From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
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>,
Alexandre Julliard <julliard@winehq.org>,
Stas Sergeev <stsp@list.ru>, Fenghua Yu <fenghua.yu@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-msdos@vger.kernel.org, wine-devel@winehq.org,
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: [v6 PATCH 05/21] x86/insn-eval: Add utility functions to get register offsets
Date: Wed, 26 Apr 2017 11:13:44 -0700 [thread overview]
Message-ID: <1493230424.36058.35.camel@ranerica-desktop> (raw)
In-Reply-To: <20170412162850.huhhn6xfwls3qex6@pd.tnic>
On Wed, 2017-04-12 at 18:28 +0200, Borislav Petkov wrote:
> 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.
Will do!
>
> And do you mean get_reg_offset(), per chance?
Yes, I meant that. This was a copy/paste error.
>
> > 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.
Yes. I will reword.
>
> > 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... "
I will reword.
>
> > 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 <dave.hansen@linux.intel.com>
> > Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
> > Cc: Colin Ian King <colin.king@canonical.com>
> > Cc: Lorenzo Stoakes <lstoakes@gmail.com>
> > Cc: Qiaowei Ren <qiaowei.ren@intel.com>
> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> > Cc: Masami Hiramatsu <mhiramat@kernel.org>
> > Cc: Adrian Hunter <adrian.hunter@intel.com>
> > Cc: Kees Cook <keescook@chromium.org>
> > Cc: Thomas Garnier <thgarnie@google.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Borislav Petkov <bp@suse.de>
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
> > Cc: x86@kernel.org
> > Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
> > ---
> > 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 <asm/ptrace.h>
> >
> > 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?
Yes, I 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?!?
I will reword it to say "A struct pt_regs containing register values
indicated by the ModRM byte".
>
> > + * 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.
Will do.
>
> > + *
> > + * 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
Will make the spelling consistent.
>
> 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.
Masami Hiramatsu had originally requested to add the two functions. I
suppose the unneeded functions could be added if/when needed.
Thanks and BR,
Ricardo
next prev parent reply other threads:[~2017-04-26 18:13 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-08 0:32 [v6 PATCH 00/21] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 01/21] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri
2017-04-11 21:56 ` Borislav Petkov
2017-04-26 1:40 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 02/21] x86/mpx: Do not use SIB index if index points to R/ESP Ricardo Neri
2017-04-11 11:31 ` Borislav Petkov
2017-04-26 1:39 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 03/21] x86/mpx: Do not use R/EBP as base in the SIB byte with Mod = 0 Ricardo Neri
2017-04-11 22:08 ` Borislav Petkov
2017-04-26 2:04 ` Ricardo Neri
2017-04-26 8:05 ` Borislav Petkov
2017-04-27 22:49 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 04/21] x86/mpx, x86/insn: Relocate insn util functions to a new insn-kernel Ricardo Neri
2017-04-12 10:03 ` Borislav Petkov
2017-04-26 2:05 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 05/21] x86/insn-eval: Add utility functions to get register offsets Ricardo Neri
2017-04-12 16:28 ` Borislav Petkov
2017-04-26 18:13 ` Ricardo Neri [this message]
2017-04-28 10:40 ` Borislav Petkov
2017-03-08 0:32 ` [v6 PATCH 06/21] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri
2017-04-18 9:42 ` Borislav Petkov
2017-04-26 20:44 ` Ricardo Neri
2017-04-26 20:47 ` Ricardo Neri
2017-04-30 17:15 ` Borislav Petkov
2017-05-05 18:31 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 07/21] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri
2017-04-19 10:26 ` Borislav Petkov
2017-04-26 21:51 ` Ricardo Neri
2017-05-04 11:02 ` Borislav Petkov
2017-05-12 2:13 ` Ricardo Neri
2017-05-15 17:27 ` Borislav Petkov
2017-03-08 0:32 ` [v6 PATCH 08/21] x86/insn-eval: Add utility function to get segment descriptor base address Ricardo Neri
2017-04-20 8:25 ` Borislav Petkov
2017-04-26 22:37 ` Ricardo Neri
2017-05-05 17:19 ` Borislav Petkov
2017-05-12 2:09 ` Ricardo Neri
2017-04-26 22:52 ` Ricardo Neri
2017-05-05 17:28 ` Borislav Petkov
2017-05-12 2:06 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 09/21] x86/insn-eval: Add functions to get default operand and address sizes Ricardo Neri
2017-04-20 13:06 ` Borislav Petkov
2017-04-27 1:07 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 10/21] x86/insn-eval: Do not use R/EBP as base if mod in ModRM is zero Ricardo Neri
2017-04-21 10:52 ` Borislav Petkov
2017-04-27 1:29 ` Ricardo Neri
2017-05-07 17:20 ` Borislav Petkov
2017-05-12 1:57 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 11/21] insn/eval: Incorporate segment base in address computation Ricardo Neri
2017-04-21 14:55 ` Borislav Petkov
2017-04-27 1:31 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 12/21] x86/insn: Support both signed 32-bit and 64-bit effective addresses Ricardo Neri
2017-04-25 13:51 ` Borislav Petkov
2017-04-27 3:33 ` Ricardo Neri
2017-05-08 11:42 ` Borislav Petkov
2017-05-12 1:55 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 13/21] x86/insn-eval: Add support to resolve 16-bit addressing encodings Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 14/21] x86/insn-eval: Add wrapper function for 16-bit and 32-bit address encodings Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 15/21] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri
2017-03-08 16:08 ` Andy Lutomirski
2017-03-08 0:32 ` [v6 PATCH 16/21] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 17/21] x86: Add emulation code for UMIP instructions Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 18/21] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 19/21] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri
2017-03-08 15:54 ` Andy Lutomirski
2017-03-08 0:32 ` [v6 PATCH 20/21] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 21/21] selftests/x86: Add tests for " Ricardo Neri
2017-03-08 15:56 ` Andy Lutomirski
2017-03-10 23:38 ` Ricardo Neri
2017-03-08 14:08 ` [v6 PATCH 00/21] x86: Enable " Stas Sergeev
2017-03-08 16:06 ` Andy Lutomirski
2017-03-08 16:29 ` Stas Sergeev
2017-03-08 16:46 ` Andy Lutomirski
2017-03-08 16:53 ` Stas Sergeev
2017-03-09 1:11 ` Ricardo Neri
2017-03-09 22:05 ` Stas Sergeev
2017-03-10 2:41 ` Andy Lutomirski
2017-03-10 10:30 ` Stas Sergeev
2017-03-10 21:04 ` Andy Lutomirski
2017-03-10 21:37 ` Stas Sergeev
2017-03-09 1:15 ` Ricardo Neri
2017-03-09 22:10 ` Stas Sergeev
2017-03-10 2:39 ` Andy Lutomirski
2017-03-10 11:33 ` Stas Sergeev
2017-03-10 14:17 ` Andy Lutomirski
2017-03-11 1:22 ` Ricardo Neri
2017-03-10 23:59 ` Ricardo Neri
2017-03-13 21:25 ` Stas Sergeev
2017-03-27 23:46 ` Ricardo Neri
2017-03-28 9:38 ` Stas Sergeev
2017-03-29 4:38 ` Ricardo Neri
2017-03-29 20:55 ` Stas Sergeev
2017-03-30 5:14 ` Ricardo Neri
2017-03-30 10:10 ` Stas Sergeev
2017-03-31 1:33 ` Ricardo Neri
2017-03-31 14:11 ` Alexandre Julliard
2017-03-31 21:26 ` Stas Sergeev
2017-04-01 2:18 ` Andy Lutomirski
2017-04-04 2:02 ` Ricardo Neri
2017-04-04 6:08 ` Alexandre Julliard
2017-04-01 13:08 ` Stas Sergeev
2017-04-01 17:49 ` H. Peter Anvin
2017-04-02 15:52 ` Andy Lutomirski
2017-04-04 9:59 ` Stas Sergeev
2017-04-04 2:05 ` Ricardo Neri
2017-04-04 8:03 ` Stas Sergeev
2017-03-10 23:58 ` Ricardo Neri
2017-03-09 0:46 ` Ricardo Neri
2017-03-09 22:01 ` Stas Sergeev
2017-03-10 23:47 ` Ricardo Neri
2017-03-10 23:58 ` Stas Sergeev
2017-03-11 0:13 ` Ricardo Neri
2017-03-08 16:07 ` Andy Lutomirski
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