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From: Andy Lutomirski <luto@amacapital.net>
To: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	linux-doc@vger.kernel.org, Linux-MM <linux-mm@kvack.org>,
	linux-arch <linux-arch@vger.kernel.org>, X86 ML <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. J. Lu" <hjl.tools@gmail.com>,
	"Shanbhogue, Vedvyas" <vedvyas.shanbhogue@intel.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Jonathan Corbet <corbet@lwn.net>, Oleg Nesterov <oleg@redhat.com>,
	Arnd Bergmann <arnd@arndb.de>,
	mike.kravetz@oracle.com
Subject: Re: [PATCH 7/7] x86/cet: Add PTRACE interface for CET
Date: Thu, 7 Jun 2018 11:32:36 -0700	[thread overview]
Message-ID: <CALCETrXx4FHLad8XhrP-RrBtXnmALf7Myy4wVO+u-SKxa_D01Q@mail.gmail.com> (raw)
In-Reply-To: <20180607143855.3681-8-yu-cheng.yu@intel.com>

On Thu, Jun 7, 2018 at 7:42 AM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
>
> Add PTRACE interface for CET MSRs.
>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
> ---
>  arch/x86/include/asm/fpu/regset.h |  7 ++++---
>  arch/x86/kernel/fpu/regset.c      | 41 +++++++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/ptrace.c          | 16 +++++++++++++++
>  include/uapi/linux/elf.h          |  1 +
>  4 files changed, 62 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/fpu/regset.h b/arch/x86/include/asm/fpu/regset.h
> index d5bdffb9d27f..edad0d889084 100644
> --- a/arch/x86/include/asm/fpu/regset.h
> +++ b/arch/x86/include/asm/fpu/regset.h
> @@ -7,11 +7,12 @@
>
>  #include <linux/regset.h>
>
> -extern user_regset_active_fn regset_fpregs_active, regset_xregset_fpregs_active;
> +extern user_regset_active_fn regset_fpregs_active, regset_xregset_fpregs_active,
> +                               cetregs_active;
>  extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get,
> -                               xstateregs_get;
> +                               xstateregs_get, cetregs_get;
>  extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set,
> -                                xstateregs_set;
> +                                xstateregs_set, cetregs_set;
>
>  /*
>   * xstateregs_active == regset_fpregs_active. Please refer to the comment
> diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
> index bc02f5144b95..7008eb084d36 100644
> --- a/arch/x86/kernel/fpu/regset.c
> +++ b/arch/x86/kernel/fpu/regset.c
> @@ -160,6 +160,47 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
>         return ret;
>  }
>
> +int cetregs_active(struct task_struct *target, const struct user_regset *regset)
> +{
> +#ifdef CONFIG_X86_INTEL_CET
> +       if (target->thread.cet.shstk_enabled || target->thread.cet.ibt_enabled)
> +               return regset->n;
> +#endif
> +       return 0;
> +}
> +
> +int cetregs_get(struct task_struct *target, const struct user_regset *regset,
> +               unsigned int pos, unsigned int count,
> +               void *kbuf, void __user *ubuf)
> +{
> +       struct fpu *fpu = &target->thread.fpu;
> +       struct cet_user_state *cetregs;
> +
> +       if (!boot_cpu_has(X86_FEATURE_SHSTK))
> +               return -ENODEV;

This whole series has a boot_cpu_has, static_cpu_has, and
cpu_feature_enabled all over.  Please settle on just one, preferably
static_cpu_has.

> +
> +       cetregs = get_xsave_addr(&fpu->state.xsave, XFEATURE_MASK_SHSTK_USER);
> +
> +       fpu__prepare_read(fpu);
> +       return user_regset_copyout(&pos, &count, &kbuf, &ubuf, cetregs, 0, -1);
> +}
> +
> +int cetregs_set(struct task_struct *target, const struct user_regset *regset,
> +                 unsigned int pos, unsigned int count,
> +                 const void *kbuf, const void __user *ubuf)
> +{
> +       struct fpu *fpu = &target->thread.fpu;
> +       struct cet_user_state *cetregs;
> +
> +       if (!boot_cpu_has(X86_FEATURE_SHSTK))
> +               return -ENODEV;
> +
> +       cetregs = get_xsave_addr(&fpu->state.xsave, XFEATURE_MASK_SHSTK_USER);
> +
> +       fpu__prepare_write(fpu);
> +       return user_regset_copyin(&pos, &count, &kbuf, &ubuf, cetregs, 0, -1);

Is this called for core dumping on current?  If so, please make sure
it's correct.  (I think it is for get but maybe not for set.)

      reply	other threads:[~2018-06-07 18:33 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 14:38 [PATCH 0/7] Control Flow Enforcement - Part (4) Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 1/7] x86/cet: Add Kconfig option for user-mode Indirect Branch Tracking Yu-cheng Yu
2018-06-07 16:43   ` Randy Dunlap
2018-06-07 14:38 ` [PATCH 2/7] x86/cet: User-mode indirect branch tracking support Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 3/7] mm/mmap: Add IBT bitmap size to address space limit check Yu-cheng Yu
2018-06-07 18:39   ` Andy Lutomirski
2018-06-07 14:38 ` [PATCH 4/7] x86/cet: add arcp_prctl functions for indirect branch tracking Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 5/7] x86: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2018-06-07 20:50   ` Andy Lutomirski
2018-06-07 22:03     ` H.J. Lu
2018-06-07 23:00       ` Andy Lutomirski
2018-06-08  0:31         ` H.J. Lu
2018-06-08  0:47           ` Andy Lutomirski
2018-06-07 14:38 ` [PATCH 6/7] tools: Add cetcmd Yu-cheng Yu
2018-06-07 14:38 ` [PATCH 7/7] x86/cet: Add PTRACE interface for CET Yu-cheng Yu
2018-06-07 18:32   ` Andy Lutomirski [this message]

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