57 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2024 ARM Limited4 *5 * Common helper functions for SVE and SME functionality.6 */7 8#include <stdbool.h>9#include <kselftest.h>10#include <asm/sigcontext.h>11#include <sys/prctl.h>12 13unsigned int vls[SVE_VQ_MAX];14unsigned int nvls;15 16int sve_fill_vls(bool use_sme, int min_vls)17{18 int vq, vl;19 int pr_set_vl = use_sme ? PR_SME_SET_VL : PR_SVE_SET_VL;20 int len_mask = use_sme ? PR_SME_VL_LEN_MASK : PR_SVE_VL_LEN_MASK;21 22 /*23 * Enumerate up to SVE_VQ_MAX vector lengths24 */25 for (vq = SVE_VQ_MAX; vq > 0; --vq) {26 vl = prctl(pr_set_vl, vq * 16);27 if (vl == -1)28 return KSFT_FAIL;29 30 vl &= len_mask;31 32 /*33 * Unlike SVE, SME does not require the minimum vector length34 * to be implemented, or the VLs to be consecutive, so any call35 * to the prctl might return the single implemented VL, which36 * might be larger than 16. So to avoid this loop never37 * terminating, bail out here when we find a higher VL than38 * we asked for.39 * See the ARM ARM, DDI 0487K.a, B1.4.2: I_QQRNR and I_NWYBP.40 */41 if (vq < sve_vq_from_vl(vl))42 break;43 44 /* Skip missing VLs */45 vq = sve_vq_from_vl(vl);46 47 vls[nvls++] = vl;48 }49 50 if (nvls < min_vls) {51 fprintf(stderr, "Only %d VL supported\n", nvls);52 return KSFT_SKIP;53 }54 55 return KSFT_PASS;56}57