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 #include <linux/module.h> 20 21 #include <asm/processor.h> 22 #include <asm/hardirq.h> 23 #include <asm/nmi.h> 24 #include <asm/hw_irq.h> 25 #include <asm/apic.h> 26 #include <asm/hpet.h> 27 #include <linux/kdebug.h> 28 #include <asm/cpu.h> 29 #include <asm/reboot.h> 30 #include <asm/virtext.h> 31 32 int in_crash_kexec; 33 34 /* 35 * This is used to VMCLEAR all VMCSs loaded on the 36 * processor. And when loading kvm_intel module, the 37 * callback function pointer will be assigned. 38 * 39 * protected by rcu. 40 */ 41 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL; 42 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); 43 44 static inline void cpu_crash_vmclear_loaded_vmcss(void) 45 { 46 crash_vmclear_fn *do_vmclear_operation = NULL; 47 48 rcu_read_lock(); 49 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); 50 if (do_vmclear_operation) 51 do_vmclear_operation(); 52 rcu_read_unlock(); 53 } 54 55 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) 56 57 static void kdump_nmi_callback(int cpu, struct pt_regs *regs) 58 { 59 #ifdef CONFIG_X86_32 60 struct pt_regs fixed_regs; 61 #endif 62 63 #ifdef CONFIG_X86_32 64 if (!user_mode_vm(regs)) { 65 crash_fixup_ss_esp(&fixed_regs, regs); 66 regs = &fixed_regs; 67 } 68 #endif 69 crash_save_cpu(regs, cpu); 70 71 /* 72 * VMCLEAR VMCSs loaded on all cpus if needed. 73 */ 74 cpu_crash_vmclear_loaded_vmcss(); 75 76 /* Disable VMX or SVM if needed. 77 * 78 * We need to disable virtualization on all CPUs. 79 * Having VMX or SVM enabled on any CPU may break rebooting 80 * after the kdump kernel has finished its task. 81 */ 82 cpu_emergency_vmxoff(); 83 cpu_emergency_svm_disable(); 84 85 disable_local_APIC(); 86 } 87 88 static void kdump_nmi_shootdown_cpus(void) 89 { 90 in_crash_kexec = 1; 91 nmi_shootdown_cpus(kdump_nmi_callback); 92 93 disable_local_APIC(); 94 } 95 96 #else 97 static void kdump_nmi_shootdown_cpus(void) 98 { 99 /* There are no cpus to shootdown */ 100 } 101 #endif 102 103 void native_machine_crash_shutdown(struct pt_regs *regs) 104 { 105 /* This function is only called after the system 106 * has panicked or is otherwise in a critical state. 107 * The minimum amount of code to allow a kexec'd kernel 108 * to run successfully needs to happen here. 109 * 110 * In practice this means shooting down the other cpus in 111 * an SMP system. 112 */ 113 /* The kernel is broken so disable interrupts */ 114 local_irq_disable(); 115 116 kdump_nmi_shootdown_cpus(); 117 118 /* 119 * VMCLEAR VMCSs loaded on this cpu if needed. 120 */ 121 cpu_crash_vmclear_loaded_vmcss(); 122 123 /* Booting kdump kernel with VMX or SVM enabled won't work, 124 * because (among other limitations) we can't disable paging 125 * with the virt flags. 126 */ 127 cpu_emergency_vmxoff(); 128 cpu_emergency_svm_disable(); 129 130 #ifdef CONFIG_X86_IO_APIC 131 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ 132 ioapic_zap_locks(); 133 disable_IO_APIC(); 134 #endif 135 lapic_shutdown(); 136 #ifdef CONFIG_HPET_TIMER 137 hpet_disable(); 138 #endif 139 crash_save_cpu(regs, safe_smp_processor_id()); 140 } 141