Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

25 files changed, 1536 insertions, 0 deletions

diff --git a/tools/testing/selftests/arm64/signal/.gitignore b/tools/testing/selftests/arm64/signal/.gitignore
new file mode 100644
index 000000000..78c902045
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/.gitignore
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+mangle_*
+fake_sigreturn_*
+!*.[ch]
diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile
new file mode 100644
index 000000000..ac4ad0005
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/Makefile
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 ARM Limited
+
+# Additional include paths needed by kselftest.h and local headers
+CFLAGS += -D_GNU_SOURCE -std=gnu99 -I.
+
+SRCS := $(filter-out testcases/testcases.c,$(wildcard testcases/*.c))
+PROGS := $(patsubst %.c,%,$(SRCS))
+
+# Generated binaries to be installed by top KSFT script
+TEST_GEN_PROGS := $(notdir $(PROGS))
+
+# Get Kernel headers installed and use them.
+KSFT_KHDR_INSTALL := 1
+
+# Including KSFT lib.mk here will also mangle the TEST_GEN_PROGS list
+# to account for any OUTPUT target-dirs optionally provided by
+# the toplevel makefile
+include ../../lib.mk
+
+$(TEST_GEN_PROGS): $(PROGS)
+	cp $(PROGS) $(OUTPUT)/
+
+# Common test-unit targets to build common-layout test-cases executables
+# Needs secondary expansion to properly include the testcase c-file in pre-reqs
+.SECONDEXPANSION:
+$(PROGS): test_signals.c test_signals_utils.c testcases/testcases.c signals.S $$@.c test_signals.h test_signals_utils.h testcases/testcases.h
+	$(CC) $(CFLAGS) $^ -o $@
diff --git a/tools/testing/selftests/arm64/signal/README b/tools/testing/selftests/arm64/signal/README
new file mode 100644
index 000000000..967a531b2
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/README
@@ -0,0 +1,59 @@
+KSelfTest arm64/signal/
+=======================
+
+Signals Tests
++++++++++++++
+
+- Tests are built around a common main compilation unit: such shared main
+  enforces a standard sequence of operations needed to perform a single
+  signal-test (setup/trigger/run/result/cleanup)
+
+- The above mentioned ops are configurable on a test-by-test basis: each test
+  is described (and configured) using the descriptor signals.h::struct tdescr
+
+- Each signal testcase is compiled into its own executable: a separate
+  executable is used for each test since many tests complete successfully
+  by receiving some kind of fatal signal from the Kernel, so it's safer
+  to run each test unit in its own standalone process, so as to start each
+  test from a clean slate.
+
+- New tests can be simply defined in testcases/ dir providing a proper struct
+  tdescr overriding all the defaults we wish to change (as of now providing a
+  custom run method is mandatory though)
+
+- Signals' test-cases hereafter defined belong currently to two
+  principal families:
+
+  - 'mangle_' tests: a real signal (SIGUSR1) is raised and used as a trigger
+    and then the test case code modifies the signal frame from inside the
+    signal handler itself.
+
+  - 'fake_sigreturn_' tests: a brand new custom artificial sigframe structure
+    is placed on the stack and a sigreturn syscall is called to simulate a
+    real signal return. This kind of tests does not use a trigger usually and
+    they are just fired using some simple included assembly trampoline code.
+
+ - Most of these tests are successfully passing if the process gets killed by
+   some fatal signal: usually SIGSEGV or SIGBUS. Since while writing this
+   kind of tests it is extremely easy in fact to end-up injecting other
+   unrelated SEGV bugs in the testcases, it becomes extremely tricky to
+   be really sure that the tests are really addressing what they are meant
+   to address and they are not instead falling apart due to unplanned bugs
+   in the test code.
+   In order to alleviate the misery of the life of such test-developer, a few
+   helpers are provided:
+
+   - a couple of ASSERT_BAD/GOOD_CONTEXT() macros to easily parse a ucontext_t
+     and verify if it is indeed GOOD or BAD (depending on what we were
+     expecting), using the same logic/perspective as in the arm64 Kernel signals
+     routines.
+
+   - a sanity mechanism to be used in 'fake_sigreturn_'-alike tests: enabled by
+     default it takes care to verify that the test-execution had at least
+     successfully progressed up to the stage of triggering the fake sigreturn
+     call.
+
+  In both cases test results are expected in terms of:
+   - some fatal signal sent by the Kernel to the test process
+  or
+  - analyzing some final regs state
diff --git a/tools/testing/selftests/arm64/signal/signals.S b/tools/testing/selftests/arm64/signal/signals.S
new file mode 100644
index 000000000..9f8c1aefc
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/signals.S
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+
+#include <asm/unistd.h>
+
+.section        .rodata, "a"
+call_fmt:
+	.asciz "Calling sigreturn with fake sigframe sized:%zd at SP @%08lX\n"
+
+.text
+
+.globl fake_sigreturn
+
+/*	fake_sigreturn	x0:&sigframe,  x1:sigframe_size,  x2:misalign_bytes */
+fake_sigreturn:
+	stp	x29, x30, [sp, #-16]!
+	mov	x29, sp
+
+	mov	x20, x0
+	mov	x21, x1
+	mov	x22, x2
+
+	/* create space on the stack for fake sigframe 16 bytes-aligned */
+	add	x0, x21, x22
+	add	x0, x0, #15
+	bic	x0, x0, #15 /* round_up(sigframe_size + misalign_bytes, 16) */
+	sub	sp, sp, x0
+	add	x23, sp, x22 /* new sigframe base with misaligment if any */
+
+	ldr	x0, =call_fmt
+	mov	x1, x21
+	mov	x2, x23
+	bl	printf
+
+	/* memcpy the provided content, while still keeping SP aligned */
+	mov	x0, x23
+	mov	x1, x20
+	mov	x2, x21
+	bl	memcpy
+
+	/*
+	 * Here saving a last minute SP to current->token acts as a marker:
+	 * if we got here, we are successfully faking a sigreturn; in other
+	 * words we are sure no bad fatal signal has been raised till now
+	 * for unrelated reasons, so we should consider the possibly observed
+	 * fatal signal like SEGV coming from Kernel restore_sigframe() and
+	 * triggered as expected from our test-case.
+	 * For simplicity this assumes that current field 'token' is laid out
+	 * as first in struct tdescr
+	 */
+	ldr	x0, current
+	str	x23, [x0]
+	/* finally move SP to misaligned address...if any requested */
+	mov	sp, x23
+
+	mov	x8, #__NR_rt_sigreturn
+	svc	#0
+
+	/*
+	 * Above sigreturn should not return...looping here leads to a timeout
+	 * and ensure proper and clean test failure, instead of jumping around
+	 * on a potentially corrupted stack.
+	 */
+	b	.
diff --git a/tools/testing/selftests/arm64/signal/test_signals.c b/tools/testing/selftests/arm64/signal/test_signals.c
new file mode 100644
index 000000000..416b1ff43
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Generic test wrapper for arm64 signal tests.
+ *
+ * Each test provides its own tde struct tdescr descriptor to link with
+ * this wrapper. Framework provides common helpers.
+ */
+#include <kselftest.h>
+
+#include "test_signals.h"
+#include "test_signals_utils.h"
+
+struct tdescr *current;
+
+int main(int argc, char *argv[])
+{
+	current = &tde;
+
+	ksft_print_msg("%s :: %s\n", current->name, current->descr);
+	if (test_setup(current) && test_init(current)) {
+		test_run(current);
+		test_cleanup(current);
+	}
+	test_result(current);
+
+	return current->result;
+}
diff --git a/tools/testing/selftests/arm64/signal/test_signals.h b/tools/testing/selftests/arm64/signal/test_signals.h
new file mode 100644
index 000000000..ebe8694db
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+
+#ifndef __TEST_SIGNALS_H__
+#define __TEST_SIGNALS_H__
+
+#include <signal.h>
+#include <stdbool.h>
+#include <ucontext.h>
+
+/*
+ * Using ARCH specific and sanitized Kernel headers installed by KSFT
+ * framework since we asked for it by setting flag KSFT_KHDR_INSTALL
+ * in our Makefile.
+ */
+#include <asm/ptrace.h>
+#include <asm/hwcap.h>
+
+#define __stringify_1(x...)	#x
+#define __stringify(x...)	__stringify_1(x)
+
+#define get_regval(regname, out)			\
+{							\
+	asm volatile("mrs %0, " __stringify(regname)	\
+	: "=r" (out)					\
+	:						\
+	: "memory");					\
+}
+
+/*
+ * Feature flags used in tdescr.feats_required to specify
+ * any feature by the test
+ */
+enum {
+	FSSBS_BIT,
+	FSVE_BIT,
+	FMAX_END
+};
+
+#define FEAT_SSBS		(1UL << FSSBS_BIT)
+#define FEAT_SVE		(1UL << FSVE_BIT)
+
+/*
+ * A descriptor used to describe and configure a test case.
+ * Fields with a non-trivial meaning are described inline in the following.
+ */
+struct tdescr {
+	/* KEEP THIS FIELD FIRST for easier lookup from assembly */
+	void			*token;
+	/* when disabled token based sanity checking is skipped in handler */
+	bool			sanity_disabled;
+	/* just a name for the test-case; manadatory field */
+	char			*name;
+	char			*descr;
+	unsigned long		feats_required;
+	/* bitmask of effectively supported feats: populated at run-time */
+	unsigned long		feats_supported;
+	bool			initialized;
+	unsigned int		minsigstksz;
+	/* signum used as a test trigger. Zero if no trigger-signal is used */
+	int			sig_trig;
+	/*
+	 * signum considered as a successful test completion.
+	 * Zero when no signal is expected on success
+	 */
+	int			sig_ok;
+	/* signum expected on unsupported CPU features. */
+	int			sig_unsupp;
+	/* a timeout in second for test completion */
+	unsigned int		timeout;
+	bool			triggered;
+	bool			pass;
+	unsigned int		result;
+	/* optional sa_flags for the installed handler */
+	int			sa_flags;
+	ucontext_t		saved_uc;
+	/* used by get_current_ctx() */
+	size_t			live_sz;
+	ucontext_t		*live_uc;
+	volatile sig_atomic_t	live_uc_valid;
+	/* optional test private data */
+	void			*priv;
+
+	/* a custom setup: called alternatively to default_setup */
+	int (*setup)(struct tdescr *td);
+	/* a custom init: called by default test init after test_setup */
+	bool (*init)(struct tdescr *td);
+	/* a custom cleanup function called before test exits */
+	void (*cleanup)(struct tdescr *td);
+	/* an optional function to be used as a trigger for starting test */
+	int (*trigger)(struct tdescr *td);
+	/*
+	 * the actual test-core: invoked differently depending on the
+	 * presence of the trigger function above; this is mandatory
+	 */
+	int (*run)(struct tdescr *td, siginfo_t *si, ucontext_t *uc);
+	/* an optional function for custom results' processing */
+	void (*check_result)(struct tdescr *td);
+};
+
+extern struct tdescr tde;
+#endif
diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.c b/tools/testing/selftests/arm64/signal/test_signals_utils.c
new file mode 100644
index 000000000..22722abc9
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2019 ARM Limited */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <sys/auxv.h>
+#include <linux/auxvec.h>
+#include <ucontext.h>
+
+#include <asm/unistd.h>
+
+#include <kselftest.h>
+
+#include "test_signals.h"
+#include "test_signals_utils.h"
+#include "testcases/testcases.h"
+
+
+extern struct tdescr *current;
+
+static int sig_copyctx = SIGTRAP;
+
+static char const *const feats_names[FMAX_END] = {
+	" SSBS ",
+	" SVE ",
+};
+
+#define MAX_FEATS_SZ	128
+static char feats_string[MAX_FEATS_SZ];
+
+static inline char *feats_to_string(unsigned long feats)
+{
+	size_t flen = MAX_FEATS_SZ - 1;
+
+	for (int i = 0; i < FMAX_END; i++) {
+		if (feats & (1UL << i)) {
+			size_t tlen = strlen(feats_names[i]);
+
+			assert(flen > tlen);
+			flen -= tlen;
+			strncat(feats_string, feats_names[i], flen);
+		}
+	}
+
+	return feats_string;
+}
+
+static void unblock_signal(int signum)
+{
+	sigset_t sset;
+
+	sigemptyset(&sset);
+	sigaddset(&sset, signum);
+	sigprocmask(SIG_UNBLOCK, &sset, NULL);
+}
+
+static void default_result(struct tdescr *td, bool force_exit)
+{
+	if (td->result == KSFT_SKIP) {
+		fprintf(stderr, "==>> completed. SKIP.\n");
+	} else if (td->pass) {
+		fprintf(stderr, "==>> completed. PASS(1)\n");
+		td->result = KSFT_PASS;
+	} else {
+		fprintf(stdout, "==>> completed. FAIL(0)\n");
+		td->result = KSFT_FAIL;
+	}
+
+	if (force_exit)
+		exit(td->result);
+}
+
+/*
+ * The following handle_signal_* helpers are used by main default_handler
+ * and are meant to return true when signal is handled successfully:
+ * when false is returned instead, it means that the signal was somehow
+ * unexpected in that context and it was NOT handled; default_handler will
+ * take care of such unexpected situations.
+ */
+
+static bool handle_signal_unsupported(struct tdescr *td,
+				      siginfo_t *si, void *uc)
+{
+	if (feats_ok(td))
+		return false;
+
+	/* Mangling PC to avoid loops on original SIGILL */
+	((ucontext_t *)uc)->uc_mcontext.pc += 4;
+
+	if (!td->initialized) {
+		fprintf(stderr,
+			"Got SIG_UNSUPP @test_init. Ignore.\n");
+	} else {
+		fprintf(stderr,
+			"-- RX SIG_UNSUPP on unsupported feat...OK\n");
+		td->pass = 1;
+		default_result(current, 1);
+	}
+
+	return true;
+}
+
+static bool handle_signal_trigger(struct tdescr *td,
+				  siginfo_t *si, void *uc)
+{
+	td->triggered = 1;
+	/* ->run was asserted NON-NULL in test_setup() already */
+	td->run(td, si, uc);
+
+	return true;
+}
+
+static bool handle_signal_ok(struct tdescr *td,
+			     siginfo_t *si, void *uc)
+{
+	/*
+	 * it's a bug in the test code when this assert fail:
+	 * if sig_trig was defined, it must have been used before getting here.
+	 */
+	assert(!td->sig_trig || td->triggered);
+	fprintf(stderr,
+		"SIG_OK -- SP:0x%llX  si_addr@:%p  si_code:%d  token@:%p  offset:%ld\n",
+		((ucontext_t *)uc)->uc_mcontext.sp,
+		si->si_addr, si->si_code, td->token, td->token - si->si_addr);
+	/*
+	 * fake_sigreturn tests, which have sanity_enabled=1, set, at the very
+	 * last time, the token field to the SP address used to place the fake
+	 * sigframe: so token==0 means we never made it to the end,
+	 * segfaulting well-before, and the test is possibly broken.
+	 */
+	if (!td->sanity_disabled && !td->token) {
+		fprintf(stdout,
+			"current->token ZEROED...test is probably broken!\n");
+		abort();
+	}
+	/*
+	 * Trying to narrow down the SEGV to the ones generated by Kernel itself
+	 * via arm64_notify_segfault(). This is a best-effort check anyway, and
+	 * the si_code check may need to change if this aspect of the kernel
+	 * ABI changes.
+	 */
+	if (td->sig_ok == SIGSEGV && si->si_code != SEGV_ACCERR) {
+		fprintf(stdout,
+			"si_code != SEGV_ACCERR...test is probably broken!\n");
+		abort();
+	}
+	td->pass = 1;
+	/*
+	 * Some tests can lead to SEGV loops: in such a case we want to
+	 * terminate immediately exiting straight away; some others are not
+	 * supposed to outlive the signal handler code, due to the content of
+	 * the fake sigframe which caused the signal itself.
+	 */
+	default_result(current, 1);
+
+	return true;
+}
+
+static bool handle_signal_copyctx(struct tdescr *td,
+				  siginfo_t *si, void *uc)
+{
+	/* Mangling PC to avoid loops on original BRK instr */
+	((ucontext_t *)uc)->uc_mcontext.pc += 4;
+	memcpy(td->live_uc, uc, td->live_sz);
+	ASSERT_GOOD_CONTEXT(td->live_uc);
+	td->live_uc_valid = 1;
+	fprintf(stderr,
+		"GOOD CONTEXT grabbed from sig_copyctx handler\n");
+
+	return true;
+}
+
+static void default_handler(int signum, siginfo_t *si, void *uc)
+{
+	if (current->sig_unsupp && signum == current->sig_unsupp &&
+	    handle_signal_unsupported(current, si, uc)) {
+		fprintf(stderr, "Handled SIG_UNSUPP\n");
+	} else if (current->sig_trig && signum == current->sig_trig &&
+		   handle_signal_trigger(current, si, uc)) {
+		fprintf(stderr, "Handled SIG_TRIG\n");
+	} else if (current->sig_ok && signum == current->sig_ok &&
+		   handle_signal_ok(current, si, uc)) {
+		fprintf(stderr, "Handled SIG_OK\n");
+	} else if (signum == sig_copyctx && current->live_uc &&
+		   handle_signal_copyctx(current, si, uc)) {
+		fprintf(stderr, "Handled SIG_COPYCTX\n");
+	} else {
+		if (signum == SIGALRM && current->timeout) {
+			fprintf(stderr, "-- Timeout !\n");
+		} else {
+			fprintf(stderr,
+				"-- RX UNEXPECTED SIGNAL: %d\n", signum);
+		}
+		default_result(current, 1);
+	}
+}
+
+static int default_setup(struct tdescr *td)
+{
+	struct sigaction sa;
+
+	sa.sa_sigaction = default_handler;
+	sa.sa_flags = SA_SIGINFO | SA_RESTART;
+	sa.sa_flags |= td->sa_flags;
+	sigemptyset(&sa.sa_mask);
+	/* uncatchable signals naturally skipped ... */
+	for (int sig = 1; sig < 32; sig++)
+		sigaction(sig, &sa, NULL);
+	/*
+	 * RT Signals default disposition is Term but they cannot be
+	 * generated by the Kernel in response to our tests; so just catch
+	 * them all and report them as UNEXPECTED signals.
+	 */
+	for (int sig = SIGRTMIN; sig <= SIGRTMAX; sig++)
+		sigaction(sig, &sa, NULL);
+
+	/* just in case...unblock explicitly all we need */
+	if (td->sig_trig)
+		unblock_signal(td->sig_trig);
+	if (td->sig_ok)
+		unblock_signal(td->sig_ok);
+	if (td->sig_unsupp)
+		unblock_signal(td->sig_unsupp);
+
+	if (td->timeout) {
+		unblock_signal(SIGALRM);
+		alarm(td->timeout);
+	}
+	fprintf(stderr, "Registered handlers for all signals.\n");
+
+	return 1;
+}
+
+static inline int default_trigger(struct tdescr *td)
+{
+	return !raise(td->sig_trig);
+}
+
+int test_init(struct tdescr *td)
+{
+	if (td->sig_trig == sig_copyctx) {
+		fprintf(stdout,
+			"Signal %d is RESERVED, cannot be used as a trigger. Aborting\n",
+			sig_copyctx);
+		return 0;
+	}
+	/* just in case */
+	unblock_signal(sig_copyctx);
+
+	td->minsigstksz = getauxval(AT_MINSIGSTKSZ);
+	if (!td->minsigstksz)
+		td->minsigstksz = MINSIGSTKSZ;
+	fprintf(stderr, "Detected MINSTKSIGSZ:%d\n", td->minsigstksz);
+
+	if (td->feats_required) {
+		td->feats_supported = 0;
+		/*
+		 * Checking for CPU required features using both the
+		 * auxval and the arm64 MRS Emulation to read sysregs.
+		 */
+		if (getauxval(AT_HWCAP) & HWCAP_SSBS)
+			td->feats_supported |= FEAT_SSBS;
+		if (getauxval(AT_HWCAP) & HWCAP_SVE)
+			td->feats_supported |= FEAT_SVE;
+		if (feats_ok(td)) {
+			fprintf(stderr,
+				"Required Features: [%s] supported\n",
+				feats_to_string(td->feats_required &
+						td->feats_supported));
+		} else {
+			fprintf(stderr,
+				"Required Features: [%s] NOT supported\n",
+				feats_to_string(td->feats_required &
+						~td->feats_supported));
+			td->result = KSFT_SKIP;
+			return 0;
+		}
+	}
+
+	/* Perform test specific additional initialization */
+	if (td->init && !td->init(td)) {
+		fprintf(stderr, "FAILED Testcase initialization.\n");
+		return 0;
+	}
+	td->initialized = 1;
+	fprintf(stderr, "Testcase initialized.\n");
+
+	return 1;
+}
+
+int test_setup(struct tdescr *td)
+{
+	/* assert core invariants symptom of a rotten testcase */
+	assert(current);
+	assert(td);
+	assert(td->name);
+	assert(td->run);
+
+	/* Default result is FAIL if test setup fails */
+	td->result = KSFT_FAIL;
+	if (td->setup)
+		return td->setup(td);
+	else
+		return default_setup(td);
+}
+
+int test_run(struct tdescr *td)
+{
+	if (td->sig_trig) {
+		if (td->trigger)
+			return td->trigger(td);
+		else
+			return default_trigger(td);
+	} else {
+		return td->run(td, NULL, NULL);
+	}
+}
+
+void test_result(struct tdescr *td)
+{
+	if (td->initialized && td->result != KSFT_SKIP && td->check_result)
+		td->check_result(td);
+	default_result(td, 0);
+}
+
+void test_cleanup(struct tdescr *td)
+{
+	if (td->cleanup)
+		td->cleanup(td);
+}
diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.h b/tools/testing/selftests/arm64/signal/test_signals_utils.h
new file mode 100644
index 000000000..6772b5c8d
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.h
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+
+#ifndef __TEST_SIGNALS_UTILS_H__
+#define __TEST_SIGNALS_UTILS_H__
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "test_signals.h"
+
+int test_init(struct tdescr *td);
+int test_setup(struct tdescr *td);
+void test_cleanup(struct tdescr *td);
+int test_run(struct tdescr *td);
+void test_result(struct tdescr *td);
+
+static inline bool feats_ok(struct tdescr *td)
+{
+	return (td->feats_required & td->feats_supported) == td->feats_required;
+}
+
+/*
+ * Obtaining a valid and full-blown ucontext_t from userspace is tricky:
+ * libc getcontext does() not save all the regs and messes with some of
+ * them (pstate value in particular is not reliable).
+ *
+ * Here we use a service signal to grab the ucontext_t from inside a
+ * dedicated signal handler, since there, it is populated by Kernel
+ * itself in setup_sigframe(). The grabbed context is then stored and
+ * made available in td->live_uc.
+ *
+ * As service-signal is used a SIGTRAP induced by a 'brk' instruction,
+ * because here we have to avoid syscalls to trigger the signal since
+ * they would cause any SVE sigframe content (if any) to be removed.
+ *
+ * Anyway this function really serves a dual purpose:
+ *
+ * 1. grab a valid sigcontext into td->live_uc for result analysis: in
+ * such case it returns 1.
+ *
+ * 2. detect if, somehow, a previously grabbed live_uc context has been
+ * used actively with a sigreturn: in such a case the execution would have
+ * magically resumed in the middle of this function itself (seen_already==1):
+ * in such a case return 0, since in fact we have not just simply grabbed
+ * the context.
+ *
+ * This latter case is useful to detect when a fake_sigreturn test-case has
+ * unexpectedly survived without hitting a SEGV.
+ *
+ * Note that the case of runtime dynamically sized sigframes (like in SVE
+ * context) is still NOT addressed: sigframe size is supposed to be fixed
+ * at sizeof(ucontext_t).
+ */
+static __always_inline bool get_current_context(struct tdescr *td,
+						ucontext_t *dest_uc)
+{
+	static volatile bool seen_already;
+
+	assert(td && dest_uc);
+	/* it's a genuine invocation..reinit */
+	seen_already = 0;
+	td->live_uc_valid = 0;
+	td->live_sz = sizeof(*dest_uc);
+	memset(dest_uc, 0x00, td->live_sz);
+	td->live_uc = dest_uc;
+	/*
+	 * Grab ucontext_t triggering a SIGTRAP.
+	 *
+	 * Note that:
+	 * - live_uc_valid is declared volatile sig_atomic_t in
+	 *   struct tdescr since it will be changed inside the
+	 *   sig_copyctx handler
+	 * - the additional 'memory' clobber is there to avoid possible
+	 *   compiler's assumption on live_uc_valid and the content
+	 *   pointed by dest_uc, which are all changed inside the signal
+	 *   handler
+	 * - BRK causes a debug exception which is handled by the Kernel
+	 *   and finally causes the SIGTRAP signal to be delivered to this
+	 *   test thread. Since such delivery happens on the ret_to_user()
+	 *   /do_notify_resume() debug exception return-path, we are sure
+	 *   that the registered SIGTRAP handler has been run to completion
+	 *   before the execution path is restored here: as a consequence
+	 *   we can be sure that the volatile sig_atomic_t live_uc_valid
+	 *   carries a meaningful result. Being in a single thread context
+	 *   we'll also be sure that any access to memory modified by the
+	 *   handler (namely ucontext_t) will be visible once returned.
+	 * - note that since we are using a breakpoint instruction here
+	 *   to cause a SIGTRAP, the ucontext_t grabbed from the signal
+	 *   handler would naturally contain a PC pointing exactly to this
+	 *   BRK line, which means that, on return from the signal handler,
+	 *   or if we place the ucontext_t on the stack to fake a sigreturn,
+	 *   we'll end up in an infinite loop of BRK-SIGTRAP-handler.
+	 *   For this reason we take care to artificially move forward the
+	 *   PC to the next instruction while inside the signal handler.
+	 */
+	asm volatile ("brk #666"
+		      : "+m" (*dest_uc)
+		      :
+		      : "memory");
+
+	/*
+	 * If we get here with seen_already==1 it implies the td->live_uc
+	 * context has been used to get back here....this probably means
+	 * a test has failed to cause a SEGV...anyway live_uc does not
+	 * point to a just acquired copy of ucontext_t...so return 0
+	 */
+	if (seen_already) {
+		fprintf(stdout,
+			"Unexpected successful sigreturn detected: live_uc is stale !\n");
+		return 0;
+	}
+	seen_already = 1;
+
+	return td->live_uc_valid;
+}
+
+int fake_sigreturn(void *sigframe, size_t sz, int misalign_bytes);
+#endif
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c
new file mode 100644
index 000000000..8dc600a7d
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack including a BAD Unknown magic
+ * record: on sigreturn Kernel must spot this attempt and the test
+ * case is expected to be terminated via SEGV.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_bad_magic_run(struct tdescr *td,
+					siginfo_t *si, ucontext_t *uc)
+{
+	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
+
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	/* need at least 2*HDR_SZ space: KSFT_BAD_MAGIC + terminator. */
+	head = get_starting_head(shead, HDR_SZ * 2, GET_SF_RESV_SIZE(sf), NULL);
+	if (!head)
+		return 0;
+
+	/*
+	 * use a well known NON existent bad magic...something
+	 * we should pretty sure won't be ever defined in Kernel
+	 */
+	head->magic = KSFT_BAD_MAGIC;
+	head->size = HDR_SZ;
+	write_terminator_record(GET_RESV_NEXT_HEAD(head));
+
+	ASSERT_BAD_CONTEXT(&sf.uc);
+	fake_sigreturn(&sf, sizeof(sf), 0);
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.name = "FAKE_SIGRETURN_BAD_MAGIC",
+		.descr = "Trigger a sigreturn with a sigframe with a bad magic",
+		.sig_ok = SIGSEGV,
+		.timeout = 3,
+		.run = fake_sigreturn_bad_magic_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c
new file mode 100644
index 000000000..b3c362100
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack including a bad record overflowing
+ * the __reserved space: on sigreturn Kernel must spot this attempt and
+ * the test case is expected to be terminated via SEGV.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+#define MIN_SZ_ALIGN	16
+
+static int fake_sigreturn_bad_size_run(struct tdescr *td,
+				       siginfo_t *si, ucontext_t *uc)
+{
+	size_t resv_sz, need_sz, offset;
+	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
+
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	resv_sz = GET_SF_RESV_SIZE(sf);
+	/* at least HDR_SZ + bad sized esr_context needed */
+	need_sz = sizeof(struct esr_context) + HDR_SZ;
+	head = get_starting_head(shead, need_sz, resv_sz, &offset);
+	if (!head)
+		return 0;
+
+	/*
+	 * Use an esr_context to build a fake header with a
+	 * size greater then the free __reserved area minus HDR_SZ;
+	 * using ESR_MAGIC here since it is not checked for size nor
+	 * is limited to one instance.
+	 *
+	 * At first inject an additional normal esr_context
+	 */
+	head->magic = ESR_MAGIC;
+	head->size = sizeof(struct esr_context);
+	/* and terminate properly */
+	write_terminator_record(GET_RESV_NEXT_HEAD(head));
+	ASSERT_GOOD_CONTEXT(&sf.uc);
+
+	/*
+	 * now mess with fake esr_context size: leaving less space than
+	 * needed while keeping size value 16-aligned
+	 *
+	 * It must trigger a SEGV from Kernel on:
+	 *
+	 *	resv_sz - offset < sizeof(*head)
+	 */
+	/* at first set the maximum good 16-aligned size */
+	head->size = (resv_sz - offset - need_sz + MIN_SZ_ALIGN) & ~0xfUL;
+	/* plus a bit more of 16-aligned sized stuff */
+	head->size += MIN_SZ_ALIGN;
+	/* and terminate properly */
+	write_terminator_record(GET_RESV_NEXT_HEAD(head));
+	ASSERT_BAD_CONTEXT(&sf.uc);
+	fake_sigreturn(&sf, sizeof(sf), 0);
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.name = "FAKE_SIGRETURN_BAD_SIZE",
+		.descr = "Triggers a sigreturn with a overrun __reserved area",
+		.sig_ok = SIGSEGV,
+		.timeout = 3,
+		.run = fake_sigreturn_bad_size_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size_for_magic0.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size_for_magic0.c
new file mode 100644
index 000000000..a44b88bfc
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size_for_magic0.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack including a badly sized terminator
+ * record: on sigreturn Kernel must spot this attempt and the test case
+ * is expected to be terminated via SEGV.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_bad_size_for_magic0_run(struct tdescr *td,
+						  siginfo_t *si, ucontext_t *uc)
+{
+	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
+
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	/* at least HDR_SZ for the badly sized terminator. */
+	head = get_starting_head(shead, HDR_SZ, GET_SF_RESV_SIZE(sf), NULL);
+	if (!head)
+		return 0;
+
+	head->magic = 0;
+	head->size = HDR_SZ;
+	ASSERT_BAD_CONTEXT(&sf.uc);
+	fake_sigreturn(&sf, sizeof(sf), 0);
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.name = "FAKE_SIGRETURN_BAD_SIZE_FOR_TERMINATOR",
+		.descr = "Trigger a sigreturn using non-zero size terminator",
+		.sig_ok = SIGSEGV,
+		.timeout = 3,
+		.run = fake_sigreturn_bad_size_for_magic0_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
new file mode 100644
index 000000000..afe8915f0
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack including an additional FPSIMD
+ * record: on sigreturn Kernel must spot this attempt and the test
+ * case is expected to be terminated via SEGV.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_duplicated_fpsimd_run(struct tdescr *td,
+						siginfo_t *si, ucontext_t *uc)
+{
+	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
+
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	head = get_starting_head(shead, sizeof(struct fpsimd_context) + HDR_SZ,
+				 GET_SF_RESV_SIZE(sf), NULL);
+	if (!head)
+		return 0;
+
+	/* Add a spurious fpsimd_context */
+	head->magic = FPSIMD_MAGIC;
+	head->size = sizeof(struct fpsimd_context);
+	/* and terminate */
+	write_terminator_record(GET_RESV_NEXT_HEAD(head));
+
+	ASSERT_BAD_CONTEXT(&sf.uc);
+	fake_sigreturn(&sf, sizeof(sf), 0);
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.name = "FAKE_SIGRETURN_DUPLICATED_FPSIMD",
+		.descr = "Triggers a sigreturn including two fpsimd_context",
+		.sig_ok = SIGSEGV,
+		.timeout = 3,
+		.run = fake_sigreturn_duplicated_fpsimd_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
new file mode 100644
index 000000000..1e089e66f
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack at a misaligned SP: on sigreturn
+ * Kernel must spot this attempt and the test case is expected to be
+ * terminated via SEGV.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_misaligned_run(struct tdescr *td,
+					 siginfo_t *si, ucontext_t *uc)
+{
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	/* Forcing sigframe on misaligned SP (16 + 3) */
+	fake_sigreturn(&sf, sizeof(sf), 3);
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.name = "FAKE_SIGRETURN_MISALIGNED_SP",
+		.descr = "Triggers a sigreturn with a misaligned sigframe",
+		.sig_ok = SIGSEGV,
+		.timeout = 3,
+		.run = fake_sigreturn_misaligned_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_missing_fpsimd.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_missing_fpsimd.c
new file mode 100644
index 000000000..08ecd8073
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_missing_fpsimd.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Place a fake sigframe on the stack missing the mandatory FPSIMD
+ * record: on sigreturn Kernel must spot this attempt and the test
+ * case is expected to be terminated via SEGV.
+ */
+
+#include <stdio.h>
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+
+static int fake_sigreturn_missing_fpsimd_run(struct tdescr *td,
+					     siginfo_t *si, ucontext_t *uc)
+{
+	size_t resv_sz, offset;
+	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+
+	/* just to fill the ucontext_t with something real */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	resv_sz = GET_SF_RESV_SIZE(sf);
+	head = get_header(head, FPSIMD_MAGIC, resv_sz, &offset);
+	if (head && resv_sz - offset >= HDR_SZ) {
+		fprintf(stderr, "Mangling template header. Spare space:%zd\n",
+			resv_sz - offset);
+		/* Just overwrite fpsmid_context */
+		write_terminator_record(head);
+
+		ASSERT_BAD_CONTEXT(&sf.uc);
+		fake_sigreturn(&sf, sizeof(sf), 0);
+	}
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.name = "FAKE_SIGRETURN_MISSING_FPSIMD",
+		.descr = "Triggers a sigreturn with a missing fpsimd_context",
+		.sig_ok = SIGSEGV,
+		.timeout = 3,
+		.run = fake_sigreturn_missing_fpsimd_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_compat_toggle.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_compat_toggle.c
new file mode 100644
index 000000000..2cb118b0b
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_compat_toggle.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the execution state bit: this attempt must be spotted by Kernel and
+ * the test case is expected to be terminated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+static int mangle_invalid_pstate_run(struct tdescr *td, siginfo_t *si,
+				     ucontext_t *uc)
+{
+	ASSERT_GOOD_CONTEXT(uc);
+
+	/* This config should trigger a SIGSEGV by Kernel */
+	uc->uc_mcontext.pstate ^= PSR_MODE32_BIT;
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.sanity_disabled = true,
+		.name = "MANGLE_PSTATE_INVALID_STATE_TOGGLE",
+		.descr = "Mangling uc_mcontext with INVALID STATE_TOGGLE",
+		.sig_trig = SIGUSR1,
+		.sig_ok = SIGSEGV,
+		.run = mangle_invalid_pstate_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c
new file mode 100644
index 000000000..434b82597
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, mangling the
+ * DAIF bits in an illegal manner: this attempt must be spotted by Kernel
+ * and the test case is expected to be terminated via SEGV.
+ *
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+static int mangle_invalid_pstate_run(struct tdescr *td, siginfo_t *si,
+				     ucontext_t *uc)
+{
+	ASSERT_GOOD_CONTEXT(uc);
+
+	/*
+	 * This config should trigger a SIGSEGV by Kernel when it checks
+	 * the sigframe consistency in valid_user_regs() routine.
+	 */
+	uc->uc_mcontext.pstate |= PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT;
+
+	return 1;
+}
+
+struct tdescr tde = {
+		.sanity_disabled = true,
+		.name = "MANGLE_PSTATE_INVALID_DAIF_BITS",
+		.descr = "Mangling uc_mcontext with INVALID DAIF_BITS",
+		.sig_trig = SIGUSR1,
+		.sig_ok = SIGSEGV,
+		.run = mangle_invalid_pstate_run,
+};
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1h.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1h.c
new file mode 100644
index 000000000..95f821abd
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1h.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the mode bit to escalate exception level: this attempt must be spotted
+ * by Kernel and the test case is expected to be termninated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+#include "mangle_pstate_invalid_mode_template.h"
+
+DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(1h);
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1t.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1t.c
new file mode 100644
index 000000000..cc222d8a6
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1t.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the mode bit to escalate exception level: this attempt must be spotted
+ * by Kernel and the test case is expected to be termninated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+#include "mangle_pstate_invalid_mode_template.h"
+
+DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(1t);
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2h.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2h.c
new file mode 100644
index 000000000..2188add7d
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2h.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the mode bit to escalate exception level: this attempt must be spotted
+ * by Kernel and the test case is expected to be termninated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+#include "mangle_pstate_invalid_mode_template.h"
+
+DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(2h);
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2t.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2t.c
new file mode 100644
index 000000000..df32dd5a4
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2t.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the mode bit to escalate exception level: this attempt must be spotted
+ * by Kernel and the test case is expected to be termninated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+#include "mangle_pstate_invalid_mode_template.h"
+
+DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(2t);
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3h.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3h.c
new file mode 100644
index 000000000..9e6829b7e
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3h.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the mode bit to escalate exception level: this attempt must be spotted
+ * by Kernel and the test case is expected to be termninated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+#include "mangle_pstate_invalid_mode_template.h"
+
+DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(3h);
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3t.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3t.c
new file mode 100644
index 000000000..5685a4f10
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3t.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, toggling
+ * the mode bit to escalate exception level: this attempt must be spotted
+ * by Kernel and the test case is expected to be termninated via SEGV.
+ */
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+#include "mangle_pstate_invalid_mode_template.h"
+
+DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(3t);
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_template.h b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_template.h
new file mode 100644
index 000000000..f5bf1804d
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_template.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Utility macro to ease definition of testcases toggling mode EL
+ */
+
+#define DEFINE_TESTCASE_MANGLE_PSTATE_INVALID_MODE(_mode)		\
+									\
+static int mangle_invalid_pstate_run(struct tdescr *td, siginfo_t *si,	\
+				     ucontext_t *uc)			\
+{									\
+	ASSERT_GOOD_CONTEXT(uc);					\
+									\
+	uc->uc_mcontext.pstate &= ~PSR_MODE_MASK;			\
+	uc->uc_mcontext.pstate |= PSR_MODE_EL ## _mode;			\
+									\
+	return 1;							\
+}									\
+									\
+struct tdescr tde = {							\
+		.sanity_disabled = true,				\
+		.name = "MANGLE_PSTATE_INVALID_MODE_EL"#_mode,		\
+		.descr = "Mangling uc_mcontext INVALID MODE EL"#_mode,	\
+		.sig_trig = SIGUSR1,					\
+		.sig_ok = SIGSEGV,					\
+		.run = mangle_invalid_pstate_run,			\
+}
diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c
new file mode 100644
index 000000000..a3ac5c2d8
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2019 ARM Limited */
+#include "testcases.h"
+
+struct _aarch64_ctx *get_header(struct _aarch64_ctx *head, uint32_t magic,
+				size_t resv_sz, size_t *offset)
+{
+	size_t offs = 0;
+	struct _aarch64_ctx *found = NULL;
+
+	if (!head || resv_sz < HDR_SZ)
+		return found;
+
+	while (offs <= resv_sz - HDR_SZ &&
+	       head->magic != magic && head->magic) {
+		offs += head->size;
+		head = GET_RESV_NEXT_HEAD(head);
+	}
+	if (head->magic == magic) {
+		found = head;
+		if (offset)
+			*offset = offs;
+	}
+
+	return found;
+}
+
+bool validate_extra_context(struct extra_context *extra, char **err)
+{
+	struct _aarch64_ctx *term;
+
+	if (!extra || !err)
+		return false;
+
+	fprintf(stderr, "Validating EXTRA...\n");
+	term = GET_RESV_NEXT_HEAD(&extra->head);
+	if (!term || term->magic || term->size) {
+		*err = "Missing terminator after EXTRA context";
+		return false;
+	}
+	if (extra->datap & 0x0fUL)
+		*err = "Extra DATAP misaligned";
+	else if (extra->size & 0x0fUL)
+		*err = "Extra SIZE misaligned";
+	else if (extra->datap != (uint64_t)term + sizeof(*term))
+		*err = "Extra DATAP misplaced (not contiguous)";
+	if (*err)
+		return false;
+
+	return true;
+}
+
+bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err)
+{
+	bool terminated = false;
+	size_t offs = 0;
+	int flags = 0;
+	struct extra_context *extra = NULL;
+	struct _aarch64_ctx *head =
+		(struct _aarch64_ctx *)uc->uc_mcontext.__reserved;
+
+	if (!err)
+		return false;
+	/* Walk till the end terminator verifying __reserved contents */
+	while (head && !terminated && offs < resv_sz) {
+		if ((uint64_t)head & 0x0fUL) {
+			*err = "Misaligned HEAD";
+			return false;
+		}
+
+		switch (head->magic) {
+		case 0:
+			if (head->size)
+				*err = "Bad size for terminator";
+			else
+				terminated = true;
+			break;
+		case FPSIMD_MAGIC:
+			if (flags & FPSIMD_CTX)
+				*err = "Multiple FPSIMD_MAGIC";
+			else if (head->size !=
+				 sizeof(struct fpsimd_context))
+				*err = "Bad size for fpsimd_context";
+			flags |= FPSIMD_CTX;
+			break;
+		case ESR_MAGIC:
+			if (head->size != sizeof(struct esr_context))
+				*err = "Bad size for esr_context";
+			break;
+		case SVE_MAGIC:
+			if (flags & SVE_CTX)
+				*err = "Multiple SVE_MAGIC";
+			else if (head->size !=
+				 sizeof(struct sve_context))
+				*err = "Bad size for sve_context";
+			flags |= SVE_CTX;
+			break;
+		case EXTRA_MAGIC:
+			if (flags & EXTRA_CTX)
+				*err = "Multiple EXTRA_MAGIC";
+			else if (head->size !=
+				 sizeof(struct extra_context))
+				*err = "Bad size for extra_context";
+			flags |= EXTRA_CTX;
+			extra = (struct extra_context *)head;
+			break;
+		case KSFT_BAD_MAGIC:
+			/*
+			 * This is a BAD magic header defined
+			 * artificially by a testcase and surely
+			 * unknown to the Kernel parse_user_sigframe().
+			 * It MUST cause a Kernel induced SEGV
+			 */
+			*err = "BAD MAGIC !";
+			break;
+		default:
+			/*
+			 * A still unknown Magic: potentially freshly added
+			 * to the Kernel code and still unknown to the
+			 * tests.
+			 */
+			fprintf(stdout,
+				"SKIP Unknown MAGIC: 0x%X - Is KSFT arm64/signal up to date ?\n",
+				head->magic);
+			break;
+		}
+
+		if (*err)
+			return false;
+
+		offs += head->size;
+		if (resv_sz < offs + sizeof(*head)) {
+			*err = "HEAD Overrun";
+			return false;
+		}
+
+		if (flags & EXTRA_CTX)
+			if (!validate_extra_context(extra, err))
+				return false;
+
+		head = GET_RESV_NEXT_HEAD(head);
+	}
+
+	if (terminated && !(flags & FPSIMD_CTX)) {
+		*err = "Missing FPSIMD";
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * This function walks through the records inside the provided reserved area
+ * trying to find enough space to fit @need_sz bytes: if not enough space is
+ * available and an extra_context record is present, it throws away the
+ * extra_context record.
+ *
+ * It returns a pointer to a new header where it is possible to start storing
+ * our need_sz bytes.
+ *
+ * @shead: points to the start of reserved area
+ * @need_sz: needed bytes
+ * @resv_sz: reserved area size in bytes
+ * @offset: if not null, this will be filled with the offset of the return
+ *	    head pointer from @shead
+ *
+ * @return: pointer to a new head where to start storing need_sz bytes, or
+ *	    NULL if space could not be made available.
+ */
+struct _aarch64_ctx *get_starting_head(struct _aarch64_ctx *shead,
+				       size_t need_sz, size_t resv_sz,
+				       size_t *offset)
+{
+	size_t offs = 0;
+	struct _aarch64_ctx *head;
+
+	head = get_terminator(shead, resv_sz, &offs);
+	/* not found a terminator...no need to update offset if any */
+	if (!head)
+		return head;
+	if (resv_sz - offs < need_sz) {
+		fprintf(stderr, "Low on space:%zd. Discarding extra_context.\n",
+			resv_sz - offs);
+		head = get_header(shead, EXTRA_MAGIC, resv_sz, &offs);
+		if (!head || resv_sz - offs < need_sz) {
+			fprintf(stderr,
+				"Failed to reclaim space on sigframe.\n");
+			return NULL;
+		}
+	}
+
+	fprintf(stderr, "Available space:%zd\n", resv_sz - offs);
+	if (offset)
+		*offset = offs;
+	return head;
+}
diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.h b/tools/testing/selftests/arm64/signal/testcases/testcases.h
new file mode 100644
index 000000000..ad884c135
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+#ifndef __TESTCASES_H__
+#define __TESTCASES_H__
+
+#include <stddef.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <ucontext.h>
+#include <signal.h>
+
+/* Architecture specific sigframe definitions */
+#include <asm/sigcontext.h>
+
+#define FPSIMD_CTX	(1 << 0)
+#define SVE_CTX		(1 << 1)
+#define EXTRA_CTX	(1 << 2)
+
+#define KSFT_BAD_MAGIC	0xdeadbeef
+
+#define HDR_SZ \
+	sizeof(struct _aarch64_ctx)
+
+#define GET_SF_RESV_HEAD(sf) \
+	(struct _aarch64_ctx *)(&(sf).uc.uc_mcontext.__reserved)
+
+#define GET_SF_RESV_SIZE(sf) \
+	sizeof((sf).uc.uc_mcontext.__reserved)
+
+#define GET_UCP_RESV_SIZE(ucp) \
+	sizeof((ucp)->uc_mcontext.__reserved)
+
+#define ASSERT_BAD_CONTEXT(uc) do {					\
+	char *err = NULL;						\
+	if (!validate_reserved((uc), GET_UCP_RESV_SIZE((uc)), &err)) {	\
+		if (err)						\
+			fprintf(stderr,					\
+				"Using badly built context - ERR: %s\n",\
+				err);					\
+	} else {							\
+		abort();						\
+	}								\
+} while (0)
+
+#define ASSERT_GOOD_CONTEXT(uc) do {					 \
+	char *err = NULL;						 \
+	if (!validate_reserved((uc), GET_UCP_RESV_SIZE((uc)), &err)) {	 \
+		if (err)						 \
+			fprintf(stderr,					 \
+				"Detected BAD context - ERR: %s\n", err);\
+		abort();						 \
+	} else {							 \
+		fprintf(stderr, "uc context validated.\n");		 \
+	}								 \
+} while (0)
+
+/*
+ * A simple record-walker for __reserved area: it walks through assuming
+ * only to find a proper struct __aarch64_ctx header descriptor.
+ *
+ * Instead it makes no assumptions on the content and ordering of the
+ * records, any needed bounds checking must be enforced by the caller
+ * if wanted: this way can be used by caller on any maliciously built bad
+ * contexts.
+ *
+ * head->size accounts both for payload and header _aarch64_ctx size !
+ */
+#define GET_RESV_NEXT_HEAD(h) \
+	(struct _aarch64_ctx *)((char *)(h) + (h)->size)
+
+struct fake_sigframe {
+	siginfo_t	info;
+	ucontext_t	uc;
+};
+
+
+bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err);
+
+bool validate_extra_context(struct extra_context *extra, char **err);
+
+struct _aarch64_ctx *get_header(struct _aarch64_ctx *head, uint32_t magic,
+				size_t resv_sz, size_t *offset);
+
+static inline struct _aarch64_ctx *get_terminator(struct _aarch64_ctx *head,
+						  size_t resv_sz,
+						  size_t *offset)
+{
+	return get_header(head, 0, resv_sz, offset);
+}
+
+static inline void write_terminator_record(struct _aarch64_ctx *tail)
+{
+	if (tail) {
+		tail->magic = 0;
+		tail->size = 0;
+	}
+}
+
+struct _aarch64_ctx *get_starting_head(struct _aarch64_ctx *shead,
+				       size_t need_sz, size_t resv_sz,
+				       size_t *offset);
+#endif