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Commit cb9a19fe authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

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: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent 142b18dd

include/linux/uprobes.h

+0 −10
Original line number Diff line number Diff line
@@ -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);

	/*

kernel/events/uprobes.c

+41 −19
Original line number Diff line number Diff line
@@ -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)
@@ -580,26 +618,10 @@ 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);

	ret = prepare_uprobe(uprobe, vma->vm_file, 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(),

	 * the task can hit this breakpoint right after __replace_page().