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From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Brian Gerst <brgerst@gmail.com>,
	Chris Metcalf <cmetcalf@mellanox.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Huang Rui <ray.huang@amd.com>, Jiri Slaby <jslaby@suse.cz>,
	Jonathan Corbet <corbet@lwn.net>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Shuah Khan <shuah@kernel.org>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	ricardo.neri@intel.com,
	Adam Buchbinder <adam.buchbinder@gmail.com>,
	Colin Ian King <colin.king@canonical.com>,
	Lorenzo Stoakes <lstoakes@gmail.com>,
	Qiaowei Ren <qiaowei.ren@intel.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kees Cook <keescook@chromium.org>,
	Thomas Garnier <thgarnie@google.com>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v10 02/13] x86/insn-eval: Compute linear address in several utility functions
Date: Thu, 2 Nov 2017 19:46:20 -0700	[thread overview]
Message-ID: <20171103024620.GB24896@voyager> (raw)
In-Reply-To: <alpine.DEB.2.20.1711021206200.2090@nanos>

On Thu, Nov 02, 2017 at 12:07:13PM +0100, Thomas Gleixner wrote:
> On Thu, 2 Nov 2017, Ingo Molnar wrote:
>  
> > * Ricardo Neri <ricardo.neri-calderon@linux.intel.com> wrote:
> > 
> > > +	/*
> > > +	 * -EDOM means that we must ignore the address_offset. In such a case,
> > > +	 * in 64-bit mode the effective address relative to the RIP of the
> > > +	 * following instruction.
> > > +	 */
> > > +	if (*regoff == -EDOM) {
> > > +		if (user_64bit_mode(regs))
> > > +			tmp = (long)regs->ip + insn->length;
> > > +		else
> > > +			tmp = 0;
> > > +	} else if (*regoff < 0) {
> > > +		return -EINVAL;
> > > +	} else {
> > > +		tmp = (long)regs_get_register(regs, *regoff);
> > > +	}
> > 
> > > +	else
> > > +		indx = (long)regs_get_register(regs, indx_offset);
> > 
> > This and subsequent patches include a disgustly insane amount of type casts - why?
> > 
> > For example here 'tmp' is 'long', while regs_get_register() returns
> > 'unsigned long', but no type cast is necessary for that.
> > 
> > > +			ret = get_eff_addr_modrm(insn, regs, &addr_offset,
> > > +						 &eff_addr);
> > 
> > Also, please don't break lines slightly longer than 80 cols just to pacify 
> > checkpatch (and this holds for other patches as well) - the cure is worse than the 
> > illness!
> 
> The right thing to do here is to split out stuff into a helper function
> which removes the indentation levels or restructure the code to avoid them.

This patch introduce this several helper function. Perhaps I can add some more. For
this particular case, I think that using shorter variable names will avoid this
problem.

Thanks and BR,
Ricardo

  reply	other threads:[~2017-11-03  2:47 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-27 23:51 [PATCH v10 00/13] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 01/13] x86/insn-eval: Extend get_seg_base_addr() to also obtain segment limit Ricardo Neri
2017-11-02  9:37   ` [tip:x86/mpx] " tip-bot for Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 02/13] x86/insn-eval: Compute linear address in several utility functions Ricardo Neri
2017-11-02  8:51   ` Ingo Molnar
2017-11-02 11:07     ` Thomas Gleixner
2017-11-03  2:46       ` Ricardo Neri [this message]
2017-11-03  2:44     ` Ricardo Neri
2017-11-03 10:17       ` Ingo Molnar
2017-11-04  0:40         ` Ricardo Neri
2017-11-04  8:26           ` Ingo Molnar
2017-10-27 23:51 ` [PATCH v10 03/13] x86/insn-eval: Add support to resolve 32-bit address encodings Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 04/13] x86/insn-eval: Add wrapper function for 32 and 64-bit addresses Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 05/13] x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 06/13] x86/insn-eval: Add support to resolve 16-bit address encodings Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 07/13] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 08/13] x86: Add emulation code for UMIP instructions Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 09/13] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 10/13] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 11/13] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 12/13] selftests/x86: Add tests for User-Mode Instruction Prevention Ricardo Neri
2017-10-27 23:51 ` [PATCH v10 13/13] selftests/x86: Add tests for instruction str and sldt Ricardo Neri

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