From: Jiri Kosina jkosina@suse.cz
commit bb4b3b7762735cdaba5a40fd94c9303d9ffa147a upstream.
If spectrev2 mitigation has been enabled, RSB is filled on context switch in order to protect from various classes of spectrev2 attacks.
If this mitigation is enabled, say so in sysfs for spectrev2.
Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Peter Zijlstra peterz@infradead.org Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Andrea Arcangeli aarcange@redhat.com Cc: "WoodhouseDavid" dwmw@amazon.co.uk Cc: Andi Kleen ak@linux.intel.com Cc: Tim Chen tim.c.chen@linux.intel.com Cc: "SchauflerCasey" casey.schaufler@intel.com Link: https://lkml.kernel.org/r/nycvar.YFH.7.76.1809251438580.15880@cbobk.fhfr.pm Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/bugs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -779,10 +779,11 @@ static ssize_t cpu_show_common(struct de return sprintf(buf, "Mitigation: __user pointer sanitization\n");
case X86_BUG_SPECTRE_V2: - ret = sprintf(buf, "%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], + ret = sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled], boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "", boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "", (x86_spec_ctrl_base & SPEC_CTRL_STIBP) ? ", STIBP" : "", + boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "", spectre_v2_module_string()); return ret;