Re: [RFC perf/core 04/11] uprobes: Add data argument to uprobe_write_opcode function

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Nov 14, 2024 at 03:41:08PM -0800, Andrii Nakryiko wrote:
> On Tue, Nov 5, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding data argument to uprobe_write_opcode function and passing
> > it to newly added arch overloaded functions:
> >
> >   arch_uprobe_verify_opcode
> >   arch_uprobe_is_register
> >
> > This way each architecture can provide custmized verification.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  include/linux/uprobes.h |  6 +++++-
> >  kernel/events/uprobes.c | 25 +++++++++++++++++++------
> >  2 files changed, 24 insertions(+), 7 deletions(-)
> >
> > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> > index 7d23a4fee6f4..be306028ed59 100644
> > --- a/include/linux/uprobes.h
> > +++ b/include/linux/uprobes.h
> > @@ -182,7 +182,7 @@ 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 *insn, int len);
> > +                              unsigned long vaddr, uprobe_opcode_t *insn, int len, void *data);
> >  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);
> > @@ -215,6 +215,10 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs);
> >  extern void *arch_uretprobe_trampoline(unsigned long *psize);
> >  extern unsigned long uprobe_get_trampoline_vaddr(void);
> >  extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
> > +extern int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
> > +extern int arch_uprobe_verify_opcode(struct page *page, unsigned long vaddr,
> > +                                    uprobe_opcode_t *new_opcode, void *data);
> > +extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int len, void *data);
> >  #else /* !CONFIG_UPROBES */
> >  struct uprobes_state {
> >  };
> > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> > index 3e275717789b..944d9df1f081 100644
> > --- a/kernel/events/uprobes.c
> > +++ b/kernel/events/uprobes.c
> > @@ -264,7 +264,13 @@ static void copy_to_page(struct page *page, unsigned long vaddr, const void *src
> >         kunmap_atomic(kaddr);
> >  }
> >
> > -static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
> > +__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int len, void *data)
> > +{
> > +       return is_swbp_insn(insn);
> > +}
> > +
> > +int uprobe_verify_opcode(struct page *page, unsigned long vaddr,
> > +                        uprobe_opcode_t *new_opcode)
> >  {
> >         uprobe_opcode_t old_opcode;
> >         bool is_swbp;
> > @@ -292,6 +298,12 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
> >         return 1;
> >  }
> >
> > +__weak int arch_uprobe_verify_opcode(struct page *page, unsigned long vaddr,
> > +                                    uprobe_opcode_t *new_opcode, void *data)
> 
> why wrapping lines? even original longer code was single line

hm, adding 'uprobe_opcode_t *new_opcode' would make the line over 100 chars,
but right, surrouding code is not strict ;-) ok

jirka

> 
> 
> > +{
> > +       return uprobe_verify_opcode(page, vaddr, new_opcode);
> > +}
> > +
> >  static struct delayed_uprobe *
> >  delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
> >  {
> > @@ -471,7 +483,8 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
> >   * Return 0 (success) or a negative errno.
> >   */
> >  int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> > -                       unsigned long vaddr, uprobe_opcode_t *insn, int len)
> > +                       unsigned long vaddr, uprobe_opcode_t *insn, int len,
> > +                       void *data)
> >  {
> >         struct uprobe *uprobe;
> >         struct page *old_page, *new_page;
> > @@ -480,7 +493,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> >         bool orig_page_huge = false;
> >         unsigned int gup_flags = FOLL_FORCE;
> >
> > -       is_register = is_swbp_insn(insn);
> > +       is_register = arch_uprobe_is_register(insn, len, data);
> >         uprobe = container_of(auprobe, struct uprobe, arch);
> >
> >  retry:
> > @@ -491,7 +504,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> >         if (IS_ERR(old_page))
> >                 return PTR_ERR(old_page);
> >
> > -       ret = verify_opcode(old_page, vaddr, insn);
> > +       ret = arch_uprobe_verify_opcode(old_page, vaddr, insn, data);
> >         if (ret <= 0)
> >                 goto put_old;
> >
> > @@ -584,7 +597,7 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned
> >  {
> >         uprobe_opcode_t insn = UPROBE_SWBP_INSN;
> >
> > -       return uprobe_write_opcode(auprobe, mm, vaddr, &insn, UPROBE_SWBP_INSN_SIZE);
> > +       return uprobe_write_opcode(auprobe, mm, vaddr, &insn, UPROBE_SWBP_INSN_SIZE, NULL);
> >  }
> >
> >  /**
> > @@ -600,7 +613,7 @@ int __weak
> >  set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
> >  {
> >         return uprobe_write_opcode(auprobe, mm, vaddr,
> > -                       (uprobe_opcode_t *)&auprobe->insn, UPROBE_SWBP_INSN_SIZE);
> > +                       (uprobe_opcode_t *)&auprobe->insn, UPROBE_SWBP_INSN_SIZE, NULL);
> >  }
> >
> >  /* uprobe should have guaranteed positive refcount */
> > --
> > 2.47.0
> >