kselftest: arm64: mangle_pstate_invalid_daif_bits

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.

Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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 (file)
index 0000000..434b825
--- /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,
+};