uprobes: Introduce prepare_uprobe()
Oleg Nesterov [Sun, 30 Sep 2012 18:11:45 +0000 (20:11 +0200)]
Preparation. Extract the copy_insn/arch_uprobe_analyze_insn code
from install_breakpoint() into the new helper, prepare_uprobe().

And move uprobe->flags defines from uprobes.h to uprobes.c, nobody
else can use them anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

include/linux/uprobes.h
kernel/events/uprobes.c

index 18d839d..2459457 100644 (file)
@@ -35,16 +35,6 @@ struct inode;
 # include <asm/uprobes.h>
 #endif
 
-/* flags that denote/change uprobes behaviour */
-
-/* Have a copy of original instruction */
-#define UPROBE_COPY_INSN       0x1
-
-/* Dont run handlers when first register/ last unregister in progress*/
-#define UPROBE_RUN_HANDLER     0x2
-/* Can skip singlestep */
-#define UPROBE_SKIP_SSTEP      0x4
-
 struct uprobe_consumer {
        int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
        /*
index c718fef..4f315fa 100644 (file)
@@ -78,6 +78,13 @@ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
  */
 static atomic_t uprobe_events = ATOMIC_INIT(0);
 
+/* Have a copy of original instruction */
+#define UPROBE_COPY_INSN       0x1
+/* Dont run handlers when first register/ last unregister in progress*/
+#define UPROBE_RUN_HANDLER     0x2
+/* Can skip singlestep */
+#define UPROBE_SKIP_SSTEP      0x4
+
 struct uprobe {
        struct rb_node          rb_node;        /* node in the rb tree */
        atomic_t                ref;
@@ -563,6 +570,37 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
        return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);
 }
 
+static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
+                               struct mm_struct *mm, unsigned long vaddr)
+{
+       int ret = 0;
+
+       if (uprobe->flags & UPROBE_COPY_INSN)
+               return ret;
+
+       ret = copy_insn(uprobe, file);
+       if (ret)
+               goto out;
+
+       ret = -ENOTSUPP;
+       if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
+               goto out;
+
+       ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
+       if (ret)
+               goto out;
+
+       /* write_opcode() assumes we don't cross page boundary */
+       BUG_ON((uprobe->offset & ~PAGE_MASK) +
+                       UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
+
+       smp_wmb(); /* pairs with rmb() in find_active_uprobe() */
+       uprobe->flags |= UPROBE_COPY_INSN;
+
+ out:
+       return ret;
+}
+
 static int
 install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
                        struct vm_area_struct *vma, unsigned long vaddr)
@@ -580,25 +618,9 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
        if (!uprobe->consumers)
                return 0;
 
-       if (!(uprobe->flags & UPROBE_COPY_INSN)) {
-               ret = copy_insn(uprobe, vma->vm_file);
-               if (ret)
-                       return ret;
-
-               if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
-                       return -ENOTSUPP;
-
-               ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
-               if (ret)
-                       return ret;
-
-               /* write_opcode() assumes we don't cross page boundary */
-               BUG_ON((uprobe->offset & ~PAGE_MASK) +
-                               UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
-
-               smp_wmb(); /* pairs with rmb() in find_active_uprobe() */
-               uprobe->flags |= UPROBE_COPY_INSN;
-       }
+       ret = prepare_uprobe(uprobe, vma->vm_file, mm, vaddr);
+       if (ret)
+               return ret;
 
        /*
         * set MMF_HAS_UPROBES in advance for uprobe_pre_sstep_notifier(),