Re: [PATCH RFCv3 06/23] uprobes: Add orig argument to uprobe_write and uprobe_write_opcode

[Jiri Olsa <olsajiri@gmail.com>]

On Fri, Apr 04, 2025 at 01:33:02PM -0700, Andrii Nakryiko wrote:
> On Thu, Mar 20, 2025 at 4:43 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > The uprobe_write has special path to restore the original page when
> > we write original instruction back.
> >
> > This happens when uprobe_write detects that we want to write anything
> > else but breakpoint instruction.
> >
> > In following changes we want to use uprobe_write function for multiple
> > updates, so adding new function argument to denote that this is the
> > original instruction update. This way uprobe_write can make appropriate
> > checks and restore the original page when possible.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  arch/arm/probes/uprobes/core.c |  2 +-
> >  include/linux/uprobes.h        |  5 +++--
> >  kernel/events/uprobes.c        | 22 ++++++++++------------
> >  3 files changed, 14 insertions(+), 15 deletions(-)
> >
> > diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c
> > index f5f790c6e5f8..54a90b565285 100644
> > --- a/arch/arm/probes/uprobes/core.c
> > +++ b/arch/arm/probes/uprobes/core.c
> > @@ -30,7 +30,7 @@ int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
> >              unsigned long vaddr)
> >  {
> >         return uprobe_write_opcode(auprobe, mm, vaddr,
> > -                  __opcode_to_mem_arm(auprobe->bpinsn));
> > +                  __opcode_to_mem_arm(auprobe->bpinsn), false);
> >  }
> >
> >  bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)
> > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> > index c69a05775394..1b6a4e2b5464 100644
> > --- a/include/linux/uprobes.h
> > +++ b/include/linux/uprobes.h
> > @@ -196,9 +196,10 @@ extern bool is_swbp_insn(uprobe_opcode_t *insn);
> >  extern bool is_trap_insn(uprobe_opcode_t *insn);
> >  extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
> >  extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
> > -extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
> > +extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr,
> > +                              uprobe_opcode_t, bool);
> 
> add arg names for humans?..

yep, anything for humans.. ;-)

thanks,
jirka

> 
> >  extern int uprobe_write(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr,
> > -                       uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify);
> > +                       uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool orig);
> >  extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
> >  extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);
> >  extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);
> 
> [...]