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authorOleg Nesterov <oleg@redhat.com>2012-09-30 20:11:45 +0200
committerAnton Arapov <anton@redhat.com>2012-10-29 11:47:49 +0100
commit3d5b130382e853547624f058049b704561d31b99 (patch)
treef2408b4ed81d813fcd4c661c73ef0b34a3b3081c
parent05b2fce312e33f1ea0fa5b47992ad8302ffc4dd7 (diff)
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uprobes: Introduce prepare_uprobe()
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>
-rw-r--r--include/linux/uprobes.h10
-rw-r--r--kernel/events/uprobes.c60
2 files changed, 41 insertions, 29 deletions
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 18d839d..2459457 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -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);
/*
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c718fef..4f315fa 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -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(),