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: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-5-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Mark Brown 2021-09-13 13:55:01 +01:00 committed by Will Deacon
parent eab281e3af
commit 736e6d5a54
1 changed files with 8 additions and 3 deletions

View File

@ -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;