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

tm-sigreturn.c (2049B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3/*
      4 * Copyright 2015, Laurent Dufour, IBM Corp.
      5 *
      6 * Test the kernel's signal returning code to check reclaim is done if the
      7 * sigreturn() is called while in a transaction (suspended since active is
      8 * already dropped trough the system call path).
      9 *
     10 * The kernel must discard the transaction when entering sigreturn, since
     11 * restoring the potential TM SPRS from the signal frame is requiring to not be
     12 * in a transaction.
     13 */
     14
     15#include <signal.h>
     16#include <stdio.h>
     17#include <stdlib.h>
     18#include <string.h>
     19#include <sys/types.h>
     20#include <sys/wait.h>
     21#include <unistd.h>
     22
     23#include "tm.h"
     24#include "utils.h"
     25
     26
     27void handler(int sig)
     28{
     29	uint64_t ret;
     30
     31	asm __volatile__(
     32		"li             3,1             ;"
     33		"tbegin.                        ;"
     34		"beq            1f              ;"
     35		"li             3,0             ;"
     36		"tsuspend.                      ;"
     37		"1:                             ;"
     38		"std%X[ret]     3, %[ret]       ;"
     39		: [ret] "=m"(ret)
     40		:
     41		: "memory", "3", "cr0");
     42
     43	if (ret)
     44		exit(1);
     45
     46	/*
     47	 * We return from the signal handle while in a suspended transaction
     48	 */
     49}
     50
     51
     52int tm_sigreturn(void)
     53{
     54	struct sigaction sa;
     55	uint64_t ret = 0;
     56
     57	SKIP_IF(!have_htm());
     58	SKIP_IF(htm_is_synthetic());
     59	SKIP_IF(!is_ppc64le());
     60
     61	memset(&sa, 0, sizeof(sa));
     62	sa.sa_handler = handler;
     63	sigemptyset(&sa.sa_mask);
     64
     65	if (sigaction(SIGSEGV, &sa, NULL))
     66		exit(1);
     67
     68	asm __volatile__(
     69		"tbegin.                        ;"
     70		"beq            1f              ;"
     71		"li             3,0             ;"
     72		"std            3,0(3)          ;" /* trigger SEGV */
     73		"li             3,1             ;"
     74		"std%X[ret]     3,%[ret]        ;"
     75		"tend.                          ;"
     76		"b              2f              ;"
     77		"1:                             ;"
     78		"li             3,2             ;"
     79		"std%X[ret]     3,%[ret]        ;"
     80		"2:                             ;"
     81		: [ret] "=m"(ret)
     82		:
     83		: "memory", "3", "cr0");
     84
     85	if (ret != 2)
     86		exit(1);
     87
     88	exit(0);
     89}
     90
     91int main(void)
     92{
     93	return test_harness(tm_sigreturn, "tm_sigreturn");
     94}