From: Oleg Nesterov <oleg@redhat.com>
To: Yonghong Song <yhs@fb.com>
Cc: mingo@kernel.org, tglx@linutronix.de, peterz@infradead.org,
linux-kernel@vger.kernel.org, x86@kernel.org,
netdev@vger.kernel.org, ast@fb.com, kernel-team@fb.com
Subject: Re: [PATCH] uprobes/x86: emulate push insns for uprobe on x86
Date: Thu, 9 Nov 2017 15:47:38 +0100 [thread overview]
Message-ID: <20171109144738.GA12923@redhat.com> (raw)
In-Reply-To: <20171109080155.359718-1-yhs@fb.com>
On 11/09, Yonghong Song wrote:
>
> + if (insn_class == UPROBE_PUSH_INSN) {
> + src_ptr = get_push_reg_ptr(auprobe, regs);
> + reg_width = sizeof_long();
> + sp = regs->sp;
> + if (copy_to_user((void __user *)(sp - reg_width), src_ptr, reg_width))
> + return false;
> +
> + regs->sp = sp - reg_width;
> + regs->ip += 1 + (auprobe->push.rex_prefix != 0);
> + return true;
Another nit... You can rename push_ret_address() and use it here
src_ptr = ...;
if (push_ret_address(regs, *src_ptr))
return false;
regs->ip += ...;
return true;
and I think get_push_reg_ptr() should just return "unsigned long", not the
pointer.
And again, please make a separate method for this code. Let me repeat, the
main reason for branch_xol_ops/etc is that we simply can not execute these
insns out-of-line, we have to emulate them. "push" differs, the only reason
why we may want to emulate it is optimization.
Oleg.
next prev parent reply other threads:[~2017-11-09 14:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-09 8:01 [PATCH] uprobes/x86: emulate push insns for uprobe on x86 Yonghong Song
2017-11-09 13:44 ` Oleg Nesterov
2017-11-09 14:04 ` Oleg Nesterov
2017-11-09 21:53 ` Yonghong Song
2017-11-09 14:47 ` Oleg Nesterov [this message]
2017-11-09 23:02 Yonghong Song
2017-11-10 13:06 ` Oleg Nesterov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171109144738.GA12923@redhat.com \
--to=oleg@redhat.com \
--cc=ast@fb.com \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).