1 /*
2  * Copyright 2015, Sam Bobroff, IBM Corp.
3  * Licensed under GPLv2.
4  *
5  * Test the kernel's system call code to ensure that a system call
6  * made from within an active HTM transaction is aborted with the
7  * correct failure code.
8  * Conversely, ensure that a system call made from within a
9  * suspended transaction can succeed.
10  */
11 
12 #include <stdio.h>
13 #include <unistd.h>
14 #include <sys/syscall.h>
15 #include <asm/tm.h>
16 #include <asm/cputable.h>
17 #include <linux/auxvec.h>
18 #include <sys/time.h>
19 #include <stdlib.h>
20 
21 #include "utils.h"
22 
23 extern int getppid_tm_active(void);
24 extern int getppid_tm_suspended(void);
25 
26 unsigned retries = 0;
27 
28 #define TEST_DURATION 10 /* seconds */
29 #define TM_RETRIES 100
30 
31 long failure_code(void)
32 {
33 	return __builtin_get_texasru() >> 24;
34 }
35 
36 bool failure_is_persistent(void)
37 {
38 	return (failure_code() & TM_CAUSE_PERSISTENT) == TM_CAUSE_PERSISTENT;
39 }
40 
41 bool failure_is_syscall(void)
42 {
43 	return (failure_code() & TM_CAUSE_SYSCALL) == TM_CAUSE_SYSCALL;
44 }
45 
46 pid_t getppid_tm(bool suspend)
47 {
48 	int i;
49 	pid_t pid;
50 
51 	for (i = 0; i < TM_RETRIES; i++) {
52 		if (suspend)
53 			pid = getppid_tm_suspended();
54 		else
55 			pid = getppid_tm_active();
56 
57 		if (pid >= 0)
58 			return pid;
59 
60 		if (failure_is_persistent()) {
61 			if (failure_is_syscall())
62 				return -1;
63 
64 			printf("Unexpected persistent transaction failure.\n");
65 			printf("TEXASR 0x%016lx, TFIAR 0x%016lx.\n",
66 			       __builtin_get_texasr(), __builtin_get_tfiar());
67 			exit(-1);
68 		}
69 
70 		retries++;
71 	}
72 
73 	printf("Exceeded limit of %d temporary transaction failures.\n", TM_RETRIES);
74 	printf("TEXASR 0x%016lx, TFIAR 0x%016lx.\n",
75 	       __builtin_get_texasr(), __builtin_get_tfiar());
76 
77 	exit(-1);
78 }
79 
80 static inline bool have_htm_nosc(void)
81 {
82 #ifdef PPC_FEATURE2_HTM_NOSC
83 	return ((long)get_auxv_entry(AT_HWCAP2) & PPC_FEATURE2_HTM_NOSC);
84 #else
85 	printf("PPC_FEATURE2_HTM_NOSC not defined, can't check AT_HWCAP2\n");
86 	return false;
87 #endif
88 }
89 
90 int tm_syscall(void)
91 {
92 	unsigned count = 0;
93 	struct timeval end, now;
94 
95 	SKIP_IF(!have_htm_nosc());
96 
97 	setbuf(stdout, NULL);
98 
99 	printf("Testing transactional syscalls for %d seconds...\n", TEST_DURATION);
100 
101 	gettimeofday(&end, NULL);
102 	now.tv_sec = TEST_DURATION;
103 	now.tv_usec = 0;
104 	timeradd(&end, &now, &end);
105 
106 	for (count = 0; timercmp(&now, &end, <); count++) {
107 		/*
108 		 * Test a syscall within a suspended transaction and verify
109 		 * that it succeeds.
110 		 */
111 		FAIL_IF(getppid_tm(true) == -1); /* Should succeed. */
112 
113 		/*
114 		 * Test a syscall within an active transaction and verify that
115 		 * it fails with the correct failure code.
116 		 */
117 		FAIL_IF(getppid_tm(false) != -1);  /* Should fail... */
118 		FAIL_IF(!failure_is_persistent()); /* ...persistently... */
119 		FAIL_IF(!failure_is_syscall());    /* ...with code syscall. */
120 		gettimeofday(&now, 0);
121 	}
122 
123 	printf("%d active and suspended transactions behaved correctly.\n", count);
124 	printf("(There were %d transaction retries.)\n", retries);
125 
126 	return 0;
127 }
128 
129 int main(void)
130 {
131 	return test_harness(tm_syscall, "tm_syscall");
132 }
133