From: Andy Lutomirski <luto@amacapital.net>
To: Brian Gerst <brgerst@gmail.com>
Cc: X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Borislav Petkov <bp@suse.de>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame
Date: Sun, 19 Jun 2016 14:28:17 -0700 [thread overview]
Message-ID: <CALCETrXZyyLzHDZSO8e137WjNhHk7951Cetm6vKSmOoQusLG=g@mail.gmail.com> (raw)
In-Reply-To: <1466283378-17062-6-git-send-email-brgerst@gmail.com>
On Sat, Jun 18, 2016 at 1:56 PM, Brian Gerst <brgerst@gmail.com> wrote:
> Instead of setting up a fake pt_regs context, put the kernel thread
> function pointer and arg into the unused callee-restored registers
> of struct fork_frame.
This seems generally okay.
>
> Signed-off-by: Brian Gerst <brgerst@gmail.com>
> @@ -146,19 +147,12 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
> if (unlikely(p->flags & PF_KTHREAD)) {
> /* kernel thread */
> memset(childregs, 0, sizeof(struct pt_regs));
> - frame->ret_addr = (unsigned long) ret_from_kernel_thread;
> - task_user_gs(p) = __KERNEL_STACK_CANARY;
> - childregs->ds = __USER_DS;
> - childregs->es = __USER_DS;
> - childregs->fs = __KERNEL_PERCPU;
Is the idea that do_execve promises to initialize all these fields to
something sensible if the kernel thread in question tries to return to
user mode?
--Andy
next prev parent reply other threads:[~2016-06-19 21:29 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-18 20:56 [PATCH v2 0/6] x86: Rewrite switch_to() Brian Gerst
2016-06-18 20:56 ` [PATCH v2 1/6] x86-32, kgdb: Don't use thread.ip in sleeping_thread_to_gdb_regs() Brian Gerst
2016-06-18 20:56 ` [PATCH v2 2/6] x86-64, kgdb: clear GDB_PS on 64-bit Brian Gerst
2016-06-18 20:56 ` [PATCH v2 3/6] x86: Add struct inactive_task_frame Brian Gerst
2016-06-19 21:18 ` Andy Lutomirski
2016-06-20 15:39 ` Josh Poimboeuf
2016-06-18 20:56 ` [PATCH v2 4/6] x86: Rewrite switch_to() code Brian Gerst
2016-06-19 21:22 ` Andy Lutomirski
2016-06-20 15:44 ` Josh Poimboeuf
2016-06-18 20:56 ` [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Brian Gerst
2016-06-19 21:28 ` Andy Lutomirski [this message]
2016-06-19 22:01 ` Brian Gerst
2016-06-20 13:51 ` Borislav Petkov
2016-06-20 15:01 ` Brian Gerst
2016-06-20 15:14 ` Borislav Petkov
2016-06-22 4:24 ` Brian Gerst
2016-07-09 12:01 ` Ingo Molnar
2016-06-18 20:56 ` [PATCH v2 6/6] x86: Fix thread_saved_pc() Brian Gerst
2016-06-20 16:01 ` Josh Poimboeuf
2016-06-22 4:27 ` Brian Gerst
2016-06-24 18:12 ` Josh Poimboeuf
2016-06-19 22:05 ` [PATCH v2 0/6] x86: Rewrite switch_to() Brian Gerst
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='CALCETrXZyyLzHDZSO8e137WjNhHk7951Cetm6vKSmOoQusLG=g@mail.gmail.com' \
--to=luto@amacapital.net \
--cc=bp@suse.de \
--cc=brgerst@gmail.com \
--cc=dvlasenk@redhat.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/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).