1 /*
2 * Copyright 2014 Sony Mobile Communications Inc.
3 *
4 * Licensed under the terms of the GNU GPL License version 2
5 *
6 * Selftest for runtime system size
7 *
8 * Prints the amount of RAM that the currently running system is using.
9 *
10 * This program tries to be as small as possible itself, to
11 * avoid perturbing the system memory utilization with its
12 * own execution. It also attempts to have as few dependencies
13 * on kernel features as possible.
14 *
15 * It should be statically linked, with startup libs avoided. It uses
16 * no library calls except the syscall() function for the following 3
17 * syscalls:
18 * sysinfo(), write(), and _exit()
19 *
20 * For output, it avoids printf (which in some C libraries
21 * has large external dependencies) by implementing it's own
22 * number output and print routines, and using __builtin_strlen()
23 *
24 * The test may crash if any of the above syscalls fails because in some
25 * libc implementations (e.g. the GNU C Library) errno is saved in
26 * thread-local storage, which does not get initialized due to avoiding
27 * startup libs.
28 */
29
30 #include <sys/sysinfo.h>
31 #include <unistd.h>
32 #include <sys/syscall.h>
33
34 #define STDOUT_FILENO 1
35
print(const char * s)36 static int print(const char *s)
37 {
38 size_t len = 0;
39
40 while (s[len] != '\0')
41 len++;
42
43 return syscall(SYS_write, STDOUT_FILENO, s, len);
44 }
45
num_to_str(unsigned long num,char * buf,int len)46 static inline char *num_to_str(unsigned long num, char *buf, int len)
47 {
48 unsigned int digit;
49
50 /* put digits in buffer from back to front */
51 buf += len - 1;
52 *buf = 0;
53 do {
54 digit = num % 10;
55 *(--buf) = digit + '0';
56 num /= 10;
57 } while (num > 0);
58
59 return buf;
60 }
61
print_num(unsigned long num)62 static int print_num(unsigned long num)
63 {
64 char num_buf[30];
65
66 return print(num_to_str(num, num_buf, sizeof(num_buf)));
67 }
68
print_k_value(const char * s,unsigned long num,unsigned long units)69 static int print_k_value(const char *s, unsigned long num, unsigned long units)
70 {
71 unsigned long long temp;
72 int ccode;
73
74 print(s);
75
76 temp = num;
77 temp = (temp * units)/1024;
78 num = temp;
79 ccode = print_num(num);
80 print("\n");
81 return ccode;
82 }
83
84 /* this program has no main(), as startup libraries are not used */
_start(void)85 void _start(void)
86 {
87 int ccode;
88 struct sysinfo info;
89 unsigned long used;
90 static const char *test_name = " get runtime memory use\n";
91
92 print("TAP version 13\n");
93 print("# Testing system size.\n");
94
95 ccode = syscall(SYS_sysinfo, &info);
96 if (ccode < 0) {
97 print("not ok 1");
98 print(test_name);
99 print(" ---\n reason: \"could not get sysinfo\"\n ...\n");
100 syscall(SYS_exit, ccode);
101 }
102 print("ok 1");
103 print(test_name);
104
105 /* ignore cache complexities for now */
106 used = info.totalram - info.freeram - info.bufferram;
107 print("# System runtime memory report (units in Kilobytes):\n");
108 print(" ---\n");
109 print_k_value(" Total: ", info.totalram, info.mem_unit);
110 print_k_value(" Free: ", info.freeram, info.mem_unit);
111 print_k_value(" Buffer: ", info.bufferram, info.mem_unit);
112 print_k_value(" In use: ", used, info.mem_unit);
113 print(" ...\n");
114 print("1..1\n");
115
116 syscall(SYS_exit, 0);
117 }
118