1. 30 Nov, 2008 3 commits
    • Arnd Bergmann's avatar
      powerpc/cell/axon-msi: Retry on missing interrupt · d015fe99
      Arnd Bergmann authored
      The MSI capture logic for the axon bridge can sometimes
      lose interrupts in case of high DMA and interrupt load,
      when it signals an MSI interrupt to the MPIC interrupt
      controller while we are already handling another MSI.
      Each MSI vector gets written into a FIFO buffer in main
      memory using DMA, and that DMA access is normally flushed
      by the actual interrupt packet on the IOIF.  An MMIO
      register in the MSIC holds the position of the last
      entry in the FIFO buffer that was written.  However,
      reading that position does not flush the DMA, so that
      we can observe stale data in the buffer.
      In a stress test, we have observed the DMA to arrive
      up to 14 microseconds after reading the register.
      This patch works around this problem by retrying the
      access to the FIFO buffer.
      We can reliably detect the conditioning by writing
      an invalid MSI vector into the FIFO buffer after
      reading from it, assuming that all MSIs we get
      are valid.  After detecting an invalid MSI vector,
      we udelay(1) in the interrupt cascade for up to
      100 times before giving up.
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Dave Hansen's avatar
      powerpc: Fix boot freeze on machine with empty memory node · 4a618669
      Dave Hansen authored
      I got a bug report about a distro kernel not booting on a particular
      machine.  It would freeze during boot:
      > ...
      > Could not find start_pfn for node 1
      > [boot]0015 Setup Done
      > Built 2 zonelists in Node order, mobility grouping on.  Total pages: 123783
      > Policy zone: DMA
      > Kernel command line:
      > [boot]0020 XICS Init
      > [boot]0021 XICS Done
      > PID hash table entries: 4096 (order: 12, 32768 bytes)
      > clocksource: timebase mult[7d0000] shift[22] registered
      > Console: colour dummy device 80x25
      > console handover: boot [udbg0] -> real [hvc0]
      > Dentry cache hash table entries: 1048576 (order: 7, 8388608 bytes)
      > Inode-cache hash table entries: 524288 (order: 6, 4194304 bytes)
      > freeing bootmem node 0
      I've reproduced this on  It is caused by commit
       ("powerpc: Reserve in bootmem
      lmb reserved regions that cross NUMA nodes").
      The problem is that Jon took a loop which was (in pseudocode):
      		NODE_DATA(nid) = careful_alloc(nid);
      and broke it up into:
      		NODE_DATA(nid) = careful_alloc(nid);
      The issue comes in when the 'careful_alloc()' is called on a node with
      no memory.  It falls back to using bootmem from a previously-initialized
      node.  But, bootmem has not yet been reserved when Jon's patch is
      applied.  It gives back bogus memory (0xc000000000000000) and pukes
      later in boot.
      The following patch collapses the loop back together.  It also breaks
      the mark_reserved_regions_for_nid() code out into a function and adds
      some comments.  I think a huge part of introducing this bug is because
      for loop was too long and hard to read.
      The actual bug fix here is the:
      +		if (end_pfn <= node->node_start_pfn ||
      +		    start_pfn >= node_end_pfn)
      +			continue;
      Signed-off-by: default avatarDave Hansen <dave@linux.vnet.ibm.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Adhemerval Zanella's avatar
      powerpc: Fix IRQ assignment for some PCIe devices · 4b824de9
      Adhemerval Zanella authored
      Currently, some PCIe devices on POWER6 machines do not get interrupts
      assigned correctly.  The problem is that OF doesn't create an
      "interrupt" property for them.  The fix is for of_irq_map_pci to fall
      back to using the value in the PCI interrupt-pin register in config
      space, as we do when there is no OF device-tree node for the device.
      I have verified that this works fine with a pair of Squib-E SAS
      adapter on a P6-570.
      Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
  2. 20 Nov, 2008 1 commit
    • Jeremy Kerr's avatar
      powerpc/spufs: Fix spinning in spufs_ps_fault on signal · 60657263
      Jeremy Kerr authored
      Currently, we can end up in an infinite loop if we get a signal
      while the kernel has faulted in spufs_ps_fault. Eg:
       write(fd, some_spu_psmap_register_address, 4);
      - the write's copy_from_user will fault on the ps mapping, and
      signal_pending will be non-zero. Because returning from the fault
      handler will never clear TIF_SIGPENDING, so we'll just keep faulting,
      resulting in an unkillable process using 100% of CPU.
      This change returns VM_FAULT_SIGBUS if there's a fatal signal pending,
      letting us escape the loop.
      Signed-off-by: default avatarJeremy Kerr <jk@ozlabs.org>
  3. 19 Nov, 2008 3 commits
  4. 14 Nov, 2008 4 commits
  5. 13 Nov, 2008 2 commits
  6. 11 Nov, 2008 2 commits
  7. 08 Nov, 2008 4 commits
    • Kumar Gala's avatar
      powerpc: Updated Freescale PPC related defconfigs · ea37194d
      Kumar Gala authored
      unset CONFIG_PCI_LEGACY in the defconfigs as none of them enable
      ISDN drivers which seem to be the only place we are using pci_find_device
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
    • Li Yang's avatar
      powerpc: Update QE/CPM2 usb_ctlr structures for USB support · 2b487065
      Li Yang authored
      Fixes following build error:
        CC      drivers/usb/gadget/fsl_qe_udc.o
      drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eprx_stall_change':
      drivers/usb/gadget/fsl_qe_udc.c:156: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c:163: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eptx_stall_change':
      drivers/usb/gadget/fsl_qe_udc.c:173: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c:180: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eprx_nack':
      drivers/usb/gadget/fsl_qe_udc.c:201: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c:201: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eprx_normal':
      drivers/usb/gadget/fsl_qe_udc.c:218: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c:218: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_ep_reset':
      drivers/usb/gadget/fsl_qe_udc.c:325: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c:342: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_ep_register_init':
      drivers/usb/gadget/fsl_qe_udc.c:515: error: 'struct usb_ctlr' has no member named 'usb_usep'
      drivers/usb/gadget/fsl_qe_udc.c: In function 'ch9getstatus':
      drivers/usb/gadget/fsl_qe_udc.c:1981: error: 'struct usb_ctlr' has no member named 'usb_usep'
      make[2]: *** [drivers/usb/gadget/fsl_qe_udc.o] Error 1
      Signed-off-by: default avatarLi Yang <leoli@freescale.com>
      Signed-off-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
    • Martyn Welch's avatar
      powerpc/86xx: Correct SOC bus-frequency in GE Fanuc SBC610 DTS · 33d2d78b
      Martyn Welch authored
      This patch corrects the bus-frequency value provided in the SBC610's dts.
      Signed-off-by: default avatarMartyn Welch <martyn.welch@gefanuc.com>
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
    • Kumar Gala's avatar
      powerpc/fsl-booke: Fix synchronization bug w/local tlb invalidates · b41d6fee
      Kumar Gala authored
      The implemetation of _tlbil_pid() on Freescale Book-E cores needs
      an msync & isync after we flash invalidate the TLBs.  This was causing
      the following oops reported by Sebastian Andrzej Siewior:
        VFS: Mounted root (nfs filesystem) readonly.
        Freeing unused kernel memory: 148k init
        BUG: sleeping function called from invalid context at /home/bigeasy/git/linux-2.6-powerpc/mm/mmap.c:234
        in_atomic():1, irqs_disabled():0
        Call Trace:
        [df189df0] [c0007160] show_stack+0x48/0x148 (unreliable)
        [df189e30] [c0029480] __might_sleep+0xf0/0x100
        [df189e40] [c0070ac0] remove_vma+0x28/0x98
        [df189e50] [c0070c1c] exit_mmap+0xec/0x128
        [df189e80] [c002d2f4] mmput+0x54/0xec
        [df189ea0] [c0030b6c] exit_mm+0x10c/0x120
        [df189ed0] [c003288c] do_exit+0x1ac/0x6e8
        [df189f20] [c0032e48] do_group_exit+0x80/0xac
        [df189f40] [c000e9dc] ret_from_syscall+0x0/0x3c
        BUG: scheduling while atomic: udevd/956/0x10000002
        Modules linked in:
        Call Trace:
        [df189df0] [c0007160] show_stack+0x48/0x148 (unreliable)
        [df189e30] [c002ac88] __schedule_bug+0x58/0x6c
        [df189e40] [c023e6cc] schedule+0xa8/0x4a8
        [df189e90] [c002ad6c] __cond_resched+0x38/0x64
        [df189ea0] [c023ebc8] _cond_resched+0x3c/0x58
        [df189eb0] [c0030e70] put_files_struct+0x90/0xec
        [df189ed0] [c00328a8] do_exit+0x1c8/0x6e8
        [df189f20] [c0032e48] do_group_exit+0x80/0xac
        [df189f40] [c000e9dc] ret_from_syscall+0x0/0x3c
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
  8. 05 Nov, 2008 2 commits
  9. 31 Oct, 2008 19 commits
    • Carl Love's avatar
      Cell OProfile: Incorrect local array size in activate spu profiling function · 99219b4f
      Carl Love authored
      Updated the patch to address comments by Michael Ellerman.
      Specifically, changed upper limit in for loop to
      ARRAY_SIZE() macro and added a check to make sure the
      number of events specified by the user, which is used as
      the max for indexing various arrays, is no bigger then the
      declared size of the arrays.
      The size of the pm_signal_local array should be equal to the
      number of SPUs being configured in the array.  Currently, the
      array is of size 4 (NR_PHYS_CTRS) but being indexed by a for
      loop from 0 to 7 (NUM_SPUS_PER_NODE).
      Signed-off-by: default avatarCarl Love <carll@us.ibm.com>
    • Robert Richter's avatar
    • Paul Mackerras's avatar
      Revert "powerpc: Sync RPA note in zImage with kernel's RPA note" · 5663a123
      Paul Mackerras authored
      This reverts commit 91a00302, plus
      commit 0dcd4401 ("powerpc: Revert CHRP
      boot wrapper to real-base = 12MB on 32-bit") which depended on it.
      Commit 91a00302
       was causing NVRAM corruption on some pSeries machines,
      for as-yet unknown reasons, so this reverts it until the cause is
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Paul Mackerras's avatar
      powerpc: Fix compile errors with CONFIG_BUG=n · ebdba9af
      Paul Mackerras authored
      This makes sure we don't try to call find_bug or is_warning_bug when
      CONFIG_BUG=n and CONFIG_XMON=y.  Otherwise we get these errors:
      arch/powerpc/xmon/xmon.c: In function ‘print_bug_trap’:
      arch/powerpc/xmon/xmon.c:1364: error: implicit declaration of function ‘find_bug’
      arch/powerpc/xmon/xmon.c:1364: warning: assignment makes pointer from integer without a cast
      arch/powerpc/xmon/xmon.c:1367: error: implicit declaration of function ‘is_warning_bug’
      arch/powerpc/xmon/xmon.c:1374: error: dereferencing pointer to incomplete type
      make[2]: *** [arch/powerpc/xmon/xmon.o] Error 1
      make[1]: *** [arch/powerpc/xmon] Error 2
      make: *** [sub-make] Error 2
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Jon Smirl's avatar
      powerpc: Fix format string warning in arch/powerpc/boot/main.c · 8ba4773a
      Jon Smirl authored
      Fix format string warning in arch/powerpc/boot/main.c.  Also correct
      a typo ("uncomressed") on the same line.
       BOOTCC  arch/powerpc/boot/main.o
      arch/powerpc/boot/main.c: In function 'prep_kernel':
      arch/powerpc/boot/main.c:65: warning: format '%08x' expects type
      'unsigned int', but argument 3 has type 'long unsigned int'
      Signed-off-by: default avatarJon Smirl <jonsmirl@gmail.com>
      Acked-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • David Gibson's avatar
      powerpc: Fix bug in kernel copy of libfdt's fdt_subnode_offset_namelen() · 2dccbf4e
      David Gibson authored
      There's currently an off-by-one bug in fdt_subnode_offset_namelen()
      which causes it to keep searching after it's finished the subnodes of
      the given parent, and into the subnodes of siblings of the original
      node which come after it in the tree.  This bug was introduced in
      commit ed95d745
       ("powerpc: Update
      in-kernel dtc and libfdt to version 1.2.0").
      A patch has already been submitted to dtc/libfdt mainline.  We don't
      really want to pull in a new upstream version during the 2.6.28 cycle,
      but we should still fix this bug, hence this standalone version of the
      fix for the in-kernel libfdt.
      Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Mike Dyer's avatar
      powerpc: Remove duplicate DMA entry from mpc8313erdb device tree · 65325d5c
      Mike Dyer authored
      Commit 57436612
       added a duplicate
      DMA controller node.
      Signed-off-by: default avatarMike Dyer <mike.dyer@provision-comm.com>
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
    • Carl Love's avatar
      powerpc/cell/OProfile: Fix on-stack array size in activate spu profiling function · 210434d7
      Carl Love authored
      The size of the pm_signal_local array should be equal to the
      number of SPUs being configured in the array.  Currently, the
      array is of size 4 (NR_PHYS_CTRS) but being indexed by a for
      loop from 0 to 7 (NUM_SPUS_PER_NODE).  This could potentially
      cause an oops or random memory corruption since the pm_signal_local
      array is on the stack.  This fixes it.
      Signed-off-by: default avatarCarl Love <carll@us.ibm.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Kumar Gala's avatar
      powerpc/mpic: Fix regression caused by change of default IRQ affinity · 3c10c9c4
      Kumar Gala authored
      The Freescale implementation of MPIC only allows a single CPU destination
      for non-IPI interrupts.  We add a flag to the mpic_init to distinquish
      these variants of MPIC.  We pull in the irq_choose_cpu from sparc64 to
      select a single CPU as the destination of the interrupt.
      This is to deal with the fact that the default smp affinity was
      changed by commit 18404756
      Expose default irq affinity mask (take 3)") to be all CPUs.
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Mark Nelson's avatar
      powerpc: Update remaining dma_mapping_ops to use map/unmap_page · f9226d57
      Mark Nelson authored
      After the merge of the 32 and 64bit DMA code, dma_direct_ops lost
      their map/unmap_single() functions but gained map/unmap_page().  This
      caused a problem for Cell because Cell's dma_iommu_fixed_ops called
      the dma_direct_ops if the fixed linear mapping was to be used or the
      iommu ops if the dynamic window was to be used.  So in order to fix
      this problem we need to update the 64bit DMA code to use
      First, we update the generic IOMMU code so that iommu_map_single()
      becomes iommu_map_page() and iommu_unmap_single() becomes
      iommu_unmap_page().  Then we propagate these changes up through all
      the callers of these two functions and in the process update all the
      dma_mapping_ops so that they have map/unmap_page rahter than
      map/unmap_single.  We can do this because on 64bit there is no HIGHMEM
      memory so map/unmap_page ends up performing exactly the same function
      as map/unmap_single, just taking different arguments.
      This has no affect on drivers because the dma_map_single_attrs() just
      ends up calling the map_page() function of the appropriate
      dma_mapping_ops and similarly the dma_unmap_single_attrs() calls
      This fixes an oops on Cell blades, which oops on boot without this
      because they call dma_direct_ops.map_single, which is NULL.
      Signed-off-by: default avatarMark Nelson <markn@au1.ibm.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Benjamin Herrenschmidt's avatar
      powerpc/pci: Fix unmapping of IO space on 64-bit · b30115ea
      Benjamin Herrenschmidt authored
      A typo/thinko made us pass the wrong argument to __flush_hash_table_range
      when unplugging bridges, thus not flushing all the translations for
      the IO space on unplug.  The third parameter to __flush_hash_table_range
      is `end', not `size'.
      This causes the hypervisor to refuse unplugging slots.
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Nathan Fontenot's avatar
      powerpc/pci: Properly allocate bus resources for hotplug PHBs · e90a1318
      Nathan Fontenot authored
      Resources for PHB's that are dynamically added to a system are not
      properly allocated in the resource tree.
      Not having these resources allocated causes an oops when removing
      the PHB when we try to release them.
      The diff appears a bit messy, this is mainly due to moving everything
      one tab to the left in the pcibios_allocate_bus_resources routine.
      The functionality change in this routine is only that the
      list_for_each_entry() loop is pulled out and moved to the necessary
      calling routine.
      Signed-off-by: default avatarNathan Fontenot <nfont@austin.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Jeremy Kerr's avatar
      OF-device: Don't overwrite numa_node in device registration · 6098e2ee
      Jeremy Kerr authored
      Currently, the numa_node of OF-devices will be overwritten during
      device_register, which simply sets the node to -1.  On cell machines,
      this means that devices can't find their IOMMU, which is referenced
      through the device's numa node.
      Set the numa node for OF devices with no parent, and use the
      lower-level device_initialize and device_add functions, so that the
      node is preserved.
      We can remove the call to set_dev_node in of_device_alloc, as it
      will be overwritten during register.
      Signed-off-by: default avatarJeremy Kerr <jk@ozlabs.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Michael Neuling's avatar
      powerpc: Fix swapcontext system for VSX + old ucontext size · 16c29d18
      Michael Neuling authored
      Since VSX support was added, we now have two sizes of ucontext_t;
      the older, smaller size without the extra VSX state, and the new
      larger size with the extra VSX state.  A program using the
      sys_swapcontext system call and supplying smaller ucontext_t
      structures will currently get an EINVAL error if the task has
      used VSX (e.g. because of calling library code that uses VSX) and
      the old_ctx argument is non-NULL (i.e. the program is asking for
      its current context to be saved).  Thus the program will start
      getting EINVAL errors on calls that previously worked.
      This commit changes this behaviour so that we don't send an EINVAL in
      this case.  It will now return the smaller context but the VSX MSR bit
      will always be cleared to indicate that the ucontext_t doesn't include
      the extra VSX state, even if the task has executed VSX instructions.
      Both 32 and 64 bit cases are updated.
      [paulus@samba.org - also fix some access_ok() and get_user() calls]
      Thanks to Ben Herrenschmidt for noticing this problem.
      Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Michael Neuling's avatar
      powerpc: Fix compiler warning for the relocatable kernel · b160544c
      Michael Neuling authored
      Fixes this warning:
       arch/powerpc/kernel/setup_64.c:447:5: warning: "kernstart_addr" is not defined
      which arises because PHYSICAL_START is no longer a constant when
      Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Paul Mackerras's avatar
      powerpc: Work around ld bug in older binutils · 2a4b9c5a
      Paul Mackerras authored
      Commit 549e8152
       ("powerpc: Make the
      64-bit kernel as a position-independent executable") added lines to
      vmlinux.lds.S to add the extra sections needed to implement a
      relocatable kernel.  However, those lines seem to trigger a bug in
      older versions of GNU ld (such as 2.16.1) when building a
      non-relocatable kernel.  Since ld 2.16.1 is still a popular choice for
      cross-toolchains, this adds an #ifdef to vmlinux.lds.S so the added
      lines are only included when building a relocatable kernel.
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Milton Miller's avatar
      powerpc/ppc64/kdump: Better flag for running relocatable · 8b8b0cc1
      Milton Miller authored
      The __kdump_flag ABI is overly constraining for future development.
      As of 2.6.27, the kernel entry point has 4 constraints:  Offset 0 is
      the starting point for the master (boot) cpu (entered with r3 pointing
      to the device tree structure), offset 0x60 is code for the slave cpus
      (entered with r3 set to their device tree physical id), offset 0x20 is
      used by the iseries hypervisor, and secondary cpus must be well behaved
      when the first 256 bytes are copied to address 0.
      Placing the __kdump_flag at 0x18 is bad because:
      - It was taking the last 8 bytes before the iseries hypervisor data.
      - It was 8 bytes for a boolean flag
      - It had no way of identifying that the flag was present
      - It does leave any room for the master to add any additional code
        before branching, which hurts debug.
      - It will be unnecessarily hard for 32 bit code to be common (8 bytes)
      Now that we have eliminated the use of __kdump_flag in favor of
      the standard is_kdump_kernel(), this flag only controls run without
      relocating the kernel to PHYSICAL_START (0), so rename it __run_at_load.
      Move the flag to 0x5c, 1 word before the secondary cpu entry point at
      0x60.  Initialize it with "run0" to say it will run at 0 unless it is
      set to 1.  It only exists if we are relocatable.
      Signed-off-by: default avatarMilton Miller <miltonm@bga.com>
      Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Milton Miller's avatar
      powerpc: Use is_kdump_kernel() · 62a8bd6c
      Milton Miller authored
      linux/crash_dump.h defines is_kdump_kernel() to be used by code that
      needs to know if the previous kernel crashed instead of a (clean) boot
      or reboot.
      This updates the just added powerpc code to use it.  This is needed
      for the next commit, which will remove __kdump_flag.
      Signed-off-by: default avatarMilton Miller <miltonm@bga.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    • Milton Miller's avatar
      powerpc: Kexec exit should not use magic numbers · 1767c8f3
      Milton Miller authored
      Commit 54622f10
       ("powerpc: Support for
      relocatable kdump kernel") added a magic flag value in a register to
      tell purgatory that it should be a panic kernel.  This part is wrong
      and is reverted by this commit.
      The kernel gets a list of memory blocks and a entry point from user space.
      Its job is to copy the blocks into place and then branch to the designated
      entry point (after turning "off" the mmu).
      The user space tool inserts a trampoline, called purgatory, that runs
      before the user supplied code.   Its job is to establish the entry
      environment for the new kernel or other application based on the contents
      of memory.  The purgatory code is compiled and embedded in the tool,
      where it is later patched using the elf symbol table using elf symbols.
      Since the tool knows it is creating a purgatory that will run after a
      kernel crash, it should just patch purgatory (or the kernel directly)
      if something needs to happen.
      Signed-off-by: default avatarMilton Miller <miltonm@bga.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>