1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2008
4 * Copyright (c) Paul Mackerras, IBM Corp., 2008
5 * Copyright (c) 2018-2023 Linux Test Project
6 */
7
8 /*
9 * Test little-endian mode switch system call. Requires a 64-bit
10 * processor that supports little-endian mode,such as POWER6.
11 */
12
13 #include <errno.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <unistd.h>
17 #include <elf.h>
18 #include <sys/types.h>
19 #include <sys/wait.h>
20
21 #include "tst_test.h"
22
23 #if defined(__powerpc64__) || defined(__powerpc__)
24
25 # ifndef PPC_FEATURE_TRUE_LE
26 # define PPC_FEATURE_TRUE_LE 0x00000002
27 # endif
28
29 # ifdef HAVE_GETAUXVAL
30 # include <sys/auxv.h>
31
32 /*
33 * Make minimal call to 0x1ebe. If we get ENOSYS then syscall is not
34 * available, likely because of:
35 * commit 727f13616c45 ("powerpc: Disable the fast-endian switch syscall by default")
36 * If we get any other outcome, including crashes with various signals,
37 * then we assume syscall is available and carry on with the test.
38 */
check_le_switch_supported(void)39 void check_le_switch_supported(void)
40 {
41 int status;
42
43 if (SAFE_FORK() == 0) {
44 syscall(0x1ebe);
45 exit(errno);
46 }
47
48 if (!(getauxval(AT_HWCAP) & PPC_FEATURE_TRUE_LE))
49 tst_brk(TCONF, "Processor does not support little-endian mode");
50
51 SAFE_WAIT(&status);
52 if (WIFSIGNALED(status)) {
53 int sig = WTERMSIG(status);
54
55 tst_res(TINFO, "check exited with sig %d", sig);
56 } else if (WIFEXITED(status)) {
57 int rc = WEXITSTATUS(status);
58
59 tst_res(TINFO, "check exited with %d", rc);
60 if (rc == ENOSYS)
61 tst_brk(TCONF, "fast endian switch (0x1ebe) N/A");
62 }
63 }
64
test_le_switch(void)65 void test_le_switch(void)
66 {
67 int status;
68
69 if (SAFE_FORK() == 0) {
70 register int r0 asm("r0") = 0x1ebe;
71
72 asm volatile ("sc; .long 0x02000044"
73 : "=&r" (r0)
74 : "0"(r0)
75 : "cr0", "r9", "r10", "r11", "r12");
76 exit(0);
77 }
78
79 SAFE_WAIT(&status);
80 if (WIFSIGNALED(status)) {
81 int sig = WTERMSIG(status);
82
83 tst_res(TFAIL, "test exited with sig %d", sig);
84 } else if (WIFEXITED(status)) {
85 int rc = WEXITSTATUS(status);
86
87 if (rc != 0)
88 tst_res(TFAIL, "test exited with %d", rc);
89 else
90 tst_res(TPASS, "endian_switch() syscall tests passed");
91 }
92 }
93
endian_test(void)94 static void endian_test(void)
95 {
96 check_le_switch_supported();
97 test_le_switch();
98 }
99
100 static struct tst_test test = {
101 .test_all = endian_test,
102 .forks_child = 1,
103 };
104
105 # else
106 TST_TEST_TCONF("Toolchain does not have <sys/auxv.h>");
107 # endif /* HAVE_GETAUXVAL */
108
109 #else /* defined (__powerpc64__) || (__powerpc__) */
110 TST_TEST_TCONF("This system does not support running of switch() syscall");
111 #endif
112