// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2014 Sony Mobile Communications Inc.
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*
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* Selftest for runtime system size
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*
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* Prints the amount of RAM that the currently running system is using.
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*
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* This program tries to be as small as possible itself, to
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* avoid perturbing the system memory utilization with its
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* own execution. It also attempts to have as few dependencies
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* on kernel features as possible.
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*
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* It should be statically linked, with startup libs avoided. It uses
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* no library calls except the syscall() function for the following 3
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* syscalls:
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* sysinfo(), write(), and _exit()
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*
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* For output, it avoids printf (which in some C libraries
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* has large external dependencies) by implementing it's own
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* number output and print routines, and using __builtin_strlen()
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*
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* The test may crash if any of the above syscalls fails because in some
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* libc implementations (e.g. the GNU C Library) errno is saved in
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* thread-local storage, which does not get initialized due to avoiding
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* startup libs.
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*/
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#include <sys/sysinfo.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#define STDOUT_FILENO 1
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static int print(const char *s)
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{
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size_t len = 0;
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while (s[len] != '\0')
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len++;
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return syscall(SYS_write, STDOUT_FILENO, s, len);
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}
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static inline char *num_to_str(unsigned long num, char *buf, int len)
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{
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unsigned int digit;
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/* put digits in buffer from back to front */
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buf += len - 1;
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*buf = 0;
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do {
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digit = num % 10;
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*(--buf) = digit + '0';
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num /= 10;
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} while (num > 0);
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return buf;
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}
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static int print_num(unsigned long num)
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{
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char num_buf[30];
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return print(num_to_str(num, num_buf, sizeof(num_buf)));
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}
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static int print_k_value(const char *s, unsigned long num, unsigned long units)
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{
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unsigned long long temp;
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int ccode;
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print(s);
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temp = num;
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temp = (temp * units)/1024;
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num = temp;
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ccode = print_num(num);
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print("\n");
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return ccode;
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}
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/* this program has no main(), as startup libraries are not used */
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void _start(void)
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{
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int ccode;
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struct sysinfo info;
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unsigned long used;
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static const char *test_name = " get runtime memory use\n";
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print("TAP version 13\n");
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print("# Testing system size.\n");
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ccode = syscall(SYS_sysinfo, &info);
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if (ccode < 0) {
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print("not ok 1");
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print(test_name);
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print(" ---\n reason: \"could not get sysinfo\"\n ...\n");
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syscall(SYS_exit, ccode);
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}
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print("ok 1");
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print(test_name);
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/* ignore cache complexities for now */
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used = info.totalram - info.freeram - info.bufferram;
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print("# System runtime memory report (units in Kilobytes):\n");
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print(" ---\n");
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print_k_value(" Total: ", info.totalram, info.mem_unit);
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print_k_value(" Free: ", info.freeram, info.mem_unit);
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print_k_value(" Buffer: ", info.bufferram, info.mem_unit);
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print_k_value(" In use: ", used, info.mem_unit);
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print(" ...\n");
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print("1..1\n");
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syscall(SYS_exit, 0);
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}
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