cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tm-signal-context-chk-vmx.c (4063B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Copyright 2016, Cyril Bur, IBM Corp.
      4 *
      5 * Test the kernel's signal frame code.
      6 *
      7 * The kernel sets up two sets of ucontexts if the signal was to be
      8 * delivered while the thread was in a transaction (referred too as
      9 * first and second contexts).
     10 * Expected behaviour is that the checkpointed state is in the user
     11 * context passed to the signal handler (first context). The speculated
     12 * state can be accessed with the uc_link pointer (second context).
     13 *
     14 * The rationale for this is that if TM unaware code (which linked
     15 * against TM libs) installs a signal handler it will not know of the
     16 * speculative nature of the 'live' registers and may infer the wrong
     17 * thing.
     18 */
     19
     20#include <stdlib.h>
     21#include <stdio.h>
     22#include <string.h>
     23#include <signal.h>
     24#include <unistd.h>
     25
     26#include <altivec.h>
     27
     28#include "utils.h"
     29#include "tm.h"
     30
     31#define MAX_ATTEMPT 500000
     32
     33#define NV_VMX_REGS 12 /* Number of non-volatile VMX registers */
     34#define VMX20 20 /* First non-volatile register to check in vr20-31 subset */
     35
     36long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
     37
     38static sig_atomic_t fail, broken;
     39
     40/* Test only non-volatile registers, i.e. 12 vmx registers from vr20 to vr31 */
     41vector int vms[] = {
     42	/* First context will be set with these values, i.e. non-speculative */
     43	/* VMX20     ,  VMX21      , ... */
     44	{ 1, 2, 3, 4},{ 5, 6, 7, 8},{ 9,10,11,12},
     45	{13,14,15,16},{17,18,19,20},{21,22,23,24},
     46	{25,26,27,28},{29,30,31,32},{33,34,35,36},
     47	{37,38,39,40},{41,42,43,44},{45,46,47,48},
     48	/* Second context will be set with these values, i.e. speculative */
     49	/* VMX20        , VMX21            , ... */
     50	{ -1, -2, -3, -4},{ -5, -6, -7, -8},{ -9,-10,-11,-12},
     51	{-13,-14,-15,-16},{-17,-18,-19,-20},{-21,-22,-23,-24},
     52	{-25,-26,-27,-28},{-29,-30,-31,-32},{-33,-34,-35,-36},
     53	{-37,-38,-39,-40},{-41,-42,-43,-44},{-45,-46,-47,-48}
     54};
     55
     56static void signal_usr1(int signum, siginfo_t *info, void *uc)
     57{
     58	int i, j;
     59	ucontext_t *ucp = uc;
     60	ucontext_t *tm_ucp = ucp->uc_link;
     61
     62	for (i = 0; i < NV_VMX_REGS; i++) {
     63		/* Check first context. Print all mismatches. */
     64		fail = memcmp(ucp->uc_mcontext.v_regs->vrregs[VMX20 + i],
     65				&vms[i], sizeof(vector int));
     66		if (fail) {
     67			broken = 1;
     68			printf("VMX%d (1st context) == 0x", VMX20 + i);
     69			/* Print actual value in first context. */
     70			for (j = 0; j < 4; j++)
     71				printf("%08x", ucp->uc_mcontext.v_regs->vrregs[VMX20 + i][j]);
     72			printf(" instead of 0x");
     73			/* Print expected value. */
     74			for (j = 0; j < 4; j++)
     75				printf("%08x", vms[i][j]);
     76			printf(" (expected)\n");
     77		}
     78	}
     79
     80	for (i = 0; i < NV_VMX_REGS; i++)  {
     81		/* Check second context. Print all mismatches. */
     82		fail = memcmp(tm_ucp->uc_mcontext.v_regs->vrregs[VMX20 + i],
     83				&vms[NV_VMX_REGS + i], sizeof (vector int));
     84		if (fail) {
     85			broken = 1;
     86			printf("VMX%d (2nd context) == 0x", NV_VMX_REGS + i);
     87			/* Print actual value in second context. */
     88			for (j = 0; j < 4; j++)
     89				printf("%08x", tm_ucp->uc_mcontext.v_regs->vrregs[VMX20 + i][j]);
     90			printf(" instead of 0x");
     91			/* Print expected value. */
     92			for (j = 0; j < 4; j++)
     93				printf("%08x", vms[NV_VMX_REGS + i][j]);
     94			printf(" (expected)\n");
     95		}
     96	}
     97}
     98
     99static int tm_signal_context_chk()
    100{
    101	struct sigaction act;
    102	int i;
    103	long rc;
    104	pid_t pid = getpid();
    105
    106	SKIP_IF(!have_htm());
    107	SKIP_IF(htm_is_synthetic());
    108
    109	act.sa_sigaction = signal_usr1;
    110	sigemptyset(&act.sa_mask);
    111	act.sa_flags = SA_SIGINFO;
    112	if (sigaction(SIGUSR1, &act, NULL) < 0) {
    113		perror("sigaction sigusr1");
    114		exit(1);
    115	}
    116
    117	i = 0;
    118	while (i < MAX_ATTEMPT && !broken) {
    119		/*
    120		 * tm_signal_self_context_load will set both first and second
    121		 * contexts accordingly to the values passed through non-NULL
    122		 * array pointers to it, in that case 'vms', and invoke the
    123		 * signal handler installed for SIGUSR1.
    124		 */
    125		rc = tm_signal_self_context_load(pid, NULL, NULL, vms, NULL);
    126		FAIL_IF(rc != pid);
    127		i++;
    128	}
    129
    130	return (broken);
    131}
    132
    133int main(void)
    134{
    135	return test_harness(tm_signal_context_chk, "tm_signal_context_chk_vmx");
    136}