Merge branch 'for-next/cpufeature' into for-next/core

* for-next/cpufeature:
  arm64: Align boot cpucap handling with system cpucap handling
  arm64: Cleanup system cpucap handling
  arm64: Kconfig: drop KAISER reference from KPTI option description
  arm64: mm: Only map KPTI trampoline if it is going to be used
  arm64: Get rid of ARM64_HAS_NO_HW_PREFETCH

Author: willdeacon

arch/arm64/Kconfig

@@ -1549,7 +1549,7 @@ config ARCH_FORCE_MAX_ORDER
 	  Don't change if unsure.
 
 config UNMAP_KERNEL_AT_EL0
-	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
+	bool "Unmap kernel when running in userspace (KPTI)" if EXPERT
 	default y
 	help
 	  Speculation attacks against some high-performance processors can

arch/arm64/include/asm/cpufeature.h

@@ -617,6 +617,7 @@ static inline bool id_aa64pfr1_mte(u64 pfr1)
 	return val >= ID_AA64PFR1_EL1_MTE_MTE2;
 }
 
+void __init setup_boot_cpu_features(void);
 void __init setup_system_features(void);
 void __init setup_user_features(void);
 

arch/arm64/kernel/cpufeature.c

@@ -1081,25 +1081,6 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 
 	if (id_aa64pfr1_mte(info->reg_id_aa64pfr1))
 		init_cpu_ftr_reg(SYS_GMID_EL1, info->reg_gmid);
-
-	/*
-	 * Initialize the indirect array of CPU capabilities pointers before we
-	 * handle the boot CPU below.
-	 */
-	init_cpucap_indirect_list();
-
-	/*
-	 * Detect broken pseudo-NMI. Must be called _before_ the call to
-	 * setup_boot_cpu_capabilities() since it interacts with
-	 * can_use_gic_priorities().
-	 */
-	detect_system_supports_pseudo_nmi();
-
-	/*
-	 * Detect and enable early CPU capabilities based on the boot CPU,
-	 * after we have initialised the CPU feature infrastructure.
-	 */
-	setup_boot_cpu_capabilities();
 }
 
 static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
@@ -1584,16 +1565,6 @@ static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry,
 	return has_sre;
 }
 
-static bool has_no_hw_prefetch(const struct arm64_cpu_capabilities *entry, int __unused)
-{
-	u32 midr = read_cpuid_id();
-
-	/* Cavium ThunderX pass 1.x and 2.x */
-	return midr_is_cpu_model_range(midr, MIDR_THUNDERX,
-		MIDR_CPU_VAR_REV(0, 0),
-		MIDR_CPU_VAR_REV(1, MIDR_REVISION_MASK));
-}
-
 static bool has_cache_idc(const struct arm64_cpu_capabilities *entry,
 			  int scope)
 {
@@ -2321,12 +2292,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		ARM64_CPUID_FIELDS(ID_AA64ISAR0_EL1, ATOMIC, IMP)
 	},
 #endif /* CONFIG_ARM64_LSE_ATOMICS */
-	{
-		.desc = "Software prefetching using PRFM",
-		.capability = ARM64_HAS_NO_HW_PREFETCH,
-		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,
-		.matches = has_no_hw_prefetch,
-	},
 	{
 		.desc = "Virtualization Host Extensions",
 		.capability = ARM64_HAS_VIRT_HOST_EXTN,
@@ -3271,14 +3236,6 @@ void check_local_cpu_capabilities(void)
 		verify_local_cpu_capabilities();
 }
 
-static void __init setup_boot_cpu_capabilities(void)
-{
-	/* Detect capabilities with either SCOPE_BOOT_CPU or SCOPE_LOCAL_CPU */
-	update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
-	/* Enable the SCOPE_BOOT_CPU capabilities alone right away */
-	enable_cpu_capabilities(SCOPE_BOOT_CPU);
-}
-
 bool this_cpu_has_cap(unsigned int n)
 {
 	if (!WARN_ON(preemptible()) && n < ARM64_NCAPS) {
@@ -3334,44 +3291,82 @@ unsigned long cpu_get_elf_hwcap2(void)
 	return elf_hwcap[1];
 }
 
-void __init setup_system_features(void)
+static void __init setup_boot_cpu_capabilities(void)
 {
-	int i;
 	/*
-	 * The system-wide safe feature feature register values have been
-	 * finalized. Finalize and log the available system capabilities.
+	 * The boot CPU's feature register values have been recorded. Detect
+	 * boot cpucaps and local cpucaps for the boot CPU, then enable and
+	 * patch alternatives for the available boot cpucaps.
 	 */
-	update_cpu_capabilities(SCOPE_SYSTEM);
-	if (IS_ENABLED(CONFIG_ARM64_SW_TTBR0_PAN) &&
-	    !cpus_have_cap(ARM64_HAS_PAN))
-		pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");
+	update_cpu_capabilities(SCOPE_BOOT_CPU | SCOPE_LOCAL_CPU);
+	enable_cpu_capabilities(SCOPE_BOOT_CPU);
+	apply_boot_alternatives();
+}
 
+void __init setup_boot_cpu_features(void)
+{
 	/*
-	 * Enable all the available capabilities which have not been enabled
-	 * already.
+	 * Initialize the indirect array of CPU capabilities pointers before we
+	 * handle the boot CPU.
 	 */
-	enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU);
+	init_cpucap_indirect_list();
 
-	kpti_install_ng_mappings();
+	/*
+	 * Detect broken pseudo-NMI. Must be called _before_ the call to
+	 * setup_boot_cpu_capabilities() since it interacts with
+	 * can_use_gic_priorities().
+	 */
+	detect_system_supports_pseudo_nmi();
 
-	sve_setup();
-	sme_setup();
+	setup_boot_cpu_capabilities();
+}
 
+static void __init setup_system_capabilities(void)
+{
 	/*
-	 * Check for sane CTR_EL0.CWG value.
+	 * The system-wide safe feature register values have been finalized.
+	 * Detect, enable, and patch alternatives for the available system
+	 * cpucaps.
 	 */
-	if (!cache_type_cwg())
-		pr_warn("No Cache Writeback Granule information, assuming %d\n",
-			ARCH_DMA_MINALIGN);
+	update_cpu_capabilities(SCOPE_SYSTEM);
+	enable_cpu_capabilities(SCOPE_ALL & ~SCOPE_BOOT_CPU);
+	apply_alternatives_all();
 
-	for (i = 0; i < ARM64_NCAPS; i++) {
+	/*
+	 * Log any cpucaps with a cpumask as these aren't logged by
+	 * update_cpu_capabilities().
+	 */
+	for (int i = 0; i < ARM64_NCAPS; i++) {
 		const struct arm64_cpu_capabilities *caps = cpucap_ptrs[i];
 
 		if (caps && caps->cpus && caps->desc &&
 			cpumask_any(caps->cpus) < nr_cpu_ids)
 			pr_info("detected: %s on CPU%*pbl\n",
 				caps->desc, cpumask_pr_args(caps->cpus));
 	}
+
+	/*
+	 * TTBR0 PAN doesn't have its own cpucap, so log it manually.
+	 */
+	if (system_uses_ttbr0_pan())
+		pr_info("emulated: Privileged Access Never (PAN) using TTBR0_EL1 switching\n");
+}
+
+void __init setup_system_features(void)
+{
+	setup_system_capabilities();
+
+	kpti_install_ng_mappings();
+
+	sve_setup();
+	sme_setup();
+
+	/*
+	 * Check for sane CTR_EL0.CWG value.
+	 */
+	if (!cache_type_cwg())
+		pr_warn("No Cache Writeback Granule information, assuming %d\n",
+			ARCH_DMA_MINALIGN);
 }
 
 void __init setup_user_features(void)

arch/arm64/kernel/fpsimd.c

@@ -1171,7 +1171,7 @@ void __init sve_setup(void)
 	unsigned long b;
 	int max_bit;
 
-	if (!cpus_have_cap(ARM64_SVE))
+	if (!system_supports_sve())
 		return;
 
 	/*
@@ -1301,7 +1301,7 @@ void __init sme_setup(void)
 	struct vl_info *info = &vl_info[ARM64_VEC_SME];
 	int min_bit, max_bit;
 
-	if (!cpus_have_cap(ARM64_SME))
+	if (!system_supports_sme())
 		return;
 
 	/*

arch/arm64/kernel/smp.c

@@ -439,9 +439,8 @@ static void __init hyp_mode_check(void)
 void __init smp_cpus_done(unsigned int max_cpus)
 {
 	pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
-	setup_system_features();
 	hyp_mode_check();
-	apply_alternatives_all();
+	setup_system_features();
 	setup_user_features();
 	mark_linear_text_alias_ro();
 }
@@ -454,14 +453,9 @@ void __init smp_prepare_boot_cpu(void)
 	 * freed shortly, so we must move over to the runtime per-cpu area.
 	 */
 	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
-	cpuinfo_store_boot_cpu();
 
-	/*
-	 * We now know enough about the boot CPU to apply the
-	 * alternatives that cannot wait until interrupt handling
-	 * and/or scheduling is enabled.
-	 */
-	apply_boot_alternatives();
+	cpuinfo_store_boot_cpu();
+	setup_boot_cpu_features();
 
 	/* Conditionally switch to GIC PMR for interrupt masking */
 	if (system_uses_irq_prio_masking())

arch/arm64/lib/copy_page.S

@@ -18,13 +18,6 @@
  *	x1 - src
  */
 SYM_FUNC_START(__pi_copy_page)
-alternative_if ARM64_HAS_NO_HW_PREFETCH
-	// Prefetch three cache lines ahead.
-	prfm	pldl1strm, [x1, #128]
-	prfm	pldl1strm, [x1, #256]
-	prfm	pldl1strm, [x1, #384]
-alternative_else_nop_endif
-
 	ldp	x2, x3, [x1]
 	ldp	x4, x5, [x1, #16]
 	ldp	x6, x7, [x1, #32]
@@ -39,10 +32,6 @@ alternative_else_nop_endif
 1:
 	tst	x0, #(PAGE_SIZE - 1)
 
-alternative_if ARM64_HAS_NO_HW_PREFETCH
-	prfm	pldl1strm, [x1, #384]
-alternative_else_nop_endif
-
 	stnp	x2, x3, [x0, #-256]
 	ldp	x2, x3, [x1]
 	stnp	x4, x5, [x0, #16 - 256]

arch/arm64/mm/mmu.c

@@ -674,6 +674,9 @@ static int __init map_entry_trampoline(void)
 {
 	int i;
 
+	if (!arm64_kernel_unmapped_at_el0())
+		return 0;
+
 	pgprot_t prot = kernel_exec_prot();
 	phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
 

arch/arm64/tools/cpucaps

@@ -40,7 +40,6 @@ HAS_LDAPR
 HAS_LSE_ATOMICS
 HAS_MOPS
 HAS_NESTED_VIRT
-HAS_NO_HW_PREFETCH
 HAS_PAN
 HAS_S1PIE
 HAS_RAS_EXTN