Messages in this thread Patch in this message | | | Date | Sat, 6 Oct 2012 19:10:10 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 5/7] uprobes: Introduce uprobe_copy_insn() |
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On 10/06, Srikar Dronamraju wrote: > > * Oleg Nesterov <oleg@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 <oleg@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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