selftest/powerpc: Add test for sigreturn in transaction

TEST_GEN_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack \

	tm-vmxcopy tm-fork tm-tar tm-tmspr tm-vmx-unavail tm-unavailable tm-trap \

	$(SIGNAL_CONTEXT_CHK_TESTS)

	$(SIGNAL_CONTEXT_CHK_TESTS) tm-sigreturn

include ../../lib.mk

// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright 2015, Laurent Dufour, IBM Corp.

 *

 * Test the kernel's signal returning code to check reclaim is done if the

 * sigreturn() is called while in a transaction (suspended since active is

 * already dropped trough the system call path).

 *

 * The kernel must discard the transaction when entering sigreturn, since

 * restoring the potential TM SPRS from the signal frame is requiring to not be

 * in a transaction.

 */

#include <signal.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <unistd.h>

#include "tm.h"

#include "utils.h"

void handler(int sig)

{

	uint64_t ret;

	asm __volatile__(

		"li             3,1             ;"

		"tbegin.                        ;"

		"beq            1f              ;"

		"li             3,0             ;"

		"tsuspend.                      ;"

		"1:                             ;"

		"std%X[ret]     3, %[ret]       ;"

		: [ret] "=m"(ret)

		:

		: "memory", "3", "cr0");

	if (ret)

		exit(1);

	/*

	 * We return from the signal handle while in a suspended transaction

	 */

}

int tm_sigreturn(void)

{

	struct sigaction sa;

	uint64_t ret = 0;

	SKIP_IF(!have_htm());

	memset(&sa, 0, sizeof(sa));

	sa.sa_handler = handler;

	sigemptyset(&sa.sa_mask);

	if (sigaction(SIGSEGV, &sa, NULL))

		exit(1);

	asm __volatile__(

		"tbegin.                        ;"

		"beq            1f              ;"

		"li             3,0             ;"

		"std            3,0(3)          ;" /* trigger SEGV */

		"li             3,1             ;"

		"std%X[ret]     3,%[ret]        ;"

		"tend.                          ;"

		"b              2f              ;"

		"1:                             ;"

		"li             3,2             ;"

		"std%X[ret]     3,%[ret]        ;"

		"2:                             ;"

		: [ret] "=m"(ret)

		:

		: "memory", "3", "cr0");

	if (ret != 2)

		exit(1);

	exit(0);

}

int main(void)

{

	return test_harness(tm_sigreturn, "tm_sigreturn");

}