Merge tag 'x86_cpu_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cpu model updates from Borislav Petkov:

 - Add Emerald Rapids to the list of Intel models supporting PPIN

 - Finally use a CPUID bit for split lock detection instead of
   enumerating every model

 - Make sure automatic IBRS is set on AMD, even though the AP bringup
   code does that now by replicating the MSR which contains the switch

* tag 'x86_cpu_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add Xeon Emerald Rapids to list of CPUs that support PPIN
  x86/split_lock: Enumerate architectural split lock disable bit
  x86/CPU/AMD: Make sure EFER[AIBRSE] is set

5 files changed, 43 insertions, 46 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 1547781e505b..571abf808ea3 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1009,6 +1009,17 @@ static void init_amd(struct cpuinfo_x86 *c)
 		msr_set_bit(MSR_K7_HWCR, MSR_K7_HWCR_IRPERF_EN_BIT);
 
 	check_null_seg_clears_base(c);
+
+	/*
+	 * Make sure EFER[AIBRSE - Automatic IBRS Enable] is set. The APs are brought up
+	 * using the trampoline code and as part of it, MSR_EFER gets prepared there in
+	 * order to be replicated onto them. Regardless, set it here again, if not set,
+	 * to protect against any future refactoring/code reorganization which might
+	 * miss setting this important bit.
+	 */
+	if (spectre_v2_in_eibrs_mode(spectre_v2_enabled) &&
+	    cpu_has(c, X86_FEATURE_AUTOIBRS))
+		WARN_ON_ONCE(msr_set_bit(MSR_EFER, _EFER_AUTOIBRS));
 }
 
 #ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index f9d060e71c3e..182af64387d0 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -784,8 +784,7 @@ static int __init nospectre_v1_cmdline(char *str)
 }
 early_param("nospectre_v1", nospectre_v1_cmdline);
 
-static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
-	SPECTRE_V2_NONE;
+enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init = SPECTRE_V2_NONE;
 
 #undef pr_fmt
 #define pr_fmt(fmt)     "RETBleed: " fmt
@@ -1133,13 +1132,6 @@ spectre_v2_parse_user_cmdline(void)
 	return SPECTRE_V2_USER_CMD_AUTO;
 }
 
-static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mode)
-{
-	return mode == SPECTRE_V2_EIBRS ||
-	       mode == SPECTRE_V2_EIBRS_RETPOLINE ||
-	       mode == SPECTRE_V2_EIBRS_LFENCE;
-}
-
 static inline bool spectre_v2_in_ibrs_mode(enum spectre_v2_mitigation mode)
 {
 	return spectre_v2_in_eibrs_mode(mode) || mode == SPECTRE_V2_IBRS;
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8cd4126d8253..80710a68ef7d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -121,6 +121,7 @@ static const struct x86_cpu_id ppin_cpuids[] = {
 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, &ppin_info[X86_VENDOR_INTEL]),
 	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, &ppin_info[X86_VENDOR_INTEL]),
 	X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, &ppin_info[X86_VENDOR_INTEL]),
+	X86_MATCH_INTEL_FAM6_MODEL(EMERALDRAPIDS_X, &ppin_info[X86_VENDOR_INTEL]),
 	X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL, &ppin_info[X86_VENDOR_INTEL]),
 	X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM, &ppin_info[X86_VENDOR_INTEL]),
 
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index 57a5349e6954..f97b0fe13da8 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -83,4 +83,12 @@ unsigned int aperfmperf_get_khz(int cpu);
 extern void x86_spec_ctrl_setup_ap(void);
 extern void update_srbds_msr(void);
 
+extern enum spectre_v2_mitigation spectre_v2_enabled;
+
+static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mode)
+{
+	return mode == SPECTRE_V2_EIBRS ||
+	       mode == SPECTRE_V2_EIBRS_RETPOLINE ||
+	       mode == SPECTRE_V2_EIBRS_LFENCE;
+}
 #endif /* ARCH_X86_CPU_H */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 291d4167fab8..1c648b09e053 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1451,31 +1451,13 @@ void handle_bus_lock(struct pt_regs *regs)
 }
 
 /*
- * Bits in the IA32_CORE_CAPABILITIES are not architectural, so they should
- * only be trusted if it is confirmed that a CPU model implements a
- * specific feature at a particular bit position.
- *
- * The possible driver data field values:
- *
- * - 0: CPU models that are known to have the per-core split-lock detection
- *	feature even though they do not enumerate IA32_CORE_CAPABILITIES.
- *
- * - 1: CPU models which may enumerate IA32_CORE_CAPABILITIES and if so use
- *      bit 5 to enumerate the per-core split-lock detection feature.
+ * CPU models that are known to have the per-core split-lock detection
+ * feature even though they do not enumerate IA32_CORE_CAPABILITIES.
  */
 static const struct x86_cpu_id split_lock_cpu_ids[] __initconst = {
-	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,		0),
-	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L,		0),
-	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,		0),
-	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT,	1),
-	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_D,	1),
-	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_L,	1),
-	X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE_L,		1),
-	X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE,		1),
-	X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X,	1),
-	X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE,		1),
-	X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE_L,		1),
-	X86_MATCH_INTEL_FAM6_MODEL(RAPTORLAKE,		1),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,	0),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L,	0),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,	0),
 	{}
 };
 
@@ -1487,24 +1469,27 @@ static void __init split_lock_setup(struct cpuinfo_x86 *c)
 	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return;
 
+	/* Check for CPUs that have support but do not enumerate it: */
 	m = x86_match_cpu(split_lock_cpu_ids);
-	if (!m)
-		return;
+	if (m)
+		goto supported;
 
-	switch (m->driver_data) {
-	case 0:
-		break;
-	case 1:
-		if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITIES))
-			return;
-		rdmsrl(MSR_IA32_CORE_CAPS, ia32_core_caps);
-		if (!(ia32_core_caps & MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT))
-			return;
-		break;
-	default:
+	if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITIES))
 		return;
-	}
 
+	/*
+	 * Not all bits in MSR_IA32_CORE_CAPS are architectural, but
+	 * MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT is.  All CPUs that set
+	 * it have split lock detection.
+	 */
+	rdmsrl(MSR_IA32_CORE_CAPS, ia32_core_caps);
+	if (ia32_core_caps & MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT)
+		goto supported;
+
+	/* CPU is not in the model list and does not have the MSR bit: */
+	return;
+
+supported:
 	cpu_model_supports_sld = true;
 	__split_lock_setup();
 }