2 * Architecture specific (PPC64) functions for kexec based crash dumps.
4 * Copyright (C) 2005, IBM Corp.
6 * Created by: Haren Myneni
8 * This source code is licensed under the GNU General Public License,
9 * Version 2. See the file COPYING for more details.
15 #include <linux/kernel.h>
16 #include <linux/smp.h>
17 #include <linux/reboot.h>
18 #include <linux/kexec.h>
19 #include <linux/bootmem.h>
20 #include <linux/crash_dump.h>
21 #include <linux/delay.h>
22 #include <linux/elf.h>
23 #include <linux/elfcore.h>
24 #include <linux/init.h>
25 #include <linux/types.h>
27 #include <asm/processor.h>
28 #include <asm/machdep.h>
29 #include <asm/kdump.h>
31 #include <asm/firmware.h>
36 #define DBG(fmt...) udbg_printf(fmt)
41 /* This keeps a track of which one is crashing cpu. */
42 int crashing_cpu
= -1;
44 static u32
*append_elf_note(u32
*buf
, char *name
, unsigned type
, void *data
,
49 note
.n_namesz
= strlen(name
) + 1;
50 note
.n_descsz
= data_len
;
52 memcpy(buf
, ¬e
, sizeof(note
));
53 buf
+= (sizeof(note
) +3)/4;
54 memcpy(buf
, name
, note
.n_namesz
);
55 buf
+= (note
.n_namesz
+ 3)/4;
56 memcpy(buf
, data
, note
.n_descsz
);
57 buf
+= (note
.n_descsz
+ 3)/4;
62 static void final_note(u32
*buf
)
69 memcpy(buf
, ¬e
, sizeof(note
));
72 static void crash_save_this_cpu(struct pt_regs
*regs
, int cpu
)
74 struct elf_prstatus prstatus
;
77 if ((cpu
< 0) || (cpu
>= NR_CPUS
))
80 /* Using ELF notes here is opportunistic.
81 * I need a well defined structure format
82 * for the data I pass, and I need tags
83 * on the data to indicate what information I have
84 * squirrelled away. ELF notes happen to provide
85 * all of that that no need to invent something new.
87 buf
= (u32
*)per_cpu_ptr(crash_notes
, cpu
);
91 memset(&prstatus
, 0, sizeof(prstatus
));
92 prstatus
.pr_pid
= current
->pid
;
93 elf_core_copy_regs(&prstatus
.pr_reg
, regs
);
94 buf
= append_elf_note(buf
, "CORE", NT_PRSTATUS
, &prstatus
,
100 static atomic_t waiting_for_crash_ipi
;
102 void crash_ipi_callback(struct pt_regs
*regs
)
104 int cpu
= smp_processor_id();
106 if (cpu
== crashing_cpu
)
109 if (!cpu_online(cpu
))
112 if (ppc_md
.kexec_cpu_down
)
113 ppc_md
.kexec_cpu_down(1, 1);
117 crash_save_this_cpu(regs
, cpu
);
118 atomic_dec(&waiting_for_crash_ipi
);
123 static void crash_kexec_prepare_cpus(void)
127 atomic_set(&waiting_for_crash_ipi
, num_online_cpus() - 1);
129 crash_send_ipi(crash_ipi_callback
);
133 * FIXME: Until we will have the way to stop other CPUSs reliabally,
134 * the crash CPU will send an IPI and wait for other CPUs to
135 * respond. If not, proceed the kexec boot even though we failed to
136 * capture other CPU states.
137 * Delay of at least 10 seconds.
139 printk(KERN_ALERT
"Sending IPI to other cpus...\n");
141 while ((atomic_read(&waiting_for_crash_ipi
) > 0) && (--msecs
> 0)) {
146 /* Would it be better to replace the trap vector here? */
149 * FIXME: In case if we do not get all CPUs, one possibility: ask the
150 * user to do soft reset such that we get all.
151 * IPI handler is already set by the panic cpu initially. Therefore,
152 * all cpus could invoke this handler from die() and the panic CPU
153 * will call machine_kexec() directly from this handler to do
156 if (atomic_read(&waiting_for_crash_ipi
))
157 printk(KERN_ALERT
"done waiting: %d cpus not responding\n",
158 atomic_read(&waiting_for_crash_ipi
));
159 /* Leave the IPI callback set */
162 static void crash_kexec_prepare_cpus(void)
165 * move the secondarys to us so that we can copy
166 * the new kernel 0-0x100 safely
168 * do this if kexec in setup.c ?
175 void default_machine_crash_shutdown(struct pt_regs
*regs
)
178 * This function is only called after the system
179 * has paniced or is otherwise in a critical state.
180 * The minimum amount of code to allow a kexec'd kernel
181 * to run successfully needs to happen here.
183 * In practice this means stopping other cpus in
185 * The kernel is broken so disable interrupts.
189 if (ppc_md
.kexec_cpu_down
)
190 ppc_md
.kexec_cpu_down(1, 0);
193 * Make a note of crashing cpu. Will be used in machine_kexec
194 * such that another IPI will not be sent.
196 crashing_cpu
= smp_processor_id();
197 crash_kexec_prepare_cpus();
198 crash_save_this_cpu(regs
, crashing_cpu
);