2 files changed, 18 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 5355244c99ff..60c60ccf5e3c 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -195,8 +195,9 @@ __ftrace_make_nop(struct module *mod,
                 return -EINVAL;
         }
 
-        offset = (unsigned)((unsigned short)jmp[0]) << 16 |
-                (unsigned)((unsigned short)jmp[1]);
+        /* The bottom half is signed extended */
+        offset = ((unsigned)((unsigned short)jmp[0]) << 16) +
+                (int)((short)jmp[1]);
 
         DEBUGP(" %x ", offset);
 
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 19b12d2cbb4b..0f4181272311 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -561,8 +561,21 @@ int pci_mmap_legacy_page_range(struct pci_bus *bus,
                  (unsigned long long)(offset + size - 1));
 
         if (mmap_state == pci_mmap_mem) {
-                if ((offset + size) > hose->isa_mem_size)
-                        return -ENXIO;
+                /* Hack alert !
+                 *
+                 * Because X is lame and can fail starting if it gets an error trying
+                 * to mmap legacy_mem (instead of just moving on without legacy memory
+                 * access) we fake it here by giving it anonymous memory, effectively
+                 * behaving just like /dev/zero
+                 */
+                if ((offset + size) > hose->isa_mem_size) {
+                        printk(KERN_DEBUG
+                               "Process %s (pid:%d) mapped non-existing PCI legacy memory for 0%04x:%02x\n",
+                               current->comm, current->pid, pci_domain_nr(bus), bus->number);
+                        if (vma->vm_flags & VM_SHARED)
+                                return shmem_zero_setup(vma);
+                        return 0;
+                }
                 offset += hose->isa_mem_phys;
         } else {
                 unsigned long io_offset = (unsigned long)hose->io_base_virt - _IO_BASE;