Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755241AbdDLQ3W (ORCPT ); Wed, 12 Apr 2017 12:29:22 -0400 Received: from mx2.suse.de ([195.135.220.15]:33281 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755230AbdDLQ3N (ORCPT ); Wed, 12 Apr 2017 12:29:13 -0400 Date: Wed, 12 Apr 2017 18:28:50 +0200 From: Borislav Petkov To: Ricardo Neri Cc: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Andrew Morton , Brian Gerst , Chris Metcalf , Dave Hansen , Paolo Bonzini , Masami Hiramatsu , Huang Rui , Jiri Slaby , Jonathan Corbet , "Michael S. Tsirkin" , Paul Gortmaker , Vlastimil Babka , Chen Yucong , Alexandre Julliard , Stas Sergeev , Fenghua Yu , "Ravi V. Shankar" , Shuah Khan , linux-kernel@vger.kernel.org, x86@kernel.org, linux-msdos@vger.kernel.org, wine-devel@winehq.org, Adam Buchbinder , Colin Ian King , Lorenzo Stoakes , Qiaowei Ren , Arnaldo Carvalho de Melo , Adrian Hunter , Kees Cook , Thomas Garnier , Dmitry Vyukov Subject: Re: [v6 PATCH 05/21] x86/insn-eval: Add utility functions to get register offsets Message-ID: <20170412162850.huhhn6xfwls3qex6@pd.tnic> References: <20170308003254.27833-1-ricardo.neri-calderon@linux.intel.com> <20170308003254.27833-6-ricardo.neri-calderon@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170308003254.27833-6-ricardo.neri-calderon@linux.intel.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5475 Lines: 149 On Tue, Mar 07, 2017 at 04:32:38PM -0800, Ricardo Neri wrote: > The function insn_get_reg_offset takes as argument an enumeration that Please end function names with parentheses. And do you mean get_reg_offset(), per chance? > indicates the type of offset that is returned: the R/M part of the ModRM > byte, the index of the SIB byte or the base of the SIB byte. Err, you mean, it returns the offset to the register the argument specifies. > Callers of > this function would need the definition of such enumeration. This is not > needed. Instead, helper functions can be defined for this purpose can be > added. "Instead, add helpers... " > These functions are useful in cases when, for instance, the caller > needs to decide whether the operand is a register or a memory location by > looking at the mod part of the ModRM byte. > > Cc: Dave Hansen > Cc: Adam Buchbinder > Cc: Colin Ian King > Cc: Lorenzo Stoakes > Cc: Qiaowei Ren > Cc: Arnaldo Carvalho de Melo > Cc: Masami Hiramatsu > Cc: Adrian Hunter > Cc: Kees Cook > Cc: Thomas Garnier > Cc: Peter Zijlstra > Cc: Borislav Petkov > Cc: Dmitry Vyukov > Cc: Ravi V. Shankar > Cc: x86@kernel.org > Signed-off-by: Ricardo Neri > --- > arch/x86/include/asm/insn-eval.h | 3 +++ > arch/x86/lib/insn-eval.c | 51 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 54 insertions(+) > > diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h > index 5cab1b1..754211b 100644 > --- a/arch/x86/include/asm/insn-eval.h > +++ b/arch/x86/include/asm/insn-eval.h > @@ -12,5 +12,8 @@ > #include > > void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs); > +int insn_get_reg_offset_modrm_rm(struct insn *insn, struct pt_regs *regs); > +int insn_get_reg_offset_sib_base(struct insn *insn, struct pt_regs *regs); > +int insn_get_reg_offset_sib_base(struct insn *insn, struct pt_regs *regs); Forgotten to edit the copy-paste? Which means, nothing really needs insn_get_reg_offset_sib_index() and you can get rid of it? > #endif /* _ASM_X86_INSN_EVAL_H */ > diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c > index 23cf010..78df1c9 100644 > --- a/arch/x86/lib/insn-eval.c > +++ b/arch/x86/lib/insn-eval.c > @@ -98,6 +98,57 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs, > return regoff[regno]; > } > > +/** > + * insn_get_reg_offset_modrm_rm - Obtain register in r/m part of ModRM byte > + * @insn: Instruction structure containing the ModRM byte > + * @regs: Set of registers indicated by the ModRM byte That's simply struct pt_regs - not a set of registers indicated by ModRM?!? > + * Obtain the register indicated by the r/m part of the ModRM byte. The > + * register is obtained as an offset from the base of pt_regs. In specific > + * cases, the returned value can be -EDOM to indicate that the particular value > + * of ModRM does not refer to a register. Put that sentence under the "Return: " paragraph below so that it is immediately obvious what the retvals are. > + * > + * Return: Register indicated by r/m, as an offset within struct pt_regs > + */ > +int insn_get_reg_offset_modrm_rm(struct insn *insn, struct pt_regs *regs) That name is too long: insn_get_modrm_rm_off() should be enough. > +{ > + return get_reg_offset(insn, regs, REG_TYPE_RM); > +} > + > +/** > + * insn_get_reg_offset_sib_base - Obtain register in base part of SiB byte > + * @insn: Instruction structure containing the SiB byte > + * @regs: Set of registers indicated by the SiB byte > + * > + * Obtain the register indicated by the base part of the SiB byte. The > + * register is obtained as an offset from the base of pt_regs. In specific > + * cases, the returned value can be -EDOM to indicate that the particular value > + * of SiB does not refer to a register. > + * > + * Return: Register indicated by SiB's base, as an offset within struct pt_regs Let's stick to a single spelling: SIB, all caps. > + */ > +int insn_get_reg_offset_sib_base(struct insn *insn, struct pt_regs *regs) insn_get_sib_base_off() Ditto for the rest of the comments on insn_get_reg_offset_modrm_rm() above. > +{ > + return get_reg_offset(insn, regs, REG_TYPE_BASE); > +} > + > +/** > + * insn_get_reg_offset_sib_index - Obtain register in index part of SiB byte > + * @insn: Instruction structure containing the SiB byte > + * @regs: Set of registers indicated by the SiB byte > + * > + * Obtain the register indicated by the index part of the SiB byte. The > + * register is obtained as an offset from the index of pt_regs. In specific > + * cases, the returned value can be -EDOM to indicate that the particular value > + * of SiB does not refer to a register. > + * > + * Return: Register indicated by SiB's base, as an offset within struct pt_regs > + */ > +int insn_get_reg_offset_sib_index(struct insn *insn, struct pt_regs *regs) insn_get_sib_idx_off() And again, if this function is unused, don't add it. Thanks. -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --