Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "There's good stuff across the board, including some nice mm
  improvements for CPUs with the 'noabort' BBML2 feature and a clever
  patch to allow ptdump to play nicely with block mappings in the
  vmalloc area.

  Confidential computing:

   - Add support for accepting secrets from firmware (e.g. ACPI CCEL)
     and mapping them with appropriate attributes.

  CPU features:

   - Advertise atomic floating-point instructions to userspace

   - Extend Spectre workarounds to cover additional Arm CPU variants

   - Extend list of CPUs that support break-before-make level 2 and
     guarantee not to generate TLB conflict aborts for changes of
     mapping granularity (BBML2_NOABORT)

   - Add GCS support to our uprobes implementation.

  Documentation:

   - Remove bogus SME documentation concerning register state when
     entering/exiting streaming mode.

  Entry code:

   - Switch over to the generic IRQ entry code (GENERIC_IRQ_ENTRY)

   - Micro-optimise syscall entry path with a compiler branch hint.

  Memory management:

   - Enable huge mappings in vmalloc space even when kernel page-table
     dumping is enabled

   - Tidy up the types used in our early MMU setup code

   - Rework rodata= for closer parity with the behaviour on x86

   - For CPUs implementing BBML2_NOABORT, utilise block mappings in the
     linear map even when rodata= applies to virtual aliases

   - Don't re-allocate the virtual region between '_text' and '_stext',
     as doing so confused tools parsing /proc/vmcore.

  Miscellaneous:

   - Clean-up Kconfig menuconfig text for architecture features

   - Avoid redundant bitmap_empty() during determination of supported
     SME vector lengths

   - Re-enable warnings when building the 32-bit vDSO object

   - Avoid breaking our eggs at the wrong end.

  Perf and PMUs:

   - Support for v3 of the Hisilicon L3C PMU

   - Support for Hisilicon's MN and NoC PMUs

   - Support for Fujitsu's Uncore PMU

   - Support for SPE's extended event filtering feature

   - Preparatory work to enable data source filtering in SPE

   - Support for multiple lanes in the DWC PCIe PMU

   - Support for i.MX94 in the IMX DDR PMU driver

   - MAINTAINERS update (Thank you, Yicong)

   - Minor driver fixes (PERF_IDX2OFF() overflow, CMN register offsets).

  Selftests:

   - Add basic LSFE check to the existing hwcaps test

   - Support nolibc in GCS tests

   - Extend SVE ptrace test to pass unsupported regsets and invalid
     vector lengths

   - Minor cleanups (typos, cosmetic changes).

  System registers:

   - Fix ID_PFR1_EL1 definition

   - Fix incorrect signedness of some fields in ID_AA64MMFR4_EL1

   - Sync TCR_EL1 definition with the latest Arm ARM (L.b)

   - Be stricter about the input fed into our AWK sysreg generator
     script

   - Typo fixes and removal of redundant definitions.

  ACPI, EFI and PSCI:

   - Decouple Arm's "Software Delegated Exception Interface" (SDEI)
     support from the ACPI GHES code so that it can be used by platforms
     booted with device-tree

   - Remove unnecessary per-CPU tracking of the FPSIMD state across EFI
     runtime calls

   - Fix a node refcount imbalance in the PSCI device-tree code.

  CPU Features:

   - Ensure register sanitisation is applied to fields in ID_AA64MMFR4

   - Expose AIDR_EL1 to userspace via sysfs, primarily so that KVM
     guests can reliably query the underlying CPU types from the VMM

   - Re-enabling of SME support (CONFIG_ARM64_SME) as a result of fixes
     to our context-switching, signal handling and ptrace code"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (93 commits)
  arm64: cpufeature: Remove duplicate asm/mmu.h header
  arm64: Kconfig: Make CPU_BIG_ENDIAN depend on BROKEN
  perf/dwc_pcie: Fix use of uninitialized variable
  arm/syscalls: mark syscall invocation as likely in invoke_syscall
  Documentation: hisi-pmu: Add introduction to HiSilicon V3 PMU
  Documentation: hisi-pmu: Fix of minor format error
  drivers/perf: hisi: Add support for L3C PMU v3
  drivers/perf: hisi: Refactor the event configuration of L3C PMU
  drivers/perf: hisi: Extend the field of tt_core
  drivers/perf: hisi: Extract the event filter check of L3C PMU
  drivers/perf: hisi: Simplify the probe process of each L3C PMU version
  drivers/perf: hisi: Export hisi_uncore_pmu_isr()
  drivers/perf: hisi: Relax the event ID check in the framework
  perf: Fujitsu: Add the Uncore PMU driver
  arm64: map [_text, _stext) virtual address range non-executable+read-only
  arm64/sysreg: Update TCR_EL1 register
  arm64: Enable vmalloc-huge with ptdump
  arm64: cpufeature: add Neoverse-V3AE to BBML2 allow list
  arm64: errata: Apply workarounds for Neoverse-V3AE
  arm64: cputype: Add Neoverse-V3AE definitions
  ...

14 files changed, 144 insertions, 32 deletions

diff --git a/tools/testing/selftests/arm64/abi/hwcap.c b/tools/testing/selftests/arm64/abi/hwcap.c
index 002ec38a8bbb..3b96d090c5eb 100644
--- a/tools/testing/selftests/arm64/abi/hwcap.c
+++ b/tools/testing/selftests/arm64/abi/hwcap.c
@@ -17,6 +17,8 @@
 #include <asm/sigcontext.h>
 #include <asm/unistd.h>
 
+#include <linux/auxvec.h>
+
 #include "../../kselftest.h"
 
 #define TESTS_PER_HWCAP 3
@@ -55,7 +57,6 @@ static void cmpbr_sigill(void)
 	/* Not implemented, too complicated and unreliable anyway */
 }
 
-
 static void crc32_sigill(void)
 {
 	/* CRC32W W0, W0, W1 */
@@ -169,6 +170,18 @@ static void lse128_sigill(void)
 		     : "cc", "memory");
 }
 
+static void lsfe_sigill(void)
+{
+	float __attribute__ ((aligned (16))) mem;
+	register float *memp asm ("x0") = &mem;
+
+	/* STFADD H0, [X0] */
+	asm volatile(".inst 0x7c20801f"
+		     : "+r" (memp)
+		     :
+		     : "memory");
+}
+
 static void lut_sigill(void)
 {
 	/* LUTI2 V0.16B, { V0.16B }, V[0] */
@@ -763,6 +776,13 @@ static const struct hwcap_data {
 		.sigill_fn = lse128_sigill,
 	},
 	{
+		.name = "LSFE",
+		.at_hwcap = AT_HWCAP3,
+		.hwcap_bit = HWCAP3_LSFE,
+		.cpuinfo = "lsfe",
+		.sigill_fn = lsfe_sigill,
+	},
+	{
 		.name = "LUT",
 		.at_hwcap = AT_HWCAP2,
 		.hwcap_bit = HWCAP2_LUT,
diff --git a/tools/testing/selftests/arm64/abi/tpidr2.c b/tools/testing/selftests/arm64/abi/tpidr2.c
index f58a9f89b952..4c89ab0f1010 100644
--- a/tools/testing/selftests/arm64/abi/tpidr2.c
+++ b/tools/testing/selftests/arm64/abi/tpidr2.c
@@ -227,10 +227,10 @@ int main(int argc, char **argv)
 	ret = open("/proc/sys/abi/sme_default_vector_length", O_RDONLY, 0);
 	if (ret >= 0) {
 		ksft_test_result(default_value(), "default_value\n");
-		ksft_test_result(write_read, "write_read\n");
-		ksft_test_result(write_sleep_read, "write_sleep_read\n");
-		ksft_test_result(write_fork_read, "write_fork_read\n");
-		ksft_test_result(write_clone_read, "write_clone_read\n");
+		ksft_test_result(write_read(), "write_read\n");
+		ksft_test_result(write_sleep_read(), "write_sleep_read\n");
+		ksft_test_result(write_fork_read(), "write_fork_read\n");
+		ksft_test_result(write_clone_read(), "write_clone_read\n");
 
 	} else {
 		ksft_print_msg("SME support not present\n");
diff --git a/tools/testing/selftests/arm64/bti/assembler.h b/tools/testing/selftests/arm64/bti/assembler.h
index 04e7b72880ef..141cdcbf0b8f 100644
--- a/tools/testing/selftests/arm64/bti/assembler.h
+++ b/tools/testing/selftests/arm64/bti/assembler.h
@@ -14,7 +14,6 @@
 #define GNU_PROPERTY_AARCH64_FEATURE_1_BTI	(1U << 0)
 #define GNU_PROPERTY_AARCH64_FEATURE_1_PAC	(1U << 1)
 
-
 .macro startfn name:req
 	.globl \name
 \name:
diff --git a/tools/testing/selftests/arm64/fp/fp-ptrace.c b/tools/testing/selftests/arm64/fp/fp-ptrace.c
index cdd7a45c045d..a85c19e9524e 100644
--- a/tools/testing/selftests/arm64/fp/fp-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/fp-ptrace.c
@@ -1568,7 +1568,6 @@ static void run_sve_tests(void)
 					  &test_config);
 		}
 	}
-
 }
 
 static void run_sme_tests(void)
diff --git a/tools/testing/selftests/arm64/fp/fp-stress.c b/tools/testing/selftests/arm64/fp/fp-stress.c
index 74e23208b94c..9349aa630c84 100644
--- a/tools/testing/selftests/arm64/fp/fp-stress.c
+++ b/tools/testing/selftests/arm64/fp/fp-stress.c
@@ -105,8 +105,8 @@ static void child_start(struct child_data *child, const char *program)
 
 		/*
 		 * Read from the startup pipe, there should be no data
-		 * and we should block until it is closed.  We just
-		 * carry on on error since this isn't super critical.
+		 * and we should block until it is closed. We just
+		 * carry-on on error since this isn't super critical.
 		 */
 		ret = read(3, &i, sizeof(i));
 		if (ret < 0)
@@ -549,7 +549,7 @@ int main(int argc, char **argv)
 
 	evs = calloc(tests, sizeof(*evs));
 	if (!evs)
-		ksft_exit_fail_msg("Failed to allocated %d epoll events\n",
+		ksft_exit_fail_msg("Failed to allocate %d epoll events\n",
 				   tests);
 
 	for (i = 0; i < cpus; i++) {
diff --git a/tools/testing/selftests/arm64/fp/kernel-test.c b/tools/testing/selftests/arm64/fp/kernel-test.c
index e3cec3723ffa..0c40007d1282 100644
--- a/tools/testing/selftests/arm64/fp/kernel-test.c
+++ b/tools/testing/selftests/arm64/fp/kernel-test.c
@@ -188,13 +188,13 @@ static bool create_socket(void)
 
 	ref = malloc(digest_len);
 	if (!ref) {
-		printf("Failed to allocated %d byte reference\n", digest_len);
+		printf("Failed to allocate %d byte reference\n", digest_len);
 		return false;
 	}
 
 	digest = malloc(digest_len);
 	if (!digest) {
-		printf("Failed to allocated %d byte digest\n", digest_len);
+		printf("Failed to allocate %d byte digest\n", digest_len);
 		return false;
 	}
 
diff --git a/tools/testing/selftests/arm64/fp/sve-ptrace.c b/tools/testing/selftests/arm64/fp/sve-ptrace.c
index b22303778fb0..e0fc3a001e28 100644
--- a/tools/testing/selftests/arm64/fp/sve-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/sve-ptrace.c
@@ -66,7 +66,7 @@ static const struct vec_type vec_types[] = {
 };
 
 #define VL_TESTS (((TEST_VQ_MAX - SVE_VQ_MIN) + 1) * 4)
-#define FLAG_TESTS 2
+#define FLAG_TESTS 4
 #define FPSIMD_TESTS 2
 
 #define EXPECTED_TESTS ((VL_TESTS + FLAG_TESTS + FPSIMD_TESTS) * ARRAY_SIZE(vec_types))
@@ -95,19 +95,27 @@ static int do_child(void)
 static int get_fpsimd(pid_t pid, struct user_fpsimd_state *fpsimd)
 {
 	struct iovec iov;
+	int ret;
 
 	iov.iov_base = fpsimd;
 	iov.iov_len = sizeof(*fpsimd);
-	return ptrace(PTRACE_GETREGSET, pid, NT_PRFPREG, &iov);
+	ret = ptrace(PTRACE_GETREGSET, pid, NT_PRFPREG, &iov);
+	if (ret == -1)
+		ksft_perror("ptrace(PTRACE_GETREGSET)");
+	return ret;
 }
 
 static int set_fpsimd(pid_t pid, struct user_fpsimd_state *fpsimd)
 {
 	struct iovec iov;
+	int ret;
 
 	iov.iov_base = fpsimd;
 	iov.iov_len = sizeof(*fpsimd);
-	return ptrace(PTRACE_SETREGSET, pid, NT_PRFPREG, &iov);
+	ret = ptrace(PTRACE_SETREGSET, pid, NT_PRFPREG, &iov);
+	if (ret == -1)
+		ksft_perror("ptrace(PTRACE_SETREGSET)");
+	return ret;
 }
 
 static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type,
@@ -115,8 +123,9 @@ static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type,
 {
 	struct user_sve_header *sve;
 	void *p;
-	size_t sz = sizeof *sve;
+	size_t sz = sizeof(*sve);
 	struct iovec iov;
+	int ret;
 
 	while (1) {
 		if (*size < sz) {
@@ -132,8 +141,11 @@ static struct user_sve_header *get_sve(pid_t pid, const struct vec_type *type,
 
 		iov.iov_base = *buf;
 		iov.iov_len = sz;
-		if (ptrace(PTRACE_GETREGSET, pid, type->regset, &iov))
+		ret = ptrace(PTRACE_GETREGSET, pid, type->regset, &iov);
+		if (ret) {
+			ksft_perror("ptrace(PTRACE_GETREGSET)");
 			goto error;
+		}
 
 		sve = *buf;
 		if (sve->size <= sz)
@@ -152,10 +164,46 @@ static int set_sve(pid_t pid, const struct vec_type *type,
 		   const struct user_sve_header *sve)
 {
 	struct iovec iov;
+	int ret;
 
 	iov.iov_base = (void *)sve;
 	iov.iov_len = sve->size;
-	return ptrace(PTRACE_SETREGSET, pid, type->regset, &iov);
+	ret = ptrace(PTRACE_SETREGSET, pid, type->regset, &iov);
+	if (ret == -1)
+		ksft_perror("ptrace(PTRACE_SETREGSET)");
+	return ret;
+}
+
+/* A read operation fails */
+static void read_fails(pid_t child, const struct vec_type *type)
+{
+	struct user_sve_header *new_sve = NULL;
+	size_t new_sve_size = 0;
+	void *ret;
+
+	ret = get_sve(child, type, (void **)&new_sve, &new_sve_size);
+
+	ksft_test_result(ret == NULL, "%s unsupported read fails\n",
+			 type->name);
+
+	free(new_sve);
+}
+
+/* A write operation fails */
+static void write_fails(pid_t child, const struct vec_type *type)
+{
+	struct user_sve_header sve;
+	int ret;
+
+	/* Just the header, no data */
+	memset(&sve, 0, sizeof(sve));
+	sve.size = sizeof(sve);
+	sve.flags = SVE_PT_REGS_SVE;
+	sve.vl = SVE_VL_MIN;
+	ret = set_sve(child, type, &sve);
+
+	ksft_test_result(ret != 0, "%s unsupported write fails\n",
+			 type->name);
 }
 
 /* Validate setting and getting the inherit flag */
@@ -270,6 +318,25 @@ static void check_u32(unsigned int vl, const char *reg,
 	}
 }
 
+/* Set out of range VLs */
+static void ptrace_set_vl_ranges(pid_t child, const struct vec_type *type)
+{
+	struct user_sve_header sve;
+	int ret;
+
+	memset(&sve, 0, sizeof(sve));
+	sve.flags = SVE_PT_REGS_SVE;
+	sve.size = sizeof(sve);
+
+	ret = set_sve(child, type, &sve);
+	ksft_test_result(ret != 0, "%s Set invalid VL 0\n", type->name);
+
+	sve.vl = SVE_VL_MAX + SVE_VQ_BYTES;
+	ret = set_sve(child, type, &sve);
+	ksft_test_result(ret != 0, "%s Set invalid VL %d\n", type->name,
+			 SVE_VL_MAX + SVE_VQ_BYTES);
+}
+
 /* Access the FPSIMD registers via the SVE regset */
 static void ptrace_sve_fpsimd(pid_t child, const struct vec_type *type)
 {
@@ -683,6 +750,20 @@ static int do_parent(pid_t child)
 	}
 
 	for (i = 0; i < ARRAY_SIZE(vec_types); i++) {
+		/*
+		 * If the vector type isn't supported reads and writes
+		 * should fail.
+		 */
+		if (!(getauxval(vec_types[i].hwcap_type) & vec_types[i].hwcap)) {
+			read_fails(child, &vec_types[i]);
+			write_fails(child, &vec_types[i]);
+		} else {
+			ksft_test_result_skip("%s unsupported read fails\n",
+					      vec_types[i].name);
+			ksft_test_result_skip("%s unsupported write fails\n",
+					      vec_types[i].name);
+		}
+
 		/* FPSIMD via SVE regset */
 		if (getauxval(vec_types[i].hwcap_type) & vec_types[i].hwcap) {
 			ptrace_sve_fpsimd(child, &vec_types[i]);
@@ -703,6 +784,17 @@ static int do_parent(pid_t child)
 					      vec_types[i].name);
 		}
 
+		/* Setting out of bounds VLs should fail */
+		if (getauxval(vec_types[i].hwcap_type) & vec_types[i].hwcap) {
+			ptrace_set_vl_ranges(child, &vec_types[i]);
+		} else {
+			ksft_test_result_skip("%s Set invalid VL 0\n",
+					      vec_types[i].name);
+			ksft_test_result_skip("%s Set invalid VL %d\n",
+					      vec_types[i].name,
+					      SVE_VL_MAX + SVE_VQ_BYTES);
+		}
+
 		/* Step through every possible VQ */
 		for (vq = SVE_VQ_MIN; vq <= TEST_VQ_MAX; vq++) {
 			vl = sve_vl_from_vq(vq);
diff --git a/tools/testing/selftests/arm64/fp/vec-syscfg.c b/tools/testing/selftests/arm64/fp/vec-syscfg.c
index ea9c7d47790f..2d75d342eeb9 100644
--- a/tools/testing/selftests/arm64/fp/vec-syscfg.c
+++ b/tools/testing/selftests/arm64/fp/vec-syscfg.c
@@ -690,7 +690,6 @@ static inline void smstop(void)
 	asm volatile("msr S0_3_C4_C6_3, xzr");
 }
 
-
 /*
  * Verify we can change the SVE vector length while SME is active and
  * continue to use SME afterwards.
diff --git a/tools/testing/selftests/arm64/fp/zt-ptrace.c b/tools/testing/selftests/arm64/fp/zt-ptrace.c
index 584b8d59b7ea..a7f34040fbf1 100644
--- a/tools/testing/selftests/arm64/fp/zt-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/zt-ptrace.c
@@ -108,7 +108,6 @@ static int get_zt(pid_t pid, char zt[ZT_SIG_REG_BYTES])
 	return ptrace(PTRACE_GETREGSET, pid, NT_ARM_ZT, &iov);
 }
 
-
 static int set_zt(pid_t pid, const char zt[ZT_SIG_REG_BYTES])
 {
 	struct iovec iov;
diff --git a/tools/testing/selftests/arm64/gcs/Makefile b/tools/testing/selftests/arm64/gcs/Makefile
index d2f3497a9103..1fbbf0ca1f02 100644
--- a/tools/testing/selftests/arm64/gcs/Makefile
+++ b/tools/testing/selftests/arm64/gcs/Makefile
@@ -14,11 +14,11 @@ LDLIBS+=-lpthread
 include ../../lib.mk
 
 $(OUTPUT)/basic-gcs: basic-gcs.c
-	$(CC) -g -fno-asynchronous-unwind-tables -fno-ident -s -Os -nostdlib \
-		-static -include ../../../../include/nolibc/nolibc.h \
+	$(CC) $(CFLAGS) -fno-asynchronous-unwind-tables -fno-ident -s -nostdlib -nostdinc \
+		-static -I../../../../include/nolibc -include ../../../../include/nolibc/nolibc.h \
 		-I../../../../../usr/include \
 		-std=gnu99 -I../.. -g \
-		-ffreestanding -Wall $^ -o $@ -lgcc
+		-ffreestanding $^ -o $@ -lgcc
 
 $(OUTPUT)/gcs-stress-thread: gcs-stress-thread.S
 	$(CC) -nostdlib $^ -o $@
diff --git a/tools/testing/selftests/arm64/gcs/basic-gcs.c b/tools/testing/selftests/arm64/gcs/basic-gcs.c
index 54f9c888249d..250977abc398 100644
--- a/tools/testing/selftests/arm64/gcs/basic-gcs.c
+++ b/tools/testing/selftests/arm64/gcs/basic-gcs.c
@@ -10,6 +10,7 @@
 
 #include <sys/mman.h>
 #include <asm/mman.h>
+#include <asm/hwcap.h>
 #include <linux/sched.h>
 
 #include "kselftest.h"
@@ -386,14 +387,13 @@ int main(void)
 
 	ksft_print_header();
 
-	/*
-	 * We don't have getauxval() with nolibc so treat a failure to
-	 * read GCS state as a lack of support and skip.
-	 */
+	if (!(getauxval(AT_HWCAP) & HWCAP_GCS))
+		ksft_exit_skip("SKIP GCS not supported\n");
+
 	ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS,
 			  &gcs_mode, 0, 0, 0);
 	if (ret != 0)
-		ksft_exit_skip("Failed to read GCS state: %d\n", ret);
+		ksft_exit_fail_msg("Failed to read GCS state: %d\n", ret);
 
 	if (!(gcs_mode & PR_SHADOW_STACK_ENABLE)) {
 		gcs_mode = PR_SHADOW_STACK_ENABLE;
@@ -410,7 +410,7 @@ int main(void)
 	}
 
 	/* One last test: disable GCS, we can do this one time */
-	my_syscall5(__NR_prctl, PR_SET_SHADOW_STACK_STATUS, 0, 0, 0, 0);
+	ret = my_syscall5(__NR_prctl, PR_SET_SHADOW_STACK_STATUS, 0, 0, 0, 0);
 	if (ret != 0)
 		ksft_print_msg("Failed to disable GCS: %d\n", ret);
 
diff --git a/tools/testing/selftests/arm64/gcs/gcs-locking.c b/tools/testing/selftests/arm64/gcs/gcs-locking.c
index 989f75a491b7..1e6abb136ffd 100644
--- a/tools/testing/selftests/arm64/gcs/gcs-locking.c
+++ b/tools/testing/selftests/arm64/gcs/gcs-locking.c
@@ -165,7 +165,6 @@ TEST_F(valid_modes, lock_enable_disable_others)
 	ASSERT_EQ(ret, 0);
 	ASSERT_EQ(mode, PR_SHADOW_STACK_ALL_MODES);
 
-
 	ret = my_syscall2(__NR_prctl, PR_SET_SHADOW_STACK_STATUS,
 			  variant->mode);
 	ASSERT_EQ(ret, 0);
diff --git a/tools/testing/selftests/arm64/gcs/gcs-stress.c b/tools/testing/selftests/arm64/gcs/gcs-stress.c
index bbc7f4950c13..cf316d78ea97 100644
--- a/tools/testing/selftests/arm64/gcs/gcs-stress.c
+++ b/tools/testing/selftests/arm64/gcs/gcs-stress.c
@@ -433,7 +433,7 @@ int main(int argc, char **argv)
 
 	evs = calloc(tests, sizeof(*evs));
 	if (!evs)
-		ksft_exit_fail_msg("Failed to allocated %d epoll events\n",
+		ksft_exit_fail_msg("Failed to allocate %d epoll events\n",
 				   tests);
 
 	for (i = 0; i < gcs_threads; i++)
diff --git a/tools/testing/selftests/arm64/pauth/exec_target.c b/tools/testing/selftests/arm64/pauth/exec_target.c
index 4435600ca400..e597861b26d6 100644
--- a/tools/testing/selftests/arm64/pauth/exec_target.c
+++ b/tools/testing/selftests/arm64/pauth/exec_target.c
@@ -13,7 +13,12 @@ int main(void)
 	unsigned long hwcaps;
 	size_t val;
 
-	fread(&val, sizeof(size_t), 1, stdin);
+	size_t size = fread(&val, sizeof(size_t), 1, stdin);
+
+	if (size != 1) {
+		fprintf(stderr, "Could not read input from stdin\n");
+		return EXIT_FAILURE;
+	}
 
 	/* don't try to execute illegal (unimplemented) instructions) caller
 	 * should have checked this and keep worker simple