#include <asm/hardirq.h>
#include <asm/nmi.h>
#include <asm/hw_irq.h>
+#include <asm/apic.h>
+#include <mach_ipi.h>
-#define MAX_NOTE_BYTES 1024
-typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
note_buf_t crash_notes[NR_CPUS];
+/* This keeps a track of which one is crashing cpu. */
+static int crashing_cpu;
-void machine_crash_shutdown(void)
+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);
+}
+
+static void crash_get_current_regs(struct pt_regs *regs)
+{
+ __asm__ __volatile__("movl %%ebx,%0" : "=m"(regs->ebx));
+ __asm__ __volatile__("movl %%ecx,%0" : "=m"(regs->ecx));
+ __asm__ __volatile__("movl %%edx,%0" : "=m"(regs->edx));
+ __asm__ __volatile__("movl %%esi,%0" : "=m"(regs->esi));
+ __asm__ __volatile__("movl %%edi,%0" : "=m"(regs->edi));
+ __asm__ __volatile__("movl %%ebp,%0" : "=m"(regs->ebp));
+ __asm__ __volatile__("movl %%eax,%0" : "=m"(regs->eax));
+ __asm__ __volatile__("movl %%esp,%0" : "=m"(regs->esp));
+ __asm__ __volatile__("movw %%ss, %%ax;" :"=a"(regs->xss));
+ __asm__ __volatile__("movw %%cs, %%ax;" :"=a"(regs->xcs));
+ __asm__ __volatile__("movw %%ds, %%ax;" :"=a"(regs->xds));
+ __asm__ __volatile__("movw %%es, %%ax;" :"=a"(regs->xes));
+ __asm__ __volatile__("pushfl; popl %0" :"=m"(regs->eflags));
+
+ regs->eip = (unsigned long)current_text_addr();
+}
+
+/* CPU does not save ss and esp on stack if execution is already
+ * running in kernel mode at the time of NMI occurrence. This code
+ * fixes it.
+ */
+static void crash_setup_regs(struct pt_regs *newregs, struct pt_regs *oldregs)
+{
+ memcpy(newregs, oldregs, sizeof(*newregs));
+ newregs->esp = (unsigned long)&(oldregs->esp);
+ __asm__ __volatile__("xorl %eax, %eax;");
+ __asm__ __volatile__ ("movw %%ss, %%ax;" :"=a"(newregs->xss));
+}
+
+/* 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)
+ crash_setup_regs(®s, saved_regs);
+ else
+ crash_get_current_regs(®s);
+ crash_save_this_cpu(®s, cpu);
+}
+
+#ifdef CONFIG_SMP
+static atomic_t waiting_for_crash_ipi;
+
+static int crash_nmi_callback(struct pt_regs *regs, int cpu)
+{
+ struct pt_regs fixed_regs;
+
+ /* Don't do anything if this handler is invoked on crashing cpu.
+ * Otherwise, system will completely hang. Crashing cpu can get
+ * an NMI if system was initially booted with nmi_watchdog parameter.
+ */
+ if (cpu == crashing_cpu)
+ return 1;
+ local_irq_disable();
+
+ if (!user_mode(regs)) {
+ crash_setup_regs(&fixed_regs, regs);
+ regs = &fixed_regs;
+ }
+ crash_save_this_cpu(regs, cpu);
+ disable_local_APIC();
+ atomic_dec(&waiting_for_crash_ipi);
+ /* Assume hlt works */
+ halt();
+ for(;;);
+
+ return 1;
+}
+
+/*
+ * By using the NMI code instead of a vector we just sneak thru the
+ * word generator coming out with just what we want. AND it does
+ * not matter if clustered_apic_mode is set or not.
+ */
+static void smp_send_nmi_allbutself(void)
+{
+ send_IPI_allbutself(APIC_DM_NMI);
+}
+
+static void nmi_shootdown_cpus(void)
+{
+ unsigned long msecs;
+
+ atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+ /* Would it be better to replace the trap vector here? */
+ set_nmi_callback(crash_nmi_callback);
+ /* Ensure the new callback function is set before sending
+ * out the NMI
+ */
+ wmb();
+
+ smp_send_nmi_allbutself();
+
+ msecs = 1000; /* Wait at most a second for the other cpus to stop */
+ while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
+ mdelay(1);
+ msecs--;
+ }
+
+ /* Leave the nmi callback set */
+ disable_local_APIC();
+}
+#else
+static void nmi_shootdown_cpus(void)
+{
+ /* There are no cpus to shootdown */
+}
+#endif
+
+void machine_crash_shutdown(struct pt_regs *regs)
{
/* This function is only called after the system
* has paniced or is otherwise in a critical state.
* In practice this means shooting down the other cpus in
* an SMP system.
*/
+ /* The kernel is broken so disable interrupts */
+ local_irq_disable();
+
+ /* Make a note of crashing cpu. Will be used in NMI callback.*/
+ crashing_cpu = smp_processor_id();
+ nmi_shootdown_cpus();
+ lapic_shutdown();
+#if defined(CONFIG_X86_IO_APIC)
+ disable_IO_APIC();
+#endif
+ crash_save_self(regs);
}
projects / linux-2.6 / blobdiff