. That way, if some
@@ -785,7 +786,7 @@ asmlinkage void do_magic_suspend_2(void)
 {
 	int is_problem;
 	read_swapfiles();
-	device_power_down(4);
+	device_power_down(3);
 	is_problem = suspend_prepare_image();
 	device_power_up();
 	spin_unlock_irq(&suspend_pagedir_lock);
@@ -802,7 +803,6 @@ asmlinkage void do_magic_suspend_2(void)
 	barrier();
 	mb();
 	spin_lock_irq(&suspend_pagedir_lock);	/* Done to disable interrupts */ 
-	mdelay(1000);
 
 	free_pages((unsigned long) pagedir_nosave, pagedir_order);
 	spin_unlock_irq(&suspend_pagedir_lock);
@@ -839,9 +839,10 @@ int software_suspend(void)
                    need half of memory free. */
 
 		free_some_memory();
-		
-		/* Save state of all device drivers, and stop them. */		   
-		if ((res = device_suspend(4))==0)
+		disable_nonboot_cpus();
+		/* Save state of all device drivers, and stop them. */
+		printk("Suspending devices... ");
+		if ((res = device_suspend(3))==0) {
 			/* If stopping device drivers worked, we proceed basically into
 			 * suspend_save_image.
 			 *
@@ -852,7 +853,9 @@ int software_suspend(void)
 			 * using normal kernel mechanism.
 			 */
 			do_magic(0);
+		}
 		thaw_processes();
+		enable_nonboot_cpus();
 	} else
 		res = -EBUSY;
 	software_suspend_enabled = 1;
@@ -1192,7 +1195,9 @@ static int __init software_resume(void)
 	printk( "resuming from %s\n", resume_file);
 	if (read_suspend_image(resume_file, 0))
 		goto read_failure;
-	device_suspend(4);
+	/* FIXME: Should we stop processes here, just to be safer? */
+	disable_nonboot_cpus();
+	device_suspend(3);
 	do_magic(1);
 	panic("This never returns");