Merge branch 'for-next/c1-pro-erratum-4193714' into for-next/core

* for-next/c1-pro-erratum-4193714:
  : Work around C1-Pro erratum 4193714 (CVE-2026-0995)
  arm64: errata: Work around early CME DVMSync acknowledgement
  arm64: cputype: Add C1-Pro definitions
  arm64: tlb: Pass the corresponding mm to __tlbi_sync_s1ish()
  arm64: tlb: Introduce __tlbi_sync_s1ish_{kernel,batch}() for TLB maintenance

13 files changed, 284 insertions, 10 deletions

diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst
index 65ed6ea33751..8c7ef3a5629d 100644
--- a/Documentation/arch/arm64/silicon-errata.rst
+++ b/Documentation/arch/arm64/silicon-errata.rst
@@ -202,6 +202,8 @@ stable kernels.
 +----------------+-----------------+-----------------+-----------------------------+
 | ARM            | Neoverse-V3AE   | #3312417        | ARM64_ERRATUM_3194386       |
 +----------------+-----------------+-----------------+-----------------------------+
+| ARM            | C1-Pro          | #4193714        | ARM64_ERRATUM_4193714       |
++----------------+-----------------+-----------------+-----------------------------+
 | ARM            | MMU-500         | #841119,826419  | ARM_SMMU_MMU_500_CPRE_ERRATA|
 |                |                 | #562869,1047329 |                             |
 +----------------+-----------------+-----------------+-----------------------------+
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a60038520cee..f7632c3ff4d2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1149,6 +1149,18 @@ config ARM64_ERRATUM_4311569
 
 	  If unsure, say Y.
 
+config ARM64_ERRATUM_4193714
+	bool "C1-Pro: 4193714: SME DVMSync early acknowledgement"
+	depends on ARM64_SME
+	default y
+	help
+	  Enable workaround for C1-Pro acknowledging the DVMSync before
+	  the SME memory accesses are complete. This will cause TLB
+	  maintenance for processes using SME to also issue an IPI to
+	  the affected CPUs.
+
+	  If unsure, say Y.
+
 config CAVIUM_ERRATUM_22375
 	bool "Cavium erratum 22375, 24313"
 	default y
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 6e3da333442e..d0d3cdd5763c 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -64,6 +64,8 @@ cpucap_is_possible(const unsigned int cap)
 		return IS_ENABLED(CONFIG_ARM64_WORKAROUND_REPEAT_TLBI);
 	case ARM64_WORKAROUND_SPECULATIVE_SSBS:
 		return IS_ENABLED(CONFIG_ARM64_ERRATUM_3194386);
+	case ARM64_WORKAROUND_4193714:
+		return IS_ENABLED(CONFIG_ARM64_ERRATUM_4193714);
 	case ARM64_MPAM:
 		/*
 		 * KVM MPAM support doesn't rely on the host kernel supporting MPAM.
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 08860d482e60..7b518e81dd15 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -98,6 +98,7 @@
 #define ARM_CPU_PART_CORTEX_A725	0xD87
 #define ARM_CPU_PART_CORTEX_A720AE	0xD89
 #define ARM_CPU_PART_NEOVERSE_N3	0xD8E
+#define ARM_CPU_PART_C1_PRO		0xD8B
 
 #define APM_CPU_PART_XGENE		0x000
 #define APM_CPU_VAR_POTENZA		0x00
@@ -189,6 +190,7 @@
 #define MIDR_CORTEX_A725 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A725)
 #define MIDR_CORTEX_A720AE MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A720AE)
 #define MIDR_NEOVERSE_N3 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_NEOVERSE_N3)
+#define MIDR_C1_PRO MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_C1_PRO)
 #define MIDR_THUNDERX	MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX)
 #define MIDR_THUNDERX_81XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_81XX)
 #define MIDR_THUNDERX_83XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_83XX)
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 1d2e33559bd5..d9d00b45ab11 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -428,6 +428,24 @@ static inline size_t sme_state_size(struct task_struct const *task)
 	return __sme_state_size(task_get_sme_vl(task));
 }
 
+void sme_enable_dvmsync(void);
+void sme_set_active(void);
+void sme_clear_active(void);
+
+static inline void sme_enter_from_user_mode(void)
+{
+	if (alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714) &&
+	    test_thread_flag(TIF_SME))
+		sme_clear_active();
+}
+
+static inline void sme_exit_to_user_mode(void)
+{
+	if (alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714) &&
+	    test_thread_flag(TIF_SME))
+		sme_set_active();
+}
+
 #else
 
 static inline void sme_user_disable(void) { BUILD_BUG(); }
@@ -456,6 +474,9 @@ static inline size_t sme_state_size(struct task_struct const *task)
 	return 0;
 }
 
+static inline void sme_enter_from_user_mode(void) { }
+static inline void sme_exit_to_user_mode(void) { }
+
 #endif /* ! CONFIG_ARM64_SME */
 
 /* For use by EFI runtime services calls only */
diff --git a/arch/arm64/include/asm/tlbbatch.h b/arch/arm64/include/asm/tlbbatch.h
index fedb0b87b8db..6297631532e5 100644
--- a/arch/arm64/include/asm/tlbbatch.h
+++ b/arch/arm64/include/asm/tlbbatch.h
@@ -2,11 +2,17 @@
 #ifndef _ARCH_ARM64_TLBBATCH_H
 #define _ARCH_ARM64_TLBBATCH_H
 
+#include <linux/cpumask.h>
+
 struct arch_tlbflush_unmap_batch {
+#ifdef CONFIG_ARM64_ERRATUM_4193714
 	/*
-	 * For arm64, HW can do tlb shootdown, so we don't
-	 * need to record cpumask for sending IPI
+	 * Track CPUs that need SME DVMSync on completion of this batch.
+	 * Otherwise, the arm64 HW can do tlb shootdown, so we don't need to
+	 * record cpumask for sending IPI
 	 */
+	cpumask_var_t cpumask;
+#endif
 };
 
 #endif /* _ARCH_ARM64_TLBBATCH_H */
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index 47fa4d39a461..c0bf5b398041 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -80,6 +80,71 @@ static inline unsigned long get_trans_granule(void)
 	}
 }
 
+#ifdef CONFIG_ARM64_ERRATUM_4193714
+
+void sme_do_dvmsync(const struct cpumask *mask);
+
+static inline void sme_dvmsync(struct mm_struct *mm)
+{
+	if (!alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714))
+		return;
+
+	sme_do_dvmsync(mm_cpumask(mm));
+}
+
+static inline void sme_dvmsync_add_pending(struct arch_tlbflush_unmap_batch *batch,
+					   struct mm_struct *mm)
+{
+	if (!alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714))
+		return;
+
+	/*
+	 * Order the mm_cpumask() read after the hardware DVMSync.
+	 */
+	dsb(ish);
+	if (cpumask_empty(mm_cpumask(mm)))
+		return;
+
+	/*
+	 * Allocate the batch cpumask on first use. Fall back to an immediate
+	 * IPI for this mm in case of failure.
+	 */
+	if (!cpumask_available(batch->cpumask) &&
+	    !zalloc_cpumask_var(&batch->cpumask, GFP_ATOMIC)) {
+		sme_do_dvmsync(mm_cpumask(mm));
+		return;
+	}
+
+	cpumask_or(batch->cpumask, batch->cpumask, mm_cpumask(mm));
+}
+
+static inline void sme_dvmsync_batch(struct arch_tlbflush_unmap_batch *batch)
+{
+	if (!alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714))
+		return;
+
+	if (!cpumask_available(batch->cpumask))
+		return;
+
+	sme_do_dvmsync(batch->cpumask);
+	cpumask_clear(batch->cpumask);
+}
+
+#else
+
+static inline void sme_dvmsync(struct mm_struct *mm)
+{
+}
+static inline void sme_dvmsync_add_pending(struct arch_tlbflush_unmap_batch *batch,
+					   struct mm_struct *mm)
+{
+}
+static inline void sme_dvmsync_batch(struct arch_tlbflush_unmap_batch *batch)
+{
+}
+
+#endif /* CONFIG_ARM64_ERRATUM_4193714 */
+
 /*
  * Level-based TLBI operations.
  *
@@ -213,7 +278,21 @@ do {										\
  * Complete broadcast TLB maintenance issued by the host which invalidates
  * stage 1 information in the host's own translation regime.
  */
-static inline void __tlbi_sync_s1ish(void)
+static inline void __tlbi_sync_s1ish(struct mm_struct *mm)
+{
+	dsb(ish);
+	__repeat_tlbi_sync(vale1is, 0);
+	sme_dvmsync(mm);
+}
+
+static inline void __tlbi_sync_s1ish_batch(struct arch_tlbflush_unmap_batch *batch)
+{
+	dsb(ish);
+	__repeat_tlbi_sync(vale1is, 0);
+	sme_dvmsync_batch(batch);
+}
+
+static inline void __tlbi_sync_s1ish_kernel(void)
 {
 	dsb(ish);
 	__repeat_tlbi_sync(vale1is, 0);
@@ -322,7 +401,7 @@ static inline void flush_tlb_all(void)
 {
 	dsb(ishst);
 	__tlbi(vmalle1is);
-	__tlbi_sync_s1ish();
+	__tlbi_sync_s1ish_kernel();
 	isb();
 }
 
@@ -334,7 +413,7 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
 	asid = __TLBI_VADDR(0, ASID(mm));
 	__tlbi(aside1is, asid);
 	__tlbi_user(aside1is, asid);
-	__tlbi_sync_s1ish();
+	__tlbi_sync_s1ish(mm);
 	mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL);
 }
 
@@ -355,7 +434,7 @@ static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
  */
 static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
 {
-	__tlbi_sync_s1ish();
+	__tlbi_sync_s1ish_batch(batch);
 }
 
 /*
@@ -557,7 +636,7 @@ static __always_inline void __do_flush_tlb_range(struct vm_area_struct *vma,
 
 	if (!(flags & TLBF_NOSYNC)) {
 		if (!(flags & TLBF_NOBROADCAST))
-			__tlbi_sync_s1ish();
+			__tlbi_sync_s1ish(mm);
 		else
 			dsb(nsh);
 	}
@@ -618,7 +697,7 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
 	dsb(ishst);
 	__flush_s1_tlb_range_op(vaale1is, start, pages, stride, 0,
 				TLBI_TTL_UNKNOWN);
-	__tlbi_sync_s1ish();
+	__tlbi_sync_s1ish_kernel();
 	isb();
 }
 
@@ -632,7 +711,7 @@ static inline void __flush_tlb_kernel_pgtable(unsigned long kaddr)
 
 	dsb(ishst);
 	__tlbi(vaae1is, addr);
-	__tlbi_sync_s1ish();
+	__tlbi_sync_s1ish_kernel();
 	isb();
 }
 
@@ -643,6 +722,7 @@ static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *b
 
 	__flush_tlb_range(&vma, start, end, PAGE_SIZE, 3,
 			  TLBF_NOWALKCACHE | TLBF_NOSYNC);
+	sme_dvmsync_add_pending(batch, mm);
 }
 
 static inline bool __pte_flags_need_flush(ptdesc_t oldval, ptdesc_t newval)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 5c0ab6bfd44a..5377e4c2eba2 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -11,6 +11,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/cpufeature.h>
+#include <asm/fpsimd.h>
 #include <asm/kvm_asm.h>
 #include <asm/smp_plat.h>
 
@@ -575,6 +576,23 @@ static const struct midr_range erratum_spec_ssbs_list[] = {
 };
 #endif
 
+#ifdef CONFIG_ARM64_ERRATUM_4193714
+static bool has_sme_dvmsync_erratum(const struct arm64_cpu_capabilities *entry,
+				    int scope)
+{
+	if (!id_aa64pfr1_sme(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1)))
+		return false;
+
+	return is_affected_midr_range(entry, scope);
+}
+
+static void cpu_enable_sme_dvmsync(const struct arm64_cpu_capabilities *__unused)
+{
+	if (this_cpu_has_cap(ARM64_WORKAROUND_4193714))
+		sme_enable_dvmsync();
+}
+#endif
+
 #ifdef CONFIG_AMPERE_ERRATUM_AC03_CPU_38
 static const struct midr_range erratum_ac03_cpu_38_list[] = {
 	MIDR_ALL_VERSIONS(MIDR_AMPERE1),
@@ -901,6 +919,18 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		.matches = need_arm_si_l1_workaround_4311569,
 	},
 #endif
+#ifdef CONFIG_ARM64_ERRATUM_4193714
+	{
+		.desc = "C1-Pro SME DVMSync early acknowledgement",
+		.capability = ARM64_WORKAROUND_4193714,
+		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
+		.matches = has_sme_dvmsync_erratum,
+		.cpu_enable = cpu_enable_sme_dvmsync,
+		/* C1-Pro r0p0 - r1p2 (the latter only when REVIDR_EL1[0]==0) */
+		.midr_range = MIDR_RANGE(MIDR_C1_PRO, 0, 0, 1, 2),
+		MIDR_FIXED(MIDR_CPU_VAR_REV(1, 2), BIT(0)),
+	},
+#endif
 #ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
 	{
 		.desc = "ARM errata 2966298, 3117295",
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index f42ce7b5c67f..cb54335465f6 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -21,6 +21,7 @@
 #include <asm/daifflags.h>
 #include <asm/esr.h>
 #include <asm/exception.h>
+#include <asm/fpsimd.h>
 #include <asm/irq_regs.h>
 #include <asm/kprobes.h>
 #include <asm/mmu.h>
@@ -70,6 +71,7 @@ static __always_inline void arm64_enter_from_user_mode(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);
 	mte_disable_tco_entry(current);
+	sme_enter_from_user_mode();
 }
 
 /*
@@ -83,6 +85,7 @@ static __always_inline void arm64_exit_to_user_mode(struct pt_regs *regs)
 	local_irq_disable();
 	exit_to_user_mode_prepare_legacy(regs);
 	local_daif_mask();
+	sme_exit_to_user_mode();
 	mte_check_tfsr_exit();
 	exit_to_user_mode();
 }
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 9de1d8a604cb..60a45d600b46 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -15,6 +15,7 @@
 #include <linux/compiler.h>
 #include <linux/cpu.h>
 #include <linux/cpu_pm.h>
+#include <linux/cpumask.h>
 #include <linux/ctype.h>
 #include <linux/kernel.h>
 #include <linux/linkage.h>
@@ -28,6 +29,7 @@
 #include <linux/sched/task_stack.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
+#include <linux/smp.h>
 #include <linux/stddef.h>
 #include <linux/sysctl.h>
 #include <linux/swab.h>
@@ -1358,6 +1360,83 @@ void do_sve_acc(unsigned long esr, struct pt_regs *regs)
 	put_cpu_fpsimd_context();
 }
 
+#ifdef CONFIG_ARM64_ERRATUM_4193714
+
+/*
+ * SME/CME erratum handling.
+ */
+static cpumask_t sme_dvmsync_cpus;
+
+/*
+ * These helpers are only called from non-preemptible contexts, so
+ * smp_processor_id() is safe here.
+ */
+void sme_set_active(void)
+{
+	unsigned int cpu = smp_processor_id();
+
+	if (!cpumask_test_cpu(cpu, &sme_dvmsync_cpus))
+		return;
+
+	cpumask_set_cpu(cpu, mm_cpumask(current->mm));
+
+	/*
+	 * A subsequent (post ERET) SME access may use a stale address
+	 * translation. On C1-Pro, a TLBI+DSB on a different CPU will wait for
+	 * the completion of cpumask_set_cpu() above as it appears in program
+	 * order before the SME access. The post-TLBI+DSB read of mm_cpumask()
+	 * will lead to the IPI being issued.
+	 *
+	 * https://lore.kernel.org/r/ablEXwhfKyJW1i7l@J2N7QTR9R3
+	 */
+}
+
+void sme_clear_active(void)
+{
+	unsigned int cpu = smp_processor_id();
+
+	if (!cpumask_test_cpu(cpu, &sme_dvmsync_cpus))
+		return;
+
+	/*
+	 * With SCTLR_EL1.IESB enabled, the SME memory transactions are
+	 * completed on entering EL1.
+	 */
+	cpumask_clear_cpu(cpu, mm_cpumask(current->mm));
+}
+
+static void sme_dvmsync_ipi(void *unused)
+{
+	/*
+	 * With SCTLR_EL1.IESB on, taking an exception is sufficient to ensure
+	 * the completion of the SME memory accesses, so no need for an
+	 * explicit DSB.
+	 */
+}
+
+void sme_do_dvmsync(const struct cpumask *mask)
+{
+	/*
+	 * This is called from the TLB maintenance functions after the DSB ISH
+	 * to send the hardware DVMSync message. If this CPU sees the mask as
+	 * empty, the remote CPU executing sme_set_active() would have seen
+	 * the DVMSync and no IPI required.
+	 */
+	if (cpumask_empty(mask))
+		return;
+
+	preempt_disable();
+	smp_call_function_many(mask, sme_dvmsync_ipi, NULL, true);
+	preempt_enable();
+}
+
+void sme_enable_dvmsync(void)
+{
+	cpumask_set_cpu(smp_processor_id(), &sme_dvmsync_cpus);
+}
+
+#endif /* CONFIG_ARM64_ERRATUM_4193714 */
+
 /*
  * Trapped SME access
  *
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index c0bf1f46cdc6..033643cd4e5e 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -26,6 +26,7 @@
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
+#include <linux/cpumask.h>
 #include <linux/cpu.h>
 #include <linux/elfcore.h>
 #include <linux/pm.h>
@@ -340,8 +341,41 @@ void flush_thread(void)
 	flush_gcs();
 }
 
+#ifdef CONFIG_ARM64_ERRATUM_4193714
+
+static void arch_dup_tlbbatch_mask(struct task_struct *dst)
+{
+	/*
+	 * Clear the inherited cpumask with memset() to cover both cases where
+	 * cpumask_var_t is a pointer or an array. It will be allocated lazily
+	 * in sme_dvmsync_add_pending() if CPUMASK_OFFSTACK=y.
+	 */
+	if (alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714))
+		memset(&dst->tlb_ubc.arch.cpumask, 0,
+		       sizeof(dst->tlb_ubc.arch.cpumask));
+}
+
+static void arch_release_tlbbatch_mask(struct task_struct *tsk)
+{
+	if (alternative_has_cap_unlikely(ARM64_WORKAROUND_4193714))
+		free_cpumask_var(tsk->tlb_ubc.arch.cpumask);
+}
+
+#else
+
+static void arch_dup_tlbbatch_mask(struct task_struct *dst)
+{
+}
+
+static void arch_release_tlbbatch_mask(struct task_struct *tsk)
+{
+}
+
+#endif /* CONFIG_ARM64_ERRATUM_4193714 */
+
 void arch_release_task_struct(struct task_struct *tsk)
 {
+	arch_release_tlbbatch_mask(tsk);
 	fpsimd_release_task(tsk);
 }
 
@@ -357,6 +391,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 
 	*dst = *src;
 
+	arch_dup_tlbbatch_mask(dst);
+
 	/*
 	 * Drop stale reference to src's sve_state and convert dst to
 	 * non-streaming FPSIMD mode.
diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c
index 7e9860143add..0451f96c2c3f 100644
--- a/arch/arm64/kernel/sys_compat.c
+++ b/arch/arm64/kernel/sys_compat.c
@@ -37,7 +37,7 @@ __do_compat_cache_op(unsigned long start, unsigned long end)
 			 * We pick the reserved-ASID to minimise the impact.
 			 */
 			__tlbi(aside1is, 0UL);
-			__tlbi_sync_s1ish();
+			__tlbi_sync_s1ish(current->mm);
 		}
 
 		ret = caches_clean_inval_user_pou(start, start + chunk);
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index b7286d977788..811c2479e82d 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -106,6 +106,7 @@ WORKAROUND_2077057
 WORKAROUND_2457168
 WORKAROUND_2645198
 WORKAROUND_2658417
+WORKAROUND_4193714
 WORKAROUND_4311569
 WORKAROUND_AMPERE_AC03_CPU_38
 WORKAROUND_AMPERE_AC04_CPU_23