From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (193.142.43.55:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 06 Apr 2020 18:32:08 -0000 Received: from mail-pl1-x633.google.com ([2607:f8b0:4864:20::633]) by Galois.linutronix.de with esmtps (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1jLWXX-0007U5-E1 for speck@linutronix.de; Mon, 06 Apr 2020 20:32:07 +0200 Received: by mail-pl1-x633.google.com with SMTP id w3so165385plz.5 for ; Mon, 06 Apr 2020 11:32:07 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id o128sm11995025pfb.58.2020.04.06.11.31.59 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Apr 2020 11:31:59 -0700 (PDT) Date: Mon, 6 Apr 2020 11:31:58 -0700 From: Kees Cook Subject: [MODERATED] Re: [PATCH 1/3] V5 more sampling fun 1 Message-ID: <202004061131.40E8E1F@keescook> References: <5e8b7166.1c69fb81.4c99a.3619SMTPIN_ADDED_BROKEN@mx.google.com> MIME-Version: 1.0 In-Reply-To: <5e8b7166.1c69fb81.4c99a.3619SMTPIN_ADDED_BROKEN@mx.google.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: speck@linutronix.de List-ID: On Mon, Mar 16, 2020 at 05:56:27PM -0700, speck for mark gross wrote: > From: mark gross > Subject: [PATCH 1/3] x86/cpu: Add stepping field to x86_cpu_id structure > > Intel uses the same family/model for several CPUs. Sometimes the > stepping must be checked to tell them apart. > > On X86 there can be at most 16 steppings, add steppings bitmask to > x86_cpu_id and X86_MATCH_VENDOR_FAMILY_MODEL_STEPPING_FEATURE macro and > support for matching against family/model/stepping. > > Signed-off-by: Mark Gross Reviewed-by: Kees Cook -Kees > Reviewed-by: Tony Luck > --- > arch/x86/include/asm/cpu_device_id.h | 26 +++++++++++++++++++++++--- > arch/x86/kernel/cpu/match.c | 7 ++++++- > include/linux/mod_devicetable.h | 2 ++ > 3 files changed, 31 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h > index cf3d621c6892..d8ecd0d72e04 100644 > --- a/arch/x86/include/asm/cpu_device_id.h > +++ b/arch/x86/include/asm/cpu_device_id.h > @@ -21,11 +21,12 @@ > #define X86_CENTAUR_FAM6_NANO 0xf > > /** > - * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Base macro for CPU matching > + * X86_MATCH_VENDOR_FAM_MODEL_STEPPING_FEATURE - Base macro for CPU matching > * @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY > * The name is expanded to X86_VENDOR_@_vendor > * @_family: The family number or X86_FAMILY_ANY > * @_model: The model number, model constant or X86_MODEL_ANY > + * @_steppings: Bitmask for steppings, stepping constant or X86_STEPPING_ANY > * @_feature: A X86_FEATURE bit or X86_FEATURE_ANY > * @_data: Driver specific data or NULL. The internal storage > * format is unsigned long. The supplied value, pointer > @@ -37,15 +38,34 @@ > * into another macro at the usage site for good reasons, then please > * start this local macro with X86_MATCH to allow easy grepping. > */ > -#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(_vendor, _family, _model, \ > - _feature, _data) { \ > +#define X86_MATCH_VENDOR_FAM_MODEL_STEPPING_FEATURE(_vendor, _family, _model, \ > + _steppings, _feature, _data) { \ > .vendor = X86_VENDOR_##_vendor, \ > .family = _family, \ > .model = _model, \ > + .steppings = _steppings, \ > .feature = _feature, \ > .driver_data = (unsigned long) _data \ > } > > +/** > + * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Base macro for CPU matching > + * @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY > + * The name is expanded to X86_VENDOR_@_vendor > + * @_family: The family number or X86_FAMILY_ANY > + * @_model: The model number, model constant or X86_MODEL_ANY > + * @_feature: A X86_FEATURE bit or X86_FEATURE_ANY > + * @_data: Driver specific data or NULL. The internal storage > + * format is unsigned long. The supplied value, pointer > + * etc. is casted to unsigned long internally. > + * > + * The steppings arguments of X86_MATCH_VENDOR_FAM_MODEL_STEPPING_FEATURE() is > + * set to wildcards. > + */ > +#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data) \ > + X86_MATCH_VENDOR_FAM_MODEL_STEPPING_FEATURE(vendor, family, model, \ > + X86_STEPPING_ANY, feature, data) > + > /** > * X86_MATCH_VENDOR_FAM_FEATURE - Macro for matching vendor, family and CPU feature > * @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY > diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c > index d3482eb43ff3..dac48301b5a7 100644 > --- a/arch/x86/kernel/cpu/match.c > +++ b/arch/x86/kernel/cpu/match.c > @@ -39,13 +39,18 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match) > const struct x86_cpu_id *m; > struct cpuinfo_x86 *c = &boot_cpu_data; > > - for (m = match; m->vendor | m->family | m->model | m->feature; m++) { > + for (m = match; > + m->vendor | m->family | m->model | m->steppings | m->feature; > + m++) { > if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor) > continue; > if (m->family != X86_FAMILY_ANY && c->x86 != m->family) > continue; > if (m->model != X86_MODEL_ANY && c->x86_model != m->model) > continue; > + if (m->steppings != X86_STEPPING_ANY && > + !(BIT(c->x86_stepping) & m->steppings)) > + continue; > if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature)) > continue; > return m; > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h > index 4c2ddd0941a7..0754b8d71262 100644 > --- a/include/linux/mod_devicetable.h > +++ b/include/linux/mod_devicetable.h > @@ -663,6 +663,7 @@ struct x86_cpu_id { > __u16 vendor; > __u16 family; > __u16 model; > + __u16 steppings; > __u16 feature; /* bit index */ > kernel_ulong_t driver_data; > }; > @@ -671,6 +672,7 @@ struct x86_cpu_id { > #define X86_VENDOR_ANY 0xffff > #define X86_FAMILY_ANY 0 > #define X86_MODEL_ANY 0 > +#define X86_STEPPING_ANY 0 > #define X86_FEATURE_ANY 0 /* Same as FPU, you can't test for that */ > > /* > -- > 2.17.1 -- Kees Cook