On 10/06, Srikar Dronamraju wrote:
>
> * Oleg Nesterov <o...@redhat.com> [2012-09-30 21:42:17]:
>
> > +static int uprobe_copy_insn(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;
> > + ret = 0;
> > + out:
> > + return ret;
> > +}
> > +
>
> 2 nits:
> why do we need to reset ret before out label? I think its redudant.
> arch_uprobe_analyze_insn() should have set it to 0 already. No?
OK,
> blank line above out:
OK, see the updated patch below.
> Currently only extern functions start with uprobe_ but we already have
> copy_insn, and __copy_insn, So can think of any names for
> uprobe_copy_insn.
Yes ;) plus it is not only "copy", it does _analyze
> Not sure test_and_copy_insn() is a good alternative.
perhaps prepare_uprobe()... But I agree with any naming, just tell me
what you prefer and I'll update the patch again.
==============================================================================
[PATCH 5/7] uprobes: Introduce uprobe_copy_insn()
Preparation. Extract the copy_insn/arch_uprobe_analyze_insn code
from install_breakpoint() into the new helper, uprobe_copy_insn().
And move uprobe->flags defines from uprobes.h to uprobes.c, nobody
else can use them anyway.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
include/linux/uprobes.h | 10 --------
kernel/events/uprobes.c | 60 ++++++++++++++++++++++++++++++++---------------
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 dd44311..98b60bc 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 uprobe_copy_insn(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 = uprobe_copy_insn(uprobe, vma->vm_file, mm, vaddr);
+ if (ret)
+ return ret;
/*
* set MMF_HAS_UPROBES in advance for uprobe_pre_sstep_notifier(),
--
1.5.5.1
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