Merge branch 'for-next/late-arrivals' into for-next/core

Late patches for 5.10: MTE selftests, minor KCSAN preparation and removal
of some unused prototypes.

(Amit Daniel Kachhap and others)
* for-next/late-arrivals:
  arm64: random: Remove no longer needed prototypes
  arm64: initialize per-cpu offsets earlier
  kselftest/arm64: Check mte tagged user address in kernel
  kselftest/arm64: Verify KSM page merge for MTE pages
  kselftest/arm64: Verify all different mmap MTE options
  kselftest/arm64: Check forked child mte memory accessibility
  kselftest/arm64: Verify mte tag inclusion via prctl
  kselftest/arm64: Add utilities and a test to validate mte memory

Author: willdeacon

arch/arm64/include/asm/archrandom.h

@@ -79,10 +79,5 @@ arch_get_random_seed_long_early(unsigned long *v)
 }
 #define arch_get_random_seed_long_early arch_get_random_seed_long_early
 
-#else
-
-static inline bool __arm64_rndr(unsigned long *v) { return false; }
-static inline bool __init __early_cpu_has_rndr(void) { return false; }
-
 #endif /* CONFIG_ARCH_RANDOM */
 #endif /* _ASM_ARCHRANDOM_H */

arch/arm64/include/asm/cpu.h

@@ -68,4 +68,6 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info);
 void update_cpu_features(int cpu, struct cpuinfo_arm64 *info,
 				 struct cpuinfo_arm64 *boot);
 
+void init_this_cpu_offset(void);
+
 #endif /* __ASM_CPU_H */

arch/arm64/kernel/head.S

@@ -448,6 +448,8 @@ SYM_FUNC_START_LOCAL(__primary_switched)
 	bl	__pi_memset
 	dsb	ishst				// Make zero page visible to PTW
 
+	bl	init_this_cpu_offset
+
 #ifdef CONFIG_KASAN
 	bl	kasan_early_init
 #endif
@@ -754,6 +756,7 @@ SYM_FUNC_START_LOCAL(__secondary_switched)
 	ptrauth_keys_init_cpu x2, x3, x4, x5
 #endif
 
+	bl	init_this_cpu_offset
 	b	secondary_start_kernel
 SYM_FUNC_END(__secondary_switched)
 

arch/arm64/kernel/setup.c

@@ -87,12 +87,6 @@ void __init smp_setup_processor_id(void)
 	u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
 	set_cpu_logical_map(0, mpidr);
 
-	/*
-	 * clear __my_cpu_offset on boot CPU to avoid hang caused by
-	 * using percpu variable early, for example, lockdep will
-	 * access percpu variable inside lock_release
-	 */
-	set_my_cpu_offset(0);
 	pr_info("Booting Linux on physical CPU 0x%010lx [0x%08x]\n",
 		(unsigned long)mpidr, read_cpuid_id());
 }
@@ -282,6 +276,12 @@ u64 cpu_logical_map(int cpu)
 }
 EXPORT_SYMBOL_GPL(cpu_logical_map);
 
+void noinstr init_this_cpu_offset(void)
+{
+	unsigned int cpu = task_cpu(current);
+	set_my_cpu_offset(per_cpu_offset(cpu));
+}
+
 void __init __no_sanitize_address setup_arch(char **cmdline_p)
 {
 	init_mm.start_code = (unsigned long) _text;

arch/arm64/kernel/smp.c

@@ -192,10 +192,7 @@ asmlinkage notrace void secondary_start_kernel(void)
 	u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
 	struct mm_struct *mm = &init_mm;
 	const struct cpu_operations *ops;
-	unsigned int cpu;
-
-	cpu = task_cpu(current);
-	set_my_cpu_offset(per_cpu_offset(cpu));
+	unsigned int cpu = smp_processor_id();
 
 	/*
 	 * All kernel threads share the same mm context; grab a
@@ -435,7 +432,13 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
 void __init smp_prepare_boot_cpu(void)
 {
-	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
+	/*
+	 * Now that setup_per_cpu_areas() has allocated the runtime per-cpu
+	 * areas it is only safe to read the CPU0 boot-time area, and we must
+	 * reinitialize the offset to point to the runtime area.
+	 */
+	init_this_cpu_offset();
+
 	cpuinfo_store_boot_cpu();
 
 	/*

tools/testing/selftests/arm64/Makefile

@@ -4,7 +4,7 @@
 ARCH ?= $(shell uname -m 2>/dev/null || echo not)
 
 ifneq (,$(filter $(ARCH),aarch64 arm64))
-ARM64_SUBTARGETS ?= tags signal pauth fp
+ARM64_SUBTARGETS ?= tags signal pauth fp mte
 else
 ARM64_SUBTARGETS :=
 endif

tools/testing/selftests/arm64/mte/.gitignore

@@ -0,0 +1,6 @@
+check_buffer_fill
+check_tags_inclusion
+check_child_memory
+check_mmap_options
+check_ksm_options
+check_user_mem

tools/testing/selftests/arm64/mte/Makefile

@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2020 ARM Limited
+
+CFLAGS += -std=gnu99 -I.
+SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
+PROGS := $(patsubst %.c,%,$(SRCS))
+
+#Add mte compiler option
+ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
+CFLAGS += -march=armv8.5-a+memtag
+endif
+
+#check if the compiler works well
+mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)
+
+ifeq ($(mte_cc_support),1)
+# Generated binaries to be installed by top KSFT script
+TEST_GEN_PROGS := $(PROGS)
+
+# Get Kernel headers installed and use them.
+KSFT_KHDR_INSTALL := 1
+endif
+
+# Include KSFT lib.mk.
+include ../../lib.mk
+
+ifeq ($(mte_cc_support),1)
+$(TEST_GEN_PROGS): mte_common_util.c mte_common_util.h mte_helper.S
+endif