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/types.h> 11 #include <linux/kernel.h> 12 #include <linux/smp.h> 13 #include <linux/reboot.h> 14 #include <linux/kexec.h> 15 #include <linux/delay.h> 16 #include <linux/elf.h> 17 #include <linux/elfcore.h> 18 #include <linux/module.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 /* 34 * This is used to VMCLEAR all VMCSs loaded on the 35 * processor. And when loading kvm_intel module, the 36 * callback function pointer will be assigned. 37 * 38 * protected by rcu. 39 */ 40 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL; 41 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); 42 43 static inline void cpu_crash_vmclear_loaded_vmcss(void) 44 { 45 crash_vmclear_fn *do_vmclear_operation = NULL; 46 47 rcu_read_lock(); 48 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); 49 if (do_vmclear_operation) 50 do_vmclear_operation(); 51 rcu_read_unlock(); 52 } 53 54 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) 55 56 static void kdump_nmi_callback(int cpu, struct pt_regs *regs) 57 { 58 #ifdef CONFIG_X86_32 59 struct pt_regs fixed_regs; 60 61 if (!user_mode_vm(regs)) { 62 crash_fixup_ss_esp(&fixed_regs, regs); 63 regs = &fixed_regs; 64 } 65 #endif 66 crash_save_cpu(regs, cpu); 67 68 /* 69 * VMCLEAR VMCSs loaded on all cpus if needed. 70 */ 71 cpu_crash_vmclear_loaded_vmcss(); 72 73 /* Disable VMX or SVM if needed. 74 * 75 * We need to disable virtualization on all CPUs. 76 * Having VMX or SVM enabled on any CPU may break rebooting 77 * after the kdump kernel has finished its task. 78 */ 79 cpu_emergency_vmxoff(); 80 cpu_emergency_svm_disable(); 81 82 disable_local_APIC(); 83 } 84 85 static void kdump_nmi_shootdown_cpus(void) 86 { 87 in_crash_kexec = 1; 88 nmi_shootdown_cpus(kdump_nmi_callback); 89 90 disable_local_APIC(); 91 } 92 93 #else 94 static void kdump_nmi_shootdown_cpus(void) 95 { 96 /* There are no cpus to shootdown */ 97 } 98 #endif 99 100 void native_machine_crash_shutdown(struct pt_regs *regs) 101 { 102 /* This function is only called after the system 103 * has panicked or is otherwise in a critical state. 104 * The minimum amount of code to allow a kexec'd kernel 105 * to run successfully needs to happen here. 106 * 107 * In practice this means shooting down the other cpus in 108 * an SMP system. 109 */ 110 /* The kernel is broken so disable interrupts */ 111 local_irq_disable(); 112 113 kdump_nmi_shootdown_cpus(); 114 115 /* 116 * VMCLEAR VMCSs loaded on this cpu if needed. 117 */ 118 cpu_crash_vmclear_loaded_vmcss(); 119 120 /* Booting kdump kernel with VMX or SVM enabled won't work, 121 * because (among other limitations) we can't disable paging 122 * with the virt flags. 123 */ 124 cpu_emergency_vmxoff(); 125 cpu_emergency_svm_disable(); 126 127 #ifdef CONFIG_X86_IO_APIC 128 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ 129 ioapic_zap_locks(); 130 disable_IO_APIC(); 131 #endif 132 lapic_shutdown(); 133 #ifdef CONFIG_HPET_TIMER 134 hpet_disable(); 135 #endif 136 crash_save_cpu(regs, safe_smp_processor_id()); 137 } 138