cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

get_size.c (2889B)

      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
     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}