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.lin...@arm.com>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Rafael J. Wysocki <raf...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Waiman Long <long...@redhat.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Jiri Kosina <jkos...@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
