linux-kernel - Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES

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Message-ID: <CALCETrUSQB2FG4HMS=uKaK2cgMxd_X9pg4W4UjUz=nvF0JNFpA@mail.gmail.com>
Date:	Mon, 22 Feb 2016 14:45:54 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	Yu-cheng Yu <yu-cheng.yu@...el.com>
Cc:	X86 ML <x86@...nel.org>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Andy Lutomirski <luto@...nel.org>,
	Borislav Petkov <bp@...e.de>,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>,
	"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
	Fenghua Yu <fenghua.yu@...el.com>
Subject: Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES

On Mon, Feb 22, 2016 at 11:00 AM, Yu-cheng Yu <yu-cheng.yu@...el.com> wrote:
> XSAVES uses compacted format and is a kernel instruction. The kernel
> should use standard-format, non-supervisor state data for PTRACE.
>

> +/*
> + * Convert from kernel XSAVES compacted format to standard format and copy
> + * to a ptrace buffer. It supports partial copy but pos always starts from
> + * zero. This is called from xstateregs_get() and there we check the cpu
> + * has XSAVES.
> + */
> +int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
> +                       void __user *ubuf, const struct xregs_state *xsave)

Now that you've written this code, can it be shared with the signal
handling code?

--Andy


--Andy