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 <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Rafael J. Wysocki <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Waiman Long <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Jiri Kosina <[email protected]> --- 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; + 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 + #endif /* _LINUX_CPU_H_ */ -- 2.17.2
