cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sve_regs.c (2530B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2021 ARM Limited
      4 *
      5 * Verify that the SVE register context in signal frames is set up as
      6 * expected.
      7 */
      8
      9#include <signal.h>
     10#include <ucontext.h>
     11#include <sys/prctl.h>
     12
     13#include "test_signals_utils.h"
     14#include "testcases.h"
     15
     16struct fake_sigframe sf;
     17static unsigned int vls[SVE_VQ_MAX];
     18unsigned int nvls = 0;
     19
     20static bool sve_get_vls(struct tdescr *td)
     21{
     22	int vq, vl;
     23
     24	/*
     25	 * Enumerate up to SVE_VQ_MAX vector lengths
     26	 */
     27	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
     28		vl = prctl(PR_SVE_SET_VL, vq * 16);
     29		if (vl == -1)
     30			return false;
     31
     32		vl &= PR_SVE_VL_LEN_MASK;
     33
     34		/* Skip missing VLs */
     35		vq = sve_vq_from_vl(vl);
     36
     37		vls[nvls++] = vl;
     38	}
     39
     40	/* We need at least one VL */
     41	if (nvls < 1) {
     42		fprintf(stderr, "Only %d VL supported\n", nvls);
     43		return false;
     44	}
     45
     46	return true;
     47}
     48
     49static void setup_sve_regs(void)
     50{
     51	/* RDVL x16, #1 so we should have SVE regs; real data is TODO */
     52	asm volatile(".inst 0x04bf5030" : : : "x16" );
     53}
     54
     55static int do_one_sve_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
     56			 unsigned int vl)
     57{
     58	size_t resv_sz, offset;
     59	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
     60	struct sve_context *sve;
     61
     62	fprintf(stderr, "Testing VL %d\n", vl);
     63
     64	if (prctl(PR_SVE_SET_VL, vl) == -1) {
     65		fprintf(stderr, "Failed to set VL\n");
     66		return 1;
     67	}
     68
     69	/*
     70	 * Get a signal context which should have a SVE frame and registers
     71	 * in it.
     72	 */
     73	setup_sve_regs();
     74	if (!get_current_context(td, &sf.uc))
     75		return 1;
     76
     77	resv_sz = GET_SF_RESV_SIZE(sf);
     78	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
     79	if (!head) {
     80		fprintf(stderr, "No SVE context\n");
     81		return 1;
     82	}
     83
     84	sve = (struct sve_context *)head;
     85	if (sve->vl != vl) {
     86		fprintf(stderr, "Got VL %d, expected %d\n", sve->vl, vl);
     87		return 1;
     88	}
     89
     90	/* The actual size validation is done in get_current_context() */
     91	fprintf(stderr, "Got expected size %u and VL %d\n",
     92		head->size, sve->vl);
     93
     94	return 0;
     95}
     96
     97static int sve_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
     98{
     99	int i;
    100
    101	for (i = 0; i < nvls; i++) {
    102		/*
    103		 * TODO: the signal test helpers can't currently cope
    104		 * with signal frames bigger than struct sigcontext,
    105		 * skip VLs that will trigger that.
    106		 */
    107		if (vls[i] > 64)
    108			continue;
    109
    110		if (do_one_sve_vl(td, si, uc, vls[i]))
    111			return 1;
    112	}
    113
    114	td->pass = 1;
    115
    116	return 0;
    117}
    118
    119struct tdescr tde = {
    120	.name = "SVE registers",
    121	.descr = "Check that we get the right SVE registers reported",
    122	.feats_required = FEAT_SVE,
    123	.timeout = 3,
    124	.init = sve_get_vls,
    125	.run = sve_regs,
    126};