Hi Cristian,
On 10/09/2019 01:04 PM, Cristian Marussi wrote:
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.
Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>
Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
[...]
+
+#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)))
+
+/*
+ * 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)
+
[...]
+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) {
+ 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_CPUID) {
+ uint64_t val = 0;
+
+ /* 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;
As discussed, these fields are never exposed to userspace via mrs. So
you may as well drop these features.
Cheers
Suzuki
