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Groups > linux.kernel > #1426043
| From | Andy Lutomirski <luto@amacapital.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame |
| Date | 2016-06-19 23:30 +0200 |
| Message-ID | <rLSs1-7KI-5@gated-at.bofh.it> (permalink) |
| References | <rLvvr-F3-3@gated-at.bofh.it> <rLvvs-F3-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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
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[PATCH v2 0/6] x86: Rewrite switch_to() Brian Gerst <brgerst@gmail.com> - 2016-06-18 23:00 +0200
[PATCH v2 6/6] x86: Fix thread_saved_pc() Brian Gerst <brgerst@gmail.com> - 2016-06-18 23:00 +0200
Re: [PATCH v2 6/6] x86: Fix thread_saved_pc() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-06-20 18:10 +0200
Re: [PATCH v2 6/6] x86: Fix thread_saved_pc() Brian Gerst <brgerst@gmail.com> - 2016-06-22 06:30 +0200
[PATCH v2 2/6] x86-64, kgdb: clear GDB_PS on 64-bit Brian Gerst <brgerst@gmail.com> - 2016-06-18 23:00 +0200
[PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Brian Gerst <brgerst@gmail.com> - 2016-06-18 23:00 +0200
Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Andy Lutomirski <luto@amacapital.net> - 2016-06-19 23:30 +0200
Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Brian Gerst <brgerst@gmail.com> - 2016-06-20 00:10 +0200
Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Borislav Petkov <bp@suse.de> - 2016-06-20 16:00 +0200
Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Brian Gerst <brgerst@gmail.com> - 2016-06-20 17:20 +0200
Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Borislav Petkov <bp@alien8.de> - 2016-06-21 13:50 +0200
Re: [PATCH v2 5/6] x86: Pass kernel thread parameters in fork_frame Brian Gerst <brgerst@gmail.com> - 2016-06-22 10:30 +0200
Re: [PATCH v2 0/6] x86: Rewrite switch_to() Brian Gerst <brgerst@gmail.com> - 2016-06-20 00:10 +0200
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