[PATCH v4 00/11] Add arm64/signal initial kselftest support

[PATCH v4 00/11] Add arm64/signal initial kselftest support

[Cristian Marussi]

Hi

this patchset aims to add the initial arch-specific arm64 support to
kselftest starting with signals-related test-cases.
A common internal test-case layout is proposed which then it is anyway
wired-up to the toplevel kselftest Makefile, so that it should be possible
at the end to run it on an arm64 target in the usual way with KSFT.

~/linux# make TARGETS=arm64 kselftest

New KSFT arm64 testcases live inside tools/testing/selftests/arm64 grouped by
family inside subdirectories: arm64/signal is the first family proposed with
this series. arm64/signal tests can be run via KSFT or standalone.

Thanks

Cristian


Notes:
-----
- further details in the included READMEs

- more tests still to be written (current strategy is going through the related
  Kernel signal-handling code and write a test for each possible and sensible code-path)
  A few ideas for more TODO testcases:
	- fake_sigreturn_unmapped_sp: SP into unmapped addrs
	- fake_sigreturn_kernelspace_sp: SP into kernel addrs
	- fake_sigreturn_sve_bad_extra_context: SVE extra context badly formed
	- mangle_sve_invalid_extra_context: SVE extra_context invalid

- SVE signal testcases and special handling will be part of an additional patch
  still to be released


Changes:
--------

 v3-->v4:
 - rebased on v5.3-rc6
 - added test descriptions
 - fixed commit messages (imperative mood)
 - added missing includes and removed unneeded ones
 - added/used new get_starting_head() helper
 - fixed/simplified signal.S::fakke_sigreturn()
 - added set_regval() macro and .init initialization func
 - better synchonization in get_current_context()
 - macroization of mangle_pstate_invalid_mode_el
 - splitted mangle_pstate_invalid_mode_el h/t
 - removed standalone mode
 - simplified CPU features checks
 - fixed/refactored get_header() and validation routines
 - simplfied docs


 v2-->v3:
 - rebased on v5.3-rc2
 - better test result characterization looking for
   SEGV_ACCERR in si_code on SIGSEGV
 - using KSFT Framework macros for retvalues
 - removed SAFE_WRITE()/dump_uc: buggy, un-needed and unused
 - reviewed generation process of test_arm64_signals.sh runner script
 - re-added a fixed fake_sigreturn_misaligned_sp testcase and a properly
   extended fake_sigreturn() helper
 - added tests' TODO notes


 v1-->v2:
- rebased on 5.2-rc7
- various makefile's cleanups
- mixed READMEs fixes
- fixed test_arm64_signals.sh runner script
- cleaned up assembly code in signal.S
- improved get_current_context() logic
- fixed SAFE_WRITE()
- common support code splitted into more chunks, each one introduced when
  needed by some new testcases
- fixed some headers validation routines in testcases.c
- removed some still broken/immature tests:
  + fake_sigreturn_misaligned
  + fake_sigreturn_overflow_reserved
  + mangle_pc_invalid
  + mangle_sp_misaligned
- fixed some other testcases:
  + mangle_pstate_ssbs_regs: better checks of SSBS bit when feature unsupported
  + mangle_pstate_invalid_compat_toggle: name fix
  + mangle_pstate_invalid_mode_el[1-3]: precautionary zeroing PSTATE.MODE
  + fake_sigreturn_bad_magic, fake_sigreturn_bad_size,
    fake_sigreturn_bad_size_for_magic0:
    - accounting for available space...dropping extra when needed
    - keeping alignent
- new testcases on FPSMID context:
  + fake_sigreturn_missing_fpsimd
  + fake_sigreturn_duplicated_fpsimd


*** BLURB HERE ***

Cristian Marussi (11):
  kselftest: arm64: add skeleton Makefile
  kselftest: arm64: add common utils and one testcase
  kselftest: arm64: mangle_pstate_invalid_daif_bits
  kselftest: arm64: mangle_pstate_invalid_mode_el[123][ht]
  kselftest: arm64: mangle_pstate_ssbs_regs
  kselftest: arm64: fake_sigreturn_bad_magic
  kselftest: arm64: fake_sigreturn_bad_size_for_magic0
  kselftest: arm64: fake_sigreturn_missing_fpsimd
  kselftest: arm64: fake_sigreturn_duplicated_fpsimd
  kselftest: arm64: fake_sigreturn_bad_size
  kselftest: arm64: fake_sigreturn_misaligned_sp

 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/arm64/Makefile        |  51 +++
 tools/testing/selftests/arm64/README          |  20 +
 tools/testing/selftests/arm64/signal/Makefile |  50 +++
 tools/testing/selftests/arm64/signal/README   |  59 +++
 .../testing/selftests/arm64/signal/signals.S  |  62 +++
 .../selftests/arm64/signal/test_signals.c     |  29 ++
 .../selftests/arm64/signal/test_signals.h     | 123 ++++++
 .../arm64/signal/test_signals_utils.c         | 367 ++++++++++++++++++
 .../arm64/signal/test_signals_utils.h         |  16 +
 .../arm64/signal/testcases/.gitignore         |   3 +
 .../testcases/fake_sigreturn_bad_magic.c      |  54 +++
 .../testcases/fake_sigreturn_bad_size.c       |  77 ++++
 .../fake_sigreturn_bad_size_for_magic0.c      |  49 +++
 .../fake_sigreturn_duplicated_fpsimd.c        |  52 +++
 .../testcases/fake_sigreturn_misaligned_sp.c  |  37 ++
 .../testcases/fake_sigreturn_missing_fpsimd.c |  50 +++
 .../mangle_pstate_invalid_compat_toggle.c     |  31 ++
 .../mangle_pstate_invalid_daif_bits.c         |  35 ++
 .../mangle_pstate_invalid_mode_el1h.c         |  15 +
 .../mangle_pstate_invalid_mode_el1t.c         |  15 +
 .../mangle_pstate_invalid_mode_el2h.c         |  15 +
 .../mangle_pstate_invalid_mode_el2t.c         |  15 +
 .../mangle_pstate_invalid_mode_el3h.c         |  15 +
 .../mangle_pstate_invalid_mode_el3t.c         |  15 +
 .../mangle_pstate_invalid_mode_template.h     |  28 ++
 .../testcases/mangle_pstate_ssbs_regs.c       |  69 ++++
 .../arm64/signal/testcases/testcases.c        | 179 +++++++++
 .../arm64/signal/testcases/testcases.h        |  90 +++++
 29 files changed, 1622 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/Makefile
 create mode 100644 tools/testing/selftests/arm64/README
 create mode 100644 tools/testing/selftests/arm64/signal/Makefile
 create mode 100644 tools/testing/selftests/arm64/signal/README
 create mode 100644 tools/testing/selftests/arm64/signal/signals.S
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals.c
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals.h
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals_utils.c
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals_utils.h
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/.gitignore
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size_for_magic0.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_missing_fpsimd.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_compat_toggle.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1h.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1t.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2h.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2t.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3h.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3t.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_template.h
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/testcases.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/testcases.h

-- 
2.17.1

[PATCH v4 01/11] kselftest: arm64: add skeleton Makefile

[Cristian Marussi]

Add a new arm64-specific empty subsystem amongst TARGETS of KSFT build
framework; keep these new arm64 KSFT testcases separated into distinct
subdirs inside tools/testing/selftests/arm64/ depending on the specific
subsystem targeted.

Run the new KSFT TARGETS=arm64 related tests from the toplevel
KSFT Makefile in the usual ways.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3--->v4
- comment reword
- simplified documentation in README
- dropped README about standalone
---
 tools/testing/selftests/Makefile       |  1 +
 tools/testing/selftests/arm64/Makefile | 51 ++++++++++++++++++++++++++
 tools/testing/selftests/arm64/README   | 20 ++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/Makefile
 create mode 100644 tools/testing/selftests/arm64/README

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 25b43a8c2b15..1722dae9381a 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 TARGETS = android
+TARGETS += arm64
 TARGETS += bpf
 TARGETS += breakpoints
 TARGETS += capabilities
diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
new file mode 100644
index 000000000000..03a0d4f71218
--- /dev/null
+++ b/tools/testing/selftests/arm64/Makefile
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 ARM Limited
+
+# When ARCH not overridden for crosscompiling, lookup machine
+ARCH ?= $(shell uname -m)
+ARCH := $(shell echo $(ARCH) | sed -e s/aarch64/arm64/)
+
+ifeq ("x$(ARCH)", "xarm64")
+SUBDIRS :=
+else
+SUBDIRS :=
+endif
+
+CFLAGS := -Wall -O2 -g
+
+export CC
+export CFLAGS
+
+all:
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		mkdir -p $$BUILD_TARGET;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+install: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+run_tests: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+# Avoid any output on non arm64 on emit_tests
+emit_tests: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+clean:
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+.PHONY: all clean install run_tests emit_tests
diff --git a/tools/testing/selftests/arm64/README b/tools/testing/selftests/arm64/README
new file mode 100644
index 000000000000..aca892e62a6c
--- /dev/null
+++ b/tools/testing/selftests/arm64/README
@@ -0,0 +1,20 @@
+KSelfTest ARM64
+===============
+
+- These tests are arm64 specific and so not built or run but just skipped
+  completely when env-variable ARCH is found to be different than 'arm64'
+  and `uname -m` reports other than 'aarch64'.
+
+- Holding true the above, ARM64 KSFT tests can be run within the KSelfTest
+  framework using standard Linux top-level-makefile targets:
+
+      $ make TARGETS=arm64 kselftest-clean
+      $ make TARGETS=arm64 kselftest
+
+      or
+
+      $ make -C tools/testing/selftests TARGETS=arm64 \
+		INSTALL_PATH=<your-installation-path> install
+
+   Further details on building and running KFST can be found in:
+     Documentation/dev-tools/kselftest.rst
-- 
2.17.1

[PATCH v4 02/11] kselftest: arm64: add common utils and one testcase

[Cristian Marussi]

Add some arm64/signal specific boilerplate and utility code to help
further testcases' development.

Introduce also one simple testcase mangle_pstate_invalid_compat_toggle
and some related helpers: it is a simple mangle testcase which messes
with the ucontext_t from within the signal handler, trying to toggle
PSTATE state bits to switch the system between 32bit/64bit execution
state. Expects SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- removed standalone mode
- fixed arm64/signal/README
- add file level comments: test layout / test description
- reduced verbosity
- removed spurious headers includes
- reviewed ID_AA64MMFR[1,2]_EL1 macros
- removed unused feats_ok
- simplified CPU features gathering
- reviewed included headers
- fixed/refactored get_header() and validation routines
- added test description
---
 tools/testing/selftests/arm64/Makefile        |   2 +-
 tools/testing/selftests/arm64/signal/Makefile |  50 ++++
 tools/testing/selftests/arm64/signal/README   |  59 ++++
 .../selftests/arm64/signal/test_signals.c     |  29 ++
 .../selftests/arm64/signal/test_signals.h     | 113 ++++++++
 .../arm64/signal/test_signals_utils.c         | 269 ++++++++++++++++++
 .../arm64/signal/test_signals_utils.h         |  13 +
 .../arm64/signal/testcases/.gitignore         |   3 +
 .../mangle_pstate_invalid_compat_toggle.c     |  31 ++
 .../arm64/signal/testcases/testcases.c        | 151 ++++++++++
 .../arm64/signal/testcases/testcases.h        |  86 ++++++
 11 files changed, 805 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/arm64/signal/Makefile
 create mode 100644 tools/testing/selftests/arm64/signal/README
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals.c
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals.h
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals_utils.c
 create mode 100644 tools/testing/selftests/arm64/signal/test_signals_utils.h
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/.gitignore
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_compat_toggle.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/testcases.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/testcases.h

diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
index 03a0d4f71218..af59dc74e0dc 100644
--- a/tools/testing/selftests/arm64/Makefile
+++ b/tools/testing/selftests/arm64/Makefile
@@ -6,7 +6,7 @@ ARCH ?= $(shell uname -m)
 ARCH := $(shell echo $(ARCH) | sed -e s/aarch64/arm64/)
 
 ifeq ("x$(ARCH)", "xarm64")
-SUBDIRS :=
+SUBDIRS := signal
 else
 SUBDIRS :=
 endif
diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile
new file mode 100644
index 000000000000..852f0a73ca00
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/Makefile
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 ARM Limited
+
+# A proper top_srcdir is needed by KSFT(lib.mk)
+top_srcdir = ../../../../..
+
+# Additional include paths needed by kselftest.h and local headers
+CFLAGS += -D_GNU_SOURCE -std=gnu99 -I. -I$(top_srcdir)/tools/testing/selftests/
+
+# Guessing as best as we can where the Kernel headers
+# could have been installed depending on ENV config and
+# type of invocation.
+ifeq ($(KBUILD_OUTPUT),)
+khdr_dir = $(top_srcdir)/usr/include
+else
+# the KSFT preferred location when KBUILD_OUTPUT is set
+khdr_dir = $(KBUILD_OUTPUT)/kselftest/usr/include
+endif
+CFLAGS += -I$(khdr_dir)
+
+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)/
+
+clean:
+	$(CLEAN)
+	rm -f $(PROGS)
+
+# Common test-unit targets to build common-layout test-cases executables
+# Needs secondary expansion to properly include the testcase c-file in pre-reqs
+.SECONDEXPANSION:
+$(PROGS): test_signals.c test_signals_utils.c testcases/testcases.c $$@.c test_signals.h test_signals_utils.h testcases/testcases.h
+	@if [ ! -d $(khdr_dir) ]; then \
+		echo -n "\n!!! WARNING: $(khdr_dir) NOT FOUND."; \
+		echo "===>  Are you sure Kernel Headers have been installed properly ?\n"; \
+	fi
+	$(CC) $(CFLAGS) $^ -o $@
diff --git a/tools/testing/selftests/arm64/signal/README b/tools/testing/selftests/arm64/signal/README
new file mode 100644
index 000000000000..967a531b245c
--- /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/test_signals.c b/tools/testing/selftests/arm64/signal/test_signals.c
new file mode 100644
index 000000000000..f05c6dbf8659
--- /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 tddescr 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)) {
+		if (test_run(current))
+			test_result(current);
+		test_cleanup(current);
+	}
+
+	return current->pass ? KSFT_PASS : KSFT_FAIL;
+}
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 000000000000..a1cf69997604
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals.h
@@ -0,0 +1,113 @@
+/* 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");					\
+}
+
+/* Regs encoding and masks naming copied in from sysreg.h */
+#define SYS_ID_AA64MMFR1_EL1	S3_0_C0_C7_1	/* MRS Emulated */
+#define SYS_ID_AA64MMFR2_EL1	S3_0_C0_C7_2	/* MRS Emulated */
+#define ID_AA64MMFR1_PAN_SHIFT	20
+#define ID_AA64MMFR2_UAO_SHIFT	4
+
+/* Local Helpers */
+#define ID_AA64MMFR1_EL1_PAN_SUPPORTED(val) \
+	(!!((val) & (0xfUL << ID_AA64MMFR1_PAN_SHIFT)))
+#define ID_AA64MMFR2_EL1_UAO_SUPPORTED(val) \
+	(!!((val) & (0xfUL << ID_AA64MMFR2_UAO_SHIFT)))
+
+#define SSBS_SYSREG		S3_3_C4_C2_6	/* EL0 supported */
+
+/*
+ * Feature flags used in tdescr.feats_required to specify
+ * any feature by the test
+ */
+enum {
+	FSSBS_BIT,
+	FPAN_BIT,
+	FUAO_BIT,
+	FMAX_END
+};
+
+#define FEAT_SSBS		(1UL << FSSBS_BIT)
+#define FEAT_PAN		(1UL << FPAN_BIT)
+#define FEAT_UAO		(1UL << FUAO_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;
+	/* optional sa_flags for the installed handler */
+	int		sa_flags;
+	ucontext_t	saved_uc;
+
+	/* a custom setup function to be called before test starts */
+	int (*setup)(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 test starting */
+	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);
+
+	void *priv;
+};
+
+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 000000000000..e2a5f37e6ad3
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c
@@ -0,0 +1,269 @@
+// 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 "test_signals.h"
+#include "test_signals_utils.h"
+#include "testcases/testcases.h"
+
+extern struct tdescr *current;
+
+static char *feats_store[FMAX_END] = {
+	" SSBS ",
+	" PAN ",
+	" UAO ",
+};
+
+#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_store[i]);
+
+			assert(flen > tlen);
+			flen -= tlen;
+			strncat(feats_string, feats_store[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->pass)
+		fprintf(stderr, "==>> completed. PASS(1)\n");
+	else
+		fprintf(stdout, "==>> completed. FAIL(0)\n");
+	if (force_exit)
+		exit(td->pass ? EXIT_SUCCESS : EXIT_FAILURE);
+}
+
+static inline bool are_feats_ok(struct tdescr *td)
+{
+	return (td->feats_required & td->feats_supported) == td->feats_required;
+}
+
+static void default_handler(int signum, siginfo_t *si, void *uc)
+{
+	if (current->sig_trig && signum == current->sig_trig) {
+		fprintf(stderr, "Handling SIG_TRIG\n");
+		current->triggered = 1;
+		/* ->run was asserted NON-NULL in test_setup() already */
+		current->run(current, si, uc);
+	} else if (signum == SIGILL && !current->initialized) {
+		/*
+		 * A SIGILL here while still not initialized means we failed
+		 * even to asses the existence of features during init
+		 */
+		fprintf(stdout,
+			"Got SIGILL test_init. Marking ALL features UNSUPPORTED.\n");
+		current->feats_supported = 0;
+	} else if (current->sig_ok && signum == current->sig_ok) {
+		/*
+		 * it's a bug in the test code when this assert fail:
+		 * if a sig_trig was defined, it must have been used before
+		 * arriving here.
+		 */
+		assert(!current->sig_trig || current->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, current->token,
+			current->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 (!current->sanity_disabled && !current->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 (current->sig_ok == SIGSEGV && si->si_code != SEGV_ACCERR) {
+			fprintf(stdout,
+				"si_code != SEGV_ACCERR...test is probably broken!\n");
+			abort();
+		}
+		fprintf(stderr, "Handling SIG_OK\n");
+		current->pass = 1;
+		/*
+		 * Some tests can lead to SEGV loops: in such a case we want
+		 * to terminate immediately exiting straight away
+		 */
+		default_result(current, 1);
+	} else {
+		if (signum == current->sig_unsupp && !are_feats_ok(current)) {
+			fprintf(stderr,
+				"-- RX SIG_UNSUPP on unsupported feat...OK\n");
+			current->pass = 1;
+		} 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);
+}
+
+static int test_init(struct tdescr *td)
+{
+	td->minsigstksz = getauxval(AT_MINSIGSTKSZ);
+	if (!td->minsigstksz)
+		td->minsigstksz = MINSIGSTKSZ;
+	fprintf(stderr, "Detected MINSTKSIGSZ:%d\n", td->minsigstksz);
+
+	if (td->feats_required) {
+		bool feats_ok = false;
+
+		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_CPUID) {
+			uint64_t val = 0;
+
+			/* Uses HWCAP to check capability */
+			if (getauxval(AT_HWCAP) & HWCAP_SSBS)
+				td->feats_supported |= FEAT_SSBS;
+			/* Uses MRS emulation to check capability */
+			get_regval(SYS_ID_AA64MMFR1_EL1, val);
+			if (ID_AA64MMFR1_EL1_PAN_SUPPORTED(val))
+				td->feats_supported |= FEAT_PAN;
+			/* Uses MRS emulation to check capability */
+			get_regval(SYS_ID_AA64MMFR2_EL1, val);
+			if (ID_AA64MMFR2_EL1_UAO_SUPPORTED(val))
+				td->feats_supported |= FEAT_UAO;
+		} else {
+			fprintf(stderr,
+				"HWCAP_CPUID NOT available. Mark ALL feats UNSUPPORTED.\n");
+		}
+		feats_ok = are_feats_ok(td);
+		fprintf(stderr,
+			"Required Features: [%s] %ssupported\n",
+			feats_ok ? feats_to_string(td->feats_supported) :
+			feats_to_string(td->feats_required ^
+					td->feats_supported),
+			!feats_ok ? "NOT " : "");
+	}
+
+	td->initialized = 1;
+	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);
+
+	if (!test_init(td))
+		return 0;
+
+	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->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 000000000000..8658d1a7d4b9
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 ARM Limited */
+
+#ifndef __TEST_SIGNALS_UTILS_H__
+#define __TEST_SIGNALS_UTILS_H__
+
+#include "test_signals.h"
+
+int test_setup(struct tdescr *td);
+void test_cleanup(struct tdescr *td);
+int test_run(struct tdescr *td);
+void test_result(struct tdescr *td);
+#endif
diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore
new file mode 100644
index 000000000000..e5aeae45febb
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore
@@ -0,0 +1,3 @@
+!*.[ch]
+mangle_*
+fake_sigreturn_*
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 000000000000..2cb118b0ba05
--- /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/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c
new file mode 100644
index 000000000000..72e3f482b177
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -0,0 +1,151 @@
+// 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)
+		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);
+	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 contiguos)";
+	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))
+				fprintf(stderr,
+					"Bad size for esr_context is not an error...just ignore.\n");
+			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;
+}
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 000000000000..00618c3202bb
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.h
@@ -0,0 +1,86 @@
+/* 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 <ucontext.h>
+#include <assert.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;						\
+	assert(!validate_reserved((uc), GET_UCP_RESV_SIZE((uc)), &err));\
+	if (err)							\
+		fprintf(stderr,						\
+			"Using badly built context - ERR: %s\n", err);	\
+} 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);\
+		assert(0);						 \
+	} else {							 \
+		fprintf(stderr, "uc context validated.\n");		 \
+	}								 \
+} while (0)
+
+/* 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;
+	}
+}
+#endif
-- 
2.17.1

[PATCH v4 03/11] kselftest: arm64: mangle_pstate_invalid_daif_bits

[Cristian Marussi]

Add a simple mangle testcase which messes with the ucontext_t from within
the signal handler, trying to set PSTATE DAIF bits to an invalid value
(masking everything). Expects SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fixed commit message
- added testcase comment description
---
 .../mangle_pstate_invalid_daif_bits.c         | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c

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 000000000000..434b82597007
--- /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,
+};
-- 
2.17.1

[PATCH v4 04/11] kselftest: arm64: mangle_pstate_invalid_mode_el[123][ht]

[Cristian Marussi]

Add 6 simple mangle testcases that mess with the ucontext_t from within
the signal handler, trying to toggle PSTATE mode bits to trick the system
into switching to EL1/EL2/EL3 using both SP_EL0(t) and SP_ELx(h).
Expects SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fixed commit message
- macroization
- splitted into 6 macro-ised testcases to address t/h SP selection modes
- added test description
---
 .../mangle_pstate_invalid_mode_el1h.c         | 15 ++++++++++
 .../mangle_pstate_invalid_mode_el1t.c         | 15 ++++++++++
 .../mangle_pstate_invalid_mode_el2h.c         | 15 ++++++++++
 .../mangle_pstate_invalid_mode_el2t.c         | 15 ++++++++++
 .../mangle_pstate_invalid_mode_el3h.c         | 15 ++++++++++
 .../mangle_pstate_invalid_mode_el3t.c         | 15 ++++++++++
 .../mangle_pstate_invalid_mode_template.h     | 28 +++++++++++++++++++
 7 files changed, 118 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1h.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el1t.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2h.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el2t.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3h.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_el3t.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_mode_template.h

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 000000000000..95f821abdf46
--- /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 000000000000..cc222d8a618a
--- /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 000000000000..2188add7d28c
--- /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 000000000000..df32dd5a479c
--- /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 000000000000..9e6829b7e5db
--- /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 000000000000..5685a4f10d06
--- /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 000000000000..f5bf1804d858
--- /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,			\
+}
-- 
2.17.1

[PATCH v4 05/11] kselftest: arm64: mangle_pstate_ssbs_regs

[Cristian Marussi]

Add a simple mangle testcase which messes with the ucontext_t from within
the signal handler, trying to set the PSTATE SSBS bit.
Expect SIGILL if SSBS feature is unsupported or that, on test PASS, the
value set in PSTATE.SSBS in the signal frame is preserved by sigreturn.

Additionally, in order to support this test specific needs:
- extend signal testing framework to allow the definition of a custom per
  test initialization function to be run at the end of test setup.
- introduced a set_regval() helper to set system register values in a
  toolchain independent way.
- introduce also a new common utility function: get_current_context()
  which can be used to grab a ucontext without the help of libc, and
  detect if such ucontext has been actively used to jump back into it.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit message
- missing include signal.h
- added .init per-test init-func
- added set_regval() helper
- added SSBS clear to 0 custom .init function
- removed volatile qualifier associated with sig_atomic_t data
- added dsb inside handler to ensure the writes related to the
  grabbed ucontext have completed
- added test description
---
 .../selftests/arm64/signal/test_signals.h     | 20 +++-
 .../arm64/signal/test_signals_utils.c         | 98 +++++++++++++++++++
 .../arm64/signal/test_signals_utils.h         |  2 +
 .../testcases/mangle_pstate_ssbs_regs.c       | 69 +++++++++++++
 4 files changed, 184 insertions(+), 5 deletions(-)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c

diff --git a/tools/testing/selftests/arm64/signal/test_signals.h b/tools/testing/selftests/arm64/signal/test_signals.h
index a1cf69997604..0767e27fbe78 100644
--- a/tools/testing/selftests/arm64/signal/test_signals.h
+++ b/tools/testing/selftests/arm64/signal/test_signals.h
@@ -27,6 +27,14 @@
 	: "memory");					\
 }
 
+#define set_regval(regname, in)				\
+{							\
+	asm volatile("msr " __stringify(regname) ", %0" \
+	:						\
+	: "r" (in)					\
+	: "memory");					\
+}
+
 /* Regs encoding and masks naming copied in from sysreg.h */
 #define SYS_ID_AA64MMFR1_EL1	S3_0_C0_C7_1	/* MRS Emulated */
 #define SYS_ID_AA64MMFR2_EL1	S3_0_C0_C7_2	/* MRS Emulated */
@@ -89,12 +97,16 @@ struct tdescr {
 	/* optional sa_flags for the installed handler */
 	int		sa_flags;
 	ucontext_t	saved_uc;
-
-	/* a custom setup function to be called before test starts */
+	/* used by get_current_ctx() */
+	size_t		live_sz;
+	ucontext_t	*live_uc;
+	sig_atomic_t	live_uc_valid;
+	/* a custom setup: called alternatively to default_setup */
 	int (*setup)(struct tdescr *td);
+	/* a custom init: called by default test initialization */
+	void (*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 test starting */
 	int (*trigger)(struct tdescr *td);
 	/*
@@ -102,10 +114,8 @@ struct tdescr {
 	 * 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);
-
 	void *priv;
 };
 
diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.c b/tools/testing/selftests/arm64/signal/test_signals_utils.c
index e2a5f37e6ad3..c6fdcb23f246 100644
--- a/tools/testing/selftests/arm64/signal/test_signals_utils.c
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c
@@ -11,12 +11,16 @@
 #include <linux/auxvec.h>
 #include <ucontext.h>
 
+#include <asm/unistd.h>
+
 #include "test_signals.h"
 #include "test_signals_utils.h"
 #include "testcases/testcases.h"
 
 extern struct tdescr *current;
 
+static int sig_copyctx = SIGUSR2;
+
 static char *feats_store[FMAX_END] = {
 	" SSBS ",
 	" PAN ",
@@ -43,6 +47,81 @@ static inline char *feats_to_string(unsigned long feats)
 	return feats_string;
 }
 
+/*
+ * 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.
+ *
+ * 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 the 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 hittig a SEGV.
+ */
+bool get_current_context(struct tdescr *td, ucontext_t *dest_uc)
+{
+	static sig_atomic_t 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 signal...
+	 * ASM equivalent of raise(sig_copyctx);
+	 *
+	 * Note that:
+	 * - live_uc_valid is declared sig_atomic_t in struct tdescr
+	 *   since it will be changed inside the sig_copyctx handler
+	 * - the kill() syscall invocation returns only after any possible
+	 *   registered signal handler for the invoked signal has returned,
+	 *   so that live_uc_valid flag is surely up to date when this
+	 *   function return it.
+	 * - the additional 'memory' clobber is there to avoid possible
+	 *   compiler's assumption on live_uc_valid, seen-already and
+	 *   the content pointed by dest_uc, which are all changed inside
+	 *   the signal handler, without resorting to the volatile qualifier
+	 *   (and keeping quiet checkpatch.pl)
+	 */
+	asm volatile ("mov x8, %0\n\t"
+		      "svc #0\n\t"
+		      "mov x1, %1\n\t"
+		      "mov x8, %2\n\t"
+		      "svc #0"
+		      :
+		      : "i" (__NR_getpid), "r" (sig_copyctx), "i" (__NR_kill)
+		      : "x1", "x8", "x0", "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 the live_uc has not
+	 * just been acquired...so return 0
+	 */
+	if (seen_already) {
+		fprintf(stdout,
+			"Successful sigreturn detected: live_uc is stale !\n");
+		return 0;
+	}
+	seen_already = 1;
+
+	return td->live_uc_valid;
+}
+
 static void unblock_signal(int signum)
 {
 	sigset_t sset;
@@ -124,6 +203,17 @@ static void default_handler(int signum, siginfo_t *si, void *uc)
 		 * to terminate immediately exiting straight away
 		 */
 		default_result(current, 1);
+	} else if (signum == sig_copyctx && current->live_uc) {
+		memcpy(current->live_uc, uc, current->live_sz);
+		ASSERT_GOOD_CONTEXT(current->live_uc);
+		current->live_uc_valid = 1;
+		/*
+		 * Ensure above writes have completed before signal
+		 * handler terminates
+		 */
+		asm volatile ("dsb sy" ::: "memory");
+		fprintf(stderr,
+			"GOOD CONTEXT grabbed from sig_copyctx handler\n");
 	} else {
 		if (signum == current->sig_unsupp && !are_feats_ok(current)) {
 			fprintf(stderr,
@@ -222,7 +312,15 @@ static int test_init(struct tdescr *td)
 			!feats_ok ? "NOT " : "");
 	}
 
+	if (td->sig_trig == sig_copyctx)
+		sig_copyctx = SIGUSR1;
+	unblock_signal(sig_copyctx);
+
+	/* Perform test specific additional initialization */
+	if (td->init)
+		td->init(td);
 	td->initialized = 1;
+
 	return 1;
 }
 
diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.h b/tools/testing/selftests/arm64/signal/test_signals_utils.h
index 8658d1a7d4b9..ce35be8ebc8e 100644
--- a/tools/testing/selftests/arm64/signal/test_signals_utils.h
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.h
@@ -10,4 +10,6 @@ int test_setup(struct tdescr *td);
 void test_cleanup(struct tdescr *td);
 int test_run(struct tdescr *td);
 void test_result(struct tdescr *td);
+
+bool get_current_context(struct tdescr *td, ucontext_t *dest_uc);
 #endif
diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c
new file mode 100644
index 000000000000..15e6f62512d5
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 ARM Limited
+ *
+ * Try to mangle the ucontext from inside a signal handler, setting the
+ * SSBS bit to 1 and veryfing that such modification is preserved.
+ */
+
+#include <stdio.h>
+#include <signal.h>
+#include <ucontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+static void mangle_invalid_pstate_ssbs_init(struct tdescr *td)
+{
+	fprintf(stderr, "Clearing SSBS to 0\n");
+	set_regval(SSBS_SYSREG, 0);
+}
+
+static int mangle_invalid_pstate_ssbs_run(struct tdescr *td,
+					  siginfo_t *si, ucontext_t *uc)
+{
+	ASSERT_GOOD_CONTEXT(uc);
+
+	/* set bit value */
+	uc->uc_mcontext.pstate |= PSR_SSBS_BIT;
+	fprintf(stderr, "SSBS set to 1 -- PSTATE: 0x%016llX\n",
+		uc->uc_mcontext.pstate);
+	/* Save after mangling...it should be preserved */
+	td->saved_uc = *uc;
+
+	return 1;
+}
+
+static void pstate_ssbs_bit_checks(struct tdescr *td)
+{
+	uint64_t val = 0;
+	ucontext_t uc;
+
+	/* This check reports some result even if MRS SSBS unsupported */
+	if (get_current_context(td, &uc))
+		fprintf(stderr,
+			"INFO: live_uc - got PSTATE: 0x%016llX -> SSBS %s\n",
+			uc.uc_mcontext.pstate,
+			(td->saved_uc.uc_mcontext.pstate & PSR_SSBS_BIT) ==
+			(uc.uc_mcontext.pstate & PSR_SSBS_BIT) ?
+			"PRESERVED" : "CLEARED");
+
+	fprintf(stderr, "Checking with MRS SSBS...\n");
+	get_regval(SSBS_SYSREG, val);
+	fprintf(stderr, "INFO: MRS SSBS - got: 0x%016lX\n", val);
+	/* pass when preserved */
+	td->pass = (val & PSR_SSBS_BIT) ==
+		   (td->saved_uc.uc_mcontext.pstate & PSR_SSBS_BIT);
+}
+
+struct tdescr tde = {
+		.sanity_disabled = true,
+		.name = "MANGLE_PSTATE_SSBS_REGS",
+		.descr = "Mangling uc_mcontext changing SSBS.(PRESERVE)",
+		.feats_required = FEAT_SSBS,
+		.sig_trig = SIGUSR1,
+		.sig_unsupp = SIGILL,
+		.init = mangle_invalid_pstate_ssbs_init,
+		.run = mangle_invalid_pstate_ssbs_run,
+		.check_result = pstate_ssbs_bit_checks,
+};
-- 
2.17.1

[PATCH v4 06/11] kselftest: arm64: fake_sigreturn_bad_magic

[Cristian Marussi]

Add a simple fake_sigreturn testcase which builds a ucontext_t with a bad
magic header and place it onto the stack. Expects a SIGSEGV on test PASS.

Introduce a common utility assembly trampoline function to invoke a
sigreturn while placing the provided sigframe at wanted alignment and
also an helper to make space when needed inside the sigframe reserved
area.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit
- fix signal.S, handle misalign requests too
- remove unneeded comments
- add signal.h include
- added get_starting_head() helper
- added test description
---
 tools/testing/selftests/arm64/signal/Makefile |  2 +-
 .../testing/selftests/arm64/signal/signals.S  | 62 +++++++++++++++++++
 .../arm64/signal/test_signals_utils.h         |  1 +
 .../testcases/fake_sigreturn_bad_magic.c      | 54 ++++++++++++++++
 .../arm64/signal/testcases/testcases.c        | 28 +++++++++
 .../arm64/signal/testcases/testcases.h        |  4 ++
 6 files changed, 150 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/arm64/signal/signals.S
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c

diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile
index 852f0a73ca00..11af7b843d8e 100644
--- a/tools/testing/selftests/arm64/signal/Makefile
+++ b/tools/testing/selftests/arm64/signal/Makefile
@@ -42,7 +42,7 @@ clean:
 # 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 $$@.c test_signals.h test_signals_utils.h testcases/testcases.h
+$(PROGS): test_signals.c test_signals_utils.c testcases/testcases.c signals.S $$@.c test_signals.h test_signals_utils.h testcases/testcases.h
 	@if [ ! -d $(khdr_dir) ]; then \
 		echo -n "\n!!! WARNING: $(khdr_dir) NOT FOUND."; \
 		echo "===>  Are you sure Kernel Headers have been installed properly ?\n"; \
diff --git a/tools/testing/selftests/arm64/signal/signals.S b/tools/testing/selftests/arm64/signal/signals.S
new file mode 100644
index 000000000000..b89fec0d5ba0
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/signals.S
@@ -0,0 +1,62 @@
+/* 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:
+	mov x20, x0
+	mov x21, x1
+	mov x22, x2
+	mov x23, sp
+
+	/* create space on the stack for fake sigframe 16 bytes-aligned */
+	add x0, x21, #16
+	bic x0, x0, #15
+	sub x23, x23, x0
+	/* any misalignment requested ? */
+	add x23, x23, x22
+
+	ldr x0, =call_fmt
+	mov x1, x21
+	mov x2, x23
+	bl printf
+
+	mov sp, x23
+
+	/* now fill it with the provided content... */
+	mov x0, sp
+	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]
+	/* SP is already pointing back to the just built fake sigframe here */
+	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_utils.h b/tools/testing/selftests/arm64/signal/test_signals_utils.h
index ce35be8ebc8e..68930f1e46e5 100644
--- a/tools/testing/selftests/arm64/signal/test_signals_utils.h
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.h
@@ -12,4 +12,5 @@ int test_run(struct tdescr *td);
 void test_result(struct tdescr *td);
 
 bool get_current_context(struct tdescr *td, ucontext_t *dest_uc);
+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 000000000000..7fb700b9801b
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c
@@ -0,0 +1,54 @@
+// 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)
+{
+	size_t resv_sz, need_sz;
+	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);
+	/* need at least 2*HDR_SZ space: KSFT_BAD_MAGIC + terminator. */
+	need_sz = HDR_SZ * 2;
+	head = get_starting_head(shead, need_sz, resv_sz, NULL);
+	if (head) {
+		/*
+		 * 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/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c
index 72e3f482b177..2effb8ded935 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.c
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -149,3 +149,31 @@ bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err)
 
 	return true;
 }
+
+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
index 00618c3202bb..7653f8a64b3d 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.h
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.h
@@ -83,4 +83,8 @@ static inline void write_terminator_record(struct _aarch64_ctx *tail)
 		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
-- 
2.17.1

[PATCH v4 07/11] kselftest: arm64: fake_sigreturn_bad_size_for_magic0

[Cristian Marussi]

Add a simple fake_sigreturn testcase which builds a ucontext_t with a
badly sized terminator record and place it onto the stack.
Expects a SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit
- add signal.h include
- using new get_starting_head() helper
- added test description
---
 .../fake_sigreturn_bad_size_for_magic0.c      | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size_for_magic0.c

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 000000000000..25017fe18214
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size_for_magic0.c
@@ -0,0 +1,49 @@
+// 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)
+{
+	size_t resv_sz, need_sz;
+	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 for the badly sized terminator. */
+	need_sz = HDR_SZ;
+	head = get_starting_head(shead, need_sz, resv_sz, NULL);
+	if (head) {
+		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,
+};
-- 
2.17.1

[PATCH v4 08/11] kselftest: arm64: fake_sigreturn_missing_fpsimd

[Cristian Marussi]

Add a simple fake_sigreturn testcase which builds a ucontext_t without
the required fpsimd_context and place it onto the stack.
Expects a SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit
- added signal.h
- added test description
---
 .../testcases/fake_sigreturn_missing_fpsimd.c | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_missing_fpsimd.c

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 000000000000..08ecd8073a1a
--- /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,
+};
-- 
2.17.1

[PATCH v4 09/11] kselftest: arm64: fake_sigreturn_duplicated_fpsimd

[Cristian Marussi]

Add a simple fake_sigreturn testcase which builds a ucontext_t with
an anomalous additional fpsimd_context and place it onto the stack.
Expects a SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit
- missing include
- using new get_starting_head() helper
- added test description
---
 .../fake_sigreturn_duplicated_fpsimd.c        | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c

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 000000000000..c7122c44f53f
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
@@ -0,0 +1,52 @@
+// 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)
+{
+	size_t resv_sz, need_sz;
+	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);
+	need_sz = HDR_SZ + sizeof(struct fpsimd_context);
+
+	head = get_starting_head(shead, need_sz, resv_sz, NULL);
+	if (head) {
+		/* Add a spurios 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,
+};
-- 
2.17.1

[PATCH v4 10/11] kselftest: arm64: fake_sigreturn_bad_size

[Cristian Marussi]

Add a simple fake_sigreturn testcase which builds a ucontext_t with a
badly sized header that causes a overrun in the __reserved area and
place it onto the stack. Expects a SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit
- missing include
- using new get_starting_head() helper
- added test description
---
 .../testcases/fake_sigreturn_bad_size.c       | 77 +++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_size.c

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 000000000000..b1156afdb691
--- /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 = HDR_SZ + sizeof(struct esr_context);
+	head = get_starting_head(shead, need_sz, resv_sz, &offset);
+	if (head) {
+		/*
+		 * 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,
+};
-- 
2.17.1

[PATCH v4 11/11] kselftest: arm64: fake_sigreturn_misaligned_sp

[Cristian Marussi]

Add a simple fake_sigreturn testcase which places a valid sigframe on a
non-16 bytes aligned SP. Expects a SIGSEGV on test PASS.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- fix commit
- use new fake_sigreturn misalig_bytes params
- removed TODO
- added test description
---
 .../testcases/fake_sigreturn_misaligned_sp.c  | 37 +++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_misaligned_sp.c

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 000000000000..1e089e66f9f3
--- /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,
+};
-- 
2.17.1