47e4282c19
Introduces a macro abstraction around capturing the bounds of a function, which many platforms handle subtly differently (Mach-O, and ELF, for example). Also introduce an arm64[^-]* -> aarch64 available feature, to enable more tests that would otherwise be excluded on Apple platforms, whose target triples tend to take the form e.g. 'arm64-apple-macosx', rather than 'aarch64-apple-macosx'. Third, we implement the has-sme check using the appropriate sysctl, as getauxval is not available on Darwin platforms.
132 lines
3.6 KiB
C++
132 lines
3.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// REQUIRES: target={{aarch64-.+}}
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// UNSUPPORTED: target={{.*-windows.*}}
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#include <libunwind.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#if defined(__APPLE__)
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#include <sys/sysctl.h>
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#else
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#include <sys/auxv.h>
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#endif
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// Basic test of unwinding with SME lazy saves. This tests libunwind disables ZA
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// (and commits a lazy save of ZA) before resuming from unwinding.
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// Note: This test requires SME (and is setup to pass on targets without SME).
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#if defined(__APPLE__)
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static bool checkHasSME() {
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int has_sme = 0;
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size_t size = sizeof(has_sme);
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if (!sysctlbyname("hw.optional.arm.FEAT_SME", &has_sme, &size, NULL, 0))
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return false;
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return has_sme != 0;
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}
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#else
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static bool checkHasSME() {
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constexpr int hwcap2_sme = (1 << 23);
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unsigned long hwcap2 = getauxval(AT_HWCAP2);
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return (hwcap2 & hwcap2_sme) != 0;
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}
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#endif
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struct TPIDR2Block {
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void *za_save_buffer;
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uint64_t num_save_slices;
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};
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__attribute__((noinline)) void private_za() {
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// Note: Lazy save active on entry to function.
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unw_context_t context;
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unw_cursor_t cursor;
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unw_getcontext(&context);
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unw_init_local(&cursor, &context);
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unw_step(&cursor);
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unw_resume(&cursor);
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}
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bool isZAOn() {
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register uint64_t svcr asm("x20");
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asm(".inst 0xd53b4254" : "=r"(svcr));
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return (svcr & 0b10) != 0;
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}
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__attribute__((noinline)) void za_function_with_lazy_save() {
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register uint64_t tmp asm("x8");
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// SMSTART ZA (should zero ZA)
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asm(".inst 0xd503457f");
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// RDSVL x8, #1 (read streaming vector length)
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asm(".inst 0x04bf5828" : "=r"(tmp));
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// Allocate and fill ZA save buffer with 0xAA.
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size_t buffer_size = tmp * tmp;
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uint8_t *za_save_buffer = (uint8_t *)alloca(buffer_size);
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memset(za_save_buffer, 0xAA, buffer_size);
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TPIDR2Block block = {za_save_buffer, tmp};
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tmp = reinterpret_cast<uint64_t>(&block);
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// MRS TPIDR2_EL0, x8 (setup lazy save of ZA)
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asm(".inst 0xd51bd0a8" ::"r"(tmp));
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// ZA should be on before unwinding.
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if (!isZAOn()) {
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fprintf(stderr, __FILE__ ": fail (ZA not on before call)\n");
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abort();
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} else {
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fprintf(stderr, __FILE__ ": pass (ZA on before call)\n");
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}
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private_za();
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// ZA should be off after unwinding.
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if (isZAOn()) {
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fprintf(stderr, __FILE__ ": fail (ZA on after unwinding)\n");
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abort();
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} else {
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fprintf(stderr, __FILE__ ": pass (ZA off after unwinding)\n");
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}
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// MRS x8, TPIDR2_EL0 (read TPIDR2_EL0)
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asm(".inst 0xd53bd0a8" : "=r"(tmp));
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// ZA should have been saved (TPIDR2_EL0 zero).
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if (tmp != 0) {
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fprintf(stderr, __FILE__ ": fail (TPIDR2_EL0 non-null after unwinding)\n");
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abort();
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} else {
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fprintf(stderr, __FILE__ ": pass (TPIDR2_EL0 null after unwinding)\n");
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}
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// ZA (all zero) should have been saved to the buffer.
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for (unsigned i = 0; i < buffer_size; ++i) {
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if (za_save_buffer[i] != 0) {
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fprintf(stderr,
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__FILE__ ": fail (za_save_buffer non-zero after unwinding)\n");
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abort();
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}
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}
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fprintf(stderr, __FILE__ ": pass (za_save_buffer zero'd after unwinding)\n");
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}
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int main(int, char **) {
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if (!checkHasSME()) {
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fprintf(stderr, __FILE__ ": pass (no SME support)\n");
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return 0; // Pass (SME is required for this test to run).
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}
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za_function_with_lazy_save();
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return 0;
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}
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