1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2014 Sony Mobile Communications Inc. 4 * 5 * Selftest for runtime system size 6 * 7 * Prints the amount of RAM that the currently running system is using. 8 * 9 * This program tries to be as small as possible itself, to 10 * avoid perturbing the system memory utilization with its 11 * own execution. It also attempts to have as few dependencies 12 * on kernel features as possible. 13 * 14 * It should be statically linked, with startup libs avoided. It uses 15 * no library calls except the syscall() function for the following 3 16 * syscalls: 17 * sysinfo(), write(), and _exit() 18 * 19 * For output, it avoids printf (which in some C libraries 20 * has large external dependencies) by implementing it's own 21 * number output and print routines, and using __builtin_strlen() 22 * 23 * The test may crash if any of the above syscalls fails because in some 24 * libc implementations (e.g. the GNU C Library) errno is saved in 25 * thread-local storage, which does not get initialized due to avoiding 26 * startup libs. 27 */ 28 29 #include <sys/sysinfo.h> 30 #include <unistd.h> 31 #include <sys/syscall.h> 32 33 #define STDOUT_FILENO 1 34 35 static int print(const char *s) 36 { 37 size_t len = 0; 38 39 while (s[len] != '\0') 40 len++; 41 42 return syscall(SYS_write, STDOUT_FILENO, s, len); 43 } 44 45 static inline char *num_to_str(unsigned long num, char *buf, int len) 46 { 47 unsigned int digit; 48 49 /* put digits in buffer from back to front */ 50 buf += len - 1; 51 *buf = 0; 52 do { 53 digit = num % 10; 54 *(--buf) = digit + '0'; 55 num /= 10; 56 } while (num > 0); 57 58 return buf; 59 } 60 61 static int print_num(unsigned long num) 62 { 63 char num_buf[30]; 64 65 return print(num_to_str(num, num_buf, sizeof(num_buf))); 66 } 67 68 static int print_k_value(const char *s, unsigned long num, unsigned long units) 69 { 70 unsigned long long temp; 71 int ccode; 72 73 print(s); 74 75 temp = num; 76 temp = (temp * units)/1024; 77 num = temp; 78 ccode = print_num(num); 79 print("\n"); 80 return ccode; 81 } 82 83 /* this program has no main(), as startup libraries are not used */ 84 void _start(void) 85 { 86 int ccode; 87 struct sysinfo info; 88 unsigned long used; 89 static const char *test_name = " get runtime memory use\n"; 90 91 print("TAP version 13\n"); 92 print("# Testing system size.\n"); 93 94 ccode = syscall(SYS_sysinfo, &info); 95 if (ccode < 0) { 96 print("not ok 1"); 97 print(test_name); 98 print(" ---\n reason: \"could not get sysinfo\"\n ...\n"); 99 syscall(SYS_exit, ccode); 100 } 101 print("ok 1"); 102 print(test_name); 103 104 /* ignore cache complexities for now */ 105 used = info.totalram - info.freeram - info.bufferram; 106 print("# System runtime memory report (units in Kilobytes):\n"); 107 print(" ---\n"); 108 print_k_value(" Total: ", info.totalram, info.mem_unit); 109 print_k_value(" Free: ", info.freeram, info.mem_unit); 110 print_k_value(" Buffer: ", info.bufferram, info.mem_unit); 111 print_k_value(" In use: ", used, info.mem_unit); 112 print(" ...\n"); 113 print("1..1\n"); 114 115 syscall(SYS_exit, 0); 116 } 117