10 files changed, 566 insertions, 17 deletions

diff --git a/arch/ppc64/Kconfig b/arch/ppc64/Kconfig
index 5f40b438b584..f804f25232ac 100644
--- a/arch/ppc64/Kconfig
+++ b/arch/ppc64/Kconfig
@@ -142,6 +142,23 @@ config PPC_SPLPAR
           processors, that is, which share physical processors between
           two or more partitions.
 
+config KEXEC
+        bool "kexec system call (EXPERIMENTAL)"
+        depends on PPC_MULTIPLATFORM && EXPERIMENTAL
+        help
+          kexec is a system call that implements the ability to shutdown your
+          current kernel, and to start another kernel.  It is like a reboot
+          but it is indepedent of the system firmware.  And like a reboot
+          you can start any kernel with it, not just Linux.
+
+          The name comes from the similiarity to the exec system call.
+
+          It is an ongoing process to be certain the hardware in a machine
+          is properly shutdown, so do not be surprised if this code does not
+          initially work for you.  It may help to enable device hotplugging
+          support.  As of this writing the exact hardware interface is
+          strongly in flux, so no good recommendation can be made.
+
 config IBMVIO
         depends on PPC_PSERIES || PPC_ISERIES
         bool
diff --git a/arch/ppc64/kernel/Makefile b/arch/ppc64/kernel/Makefile
index dffbfb7ac8d5..d9b2660ef221 100644
--- a/arch/ppc64/kernel/Makefile
+++ b/arch/ppc64/kernel/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_PPC_PSERIES) += pSeries_pci.o pSeries_lpar.o pSeries_hvCall.o \
 obj-$(CONFIG_PPC_BPA) += bpa_setup.o bpa_iommu.o bpa_nvram.o \
                          bpa_iic.o spider-pic.o
 
+obj-$(CONFIG_KEXEC)             += machine_kexec.o
 obj-$(CONFIG_EEH)               += eeh.o
 obj-$(CONFIG_PROC_FS)           += proc_ppc64.o
 obj-$(CONFIG_RTAS_FLASH)        += rtas_flash.o
diff --git a/arch/ppc64/kernel/head.S b/arch/ppc64/kernel/head.S
index 02c8f4e3e4bc..675c2708588f 100644
--- a/arch/ppc64/kernel/head.S
+++ b/arch/ppc64/kernel/head.S
@@ -1194,7 +1194,7 @@ _GLOBAL(pSeries_secondary_smp_init)
         bl      .__restore_cpu_setup
 
         /* Set up a paca value for this processor. Since we have the
-         * physical cpu id in r3, we need to search the pacas to find
+         * physical cpu id in r24, we need to search the pacas to find
          * which logical id maps to our physical one.
          */
         LOADADDR(r13, paca)             /* Get base vaddr of paca array  */
@@ -1207,8 +1207,8 @@ _GLOBAL(pSeries_secondary_smp_init)
         cmpwi   r5,NR_CPUS
         blt     1b
 
-99:     HMT_LOW                         /* Couldn't find our CPU id      */
-        b       99b
+        mr      r3,r24                  /* not found, copy phys to r3    */
+        b       .kexec_wait             /* next kernel might do better   */
 
 2:      mtspr   SPRG3,r13               /* Save vaddr of paca in SPRG3   */
         /* From now on, r24 is expected to be logica cpuid */
diff --git a/arch/ppc64/kernel/machine_kexec.c b/arch/ppc64/kernel/machine_kexec.c
new file mode 100644
index 000000000000..217965d60a45
--- /dev/null
+++ b/arch/ppc64/kernel/machine_kexec.c
@@ -0,0 +1,301 @@
+/*
+ * machine_kexec.c - handle transition of Linux booting another kernel
+ *
+ * Copyright (C) 2004-2005, IBM Corp.
+ *
+ * Created by: Milton D Miller II
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+
+#include <linux/cpumask.h>
+#include <linux/kexec.h>
+#include <linux/smp.h>
+#include <linux/thread_info.h>
+#include <linux/errno.h>
+
+#include <asm/page.h>
+#include <asm/current.h>
+#include <asm/machdep.h>
+#include <asm/cacheflush.h>
+#include <asm/paca.h>
+#include <asm/mmu.h>
+#include <asm/sections.h>       /* _end */
+#include <asm/prom.h>
+
+#define HASH_GROUP_SIZE 0x80    /* size of each hash group, asm/mmu.h */
+
+/* Have this around till we move it into crash specific file */
+note_buf_t crash_notes[NR_CPUS];
+
+/* Dummy for now. Not sure if we need to have a crash shutdown in here
+ * and if what it will achieve. Letting it be now to compile the code
+ * in generic kexec environment
+ */
+void machine_crash_shutdown(void)
+{
+        /* do nothing right now */
+        /* smp_relase_cpus() if we want smp on panic kernel */
+        /* cpu_irq_down to isolate us until we are ready */
+}
+
+int machine_kexec_prepare(struct kimage *image)
+{
+        int i;
+        unsigned long begin, end;       /* limits of segment */
+        unsigned long low, high;        /* limits of blocked memory range */
+        struct device_node *node;
+        unsigned long *basep;
+        unsigned int *sizep;
+
+        if (!ppc_md.hpte_clear_all)
+                return -ENOENT;
+
+        /*
+         * Since we use the kernel fault handlers and paging code to
+         * handle the virtual mode, we must make sure no destination
+         * overlaps kernel static data or bss.
+         */
+        for(i = 0; i < image->nr_segments; i++)
+                if (image->segment[i].mem < __pa(_end))
+                        return -ETXTBSY;
+
+        /*
+         * For non-LPAR, we absolutely can not overwrite the mmu hash
+         * table, since we are still using the bolted entries in it to
+         * do the copy.  Check that here.
+         *
+         * It is safe if the end is below the start of the blocked
+         * region (end <= low), or if the beginning is after the
+         * end of the blocked region (begin >= high).  Use the
+         * boolean identity !(a || b)  === (!a && !b).
+         */
+        if (htab_address) {
+                low = __pa(htab_address);
+                high = low + (htab_hash_mask + 1) * HASH_GROUP_SIZE;
+
+                for(i = 0; i < image->nr_segments; i++) {
+                        begin = image->segment[i].mem;
+                        end = begin + image->segment[i].memsz;
+
+                        if ((begin < high) && (end > low))
+                                return -ETXTBSY;
+                }
+        }
+
+        /* We also should not overwrite the tce tables */
+        for (node = of_find_node_by_type(NULL, "pci"); node != NULL;
+                        node = of_find_node_by_type(node, "pci")) {
+                basep = (unsigned long *)get_property(node, "linux,tce-base",
+                                                        NULL);
+                sizep = (unsigned int *)get_property(node, "linux,tce-size",
+                                                        NULL);
+                if (basep == NULL || sizep == NULL)
+                        continue;
+
+                low = *basep;
+                high = low + (*sizep);
+
+                for(i = 0; i < image->nr_segments; i++) {
+                        begin = image->segment[i].mem;
+                        end = begin + image->segment[i].memsz;
+
+                        if ((begin < high) && (end > low))
+                                return -ETXTBSY;
+                }
+        }
+
+        return 0;
+}
+
+void machine_kexec_cleanup(struct kimage *image)
+{
+        /* we do nothing in prepare that needs to be undone */
+}
+
+#define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)
+
+static void copy_segments(unsigned long ind)
+{
+        unsigned long entry;
+        unsigned long *ptr;
+        void *dest;
+        void *addr;
+
+        /*
+         * We rely on kexec_load to create a lists that properly
+         * initializes these pointers before they are used.
+         * We will still crash if the list is wrong, but at least
+         * the compiler will be quiet.
+         */
+        ptr = NULL;
+        dest = NULL;
+
+        for (entry = ind; !(entry & IND_DONE); entry = *ptr++) {
+                addr = __va(entry & PAGE_MASK);
+
+                switch (entry & IND_FLAGS) {
+                case IND_DESTINATION:
+                        dest = addr;
+                        break;
+                case IND_INDIRECTION:
+                        ptr = addr;
+                        break;
+                case IND_SOURCE:
+                        copy_page(dest, addr);
+                        dest += PAGE_SIZE;
+                }
+        }
+}
+
+void kexec_copy_flush(struct kimage *image)
+{
+        long i, nr_segments = image->nr_segments;
+        struct  kexec_segment ranges[KEXEC_SEGMENT_MAX];
+
+        /* save the ranges on the stack to efficiently flush the icache */
+        memcpy(ranges, image->segment, sizeof(ranges));
+
+        /*
+         * After this call we may not use anything allocated in dynamic
+         * memory, including *image.
+         *
+         * Only globals and the stack are allowed.
+         */
+        copy_segments(image->head);
+
+        /*
+         * we need to clear the icache for all dest pages sometime,
+         * including ones that were in place on the original copy
+         */
+        for (i = 0; i < nr_segments; i++)
+                flush_icache_range(ranges[i].mem + KERNELBASE,
+                                ranges[i].mem + KERNELBASE +
+                                ranges[i].memsz);
+}
+
+#ifdef CONFIG_SMP
+
+/* FIXME: we should schedule this function to be called on all cpus based
+ * on calling the interrupts, but we would like to call it off irq level
+ * so that the interrupt controller is clean.
+ */
+void kexec_smp_down(void *arg)
+{
+        if (ppc_md.cpu_irq_down)
+                ppc_md.cpu_irq_down();
+
+        local_irq_disable();
+        kexec_smp_wait();
+        /* NOTREACHED */
+}
+
+static void kexec_prepare_cpus(void)
+{
+        int my_cpu, i, notified=-1;
+
+        smp_call_function(kexec_smp_down, NULL, 0, /* wait */0);
+        my_cpu = get_cpu();
+
+        /* check the others cpus are now down (via paca hw cpu id == -1) */
+        for (i=0; i < NR_CPUS; i++) {
+                if (i == my_cpu)
+                        continue;
+
+                while (paca[i].hw_cpu_id != -1) {
+                        if (!cpu_possible(i)) {
+                                printk("kexec: cpu %d hw_cpu_id %d is not"
+                                                " possible, ignoring\n",
+                                                i, paca[i].hw_cpu_id);
+                                break;
+                        }
+                        if (!cpu_online(i)) {
+                                /* Fixme: this can be spinning in
+                                 * pSeries_secondary_wait with a paca
+                                 * waiting for it to go online.
+                                 */
+                                printk("kexec: cpu %d hw_cpu_id %d is not"
+                                                " online, ignoring\n",
+                                                i, paca[i].hw_cpu_id);
+                                break;
+                        }
+                        if (i != notified) {
+                                printk( "kexec: waiting for cpu %d (physical"
+                                                " %d) to go down\n",
+                                                i, paca[i].hw_cpu_id);
+                                notified = i;
+                        }
+                }
+        }
+
+        /* after we tell the others to go down */
+        if (ppc_md.cpu_irq_down)
+                ppc_md.cpu_irq_down();
+
+        put_cpu();
+
+        local_irq_disable();
+}
+
+#else /* ! SMP */
+
+static void 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_relase_cpus();
+        if (ppc_md.cpu_irq_down)
+                ppc_md.cpu_irq_down();
+        local_irq_disable();
+}
+
+#endif /* SMP */
+
+/*
+ * kexec thread structure and stack.
+ *
+ * We need to make sure that this is 16384-byte aligned due to the
+ * way process stacks are handled.  It also must be statically allocated
+ * or allocated as part of the kimage, because everything else may be
+ * overwritten when we copy the kexec image.  We piggyback on the
+ * "init_task" linker section here to statically allocate a stack.
+ *
+ * We could use a smaller stack if we don't care about anything using
+ * current, but that audit has not been performed.
+ */
+union thread_union kexec_stack
+        __attribute__((__section__(".data.init_task"))) = { };
+
+/* Our assembly helper, in kexec_stub.S */
+extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start,
+        void *image, void *control, void (*clear_all)(void)) ATTRIB_NORET;
+
+/* too late to fail here */
+void machine_kexec(struct kimage *image)
+{
+
+        /* prepare control code if any */
+
+        /* shutdown other cpus into our wait loop and quiesce interrupts */
+        kexec_prepare_cpus();
+
+        /* switch to a staticly allocated stack.  Based on irq stack code.
+         * XXX: the task struct will likely be invalid once we do the copy!
+         */
+        kexec_stack.thread_info.task = current_thread_info()->task;
+        kexec_stack.thread_info.flags = 0;
+
+        /* Some things are best done in assembly.  Finding globals with
+         * a toc is easier in C, so pass in what we can.
+         */
+        kexec_sequence(&kexec_stack, image->start, image,
+                        page_address(image->control_code_page),
+                        ppc_md.hpte_clear_all);
+        /* NOTREACHED */
+}
diff --git a/arch/ppc64/kernel/misc.S b/arch/ppc64/kernel/misc.S
index e3c73b3425dc..f3dea0c5a88c 100644
--- a/arch/ppc64/kernel/misc.S
+++ b/arch/ppc64/kernel/misc.S
@@ -680,6 +680,177 @@ _GLOBAL(kernel_thread)
         ld      r30,-16(r1)
         blr
 
+/* kexec_wait(phys_cpu)
+ *
+ * wait for the flag to change, indicating this kernel is going away but
+ * the slave code for the next one is at addresses 0 to 100.
+ *
+ * This is used by all slaves.
+ *
+ * Physical (hardware) cpu id should be in r3.
+ */
+_GLOBAL(kexec_wait)
+        bl      1f
+1:      mflr    r5
+        addi    r5,r5,kexec_flag-1b
+
+99:     HMT_LOW
+#ifdef CONFIG_KEXEC             /* use no memory without kexec */
+        lwz     r4,0(r5)
+        cmpwi   0,r4,0
+        bnea    0x60
+#endif
+        b       99b
+
+/* this can be in text because we won't change it until we are
+ * running in real anyways
+ */
+kexec_flag:
+        .long   0
+
+
+#ifdef CONFIG_KEXEC
+
+/* kexec_smp_wait(void)
+ *
+ * call with interrupts off
+ * note: this is a terminal routine, it does not save lr
+ *
+ * get phys id from paca
+ * set paca id to -1 to say we got here
+ * switch to real mode
+ * join other cpus in kexec_wait(phys_id)
+ */
+_GLOBAL(kexec_smp_wait)
+        lhz     r3,PACAHWCPUID(r13)
+        li      r4,-1
+        sth     r4,PACAHWCPUID(r13)     /* let others know we left */
+        bl      real_mode
+        b       .kexec_wait
+
+/*
+ * switch to real mode (turn mmu off)
+ * we use the early kernel trick that the hardware ignores bits
+ * 0 and 1 (big endian) of the effective address in real mode
+ *
+ * don't overwrite r3 here, it is live for kexec_wait above.
+ */
+real_mode:      /* assume normal blr return */
+1:      li      r9,MSR_RI
+        li      r10,MSR_DR|MSR_IR
+        mflr    r11             /* return address to SRR0 */
+        mfmsr   r12
+        andc    r9,r12,r9
+        andc    r10,r12,r10
+
+        mtmsrd  r9,1
+        mtspr   SPRN_SRR1,r10
+        mtspr   SPRN_SRR0,r11
+        rfid
+
+
+/*
+ * kexec_sequence(newstack, start, image, control, clear_all())
+ *
+ * does the grungy work with stack switching and real mode switches
+ * also does simple calls to other code
+ */
+
+_GLOBAL(kexec_sequence)
+        mflr    r0
+        std     r0,16(r1)
+
+        /* switch stacks to newstack -- &kexec_stack.stack */
+        stdu    r1,THREAD_SIZE-112(r3)
+        mr      r1,r3
+
+        li      r0,0
+        std     r0,16(r1)
+
+        /* save regs for local vars on new stack.
+         * yes, we won't go back, but ...
+         */
+        std     r31,-8(r1)
+        std     r30,-16(r1)
+        std     r29,-24(r1)
+        std     r28,-32(r1)
+        std     r27,-40(r1)
+        std     r26,-48(r1)
+        std     r25,-56(r1)
+
+        stdu    r1,-112-64(r1)
+
+        /* save args into preserved regs */
+        mr      r31,r3                  /* newstack (both) */
+        mr      r30,r4                  /* start (real) */
+        mr      r29,r5                  /* image (virt) */
+        mr      r28,r6                  /* control, unused */
+        mr      r27,r7                  /* clear_all() fn desc */
+        mr      r26,r8                  /* spare */
+        lhz     r25,PACAHWCPUID(r13)    /* get our phys cpu from paca */
+
+        /* disable interrupts, we are overwriting kernel data next */
+        mfmsr   r3
+        rlwinm  r3,r3,0,17,15
+        mtmsrd  r3,1
+
+        /* copy dest pages, flush whole dest image */
+        mr      r3,r29
+        bl      .kexec_copy_flush       /* (image) */
+
+        /* turn off mmu */
+        bl      real_mode
+
+        /* clear out hardware hash page table and tlb */
+        ld      r5,0(r27)               /* deref function descriptor */
+        mtctr   r5
+        bctrl                           /* ppc_md.hash_clear_all(void); */
+
+/*
+ *   kexec image calling is:
+ *      the first 0x100 bytes of the entry point are copied to 0
+ *
+ *      all slaves branch to slave = 0x60 (absolute)
+ *              slave(phys_cpu_id);
+ *
+ *      master goes to start = entry point
+ *              start(phys_cpu_id, start, 0);
+ *
+ *
+ *   a wrapper is needed to call existing kernels, here is an approximate
+ *   description of one method:
+ *
+ * v2: (2.6.10)
+ *   start will be near the boot_block (maybe 0x100 bytes before it?)
+ *   it will have a 0x60, which will b to boot_block, where it will wait
+ *   and 0 will store phys into struct boot-block and load r3 from there,
+ *   copy kernel 0-0x100 and tell slaves to back down to 0x60 again
+ *
+ * v1: (2.6.9)
+ *    boot block will have all cpus scanning device tree to see if they
+ *    are the boot cpu ?????
+ *    other device tree differences (prop sizes, va vs pa, etc)...
+ */
+
+        /* copy  0x100 bytes starting at start to 0 */
+        li      r3,0
+        mr      r4,r30
+        li      r5,0x100
+        li      r6,0
+        bl      .copy_and_flush /* (dest, src, copy limit, start offset) */
+1:      /* assume normal blr return */
+
+        /* release other cpus to the new kernel secondary start at 0x60 */
+        mflr    r5
+        li      r6,1
+        stw     r6,kexec_flag-1b(5)
+        mr      r3,r25  # my phys cpu
+        mr      r4,r30  # start, aka phys mem offset
+        mtlr    4
+        li      r5,0
+        blr     /* image->start(physid, image->start, 0); */
+#endif /* CONFIG_KEXEC */
+
 /* Why isn't this a) automatic, b) written in 'C'? */   
         .balign 8
 _GLOBAL(sys_call_table32)
@@ -951,7 +1122,7 @@ _GLOBAL(sys_call_table32)
         .llong .compat_sys_mq_timedreceive /* 265 */
         .llong .compat_sys_mq_notify
         .llong .compat_sys_mq_getsetattr
-        .llong .sys_ni_syscall          /* 268 reserved for sys_kexec_load */
+        .llong .compat_sys_kexec_load
         .llong .sys32_add_key
         .llong .sys32_request_key
         .llong .compat_sys_keyctl
@@ -1227,7 +1398,7 @@ _GLOBAL(sys_call_table)
         .llong .sys_mq_timedreceive     /* 265 */
         .llong .sys_mq_notify
         .llong .sys_mq_getsetattr
-        .llong .sys_ni_syscall          /* 268 reserved for sys_kexec_load */
+        .llong .sys_kexec_load
         .llong .sys_add_key
         .llong .sys_request_key         /* 270 */
         .llong .sys_keyctl
diff --git a/arch/ppc64/kernel/mpic.c b/arch/ppc64/kernel/mpic.c
index 593ea5b82afa..e8fbab1df37f 100644
--- a/arch/ppc64/kernel/mpic.c
+++ b/arch/ppc64/kernel/mpic.c
@@ -792,6 +792,35 @@ void mpic_setup_this_cpu(void)
 #endif /* CONFIG_SMP */
 }
 
+/*
+ * XXX: someone who knows mpic should check this.
+ * do we need to eoi the ipi here (see xics comments)?
+ * or can we reset the mpic in the new kernel?
+ */
+void mpic_teardown_this_cpu(void)
+{
+        struct mpic *mpic = mpic_primary;
+        unsigned long flags;
+        u32 msk = 1 << hard_smp_processor_id();
+        unsigned int i;
+
+        BUG_ON(mpic == NULL);
+
+        DBG("%s: teardown_this_cpu(%d)\n", mpic->name, hard_smp_processor_id());
+        spin_lock_irqsave(&mpic_lock, flags);
+
+        /* let the mpic know we don't want intrs.  */
+        for (i = 0; i < mpic->num_sources ; i++)
+                mpic_irq_write(i, MPIC_IRQ_DESTINATION,
+                        mpic_irq_read(i, MPIC_IRQ_DESTINATION) & ~msk);
+
+        /* Set current processor priority to max */
+        mpic_cpu_write(MPIC_CPU_CURRENT_TASK_PRI, 0xf);
+
+        spin_unlock_irqrestore(&mpic_lock, flags);
+}
+
+
 void mpic_send_ipi(unsigned int ipi_no, unsigned int cpu_mask)
 {
         struct mpic *mpic = mpic_primary;
diff --git a/arch/ppc64/kernel/mpic.h b/arch/ppc64/kernel/mpic.h
index 63e177143eac..99fbbc9a084c 100644
--- a/arch/ppc64/kernel/mpic.h
+++ b/arch/ppc64/kernel/mpic.h
@@ -255,6 +255,9 @@ extern unsigned int mpic_irq_get_priority(unsigned int irq);
 /* Setup a non-boot CPU */
 extern void mpic_setup_this_cpu(void);
 
+/* Clean up for kexec (or cpu offline or ...) */
+extern void mpic_teardown_this_cpu(void);
+
 /* Request IPIs on primary mpic */
 extern void mpic_request_ipis(void);
 
diff --git a/arch/ppc64/kernel/pSeries_setup.c b/arch/ppc64/kernel/pSeries_setup.c
index f2b41243342c..44d9af72d225 100644
--- a/arch/ppc64/kernel/pSeries_setup.c
+++ b/arch/ppc64/kernel/pSeries_setup.c
@@ -187,14 +187,16 @@ static void __init pSeries_setup_arch(void)
 {
         /* Fixup ppc_md depending on the type of interrupt controller */
         if (ppc64_interrupt_controller == IC_OPEN_PIC) {
-                ppc_md.init_IRQ       = pSeries_init_mpic; 
+                ppc_md.init_IRQ       = pSeries_init_mpic;
                 ppc_md.get_irq        = mpic_get_irq;
+                ppc_md.cpu_irq_down   = mpic_teardown_this_cpu;
                 /* Allocate the mpic now, so that find_and_init_phbs() can
                  * fill the ISUs */
                 pSeries_setup_mpic();
         } else {
                 ppc_md.init_IRQ       = xics_init_IRQ;
                 ppc_md.get_irq        = xics_get_irq;
+                ppc_md.cpu_irq_down   = xics_teardown_cpu;
         }
 
 #ifdef CONFIG_SMP
diff --git a/arch/ppc64/kernel/setup.c b/arch/ppc64/kernel/setup.c
index 0a47a5ef428d..d5e4866e9ac2 100644
--- a/arch/ppc64/kernel/setup.c
+++ b/arch/ppc64/kernel/setup.c
@@ -677,11 +677,16 @@ void __init setup_system(void)
         DBG(" <- setup_system()\n");
 }
 
-
-void machine_restart(char *cmd)
+/* also used by kexec */
+void machine_shutdown(void)
 {
         if (ppc_md.nvram_sync)
                 ppc_md.nvram_sync();
+}
+
+void machine_restart(char *cmd)
+{
+        machine_shutdown();
         ppc_md.restart(cmd);
 #ifdef CONFIG_SMP
         smp_send_stop();
@@ -690,13 +695,11 @@ void machine_restart(char *cmd)
         local_irq_disable();
         while (1) ;
 }
-
 EXPORT_SYMBOL(machine_restart);
-  
+
 void machine_power_off(void)
 {
-        if (ppc_md.nvram_sync)
-                ppc_md.nvram_sync();
+        machine_shutdown();
         ppc_md.power_off();
 #ifdef CONFIG_SMP
         smp_send_stop();
@@ -705,13 +708,11 @@ void machine_power_off(void)
         local_irq_disable();
         while (1) ;
 }
-
 EXPORT_SYMBOL(machine_power_off);
-  
+
 void machine_halt(void)
 {
-        if (ppc_md.nvram_sync)
-                ppc_md.nvram_sync();
+        machine_shutdown();
         ppc_md.halt();
 #ifdef CONFIG_SMP
         smp_send_stop();
@@ -720,7 +721,6 @@ void machine_halt(void)
         local_irq_disable();
         while (1) ;
 }
-
 EXPORT_SYMBOL(machine_halt);
 
 static int ppc64_panic_event(struct notifier_block *this,
diff --git a/arch/ppc64/kernel/xics.c b/arch/ppc64/kernel/xics.c
index 879f39b90a33..677c4450984a 100644
--- a/arch/ppc64/kernel/xics.c
+++ b/arch/ppc64/kernel/xics.c
@@ -647,6 +647,31 @@ static void xics_set_affinity(unsigned int virq, cpumask_t cpumask)
         }
 }
 
+void xics_teardown_cpu(void)
+{
+        int cpu = smp_processor_id();
+        int status;
+
+        ops->cppr_info(cpu, 0x00);
+        iosync();
+
+        /*
+         * we need to EOI the IPI if we got here from kexec down IPI
+         *
+         * xics doesn't care if we duplicate an EOI as long as we
+         * don't EOI and raise priority.
+         *
+         * probably need to check all the other interrupts too
+         * should we be flagging idle loop instead?
+         * or creating some task to be scheduled?
+         */
+        ops->xirr_info_set(cpu, XICS_IPI);
+
+        status = rtas_set_indicator(GLOBAL_INTERRUPT_QUEUE,
+                (1UL << interrupt_server_size) - 1 - default_distrib_server, 0);
+        WARN_ON(status != 0);
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 
 /* Interrupts are disabled. */