diff options
Diffstat (limited to 'arch/powerpc/kernel/crash.c')
| -rw-r--r-- | arch/powerpc/kernel/crash.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c new file mode 100644 index 000000000000..4681155121ef --- /dev/null +++ b/arch/powerpc/kernel/crash.c @@ -0,0 +1,264 @@ +/* + * Architecture specific (PPC64) functions for kexec based crash dumps. + * + * Copyright (C) 2005, IBM Corp. + * + * Created by: Haren Myneni + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + * + */ + +#undef DEBUG + +#include <linux/kernel.h> +#include <linux/smp.h> +#include <linux/reboot.h> +#include <linux/kexec.h> +#include <linux/bootmem.h> +#include <linux/crash_dump.h> +#include <linux/irq.h> +#include <linux/delay.h> +#include <linux/elf.h> +#include <linux/elfcore.h> +#include <linux/init.h> +#include <linux/types.h> + +#include <asm/processor.h> +#include <asm/machdep.h> +#include <asm/kdump.h> +#include <asm/lmb.h> +#include <asm/firmware.h> + +#ifdef DEBUG +#include <asm/udbg.h> +#define DBG(fmt...) udbg_printf(fmt) +#else +#define DBG(fmt...) +#endif + +/* This keeps a track of which one is crashing cpu. */ +int crashing_cpu = -1; + +static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data, + size_t data_len) +{ + struct elf_note note; + + note.n_namesz = strlen(name) + 1; + note.n_descsz = data_len; + note.n_type = type; + memcpy(buf, ¬e, sizeof(note)); + buf += (sizeof(note) +3)/4; + memcpy(buf, name, note.n_namesz); + buf += (note.n_namesz + 3)/4; + memcpy(buf, data, note.n_descsz); + buf += (note.n_descsz + 3)/4; + + return buf; +} + +static void final_note(u32 *buf) +{ + struct elf_note note; + + note.n_namesz = 0; + note.n_descsz = 0; + note.n_type = 0; + memcpy(buf, ¬e, sizeof(note)); +} + +static void crash_save_this_cpu(struct pt_regs *regs, int cpu) +{ + struct elf_prstatus prstatus; + u32 *buf; + + if ((cpu < 0) || (cpu >= NR_CPUS)) + return; + + /* Using ELF notes here is opportunistic. + * I need a well defined structure format + * for the data I pass, and I need tags + * on the data to indicate what information I have + * squirrelled away. ELF notes happen to provide + * all of that that no need to invent something new. + */ + buf = &crash_notes[cpu][0]; + memset(&prstatus, 0, sizeof(prstatus)); + prstatus.pr_pid = current->pid; + elf_core_copy_regs(&prstatus.pr_reg, regs); + buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus, + sizeof(prstatus)); + final_note(buf); +} + +/* FIXME Merge this with xmon_save_regs ?? */ +static inline void crash_get_current_regs(struct pt_regs *regs) +{ + unsigned long tmp1, tmp2; + + __asm__ __volatile__ ( + "std 0,0(%2)\n" + "std 1,8(%2)\n" + "std 2,16(%2)\n" + "std 3,24(%2)\n" + "std 4,32(%2)\n" + "std 5,40(%2)\n" + "std 6,48(%2)\n" + "std 7,56(%2)\n" + "std 8,64(%2)\n" + "std 9,72(%2)\n" + "std 10,80(%2)\n" + "std 11,88(%2)\n" + "std 12,96(%2)\n" + "std 13,104(%2)\n" + "std 14,112(%2)\n" + "std 15,120(%2)\n" + "std 16,128(%2)\n" + "std 17,136(%2)\n" + "std 18,144(%2)\n" + "std 19,152(%2)\n" + "std 20,160(%2)\n" + "std 21,168(%2)\n" + "std 22,176(%2)\n" + "std 23,184(%2)\n" + "std 24,192(%2)\n" + "std 25,200(%2)\n" + "std 26,208(%2)\n" + "std 27,216(%2)\n" + "std 28,224(%2)\n" + "std 29,232(%2)\n" + "std 30,240(%2)\n" + "std 31,248(%2)\n" + "mfmsr %0\n" + "std %0, 264(%2)\n" + "mfctr %0\n" + "std %0, 280(%2)\n" + "mflr %0\n" + "std %0, 288(%2)\n" + "bl 1f\n" + "1: mflr %1\n" + "std %1, 256(%2)\n" + "mtlr %0\n" + "mfxer %0\n" + "std %0, 296(%2)\n" + : "=&r" (tmp1), "=&r" (tmp2) + : "b" (regs)); +} + +/* We may have saved_regs from where the error came from + * or it is NULL if via a direct panic(). + */ +static void crash_save_self(struct pt_regs *saved_regs) +{ + struct pt_regs regs; + int cpu; + + cpu = smp_processor_id(); + if (saved_regs) + memcpy(®s, saved_regs, sizeof(regs)); + else + crash_get_current_regs(®s); + crash_save_this_cpu(®s, cpu); +} + +#ifdef CONFIG_SMP +static atomic_t waiting_for_crash_ipi; + +void crash_ipi_callback(struct pt_regs *regs) +{ + int cpu = smp_processor_id(); + + if (cpu == crashing_cpu) + return; + + if (!cpu_online(cpu)) + return; + + if (ppc_md.kexec_cpu_down) + ppc_md.kexec_cpu_down(1, 1); + + local_irq_disable(); + + crash_save_this_cpu(regs, cpu); + atomic_dec(&waiting_for_crash_ipi); + kexec_smp_wait(); + /* NOTREACHED */ +} + +static void crash_kexec_prepare_cpus(void) +{ + unsigned int msecs; + + atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); + + crash_send_ipi(crash_ipi_callback); + smp_wmb(); + + /* + * FIXME: Until we will have the way to stop other CPUSs reliabally, + * the crash CPU will send an IPI and wait for other CPUs to + * respond. If not, proceed the kexec boot even though we failed to + * capture other CPU states. + */ + msecs = 1000000; + while ((atomic_read(&waiting_for_crash_ipi) > 0) && (--msecs > 0)) { + barrier(); + mdelay(1); + } + + /* Would it be better to replace the trap vector here? */ + + /* + * FIXME: In case if we do not get all CPUs, one possibility: ask the + * user to do soft reset such that we get all. + * IPI handler is already set by the panic cpu initially. Therefore, + * all cpus could invoke this handler from die() and the panic CPU + * will call machine_kexec() directly from this handler to do + * kexec boot. + */ + if (atomic_read(&waiting_for_crash_ipi)) + printk(KERN_ALERT "done waiting: %d cpus not responding\n", + atomic_read(&waiting_for_crash_ipi)); + /* Leave the IPI callback set */ +} +#else +static void crash_kexec_prepare_cpus(void) +{ + /* + * move the secondarys to us so that we can copy + * the new kernel 0-0x100 safely + * + * do this if kexec in setup.c ? + */ + smp_release_cpus(); +} + +#endif + +void default_machine_crash_shutdown(struct pt_regs *regs) +{ + /* + * This function is only called after the system + * has paniced or is otherwise in a critical state. + * The minimum amount of code to allow a kexec'd kernel + * to run successfully needs to happen here. + * + * In practice this means stopping other cpus in + * an SMP system. + * The kernel is broken so disable interrupts. + */ + local_irq_disable(); + + if (ppc_md.kexec_cpu_down) + ppc_md.kexec_cpu_down(1, 0); + + /* + * Make a note of crashing cpu. Will be used in machine_kexec + * such that another IPI will not be sent. + */ + crashing_cpu = smp_processor_id(); + crash_kexec_prepare_cpus(); + crash_save_self(regs); +} |