powerpc/security/flush_utils.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002
0003 /*
0004  * Copyright 2018 IBM Corporation.
0005  */
0006
0007 #define __SANE_USERSPACE_TYPES__
0008
0009 #include <sys/types.h>
0010 #include <stdint.h>
0011 #include <unistd.h>
0012 #include <signal.h>
0013 #include <stdlib.h>
0014 #include <string.h>
0015 #include <stdio.h>
0016 #include <sys/utsname.h>
0017 #include "utils.h"
0018 #include "flush_utils.h"
0019
0020 static inline __u64 load(void *addr)
0021 {
0022     __u64 tmp;
0023
0024     asm volatile("ld %0,0(%1)" : "=r"(tmp) : "b"(addr));
0025
0026     return tmp;
0027 }
0028
0029 void syscall_loop(char *p, unsigned long iterations,
0030           unsigned long zero_size)
0031 {
0032     for (unsigned long i = 0; i < iterations; i++) {
0033         for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE)
0034             load(p + j);
0035         getppid();
0036     }
0037 }
0038
0039 void syscall_loop_uaccess(char *p, unsigned long iterations,
0040               unsigned long zero_size)
0041 {
0042     struct utsname utsname;
0043
0044     for (unsigned long i = 0; i < iterations; i++) {
0045         for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE)
0046             load(p + j);
0047         uname(&utsname);
0048     }
0049 }
0050
0051 static void sigill_handler(int signr, siginfo_t *info, void *unused)
0052 {
0053     static int warned;
0054     ucontext_t *ctx = (ucontext_t *)unused;
0055     unsigned long *pc = &UCONTEXT_NIA(ctx);
0056
0057     /* mtspr 3,RS to check for move to DSCR below */
0058     if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
0059         if (!warned++)
0060             printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
0061         *pc += 4;
0062     } else {
0063         printf("SIGILL at %p\n", pc);
0064         abort();
0065     }
0066 }
0067
0068 void set_dscr(unsigned long val)
0069 {
0070     static int init;
0071     struct sigaction sa;
0072
0073     if (!init) {
0074         memset(&sa, 0, sizeof(sa));
0075         sa.sa_sigaction = sigill_handler;
0076         sa.sa_flags = SA_SIGINFO;
0077         if (sigaction(SIGILL, &sa, NULL))
0078             perror("sigill_handler");
0079         init = 1;
0080     }
0081
0082     asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
0083 }