src/hotspot/os_cpu/linux_aarch64/safefetch_linux_aarch64.S

/*
 * Copyright (c) 2022 SAP SE. All rights reserved.
 * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "defs.S.inc"

    # Support for int SafeFetch32(int* address, int defaultval);
    #
    #  x0 : address
    #  x1 : defaultval
DECLARE_FUNC(SafeFetch32_impl):
DECLARE_FUNC(_SafeFetch32_fault):
    ldr      w0, [x0]
    ret
DECLARE_FUNC(_SafeFetch32_continuation):
    mov      x0, x1
    ret

    # Support for intptr_t SafeFetchN(intptr_t* address, intptr_t defaultval);
    #
    #  x1 : address
    #  x0 : defaultval
DECLARE_FUNC(SafeFetchN_impl):
DECLARE_FUNC(_SafeFetchN_fault):
    ldr      x0, [x0]
    ret
DECLARE_FUNC(_SafeFetchN_continuation):
    mov      x0, x1
    ret

/* Emit .note.gnu.property section in case of PAC or BTI being enabled.
 * For more details see "ELF for the Arm(R) 64-bit Architecture (AArch64)".
 * https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst
 */
#ifdef __ARM_FEATURE_BTI_DEFAULT
    #ifdef __ARM_FEATURE_PAC_DEFAULT
        #define GNU_PROPERTY_AARCH64_FEATURE 3
    #else
        #define GNU_PROPERTY_AARCH64_FEATURE 1
    #endif
#else
    #ifdef __ARM_FEATURE_PAC_DEFAULT
        #define GNU_PROPERTY_AARCH64_FEATURE 2
    #else
        #define GNU_PROPERTY_AARCH64_FEATURE 0
    #endif
#endif

#if (GNU_PROPERTY_AARCH64_FEATURE != 0)
        .pushsection .note.gnu.property, "a"
        .align  3
        .long   4          /* name length */
        .long   0x10       /* data length */
        .long   5          /* note type: NT_GNU_PROPERTY_TYPE_0 */
        .string "GNU"      /* vendor name */
        .long   0xc0000000 /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */
        .long   4          /* pr_datasze */
        .long   GNU_PROPERTY_AARCH64_FEATURE
        .long   0
        .popsection
#endif