kselftst/arm64: Test NT_ARM_SVE FPSIMD format writes on non-SVE systems

In order to allow exiting streaming mode on systems with SME but not SVE
we allow writes of FPSIMD format data via NT_ARM_SVE even when SVE is not
supported, add a test case that covers this to sve-ptrace.

We do not support reads.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/tools/testing/selftests/arm64/fp/sve-ptrace.c b/tools/testing/selftests/arm64/fp/sve-ptrace.c
index e0fc3a001e2830759dee2860074beb3d1b380775..f44d4461857519db28ad48136ff784812646d485 100644 (file)
--- a/tools/testing/selftests/arm64/fp/sve-ptrace.c
+++ b/tools/testing/selftests/arm64/fp/sve-ptrace.c
@@ -394,6 +394,58 @@ static void ptrace_sve_fpsimd(pid_t child, const struct vec_type *type)
        free(svebuf);
 }
 
+/* Write the FPSIMD registers via the SVE regset when SVE is not supported */
+static void ptrace_sve_fpsimd_no_sve(pid_t child)
+{
+       void *svebuf;
+       struct user_sve_header *sve;
+       struct user_fpsimd_state *fpsimd, new_fpsimd;
+       unsigned int i, j;
+       unsigned char *p;
+       int ret;
+
+       svebuf = malloc(SVE_PT_SIZE(0, SVE_PT_REGS_FPSIMD));
+       if (!svebuf) {
+               ksft_test_result_fail("Failed to allocate FPSIMD buffer\n");
+               return;
+       }
+
+       /* On a system without SVE the VL should be set to 0 */
+       memset(svebuf, 0, SVE_PT_SIZE(0, SVE_PT_REGS_FPSIMD));
+       sve = svebuf;
+       sve->flags = SVE_PT_REGS_FPSIMD;
+       sve->size = SVE_PT_SIZE(0, SVE_PT_REGS_FPSIMD);
+       sve->vl = 0;
+
+       /* Try to set a known FPSIMD state via PT_REGS_SVE */
+       fpsimd = (struct user_fpsimd_state *)((char *)sve +
+                                             SVE_PT_FPSIMD_OFFSET);
+       for (i = 0; i < 32; ++i) {
+               p = (unsigned char *)&fpsimd->vregs[i];
+
+               for (j = 0; j < sizeof(fpsimd->vregs[i]); ++j)
+                       p[j] = j;
+       }
+
+       ret = set_sve(child, &vec_types[0], sve);
+       ksft_test_result(ret == 0, "FPSIMD write via SVE\n");
+       if (ret) {
+               ksft_test_result_skip("Verify FPSIMD write via SVE\n");
+               goto out;
+       }
+
+       /* Verify via the FPSIMD regset */
+       if (get_fpsimd(child, &new_fpsimd)) {
+               ksft_test_result_skip("Verify FPSIMD write via SVE\n");
+               goto out;
+       }
+       ksft_test_result(memcmp(fpsimd, &new_fpsimd, sizeof(*fpsimd)) == 0,
+                        "Verify FPSIMD write via SVE\n");
+
+out:
+       free(svebuf);
+}
+
 /* Validate attempting to set SVE data and read SVE data */
 static void ptrace_set_sve_get_sve_data(pid_t child,
                                        const struct vec_type *type,
@@ -826,6 +878,15 @@ static int do_parent(pid_t child)
                }
        }
 
+       /* We support SVE writes of FPSMID format on SME only systems */
+       if (!(getauxval(AT_HWCAP) & HWCAP_SVE) &&
+           (getauxval(AT_HWCAP2) & HWCAP2_SME)) {
+               ptrace_sve_fpsimd_no_sve(child);
+       } else {
+               ksft_test_result_skip("FPSIMD write via SVE\n");
+               ksft_test_result_skip("Verify FPSIMD write via SVE\n");
+       }
+
        ret = EXIT_SUCCESS;
 
 error: