1 /*
2  * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
3  *
4  * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
5  *
6  * Copyright (C) IBM Corporation, 2004. All rights reserved.
7  *
8  */
9 
10 #include <linux/init.h>
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/smp.h>
14 #include <linux/reboot.h>
15 #include <linux/kexec.h>
16 #include <linux/delay.h>
17 #include <linux/elf.h>
18 #include <linux/elfcore.h>
19 
20 #include <asm/processor.h>
21 #include <asm/hardirq.h>
22 #include <asm/nmi.h>
23 #include <asm/hw_irq.h>
24 #include <asm/apic.h>
25 #include <asm/hpet.h>
26 #include <linux/kdebug.h>
27 #include <asm/cpu.h>
28 #include <asm/reboot.h>
29 #include <asm/virtext.h>
30 
31 int in_crash_kexec;
32 
33 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
34 
kdump_nmi_callback(int cpu,struct die_args * args)35 static void kdump_nmi_callback(int cpu, struct die_args *args)
36 {
37 	struct pt_regs *regs;
38 #ifdef CONFIG_X86_32
39 	struct pt_regs fixed_regs;
40 #endif
41 
42 	regs = args->regs;
43 
44 #ifdef CONFIG_X86_32
45 	if (!user_mode_vm(regs)) {
46 		crash_fixup_ss_esp(&fixed_regs, regs);
47 		regs = &fixed_regs;
48 	}
49 #endif
50 	crash_save_cpu(regs, cpu);
51 
52 	/* Disable VMX or SVM if needed.
53 	 *
54 	 * We need to disable virtualization on all CPUs.
55 	 * Having VMX or SVM enabled on any CPU may break rebooting
56 	 * after the kdump kernel has finished its task.
57 	 */
58 	cpu_emergency_vmxoff();
59 	cpu_emergency_svm_disable();
60 
61 	disable_local_APIC();
62 }
63 
kdump_nmi_shootdown_cpus(void)64 static void kdump_nmi_shootdown_cpus(void)
65 {
66 	in_crash_kexec = 1;
67 	nmi_shootdown_cpus(kdump_nmi_callback);
68 
69 	disable_local_APIC();
70 }
71 
72 #else
kdump_nmi_shootdown_cpus(void)73 static void kdump_nmi_shootdown_cpus(void)
74 {
75 	/* There are no cpus to shootdown */
76 }
77 #endif
78 
native_machine_crash_shutdown(struct pt_regs * regs)79 void native_machine_crash_shutdown(struct pt_regs *regs)
80 {
81 	/* This function is only called after the system
82 	 * has panicked or is otherwise in a critical state.
83 	 * The minimum amount of code to allow a kexec'd kernel
84 	 * to run successfully needs to happen here.
85 	 *
86 	 * In practice this means shooting down the other cpus in
87 	 * an SMP system.
88 	 */
89 	/* The kernel is broken so disable interrupts */
90 	local_irq_disable();
91 
92 	kdump_nmi_shootdown_cpus();
93 
94 	/* Booting kdump kernel with VMX or SVM enabled won't work,
95 	 * because (among other limitations) we can't disable paging
96 	 * with the virt flags.
97 	 */
98 	cpu_emergency_vmxoff();
99 	cpu_emergency_svm_disable();
100 
101 	lapic_shutdown();
102 #if defined(CONFIG_X86_IO_APIC)
103 	disable_IO_APIC();
104 #endif
105 #ifdef CONFIG_HPET_TIMER
106 	hpet_disable();
107 #endif
108 	crash_save_cpu(regs, safe_smp_processor_id());
109 }
110