Differential D56654 Diff 176771 tests/sys/arch/amd64/int0x80.c

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tests/sys/arch/amd64/int0x80.c

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				/*
				* SPDX-License-Identifier: BSD-2-Clause
				*
				* Copyright 2026 The FreeBSD Foundation
				*
				* This software were developed by
				* Konstantin Belousov <kib@FreeBSD.org> under sponsorship from
				* the FreeBSD Foundation.
				*/

				#include <sys/syscall.h>
				#include <err.h>
				#include <signal.h>
				#include <stdatomic.h>
				#include <stdio.h>
				#include <stdlib.h>
				#include <string.h>
				#include <unistd.h>

				#ifndef __amd64__
				#error "amd64 only"
				#endif

				/*
				* The check to see how "INT $0x80" behaves for amd64 native ABI
				* processes. Before bd8edba0792b71be3f8ed5dea9c22287e95c986a it
				* executed syscalls with amd64 calling conventions. After that
				* revision, it should raise SIGBUS.
				*/

				static uintptr_t int0x80_loc;
				static int signo;
				extern char after_int0x80[];

				static void
				sigill_action(int signo1, siginfo_t si __unused, void uctxv)
				{
				ucontext_t *uctx = uctxv;

				signo = signo1;
				int0x80_loc = uctx->uc_mcontext.mc_rip;
				}

				static int
				fire(void)
				{
				int res;

				asm volatile(
				".globl\tafter_int0x80\n"
				"\tint\t$0x80\n"
				"after_int0x80:"
				: "=a" (res)
				: "%0" (SYS_getpid)
				: "rdx", "memory", "cc");
				return (res);
				}

				int
				main(void)
				{
				struct sigaction sa;
				char signame[SIG2STR_MAX];
				int pid, res;

				res = 0;

				memset(&sa, 0, sizeof(sa));
				sa.sa_sigaction = sigill_action;
				sa.sa_flags = SA_SIGINFO;
				if (sigaction(SIGBUS, &sa, NULL) == -1)
				err(1, "catching SIGBUS");

				pid = fire();
				atomic_signal_fence(memory_order_seq_cst);
				if (int0x80_loc == 0) {
				printf("int $0x80 does not raise SIGBUS\n");
				if (pid == getpid())
				printf("and syscall worked\n");
				else
				printf("but syscall did not worked\n");
				res = 1;
				} else {
				sig2str(signo, signame);
				printf("int $0x80 raises SIG%s\n", signame);
				if (int0x80_loc == (uintptr_t)after_int0x80) {
				printf("at expected location\n");
				} else {
				printf("not at expected location\n");
				res = 1;
				}
				}
				exit(res);
				}