linux-kernel - Re: [RFC perf/core 04/11] uprobes: Add data argument to uprobe_write

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Message-ID: <CAEf4Bzbufp=pSqNHZu6+FPAqGSOqoE56R4KnewECFbdtAe-eeg@mail.gmail.com>
Date: Thu, 14 Nov 2024 15:41:08 -0800
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Jiri Olsa <jolsa@...nel.org>
Cc: Oleg Nesterov <oleg@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Andrii Nakryiko <andrii@...nel.org>, bpf@...r.kernel.org, Song Liu <songliubraving@...com>, 
	Yonghong Song <yhs@...com>, John Fastabend <john.fastabend@...il.com>, Hao Luo <haoluo@...gle.com>, 
	Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu <mhiramat@...nel.org>, 
	Alan Maguire <alan.maguire@...cle.com>, linux-kernel@...r.kernel.org, 
	linux-trace-kernel@...r.kernel.org
Subject: Re: [RFC perf/core 04/11] uprobes: Add data argument to
 uprobe_write_opcode function

On Tue, Nov 5, 2024 at 5:34 AM Jiri Olsa <jolsa@...nel.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@...nel.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


> +{
> +       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
>