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 #endif 61 62 #ifdef CONFIG_X86_32 63 if (!user_mode_vm(regs)) { 64 crash_fixup_ss_esp(&fixed_regs, regs); 65 regs = &fixed_regs; 66 } 67 #endif 68 crash_save_cpu(regs, cpu); 69 70 /* 71 * VMCLEAR VMCSs loaded on all cpus if needed. 72 */ 73 cpu_crash_vmclear_loaded_vmcss(); 74 75 /* Disable VMX or SVM if needed. 76 * 77 * We need to disable virtualization on all CPUs. 78 * Having VMX or SVM enabled on any CPU may break rebooting 79 * after the kdump kernel has finished its task. 80 */ 81 cpu_emergency_vmxoff(); 82 cpu_emergency_svm_disable(); 83 84 disable_local_APIC(); 85 } 86 87 static void kdump_nmi_shootdown_cpus(void) 88 { 89 in_crash_kexec = 1; 90 nmi_shootdown_cpus(kdump_nmi_callback); 91 92 disable_local_APIC(); 93 } 94 95 #else 96 static void kdump_nmi_shootdown_cpus(void) 97 { 98 /* There are no cpus to shootdown */ 99 } 100 #endif 101 102 void native_machine_crash_shutdown(struct pt_regs *regs) 103 { 104 /* This function is only called after the system 105 * has panicked or is otherwise in a critical state. 106 * The minimum amount of code to allow a kexec'd kernel 107 * to run successfully needs to happen here. 108 * 109 * In practice this means shooting down the other cpus in 110 * an SMP system. 111 */ 112 /* The kernel is broken so disable interrupts */ 113 local_irq_disable(); 114 115 kdump_nmi_shootdown_cpus(); 116 117 /* 118 * VMCLEAR VMCSs loaded on this cpu if needed. 119 */ 120 cpu_crash_vmclear_loaded_vmcss(); 121 122 /* Booting kdump kernel with VMX or SVM enabled won't work, 123 * because (among other limitations) we can't disable paging 124 * with the virt flags. 125 */ 126 cpu_emergency_vmxoff(); 127 cpu_emergency_svm_disable(); 128 129 #ifdef CONFIG_X86_IO_APIC 130 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ 131 ioapic_zap_locks(); 132 disable_IO_APIC(); 133 #endif 134 lapic_shutdown(); 135 #ifdef CONFIG_HPET_TIMER 136 hpet_disable(); 137 #endif 138 crash_save_cpu(regs, safe_smp_processor_id()); 139 } 140