linux-kernel - Re: [patch v3 19/36] Hexagon: Add ptrace support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 9 Sep 2011 22:15:20 +0200
From:	Jonas Bonn <jonas.bonn@...il.com>
To:	Richard Kuo <rkuo@...eaurora.org>
Cc:	linux-arch@...r.kernel.org, linux-hexagon@...r.kernel.org,
	linux-kernel@...r.kernel.org, Linas Vepstas <linas@...eaurora.org>,
	arnd@...db.de
Subject: Re: [patch v3 19/36] Hexagon: Add ptrace support

On 9 September 2011 03:09, Richard Kuo <rkuo@...eaurora.org> wrote:
> +long arch_ptrace(struct task_struct *child, long request,
> +                unsigned long addr, unsigned long data)
> +{
> +       void __user *udata = (void __user *) data;
> +
> +       switch (request) {
> +       case PTRACE_POKETEXT:   /* write the word at location addr. */
> +       case PTRACE_POKEDATA:
> +               return generic_ptrace_pokedata(child, addr, data);
> +       case PTRACE_POKEUSR:    /* write register specified by addr. */
> +               return ptrace_pokeusr(child, addr, data);
> +       case PTRACE_GETREGS:
> +               return copy_regset_to_user(child, &hexagon_user_view,
> +                                          REGSET_GPR, 0,
> +                                          sizeof(struct user_regs_struct),
> +                                          udata);
> +       case PTRACE_SETREGS:
> +               return copy_regset_from_user(child, &hexagon_user_view,
> +                                            REGSET_GPR, 0,
> +                                            sizeof(struct user_regs_struct),
> +                                            udata);
> +       default:
> +               return ptrace_request(child, request, addr, data);
> +       }
> +
> +       return 0;
> +}
>

I think that... other than for compatibility with legacy userspace
code, you shouldn't need any of these cases other than the 'default'.

PTRACE_GETREGS is replaced by PTRACE_GETREGSET and this is handled in
generic code.  POKETEXT, POKEDATA are handled in the generic code.
POKEUSR can also be done via the SETREGSET mechanism.

That said, I don't think gdbserver has been updated to use
GETREGSET/SETREGSET.  This is a bit like the uClibc/glibc issue,
though... somebody just needs to do the work to make userspace work
with the new, "clean" kernel interface.

Given all that, you shouldn't need to export pt_regs to userspace
either.  You already have a user_regs_struct which is userspace's view
of the process registers.  For OpenRISC we made pt_regs a kernel
private structure, giving us the freedom to change the stack layout of
the registers in the future while providing a stable view for
userspace.  I would suggest doing the same here.

If you do decide to make pt_regs private, you'll need to change your
struct sigcontext to use user_regs_struct, as well.

/Jonas
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/