linux-kernel - Re: [RFC PATCH 4/5] csky: ftrace: Drop duplicate implementation of arch_check_ftrace

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Date:   Wed, 9 Jun 2021 20:33:18 +0800
From:   Guo Ren <guoren@...nel.org>
To:     Punit Agrawal <punitagrawal@...il.com>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        "Naveen N . Rao" <naveen.n.rao@...ux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
        David Miller <davem@...emloft.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-csky@...r.kernel.org, Guo Ren <guoren@...ux.alibaba.com>
Subject: Re: [RFC PATCH 4/5] csky: ftrace: Drop duplicate implementation of arch_check_ftrace_location()

csky using -mcount not -fpatchable-function-entry, so
                /* Given address is not on the instruction boundary */
                if ((unsigned long)p->addr != ftrace_addr)
                        return -EILSEQ;
all right?

On Wed, Jun 9, 2021 at 6:51 PM Punit Agrawal <punitagrawal@...il.com> wrote:
>
> The csky specific arch_check_ftrace_location() shadows a weak
> implementation of the function in core code that offers the same
> functionality but with additional error checking.
>
> Drop the architecture specific function as a step towards further
> cleanup in core code.
>
> Signed-off-by: Punit Agrawal <punitagrawal@...il.com>
> Cc: Guo Ren <guoren@...ux.alibaba.com>
> ---
>  arch/csky/kernel/probes/ftrace.c | 7 -------
>  1 file changed, 7 deletions(-)
>
> diff --git a/arch/csky/kernel/probes/ftrace.c b/arch/csky/kernel/probes/ftrace.c
> index ef2bb9bd9605..b388228abbf2 100644
> --- a/arch/csky/kernel/probes/ftrace.c
> +++ b/arch/csky/kernel/probes/ftrace.c
> @@ -2,13 +2,6 @@
>
>  #include <linux/kprobes.h>
>
> -int arch_check_ftrace_location(struct kprobe *p)
> -{
> -       if (ftrace_location((unsigned long)p->addr))
> -               p->flags |= KPROBE_FLAG_FTRACE;
> -       return 0;
> -}
> -
>  /* Ftrace callback handler for kprobes -- called under preepmt disabled */
>  void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
>                            struct ftrace_ops *ops, struct ftrace_regs *fregs)
> --
> 2.30.2
>


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/