Messages in this thread | | | Subject | Re: [PATCH v3 1/7] sysfs/cpu: Allow individual architectures to select vulnerabilities | From | Suzuki K Poulose <> | Date | Mon, 14 Jan 2019 10:02:21 +0000 |
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On 09/01/2019 23:55, Jeremy Linton wrote: > As suggested on the list, https://lkml.org/lkml/2019/1/4/282, there are > a number of cases where its useful for a system to avoid exporting a > sysfs entry for a given vulnerability. This set adds an architecture > specific callback which returns the bitmap of vulnerabilities the > architecture would like to advertise. > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Rafael J. Wysocki <rafael@kernel.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Josh Poimboeuf <jpoimboe@redhat.com> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Waiman Long <longman@redhat.com> > Cc: Andi Kleen <ak@linux.intel.com> > Cc: Jiri Kosina <jkosina@suse.cz> > --- > drivers/base/cpu.c | 19 +++++++++++++++++++ > include/linux/cpu.h | 7 +++++++ > 2 files changed, 26 insertions(+) > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > index eb9443d5bae1..35f6dfb24cd6 100644 > --- a/drivers/base/cpu.c > +++ b/drivers/base/cpu.c > @@ -561,6 +561,11 @@ static struct attribute *cpu_root_vulnerabilities_attrs[] = { > NULL > }; > > +uint __weak arch_supported_vuln_attr_fields(void) > +{ > + return VULN_MELTDOWN|VULN_SPECTREV1|VULN_SPECTREV2|VULN_SSB|VULN_L1TF; > +} > + > static const struct attribute_group cpu_root_vulnerabilities_group = { > .name = "vulnerabilities", > .attrs = cpu_root_vulnerabilities_attrs, > @@ -568,6 +573,20 @@ static const struct attribute_group cpu_root_vulnerabilities_group = { > > static void __init cpu_register_vulnerabilities(void) > { > + int fld; > + int max_fields = ARRAY_SIZE(cpu_root_vulnerabilities_attrs) - 1; > + struct attribute **hd = cpu_root_vulnerabilities_attrs; > + uint enabled_fields = arch_supported_vuln_attr_fields(); > + > + /* only enable entries requested by the arch code */ > + for (fld = 0; fld < max_fields; fld++) { > + if (enabled_fields & 1 << fld) { > + *hd = cpu_root_vulnerabilities_attrs[fld]; > + hd++; > + } > + } > + *hd = NULL; > +
nit: Could we use "is_visible" callback in the attribute group to check this dynamically ?
> if (sysfs_create_group(&cpu_subsys.dev_root->kobj, > &cpu_root_vulnerabilities_group)) > pr_err("Unable to register CPU vulnerabilities\n"); > diff --git a/include/linux/cpu.h b/include/linux/cpu.h > index 218df7f4d3e1..5e45814bcc24 100644 > --- a/include/linux/cpu.h > +++ b/include/linux/cpu.h > @@ -189,4 +189,11 @@ static inline void cpu_smt_check_topology_early(void) { } > static inline void cpu_smt_check_topology(void) { } > #endif > > +/* generic cpu vulnerability attributes */ > +#define VULN_MELTDOWN 0x01 > +#define VULN_SPECTREV1 0x02 > +#define VULN_SPECTREV2 0x04 > +#define VULN_SSB 0x08 > +#define VULN_L1TF 0x10
nit: May use BIT() ?
Cheers Suzuki
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