selftests/powerpc: Add ptrace tests for TAR, PPR, DSCR in TM

This patch adds ptrace interface test for TAR, PPR, DSCR
registers inside TM context. This also adds ptrace
interface based helper functions related to checkpointed
TAR, PPR, DSCR register access.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

tools/testing/selftests/powerpc/ptrace/.gitignore

@@ -2,3 +2,4 @@ ptrace-gpr
 ptrace-tm-gpr
 ptrace-tm-spd-gpr
 ptrace-tar
+ptrace-tm-tar

tools/testing/selftests/powerpc/ptrace/Makefile

 TEST_PROGS := ptrace-gpr ptrace-tm-gpr ptrace-tm-spd-gpr \
-              ptrace-tar
+              ptrace-tar ptrace-tm-tar
 
 include ../../lib.mk
 

tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar.c

+/*
+ * Ptrace test for TAR, PPR, DSCR registers in the TM context
+ *
+ * Copyright (C) 2015 Anshuman Khandual, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include "ptrace.h"
+#include "tm.h"
+#include "ptrace-tar.h"
+
+int shm_id;
+unsigned long *cptr, *pptr;
+
+
+void tm_tar(void)
+{
+	unsigned long result, texasr;
+	unsigned long regs[3];
+	int ret;
+
+	cptr = (unsigned long *)shmat(shm_id, NULL, 0);
+
+trans:
+	cptr[1] = 0;
+	asm __volatile__(
+		"li	4, %[tar_1];"
+		"mtspr %[sprn_tar],  4;"	/* TAR_1 */
+		"li	4, %[dscr_1];"
+		"mtspr %[sprn_dscr], 4;"	/* DSCR_1 */
+		"or     31,31,31;"		/* PPR_1*/
+
+		"1: ;"
+		"tbegin.;"
+		"beq 2f;"
+
+		"li	4, %[tar_2];"
+		"mtspr %[sprn_tar],  4;"	/* TAR_2 */
+		"li	4, %[dscr_2];"
+		"mtspr %[sprn_dscr], 4;"	/* DSCR_2 */
+		"or     1,1,1;"			/* PPR_2 */
+		"tsuspend.;"
+		"li 0, 1;"
+		"stw 0, 0(%[cptr1]);"
+		"tresume.;"
+		"b .;"
+
+		"tend.;"
+		"li 0, 0;"
+		"ori %[res], 0, 0;"
+		"b 3f;"
+
+		/* Transaction abort handler */
+		"2: ;"
+		"li 0, 1;"
+		"ori %[res], 0, 0;"
+		"mfspr %[texasr], %[sprn_texasr];"
+
+		"3: ;"
+
+		: [res] "=r" (result), [texasr] "=r" (texasr)
+		: [sprn_dscr]"i"(SPRN_DSCR), [sprn_tar]"i"(SPRN_TAR),
+		[sprn_ppr]"i"(SPRN_PPR), [sprn_texasr]"i"(SPRN_TEXASR),
+		[tar_1]"i"(TAR_1), [dscr_1]"i"(DSCR_1), [tar_2]"i"(TAR_2),
+		[dscr_2]"i"(DSCR_2), [cptr1] "r" (&cptr[1])
+		: "memory", "r0", "r1", "r3", "r4", "r5", "r6"
+		);
+
+	/* TM failed, analyse */
+	if (result) {
+		if (!cptr[0])
+			goto trans;
+
+		regs[0] = mfspr(SPRN_TAR);
+		regs[1] = mfspr(SPRN_PPR);
+		regs[2] = mfspr(SPRN_DSCR);
+
+		shmdt(&cptr);
+		printf("%-30s TAR: %lu PPR: %lx DSCR: %lu\n",
+				user_read, regs[0], regs[1], regs[2]);
+
+		ret = validate_tar_registers(regs, TAR_4, PPR_4, DSCR_4);
+		if (ret)
+			exit(1);
+		exit(0);
+	}
+	shmdt(&cptr);
+	exit(1);
+}
+
+int trace_tm_tar(pid_t child)
+{
+	unsigned long regs[3];
+
+	FAIL_IF(start_trace(child));
+	FAIL_IF(show_tar_registers(child, regs));
+	printf("%-30s TAR: %lu PPR: %lx DSCR: %lu\n",
+			ptrace_read_running, regs[0], regs[1], regs[2]);
+
+	FAIL_IF(validate_tar_registers(regs, TAR_2, PPR_2, DSCR_2));
+	FAIL_IF(show_tm_checkpointed_state(child, regs));
+	printf("%-30s TAR: %lu PPR: %lx DSCR: %lu\n",
+			ptrace_read_ckpt, regs[0], regs[1], regs[2]);
+
+	FAIL_IF(validate_tar_registers(regs, TAR_1, PPR_1, DSCR_1));
+	FAIL_IF(write_ckpt_tar_registers(child, TAR_4, PPR_4, DSCR_4));
+	printf("%-30s TAR: %u PPR: %lx DSCR: %u\n",
+			ptrace_write_ckpt, TAR_4, PPR_4, DSCR_4);
+
+	pptr[0] = 1;
+	FAIL_IF(stop_trace(child));
+	return TEST_PASS;
+}
+
+int ptrace_tm_tar(void)
+{
+	pid_t pid;
+	int ret, status;
+
+	SKIP_IF(!have_htm());
+	shm_id = shmget(IPC_PRIVATE, sizeof(int) * 2, 0777|IPC_CREAT);
+	pid = fork();
+	if (pid == 0)
+		tm_tar();
+
+	pptr = (unsigned long *)shmat(shm_id, NULL, 0);
+	pptr[0] = 0;
+
+	if (pid) {
+		while (!pptr[1])
+			asm volatile("" : : : "memory");
+		ret = trace_tm_tar(pid);
+		if (ret) {
+			kill(pid, SIGTERM);
+			shmdt(&pptr);
+			shmctl(shm_id, IPC_RMID, NULL);
+			return TEST_FAIL;
+		}
+		shmdt(&pptr);
+
+		ret = wait(&status);
+		shmctl(shm_id, IPC_RMID, NULL);
+		if (ret != pid) {
+			printf("Child's exit status not captured\n");
+			return TEST_FAIL;
+		}
+
+		return (WIFEXITED(status) && WEXITSTATUS(status)) ? TEST_FAIL :
+			TEST_PASS;
+	}
+	return TEST_PASS;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(ptrace_tm_tar, "ptrace_tm_tar");
+}