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/irq.h>
26 #include <linux/types.h>
28 #include <asm/processor.h>
29 #include <asm/machdep.h>
30 #include <asm/kdump.h>
32 #include <asm/firmware.h>
37 #define DBG(fmt...) udbg_printf(fmt)
42 /* This keeps a track of which one is crashing cpu. */
43 int crashing_cpu
= -1;
45 static u32
*append_elf_note(u32
*buf
, char *name
, unsigned type
, void *data
,
50 note
.n_namesz
= strlen(name
) + 1;
51 note
.n_descsz
= data_len
;
53 memcpy(buf
, ¬e
, sizeof(note
));
54 buf
+= (sizeof(note
) +3)/4;
55 memcpy(buf
, name
, note
.n_namesz
);
56 buf
+= (note
.n_namesz
+ 3)/4;
57 memcpy(buf
, data
, note
.n_descsz
);
58 buf
+= (note
.n_descsz
+ 3)/4;
63 static void final_note(u32
*buf
)
70 memcpy(buf
, ¬e
, sizeof(note
));
73 static void crash_save_this_cpu(struct pt_regs
*regs
, int cpu
)
75 struct elf_prstatus prstatus
;
78 if ((cpu
< 0) || (cpu
>= NR_CPUS
))
81 /* Using ELF notes here is opportunistic.
82 * I need a well defined structure format
83 * for the data I pass, and I need tags
84 * on the data to indicate what information I have
85 * squirrelled away. ELF notes happen to provide
86 * all of that that no need to invent something new.
88 buf
= (u32
*)per_cpu_ptr(crash_notes
, cpu
);
92 memset(&prstatus
, 0, sizeof(prstatus
));
93 prstatus
.pr_pid
= current
->pid
;
94 elf_core_copy_regs(&prstatus
.pr_reg
, regs
);
95 buf
= append_elf_note(buf
, "CORE", NT_PRSTATUS
, &prstatus
,
101 static atomic_t waiting_for_crash_ipi
;
103 void crash_ipi_callback(struct pt_regs
*regs
)
105 int cpu
= smp_processor_id();
107 if (cpu
== crashing_cpu
)
110 if (!cpu_online(cpu
))
113 if (ppc_md
.kexec_cpu_down
)
114 ppc_md
.kexec_cpu_down(1, 1);
118 crash_save_this_cpu(regs
, cpu
);
119 atomic_dec(&waiting_for_crash_ipi
);
124 static void crash_kexec_prepare_cpus(void)
128 atomic_set(&waiting_for_crash_ipi
, num_online_cpus() - 1);
130 crash_send_ipi(crash_ipi_callback
);
134 * FIXME: Until we will have the way to stop other CPUSs reliabally,
135 * the crash CPU will send an IPI and wait for other CPUs to
136 * respond. If not, proceed the kexec boot even though we failed to
137 * capture other CPU states.
138 * Delay of at least 10 seconds.
140 printk(KERN_ALERT
"Sending IPI to other cpus...\n");
142 while ((atomic_read(&waiting_for_crash_ipi
) > 0) && (--msecs
> 0)) {
147 /* Would it be better to replace the trap vector here? */
150 * FIXME: In case if we do not get all CPUs, one possibility: ask the
151 * user to do soft reset such that we get all.
152 * IPI handler is already set by the panic cpu initially. Therefore,
153 * all cpus could invoke this handler from die() and the panic CPU
154 * will call machine_kexec() directly from this handler to do
157 if (atomic_read(&waiting_for_crash_ipi
))
158 printk(KERN_ALERT
"done waiting: %d cpus not responding\n",
159 atomic_read(&waiting_for_crash_ipi
));
160 /* Leave the IPI callback set */
163 static void crash_kexec_prepare_cpus(void)
166 * move the secondarys to us so that we can copy
167 * the new kernel 0-0x100 safely
169 * do this if kexec in setup.c ?
176 void default_machine_crash_shutdown(struct pt_regs
*regs
)
181 * This function is only called after the system
182 * has paniced or is otherwise in a critical state.
183 * The minimum amount of code to allow a kexec'd kernel
184 * to run successfully needs to happen here.
186 * In practice this means stopping other cpus in
188 * The kernel is broken so disable interrupts.
193 struct irq_desc
*desc
= irq_descp(irq
);
195 if (desc
->status
& IRQ_INPROGRESS
)
196 desc
->handler
->end(irq
);
198 if (!(desc
->status
& IRQ_DISABLED
))
199 desc
->handler
->disable(irq
);
202 if (ppc_md
.kexec_cpu_down
)
203 ppc_md
.kexec_cpu_down(1, 0);
206 * Make a note of crashing cpu. Will be used in machine_kexec
207 * such that another IPI will not be sent.
209 crashing_cpu
= smp_processor_id();
210 crash_kexec_prepare_cpus();
211 crash_save_this_cpu(regs
, crashing_cpu
);