Re: [RFC perf/core 02/11] uprobes: Make copy_from_page global

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Nov 14, 2024 at 03:40:58PM -0800, Andrii Nakryiko wrote:
> On Tue, Nov 5, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Making copy_from_page global and adding uprobe prefix.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  include/linux/uprobes.h |  1 +
> >  kernel/events/uprobes.c | 10 +++++-----
> >  2 files changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> > index 2f500bc97263..28068f9fcdc1 100644
> > --- a/include/linux/uprobes.h
> > +++ b/include/linux/uprobes.h
> > @@ -213,6 +213,7 @@ extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
> >  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);
> >  #else /* !CONFIG_UPROBES */
> >  struct uprobes_state {
> >  };
> > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> > index 0b04c051d712..e9308649bba3 100644
> > --- a/kernel/events/uprobes.c
> > +++ b/kernel/events/uprobes.c
> > @@ -250,7 +250,7 @@ bool __weak is_trap_insn(uprobe_opcode_t *insn)
> >         return is_swbp_insn(insn);
> >  }
> >
> > -static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
> > +void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
> >  {
> >         void *kaddr = kmap_atomic(page);
> >         memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
> > @@ -278,7 +278,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
> >          * is a trap variant; uprobes always wins over any other (gdb)
> >          * breakpoint.
> >          */
> > -       copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
> > +       uprobe_copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
> >         is_swbp = is_swbp_insn(&old_opcode);
> >
> >         if (is_swbp_insn(new_opcode)) {
> > @@ -1027,7 +1027,7 @@ static int __copy_insn(struct address_space *mapping, struct file *filp,
> >         if (IS_ERR(page))
> >                 return PTR_ERR(page);
> >
> > -       copy_from_page(page, offset, insn, nbytes);
> > +       uprobe_copy_from_page(page, offset, insn, nbytes);
> >         put_page(page);
> >
> >         return 0;
> > @@ -1368,7 +1368,7 @@ struct uprobe *uprobe_register(struct inode *inode,
> >                 return ERR_PTR(-EINVAL);
> >
> >         /*
> > -        * This ensures that copy_from_page(), copy_to_page() and
> > +        * This ensures that uprobe_copy_from_page(), copy_to_page() and
> 
> rename copy_to_page() for symmetry?

ok

jirka

> 
> 
> >          * __update_ref_ctr() can't cross page boundary.
> >          */
> >         if (!IS_ALIGNED(offset, UPROBE_SWBP_INSN_SIZE))
> > @@ -2288,7 +2288,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
> >         if (result < 0)
> >                 return result;
> >
> > -       copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
> > +       uprobe_copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
> >         put_page(page);
> >   out:
> >         /* This needs to return true for any variant of the trap insn */
> > --
> > 2.47.0
> >