On Tue, Jul 07, 2015 at 03:22:54AM +0200, Oleg Nesterov wrote:
> Add the new "weak" helper, arch_uretprobe_is_alive(), used by the next
> patches. It should return true if this return_instance is still valid.
> The arch agnostic version just always returns true.
>
> The patch exports "struct return_instance" for the architectures which
> want to override this hook. We can also cleanup prepare_uretprobe() if
> we pass the new return_instance to arch_uretprobe_hijack_return_addr().
>
> Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: Anton Arapov <[email protected]>
> ---
> include/linux/uprobes.h | 10 ++++++++++
> kernel/events/uprobes.c | 14 +++++---------
> 2 files changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> index 60beb5d..50d2764 100644
> --- a/include/linux/uprobes.h
> +++ b/include/linux/uprobes.h
> @@ -92,6 +92,15 @@ struct uprobe_task {
> unsigned int depth;
> };
>
> +struct return_instance {
> + struct uprobe *uprobe;
> + unsigned long func;
> + unsigned long orig_ret_vaddr; /* original return address */
> + bool chained; /* true, if instance is nested
> */
> +
> + struct return_instance *next; /* keep as stack */
> +};
> +
> struct xol_area;
>
> struct uprobes_state {
> @@ -128,6 +137,7 @@ extern bool arch_uprobe_xol_was_trapped(struct
> task_struct *tsk);
> extern int arch_uprobe_exception_notify(struct notifier_block *self,
> unsigned long val, void *data);
> extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs
> *regs);
> extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long
> trampoline_vaddr, struct pt_regs *regs);
> +extern bool arch_uretprobe_is_alive(struct return_instance *ret, struct
> pt_regs *regs);
> extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs
> *regs);
> extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
> void *src, unsigned long len);
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 98e4d97..1c71b62 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -86,15 +86,6 @@ struct uprobe {
> struct arch_uprobe arch;
> };
>
> -struct return_instance {
> - struct uprobe *uprobe;
> - unsigned long func;
> - unsigned long orig_ret_vaddr; /* original return address */
> - bool chained; /* true, if instance is nested
> */
> -
> - struct return_instance *next; /* keep as stack */
> -};
> -
> /*
> * Execute out of line area: anonymous executable mapping installed
> * by the probed task to execute the copy of the original instruction
> @@ -1818,6 +1809,11 @@ bool __weak arch_uprobe_ignore(struct arch_uprobe
> *aup, struct pt_regs *regs)
> return false;
> }
>
> +bool __weak arch_uretprobe_is_alive(struct return_instance *ret, struct
> pt_regs *regs)
> +{
> + return true;
> +}
> +
> /*
> * Run handler and ask thread to singlestep.
> * Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
> --
> 1.5.5.1
>
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