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kselftest/arm64: signal: Verify that signals can't change the SVE vector length

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We do not support changing the SVE vector length as part of signal return,
verify that this is the case if the system supports multiple vector lengths.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210819134245.13935-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Brown 2021-08-19 14:42:43 +01:00 committed by Catalin Marinas
parent c1f67a19c1
commit d25ac50ce8
1 changed files with 92 additions and 0 deletions
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92
tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c Normal file
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2021 ARM Limited
*
* Attempt to change the SVE vector length in a signal hander, this is not
* supported and is expected to segfault.
*/
#include <signal.h>
#include <ucontext.h>
#include <sys/prctl.h>
#include "test_signals_utils.h"
#include "testcases.h"
struct fake_sigframe sf;
static unsigned int vls[SVE_VQ_MAX];
unsigned int nvls = 0;
static bool sve_get_vls(struct tdescr *td)
{
int vq, vl;
/*
* Enumerate up to SVE_VQ_MAX vector lengths
*/
for (vq = SVE_VQ_MAX; vq > 0; --vq) {
vl = prctl(PR_SVE_SET_VL, vq * 16);
if (vl == -1)
return false;
vl &= PR_SVE_VL_LEN_MASK;
/* Skip missing VLs */
vq = sve_vq_from_vl(vl);
vls[nvls++] = vl;
}
/* We need at least two VLs */
if (nvls < 2) {
fprintf(stderr, "Only %d VL supported\n", nvls);
return false;
}
return true;
}
static int fake_sigreturn_sve_change_vl(struct tdescr *td,
siginfo_t *si, ucontext_t *uc)
{
size_t resv_sz, offset;
struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
struct sve_context *sve;
/* Get a signal context with a SVE frame in it */
if (!get_current_context(td, &sf.uc))
return 1;
resv_sz = GET_SF_RESV_SIZE(sf);
head = get_header(head, SVE_MAGIC, resv_sz, &offset);
if (!head) {
fprintf(stderr, "No SVE context\n");
return 1;
}
if (head->size != sizeof(struct sve_context)) {
fprintf(stderr, "SVE register state active, skipping\n");
return 1;
}
sve = (struct sve_context *)head;
/* No changes are supported; init left us at minimum VL so go to max */
fprintf(stderr, "Attempting to change VL from %d to %d\n",
sve->vl, vls[0]);
sve->vl = vls[0];
fake_sigreturn(&sf, sizeof(sf), 0);
return 1;
}
struct tdescr tde = {
.name = "FAKE_SIGRETURN_SVE_CHANGE",
.descr = "Attempt to change SVE VL",
.feats_required = FEAT_SVE,
.sig_ok = SIGSEGV,
.timeout = 3,
.init = sve_get_vls,
.run = fake_sigreturn_sve_change_vl,
};