On 24/10/2019 23:41, Suzuki K Poulose wrote:
> 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.
>
Yes I'm going to drop this code in v10 (which is also un-needed in fact by the current testcases)
Thanks
Cristian
> Cheers
> Suzuki
>
