Commit 736e6d5a authored by Mark Brown's avatar Mark Brown Committed by Will Deacon
Browse files

selftests: arm64: Document what the SVE ptrace test is doing 



Before we go modifying it further let's add some comments and output
clarifications explaining what this test is actually doing.

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-5-broonie@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent eab281e3

tools/testing/selftests/arm64/fp/sve-ptrace.c

+8 −3
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ static int do_parent(pid_t child) 
		}

	}



	/* New process should start with FPSIMD registers only */

	sve = get_sve(pid, &svebuf, &svebufsz);

	if (!sve) {

		int e = errno;
@@ -191,14 +192,15 @@ static int do_parent(pid_t child) 


		goto error;

	} else {

		ksft_test_result_pass("get_sve\n");

		ksft_test_result_pass("get_sve(FPSIMD)\n");

	}



	ksft_test_result((sve->flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD,

			 "FPSIMD registers\n");

			 "Set FPSIMD registers\n");

	if ((sve->flags & SVE_PT_REGS_MASK) != SVE_PT_REGS_FPSIMD)

		goto error;



	/* 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) {
@@ -219,6 +221,7 @@ static int do_parent(pid_t child) 
		goto error;

	}



	/* Zero the first SVE Z register */

	vq = sve_vq_from_vl(sve->vl);



	newsvebufsz = SVE_PT_SVE_ZREG_OFFSET(vq, 1);
@@ -245,6 +248,7 @@ static int do_parent(pid_t child) 
		goto error;

	}



	/* Try to read back the value we just set */

	new_sve = get_sve(pid, &newsvebuf, &newsvebufsz);

	if (!new_sve) {

		int e = errno;
@@ -257,12 +261,13 @@ static int do_parent(pid_t child) 
	}



	ksft_test_result((new_sve->flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_SVE,

			 "SVE registers\n");

			 "Get SVE registers\n");

	if ((new_sve->flags & SVE_PT_REGS_MASK) != SVE_PT_REGS_SVE)

		goto error;



	dump_sve_regs(new_sve, 3, sizeof fpsimd->vregs[0]);



	/* Verify that the register we set has the value we expected */

	p = (unsigned char *)new_sve + SVE_PT_SVE_ZREG_OFFSET(vq, 1);

	for (i = 0; i < sizeof fpsimd->vregs[0]; ++i) {

		unsigned char expected = i;