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uprobes: Introduce prepare_uprobe()

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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>
This commit is contained in:
Oleg Nesterov 2012-09-30 20:11:45 +02:00
parent 142b18ddc8
commit cb9a19fe4a
2 changed files with 41 additions and 29 deletions
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10
include/linux/uprobes.h
View File

@ -35,16 +35,6 @@ struct inode;
# include <asm/uprobes.h> # include <asm/uprobes.h>
#endif #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 { struct uprobe_consumer {
int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs); int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
/* /*

60
kernel/events/uprobes.c
View File

@ -78,6 +78,13 @@ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
*/ */
static atomic_t uprobe_events = ATOMIC_INIT(0); 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 uprobe {
struct rb_node rb_node; /* node in the rb tree */ struct rb_node rb_node; /* node in the rb tree */
atomic_t ref; 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); 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 static int
install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long vaddr) struct vm_area_struct *vma, unsigned long vaddr)
@ -580,25 +618,9 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
if (!uprobe->consumers) if (!uprobe->consumers)
return 0; return 0;
if (!(uprobe->flags & UPROBE_COPY_INSN)) { ret = prepare_uprobe(uprobe, vma->vm_file, mm, vaddr);
ret = copy_insn(uprobe, vma->vm_file); if (ret)
if (ret) return 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;
}
/* /*
* set MMF_HAS_UPROBES in advance for uprobe_pre_sstep_notifier(), * set MMF_HAS_UPROBES in advance for uprobe_pre_sstep_notifier(),