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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright 2014 Sony Mobile Communications Inc.4 *5 * Selftest for runtime system size6 *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, to10 * avoid perturbing the system memory utilization with its11 * own execution. It also attempts to have as few dependencies12 * on kernel features as possible.13 *14 * It should be statically linked, with startup libs avoided. It uses15 * no library calls except the syscall() function for the following 316 * syscalls:17 * sysinfo(), write(), and _exit()18 *19 * For output, it avoids printf (which in some C libraries20 * has large external dependencies) by implementing it's own21 * number output and print routines, and using __builtin_strlen()22 *23 * The test may crash if any of the above syscalls fails because in some24 * libc implementations (e.g. the GNU C Library) errno is saved in25 * thread-local storage, which does not get initialized due to avoiding26 * startup libs.27 */28 29#include <sys/sysinfo.h>30#include <unistd.h>31#include <sys/syscall.h>32 33#define STDOUT_FILENO 134 35static 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 45static 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 61static 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 68static 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 */84void _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