Merge tag 'x86_urgent_for_v6.18_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Remove dead code leftovers after a recent mitigations cleanup which
   fail a Clang build

 - Make sure a Retbleed mitigation message is printed only when
   necessary

 - Correct the last Zen1 microcode revision for which Entrysign sha256
   check is needed

 - Fix a NULL ptr deref when mounting the resctrl fs on a system which
   supports assignable counters but where L3 total and local bandwidth
   monitoring has been disabled at boot

* tag 'x86_urgent_for_v6.18_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/bugs: Remove dead code which might prevent from building
  x86/bugs: Qualify RETBLEED_INTEL_MSG
  x86/microcode: Fix Entrysign revision check for Zen1/Naples
  x86,fs/resctrl: Fix NULL pointer dereference with events force-disabled in mbm_event mode

1 files changed, 10 insertions, 1 deletions

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 2cd25a0d4637..fe1a2aa53c16 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -458,7 +458,16 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
 		r->mon.mbm_cfg_mask = ecx & MAX_EVT_CONFIG_BITS;
 	}
 
-	if (rdt_cpu_has(X86_FEATURE_ABMC)) {
+	/*
+	 * resctrl assumes a system that supports assignable counters can
+	 * switch to "default" mode. Ensure that there is a "default" mode
+	 * to switch to. This enforces a dependency between the independent
+	 * X86_FEATURE_ABMC and X86_FEATURE_CQM_MBM_TOTAL/X86_FEATURE_CQM_MBM_LOCAL
+	 * hardware features.
+	 */
+	if (rdt_cpu_has(X86_FEATURE_ABMC) &&
+	    (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL) ||
+	     rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL))) {
 		r->mon.mbm_cntr_assignable = true;
 		cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
 		r->mon.num_mbm_cntrs = (ebx & GENMASK(15, 0)) + 1;