x86/mpx, selftests: Add MPX self test

I've had this code for a while, but never submitted it upstream.  Now
that Skylake hardware is out in the wild, folks can actually run this
for real.  It tests the following:

	1. The MPX hardware is enabled by the kernel and doing what it
	   is supposed to
	2. The MPX management code is present and enabled in the kernel
	3. MPX Signal handling
	4. The MPX bounds table population code (on-demand population)
	5. The MPX bounds table unmapping code (kernel-initiated freeing
	   when unused)

This has also caught bugs in the XSAVE code because MPX state is
saved/restored with XSAVE.

I'm submitting it now because it would have caught the recent issues
with the compat_siginfo code not being properly augmented when new
siginfo state is added.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160608172535.5B40B0EE@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1585 insertions, 0 deletions

diff --git a/tools/testing/selftests/x86/mpx-mini-test.c b/tools/testing/selftests/x86/mpx-mini-test.c
new file mode 100644
index 000000000000..616ee9673339
--- /dev/null
+++ b/tools/testing/selftests/x86/mpx-mini-test.c
@@ -0,0 +1,1585 @@
+/*
+ * mpx-mini-test.c: routines to test Intel MPX (Memory Protection eXtentions)
+ *
+ * Written by:
+ * "Ren, Qiaowei" <qiaowei.ren@intel.com>
+ * "Wei, Gang" <gang.wei@intel.com>
+ * "Hansen, Dave" <dave.hansen@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2.
+ */
+
+/*
+ * 2014-12-05: Dave Hansen: fixed all of the compiler warnings, and made sure
+ *	       it works on 32-bit.
+ */
+
+int inspect_every_this_many_mallocs = 100;
+int zap_all_every_this_many_mallocs = 1000;
+
+#define _GNU_SOURCE
+#define _LARGEFILE64_SOURCE
+
+#include <string.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <signal.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <ucontext.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "mpx-hw.h"
+#include "mpx-debug.h"
+#include "mpx-mm.h"
+
+#ifndef __always_inline
+#define __always_inline inline __attribute__((always_inline)
+#endif
+
+#ifndef TEST_DURATION_SECS
+#define TEST_DURATION_SECS 3
+#endif
+
+void write_int_to(char *prefix, char *file, int int_to_write)
+{
+	char buf[100];
+	int fd = open(file, O_RDWR);
+	int len;
+	int ret;
+
+	assert(fd >= 0);
+	len = snprintf(buf, sizeof(buf), "%s%d", prefix, int_to_write);
+	assert(len >= 0);
+	assert(len < sizeof(buf));
+	ret = write(fd, buf, len);
+	assert(ret == len);
+	ret = close(fd);
+	assert(!ret);
+}
+
+void write_pid_to(char *prefix, char *file)
+{
+	write_int_to(prefix, file, getpid());
+}
+
+void trace_me(void)
+{
+/* tracing events dir */
+#define TED "/sys/kernel/debug/tracing/events/"
+/*
+	write_pid_to("common_pid=", TED "signal/filter");
+	write_pid_to("common_pid=", TED "exceptions/filter");
+	write_int_to("", TED "signal/enable", 1);
+	write_int_to("", TED "exceptions/enable", 1);
+*/
+	write_pid_to("", "/sys/kernel/debug/tracing/set_ftrace_pid");
+	write_int_to("", "/sys/kernel/debug/tracing/trace", 0);
+}
+
+#define test_failed() __test_failed(__FILE__, __LINE__)
+static void __test_failed(char *f, int l)
+{
+	fprintf(stderr, "abort @ %s::%d\n", f, l);
+	abort();
+}
+
+/* Error Printf */
+#define eprintf(args...)	fprintf(stderr, args)
+
+#ifdef __i386__
+
+/* i386 directory size is 4MB */
+#define REG_IP_IDX	REG_EIP
+#define REX_PREFIX
+
+#define XSAVE_OFFSET_IN_FPMEM	sizeof(struct _libc_fpstate)
+
+/*
+ * __cpuid() is from the Linux Kernel:
+ */
+static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
+		unsigned int *ecx, unsigned int *edx)
+{
+	/* ecx is often an input as well as an output. */
+	asm volatile(
+		"push %%ebx;"
+		"cpuid;"
+		"mov %%ebx, %1;"
+		"pop %%ebx"
+		: "=a" (*eax),
+		  "=g" (*ebx),
+		  "=c" (*ecx),
+		  "=d" (*edx)
+		: "0" (*eax), "2" (*ecx));
+}
+
+#else /* __i386__ */
+
+#define REG_IP_IDX	REG_RIP
+#define REX_PREFIX "0x48, "
+
+#define XSAVE_OFFSET_IN_FPMEM	0
+
+/*
+ * __cpuid() is from the Linux Kernel:
+ */
+static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
+		unsigned int *ecx, unsigned int *edx)
+{
+	/* ecx is often an input as well as an output. */
+	asm volatile(
+		"cpuid;"
+		: "=a" (*eax),
+		  "=b" (*ebx),
+		  "=c" (*ecx),
+		  "=d" (*edx)
+		: "0" (*eax), "2" (*ecx));
+}
+
+#endif /* !__i386__ */
+
+struct xsave_hdr_struct {
+	uint64_t xstate_bv;
+	uint64_t reserved1[2];
+	uint64_t reserved2[5];
+} __attribute__((packed));
+
+struct bndregs_struct {
+	uint64_t bndregs[8];
+} __attribute__((packed));
+
+struct bndcsr_struct {
+	uint64_t cfg_reg_u;
+	uint64_t status_reg;
+} __attribute__((packed));
+
+struct xsave_struct {
+	uint8_t fpu_sse[512];
+	struct xsave_hdr_struct xsave_hdr;
+	uint8_t ymm[256];
+	uint8_t lwp[128];
+	struct bndregs_struct bndregs;
+	struct bndcsr_struct bndcsr;
+} __attribute__((packed));
+
+uint8_t __attribute__((__aligned__(64))) buffer[4096];
+struct xsave_struct *xsave_buf = (struct xsave_struct *)buffer;
+
+uint8_t __attribute__((__aligned__(64))) test_buffer[4096];
+struct xsave_struct *xsave_test_buf = (struct xsave_struct *)test_buffer;
+
+uint64_t num_bnd_chk;
+
+static __always_inline void xrstor_state(struct xsave_struct *fx, uint64_t mask)
+{
+	uint32_t lmask = mask;
+	uint32_t hmask = mask >> 32;
+
+	asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
+		     : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+		     :   "memory");
+}
+
+static __always_inline void xsave_state_1(void *_fx, uint64_t mask)
+{
+	uint32_t lmask = mask;
+	uint32_t hmask = mask >> 32;
+	unsigned char *fx = _fx;
+
+	asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
+		     : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+		     :   "memory");
+}
+
+static inline uint64_t xgetbv(uint32_t index)
+{
+	uint32_t eax, edx;
+
+	asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
+		     : "=a" (eax), "=d" (edx)
+		     : "c" (index));
+	return eax + ((uint64_t)edx << 32);
+}
+
+static uint64_t read_mpx_status_sig(ucontext_t *uctxt)
+{
+	memset(buffer, 0, sizeof(buffer));
+	memcpy(buffer,
+		(uint8_t *)uctxt->uc_mcontext.fpregs + XSAVE_OFFSET_IN_FPMEM,
+		sizeof(struct xsave_struct));
+
+	return xsave_buf->bndcsr.status_reg;
+}
+
+#include <pthread.h>
+
+static uint8_t *get_next_inst_ip(uint8_t *addr)
+{
+	uint8_t *ip = addr;
+	uint8_t sib;
+	uint8_t rm;
+	uint8_t mod;
+	uint8_t base;
+	uint8_t modrm;
+
+	/* determine the prefix. */
+	switch(*ip) {
+	case 0xf2:
+	case 0xf3:
+	case 0x66:
+		ip++;
+		break;
+	}
+
+	/* look for rex prefix */
+	if ((*ip & 0x40) == 0x40)
+		ip++;
+
+	/* Make sure we have a MPX instruction. */
+	if (*ip++ != 0x0f)
+		return addr;
+
+	/* Skip the op code byte. */
+	ip++;
+
+	/* Get the modrm byte. */
+	modrm = *ip++;
+
+	/* Break it down into parts. */
+	rm = modrm & 7;
+	mod = (modrm >> 6);
+
+	/* Init the parts of the address mode. */
+	base = 8;
+
+	/* Is it a mem mode? */
+	if (mod != 3) {
+		/* look for scaled indexed addressing */
+		if (rm == 4) {
+			/* SIB addressing */
+			sib = *ip++;
+			base = sib & 7;
+			switch (mod) {
+			case 0:
+				if (base == 5)
+					ip += 4;
+				break;
+
+			case 1:
+				ip++;
+				break;
+
+			case 2:
+				ip += 4;
+				break;
+			}
+
+		} else {
+			/* MODRM addressing */
+			switch (mod) {
+			case 0:
+				/* DISP32 addressing, no base */
+				if (rm == 5)
+					ip += 4;
+				break;
+
+			case 1:
+				ip++;
+				break;
+
+			case 2:
+				ip += 4;
+				break;
+			}
+		}
+	}
+	return ip;
+}
+
+#ifdef si_lower
+static inline void *__si_bounds_lower(siginfo_t *si)
+{
+	return si->si_lower;
+}
+
+static inline void *__si_bounds_upper(siginfo_t *si)
+{
+	return si->si_upper;
+}
+#else
+static inline void **__si_bounds_hack(siginfo_t *si)
+{
+	void *sigfault = &si->_sifields._sigfault;
+	void *end_sigfault = sigfault + sizeof(si->_sifields._sigfault);
+	void **__si_lower = end_sigfault;
+
+	return __si_lower;
+}
+
+static inline void *__si_bounds_lower(siginfo_t *si)
+{
+	return *__si_bounds_hack(si);
+}
+
+static inline void *__si_bounds_upper(siginfo_t *si)
+{
+	return (*__si_bounds_hack(si)) + sizeof(void *);
+}
+#endif
+
+static int br_count;
+static int expected_bnd_index = -1;
+uint64_t shadow_plb[NR_MPX_BOUNDS_REGISTERS][2]; /* shadow MPX bound registers */
+unsigned long shadow_map[NR_MPX_BOUNDS_REGISTERS];
+
+/*
+ * The kernel is supposed to provide some information about the bounds
+ * exception in the siginfo.  It should match what we have in the bounds
+ * registers that we are checking against.  Just check against the shadow copy
+ * since it is easily available, and we also check that *it* matches the real
+ * registers.
+ */
+void check_siginfo_vs_shadow(siginfo_t* si)
+{
+	int siginfo_ok = 1;
+	void *shadow_lower = (void *)(unsigned long)shadow_plb[expected_bnd_index][0];
+	void *shadow_upper = (void *)(unsigned long)shadow_plb[expected_bnd_index][1];
+
+	if ((expected_bnd_index < 0) ||
+	    (expected_bnd_index >= NR_MPX_BOUNDS_REGISTERS)) {
+		fprintf(stderr, "ERROR: invalid expected_bnd_index: %d\n",
+			expected_bnd_index);
+		exit(6);
+	}
+	if (__si_bounds_lower(si) != shadow_lower)
+		siginfo_ok = 0;
+	if (__si_bounds_upper(si) != shadow_upper)
+		siginfo_ok = 0;
+
+	if (!siginfo_ok) {
+		fprintf(stderr, "ERROR: siginfo bounds do not match "
+			"shadow bounds for register %d\n", expected_bnd_index);
+		exit(7);
+	}
+}
+
+void handler(int signum, siginfo_t *si, void *vucontext)
+{
+	int i;
+	ucontext_t *uctxt = vucontext;
+	int trapno;
+	unsigned long ip;
+
+	dprintf1("entered signal handler\n");
+
+	trapno = uctxt->uc_mcontext.gregs[REG_TRAPNO];
+	ip = uctxt->uc_mcontext.gregs[REG_IP_IDX];
+
+	if (trapno == 5) {
+		typeof(si->si_addr) *si_addr_ptr = &si->si_addr;
+		uint64_t status = read_mpx_status_sig(uctxt);
+		uint64_t br_reason =  status & 0x3;
+
+		br_count++;
+		dprintf1("#BR 0x%jx (total seen: %d)\n", status, br_count);
+
+#define __SI_FAULT      (3 << 16)
+#define SEGV_BNDERR     (__SI_FAULT|3)  /* failed address bound checks */
+
+		dprintf2("Saw a #BR! status 0x%jx at %016lx br_reason: %jx\n",
+				status, ip, br_reason);
+		dprintf2("si_signo: %d\n", si->si_signo);
+		dprintf2("  signum: %d\n", signum);
+		dprintf2("info->si_code == SEGV_BNDERR: %d\n",
+				(si->si_code == SEGV_BNDERR));
+		dprintf2("info->si_code: %d\n", si->si_code);
+		dprintf2("info->si_lower: %p\n", __si_bounds_lower(si));
+		dprintf2("info->si_upper: %p\n", __si_bounds_upper(si));
+
+		check_siginfo_vs_shadow(si);
+
+		for (i = 0; i < 8; i++)
+			dprintf3("[%d]: %p\n", i, si_addr_ptr[i]);
+		switch (br_reason) {
+		case 0: /* traditional BR */
+			fprintf(stderr,
+				"Undefined status with bound exception:%jx\n",
+				 status);
+			exit(5);
+		case 1: /* #BR MPX bounds exception */
+			/* these are normal and we expect to see them */
+			dprintf1("bounds exception (normal): status 0x%jx at %p si_addr: %p\n",
+				status, (void *)ip, si->si_addr);
+			num_bnd_chk++;
+			uctxt->uc_mcontext.gregs[REG_IP_IDX] =
+				(greg_t)get_next_inst_ip((uint8_t *)ip);
+			break;
+		case 2:
+			fprintf(stderr, "#BR status == 2, missing bounds table,"
+					"kernel should have handled!!\n");
+			exit(4);
+			break;
+		default:
+			fprintf(stderr, "bound check error: status 0x%jx at %p\n",
+				status, (void *)ip);
+			num_bnd_chk++;
+			uctxt->uc_mcontext.gregs[REG_IP_IDX] =
+				(greg_t)get_next_inst_ip((uint8_t *)ip);
+			fprintf(stderr, "bound check error: si_addr %p\n", si->si_addr);
+			exit(3);
+		}
+	} else if (trapno == 14) {
+		eprintf("ERROR: In signal handler, page fault, trapno = %d, ip = %016lx\n",
+			trapno, ip);
+		eprintf("si_addr %p\n", si->si_addr);
+		eprintf("REG_ERR: %lx\n", (unsigned long)uctxt->uc_mcontext.gregs[REG_ERR]);
+		test_failed();
+	} else {
+		eprintf("unexpected trap %d! at 0x%lx\n", trapno, ip);
+		eprintf("si_addr %p\n", si->si_addr);
+		eprintf("REG_ERR: %lx\n", (unsigned long)uctxt->uc_mcontext.gregs[REG_ERR]);
+		test_failed();
+	}
+}
+
+static inline void cpuid_count(unsigned int op, int count,
+			       unsigned int *eax, unsigned int *ebx,
+			       unsigned int *ecx, unsigned int *edx)
+{
+	*eax = op;
+	*ecx = count;
+	__cpuid(eax, ebx, ecx, edx);
+}
+
+#define XSTATE_CPUID	    0x0000000d
+
+/*
+ * List of XSAVE features Linux knows about:
+ */
+enum xfeature_bit {
+	XSTATE_BIT_FP,
+	XSTATE_BIT_SSE,
+	XSTATE_BIT_YMM,
+	XSTATE_BIT_BNDREGS,
+	XSTATE_BIT_BNDCSR,
+	XSTATE_BIT_OPMASK,
+	XSTATE_BIT_ZMM_Hi256,
+	XSTATE_BIT_Hi16_ZMM,
+
+	XFEATURES_NR_MAX,
+};
+
+#define XSTATE_FP	       (1 << XSTATE_BIT_FP)
+#define XSTATE_SSE	      (1 << XSTATE_BIT_SSE)
+#define XSTATE_YMM	      (1 << XSTATE_BIT_YMM)
+#define XSTATE_BNDREGS	  (1 << XSTATE_BIT_BNDREGS)
+#define XSTATE_BNDCSR	   (1 << XSTATE_BIT_BNDCSR)
+#define XSTATE_OPMASK	   (1 << XSTATE_BIT_OPMASK)
+#define XSTATE_ZMM_Hi256	(1 << XSTATE_BIT_ZMM_Hi256)
+#define XSTATE_Hi16_ZMM	 (1 << XSTATE_BIT_Hi16_ZMM)
+
+#define MPX_XSTATES		(XSTATE_BNDREGS | XSTATE_BNDCSR) /* 0x18 */
+
+bool one_bit(unsigned int x, int bit)
+{
+	return !!(x & (1<<bit));
+}
+
+void print_state_component(int state_bit_nr, char *name)
+{
+	unsigned int eax, ebx, ecx, edx;
+	unsigned int state_component_size;
+	unsigned int state_component_supervisor;
+	unsigned int state_component_user;
+	unsigned int state_component_aligned;
+
+	/* See SDM Section 13.2 */
+	cpuid_count(XSTATE_CPUID, state_bit_nr, &eax, &ebx, &ecx, &edx);
+	assert(eax || ebx || ecx);
+	state_component_size = eax;
+	state_component_supervisor = ((!ebx) && one_bit(ecx, 0));
+	state_component_user = !one_bit(ecx, 0);
+	state_component_aligned = one_bit(ecx, 1);
+	printf("%8s: size: %d user: %d supervisor: %d aligned: %d\n",
+		name,
+		state_component_size,	    state_component_user,
+		state_component_supervisor, state_component_aligned);
+
+}
+
+/* Intel-defined CPU features, CPUID level 0x00000001 (ecx) */
+#define XSAVE_FEATURE_BIT       (26)  /* XSAVE/XRSTOR/XSETBV/XGETBV */
+#define OSXSAVE_FEATURE_BIT     (27) /* XSAVE enabled in the OS */
+
+bool check_mpx_support(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+
+	cpuid_count(1, 0, &eax, &ebx, &ecx, &edx);
+
+	/* We can't do much without XSAVE, so just make these assert()'s */
+	if (!one_bit(ecx, XSAVE_FEATURE_BIT)) {
+		fprintf(stderr, "processor lacks XSAVE, can not run MPX tests\n");
+		exit(0);
+	}
+
+	if (!one_bit(ecx, OSXSAVE_FEATURE_BIT)) {
+		fprintf(stderr, "processor lacks OSXSAVE, can not run MPX tests\n");
+		exit(0);
+	}
+
+	/* CPUs not supporting the XSTATE CPUID leaf do not support MPX */
+	/* Is this redundant with the feature bit checks? */
+	cpuid_count(0, 0, &eax, &ebx, &ecx, &edx);
+	if (eax < XSTATE_CPUID) {
+		fprintf(stderr, "processor lacks XSTATE CPUID leaf,"
+				" can not run MPX tests\n");
+		exit(0);
+	}
+
+	printf("XSAVE is supported by HW & OS\n");
+
+	cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
+
+	printf("XSAVE processor supported state mask: 0x%x\n", eax);
+	printf("XSAVE OS supported state mask: 0x%jx\n", xgetbv(0));
+
+	/* Make sure that the MPX states are enabled in in XCR0 */
+	if ((eax & MPX_XSTATES) != MPX_XSTATES) {
+		fprintf(stderr, "processor lacks MPX XSTATE(s), can not run MPX tests\n");
+		exit(0);
+	}
+
+	/* Make sure the MPX states are supported by XSAVE* */
+	if ((xgetbv(0) & MPX_XSTATES) != MPX_XSTATES) {
+		fprintf(stderr, "MPX XSTATE(s) no enabled in XCR0, "
+				"can not run MPX tests\n");
+		exit(0);
+	}
+
+	print_state_component(XSTATE_BIT_BNDREGS, "BNDREGS");
+	print_state_component(XSTATE_BIT_BNDCSR,  "BNDCSR");
+
+	return true;
+}
+
+void enable_mpx(void *l1base)
+{
+	/* enable point lookup */
+	memset(buffer, 0, sizeof(buffer));
+	xrstor_state(xsave_buf, 0x18);
+
+	xsave_buf->xsave_hdr.xstate_bv = 0x10;
+	xsave_buf->bndcsr.cfg_reg_u = (unsigned long)l1base | 1;
+	xsave_buf->bndcsr.status_reg = 0;
+
+	dprintf2("bf xrstor\n");
+	dprintf2("xsave cndcsr: status %jx, configu %jx\n",
+	       xsave_buf->bndcsr.status_reg, xsave_buf->bndcsr.cfg_reg_u);
+	xrstor_state(xsave_buf, 0x18);
+	dprintf2("after xrstor\n");
+
+	xsave_state_1(xsave_buf, 0x18);
+
+	dprintf1("xsave bndcsr: status %jx, configu %jx\n",
+	       xsave_buf->bndcsr.status_reg, xsave_buf->bndcsr.cfg_reg_u);
+}
+
+#include <sys/prctl.h>
+
+struct mpx_bounds_dir *bounds_dir_ptr;
+
+unsigned long __bd_incore(const char *func, int line)
+{
+	unsigned long ret = nr_incore(bounds_dir_ptr, MPX_BOUNDS_DIR_SIZE_BYTES);
+	return ret;
+}
+#define bd_incore() __bd_incore(__func__, __LINE__)
+
+void check_clear(void *ptr, unsigned long sz)
+{
+	unsigned long *i;
+
+	for (i = ptr; (void *)i < ptr + sz; i++) {
+		if (*i) {
+			dprintf1("%p is NOT clear at %p\n", ptr, i);
+			assert(0);
+		}
+	}
+	dprintf1("%p is clear for %lx\n", ptr, sz);
+}
+
+void check_clear_bd(void)
+{
+	check_clear(bounds_dir_ptr, 2UL << 30);
+}
+
+#define USE_MALLOC_FOR_BOUNDS_DIR 1
+bool process_specific_init(void)
+{
+	unsigned long size;
+	unsigned long *dir;
+	/* Guarantee we have the space to align it, add padding: */
+	unsigned long pad = getpagesize();
+
+	size = 2UL << 30; /* 2GB */
+	if (sizeof(unsigned long) == 4)
+		size = 4UL << 20; /* 4MB */
+	dprintf1("trying to allocate %ld MB bounds directory\n", (size >> 20));
+
+	if (USE_MALLOC_FOR_BOUNDS_DIR) {
+		unsigned long _dir;
+
+		dir = malloc(size + pad);
+		assert(dir);
+		_dir = (unsigned long)dir;
+		_dir += 0xfffUL;
+		_dir &= ~0xfffUL;
+		dir = (void *)_dir;
+	} else {
+		/*
+		 * This makes debugging easier because the address
+		 * calculations are simpler:
+		 */
+		dir = mmap((void *)0x200000000000, size + pad,
+				PROT_READ|PROT_WRITE,
+				MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+		if (dir == (void *)-1) {
+			perror("unable to allocate bounds directory");
+			abort();
+		}
+		check_clear(dir, size);
+	}
+	bounds_dir_ptr = (void *)dir;
+	madvise(bounds_dir_ptr, size, MADV_NOHUGEPAGE);
+	bd_incore();
+	dprintf1("bounds directory: 0x%p -> 0x%p\n", bounds_dir_ptr,
+			(char *)bounds_dir_ptr + size);
+	check_clear(dir, size);
+	enable_mpx(dir);
+	check_clear(dir, size);
+	if (prctl(43, 0, 0, 0, 0)) {
+		printf("no MPX support\n");
+		abort();
+		return false;
+	}
+	return true;
+}
+
+bool process_specific_finish(void)
+{
+	if (prctl(44)) {
+		printf("no MPX support\n");
+		return false;
+	}
+	return true;
+}
+
+void setup_handler()
+{
+	int r, rs;
+	struct sigaction newact;
+	struct sigaction oldact;
+
+	/* #BR is mapped to sigsegv */
+	int signum  = SIGSEGV;
+
+	newact.sa_handler = 0;   /* void(*)(int)*/
+	newact.sa_sigaction = handler; /* void (*)(int, siginfo_t*, void *) */
+
+	/*sigset_t - signals to block while in the handler */
+	/* get the old signal mask. */
+	rs = sigprocmask(SIG_SETMASK, 0, &newact.sa_mask);
+	assert(rs == 0);
+
+	/* call sa_sigaction, not sa_handler*/
+	newact.sa_flags = SA_SIGINFO;
+
+	newact.sa_restorer = 0;  /* void(*)(), obsolete */
+	r = sigaction(signum, &newact, &oldact);
+	assert(r == 0);
+}
+
+void mpx_prepare(void)
+{
+	dprintf2("%s()\n", __func__);
+	setup_handler();
+	process_specific_init();
+}
+
+void mpx_cleanup(void)
+{
+	printf("%s(): %jd BRs. bye...\n", __func__, num_bnd_chk);
+	process_specific_finish();
+}
+
+/*-------------- the following is test case ---------------*/
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+
+uint64_t num_lower_brs;
+uint64_t num_upper_brs;
+
+#define MPX_CONFIG_OFFSET 1024
+#define MPX_BOUNDS_OFFSET 960
+#define MPX_HEADER_OFFSET 512
+#define MAX_ADDR_TESTED (1<<28)
+#define TEST_ROUNDS 100
+
+/*
+      0F 1A /r BNDLDX-Load
+      0F 1B /r BNDSTX-Store Extended Bounds Using Address Translation
+   66 0F 1A /r BNDMOV bnd1, bnd2/m128
+   66 0F 1B /r BNDMOV bnd1/m128, bnd2
+   F2 0F 1A /r BNDCU bnd, r/m64
+   F2 0F 1B /r BNDCN bnd, r/m64
+   F3 0F 1A /r BNDCL bnd, r/m64
+   F3 0F 1B /r BNDMK bnd, m64
+*/
+
+static __always_inline void xsave_state(void *_fx, uint64_t mask)
+{
+	uint32_t lmask = mask;
+	uint32_t hmask = mask >> 32;
+	unsigned char *fx = _fx;
+
+	asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
+		     : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+		     :   "memory");
+}
+
+static __always_inline void mpx_clear_bnd0(void)
+{
+	long size = 0;
+	void *ptr = NULL;
+	/* F3 0F 1B /r BNDMK bnd, m64			*/
+	/* f3 0f 1b 04 11    bndmk  (%rcx,%rdx,1),%bnd0	*/
+	asm volatile(".byte 0xf3,0x0f,0x1b,0x04,0x11\n\t"
+		     : : "c" (ptr), "d" (size-1)
+		     :   "memory");
+}
+
+static __always_inline void mpx_make_bound_helper(unsigned long ptr,
+		unsigned long size)
+{
+	/* F3 0F 1B /r		BNDMK bnd, m64			*/
+	/* f3 0f 1b 04 11       bndmk  (%rcx,%rdx,1),%bnd0	*/
+	asm volatile(".byte 0xf3,0x0f,0x1b,0x04,0x11\n\t"
+		     : : "c" (ptr), "d" (size-1)
+		     :   "memory");
+}
+
+static __always_inline void mpx_check_lowerbound_helper(unsigned long ptr)
+{
+	/* F3 0F 1A /r	NDCL bnd, r/m64			*/
+	/* f3 0f 1a 01	bndcl  (%rcx),%bnd0		*/
+	asm volatile(".byte 0xf3,0x0f,0x1a,0x01\n\t"
+		     : : "c" (ptr)
+		     :   "memory");
+}
+
+static __always_inline void mpx_check_upperbound_helper(unsigned long ptr)
+{
+	/* F2 0F 1A /r	BNDCU bnd, r/m64	*/
+	/* f2 0f 1a 01	bndcu  (%rcx),%bnd0	*/
+	asm volatile(".byte 0xf2,0x0f,0x1a,0x01\n\t"
+		     : : "c" (ptr)
+		     :   "memory");
+}
+
+static __always_inline void mpx_movbndreg_helper()
+{
+	/* 66 0F 1B /r	BNDMOV bnd1/m128, bnd2	*/
+	/* 66 0f 1b c2	bndmov %bnd0,%bnd2	*/
+
+	asm volatile(".byte 0x66,0x0f,0x1b,0xc2\n\t");
+}
+
+static __always_inline void mpx_movbnd2mem_helper(uint8_t *mem)
+{
+	/* 66 0F 1B /r	BNDMOV bnd1/m128, bnd2	*/
+	/* 66 0f 1b 01	bndmov %bnd0,(%rcx)	*/
+	asm volatile(".byte 0x66,0x0f,0x1b,0x01\n\t"
+		     : : "c" (mem)
+		     :   "memory");
+}
+
+static __always_inline void mpx_movbnd_from_mem_helper(uint8_t *mem)
+{
+	/* 66 0F 1A /r	BNDMOV bnd1, bnd2/m128	*/
+	/* 66 0f 1a 01	bndmov (%rcx),%bnd0	*/
+	asm volatile(".byte 0x66,0x0f,0x1a,0x01\n\t"
+		     : : "c" (mem)
+		     :   "memory");
+}
+
+static __always_inline void mpx_store_dsc_helper(unsigned long ptr_addr,
+		unsigned long ptr_val)
+{
+	/* 0F 1B /r	BNDSTX-Store Extended Bounds Using Address Translation	*/
+	/* 0f 1b 04 11	bndstx %bnd0,(%rcx,%rdx,1)				*/
+	asm volatile(".byte 0x0f,0x1b,0x04,0x11\n\t"
+		     : : "c" (ptr_addr), "d" (ptr_val)
+		     :   "memory");
+}
+
+static __always_inline void mpx_load_dsc_helper(unsigned long ptr_addr,
+		unsigned long ptr_val)
+{
+	/* 0F 1A /r	BNDLDX-Load			*/
+	/*/ 0f 1a 04 11	bndldx (%rcx,%rdx,1),%bnd0	*/
+	asm volatile(".byte 0x0f,0x1a,0x04,0x11\n\t"
+		     : : "c" (ptr_addr), "d" (ptr_val)
+		     :   "memory");
+}
+
+void __print_context(void *__print_xsave_buffer, int line)
+{
+	uint64_t *bounds = (uint64_t *)(__print_xsave_buffer + MPX_BOUNDS_OFFSET);
+	uint64_t *cfg    = (uint64_t *)(__print_xsave_buffer + MPX_CONFIG_OFFSET);
+
+	int i;
+	eprintf("%s()::%d\n", "print_context", line);
+	for (i = 0; i < 4; i++) {
+		eprintf("bound[%d]: 0x%016lx 0x%016lx(0x%016lx)\n", i,
+		       (unsigned long)bounds[i*2],
+		       ~(unsigned long)bounds[i*2+1],
+			(unsigned long)bounds[i*2+1]);
+	}
+
+	eprintf("cpcfg: %jx  cpstatus: %jx\n", cfg[0], cfg[1]);
+}
+#define print_context(x) __print_context(x, __LINE__)
+#ifdef DEBUG
+#define dprint_context(x) print_context(x)
+#else
+#define dprint_context(x) do{}while(0)
+#endif
+
+void init()
+{
+	int i;
+
+	srand((unsigned int)time(NULL));
+
+	for (i = 0; i < 4; i++) {
+		shadow_plb[i][0] = 0;
+		shadow_plb[i][1] = ~(unsigned long)0;
+	}
+}
+
+long int __mpx_random(int line)
+{
+#ifdef NOT_SO_RANDOM
+	static long fake = 722122311;
+	fake += 563792075;
+	return fakse;
+#else
+	return random();
+#endif
+}
+#define mpx_random() __mpx_random(__LINE__)
+
+uint8_t *get_random_addr()
+{
+	uint8_t*addr = (uint8_t *)(unsigned long)(rand() % MAX_ADDR_TESTED);
+	return (addr - (unsigned long)addr % sizeof(uint8_t *));
+}
+
+static inline bool compare_context(void *__xsave_buffer)
+{
+	uint64_t *bounds = (uint64_t *)(__xsave_buffer + MPX_BOUNDS_OFFSET);
+
+	int i;
+	for (i = 0; i < 4; i++) {
+		dprintf3("shadow[%d]{%016lx/%016lx}\nbounds[%d]{%016lx/%016lx}\n",
+		       i, (unsigned long)shadow_plb[i][0], (unsigned long)shadow_plb[i][1],
+		       i, (unsigned long)bounds[i*2],     ~(unsigned long)bounds[i*2+1]);
+		if ((shadow_plb[i][0] != bounds[i*2]) ||
+		    (shadow_plb[i][1] != ~(unsigned long)bounds[i*2+1])) {
+			eprintf("ERROR comparing shadow to real bound register %d\n", i);
+			eprintf("shadow{0x%016lx/0x%016lx}\nbounds{0x%016lx/0x%016lx}\n",
+			       (unsigned long)shadow_plb[i][0], (unsigned long)shadow_plb[i][1],
+			       (unsigned long)bounds[i*2], (unsigned long)bounds[i*2+1]);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+void mkbnd_shadow(uint8_t *ptr, int index, long offset)
+{
+	uint64_t *lower = (uint64_t *)&(shadow_plb[index][0]);
+	uint64_t *upper = (uint64_t *)&(shadow_plb[index][1]);
+	*lower = (unsigned long)ptr;
+	*upper = (unsigned long)ptr + offset - 1;
+}
+
+void check_lowerbound_shadow(uint8_t *ptr, int index)
+{
+	uint64_t *lower = (uint64_t *)&(shadow_plb[index][0]);
+	if (*lower > (uint64_t)(unsigned long)ptr)
+		num_lower_brs++;
+	else
+		dprintf1("LowerBoundChk passed:%p\n", ptr);
+}
+
+void check_upperbound_shadow(uint8_t *ptr, int index)
+{
+	uint64_t upper = *(uint64_t *)&(shadow_plb[index][1]);
+	if (upper < (uint64_t)(unsigned long)ptr)
+		num_upper_brs++;
+	else
+		dprintf1("UpperBoundChk passed:%p\n", ptr);
+}
+
+__always_inline void movbndreg_shadow(int src, int dest)
+{
+	shadow_plb[dest][0] = shadow_plb[src][0];
+	shadow_plb[dest][1] = shadow_plb[src][1];
+}
+
+__always_inline void movbnd2mem_shadow(int src, unsigned long *dest)
+{
+	unsigned long *lower = (unsigned long *)&(shadow_plb[src][0]);
+	unsigned long *upper = (unsigned long *)&(shadow_plb[src][1]);
+	*dest = *lower;
+	*(dest+1) = *upper;
+}
+
+__always_inline void movbnd_from_mem_shadow(unsigned long *src, int dest)
+{
+	unsigned long *lower = (unsigned long *)&(shadow_plb[dest][0]);
+	unsigned long *upper = (unsigned long *)&(shadow_plb[dest][1]);
+	*lower = *src;
+	*upper = *(src+1);
+}
+
+__always_inline void stdsc_shadow(int index, uint8_t *ptr, uint8_t *ptr_val)
+{
+	shadow_map[0] = (unsigned long)shadow_plb[index][0];
+	shadow_map[1] = (unsigned long)shadow_plb[index][1];
+	shadow_map[2] = (unsigned long)ptr_val;
+	dprintf3("%s(%d, %p, %p) set shadow map[2]: %p\n", __func__,
+			index, ptr, ptr_val, ptr_val);
+	/*ptr ignored */
+}
+
+void lddsc_shadow(int index, uint8_t *ptr, uint8_t *ptr_val)
+{
+	uint64_t lower = shadow_map[0];
+	uint64_t upper = shadow_map[1];
+	uint8_t *value = (uint8_t *)shadow_map[2];
+
+	if (value != ptr_val) {
+		dprintf2("%s(%d, %p, %p) init shadow bounds[%d] "
+			 "because %p != %p\n", __func__, index, ptr,
+			 ptr_val, index, value, ptr_val);
+		shadow_plb[index][0] = 0;
+		shadow_plb[index][1] = ~(unsigned long)0;
+	} else {
+		shadow_plb[index][0] = lower;
+		shadow_plb[index][1] = upper;
+	}
+	/* ptr ignored */
+}
+
+static __always_inline void mpx_test_helper0(uint8_t *buf, uint8_t *ptr)
+{
+	mpx_make_bound_helper((unsigned long)ptr, 0x1800);
+}
+
+static __always_inline void mpx_test_helper0_shadow(uint8_t *buf, uint8_t *ptr)
+{
+	mkbnd_shadow(ptr, 0, 0x1800);
+}
+
+static __always_inline void mpx_test_helper1(uint8_t *buf, uint8_t *ptr)
+{
+	/* these are hard-coded to check bnd0 */
+	expected_bnd_index = 0;
+	mpx_check_lowerbound_helper((unsigned long)(ptr-1));
+	mpx_check_upperbound_helper((unsigned long)(ptr+0x1800));
+	/* reset this since we do not expect any more bounds exceptions */
+	expected_bnd_index = -1;
+}
+
+static __always_inline void mpx_test_helper1_shadow(uint8_t *buf, uint8_t *ptr)
+{
+	check_lowerbound_shadow(ptr-1, 0);
+	check_upperbound_shadow(ptr+0x1800, 0);
+}
+
+static __always_inline void mpx_test_helper2(uint8_t *buf, uint8_t *ptr)
+{
+	mpx_make_bound_helper((unsigned long)ptr, 0x1800);
+	mpx_movbndreg_helper();
+	mpx_movbnd2mem_helper(buf);
+	mpx_make_bound_helper((unsigned long)(ptr+0x12), 0x1800);
+}
+
+static __always_inline void mpx_test_helper2_shadow(uint8_t *buf, uint8_t *ptr)
+{
+	mkbnd_shadow(ptr, 0, 0x1800);
+	movbndreg_shadow(0, 2);
+	movbnd2mem_shadow(0, (unsigned long *)buf);
+	mkbnd_shadow(ptr+0x12, 0, 0x1800);
+}
+
+static __always_inline void mpx_test_helper3(uint8_t *buf, uint8_t *ptr)
+{
+	mpx_movbnd_from_mem_helper(buf);
+}
+
+static __always_inline void mpx_test_helper3_shadow(uint8_t *buf, uint8_t *ptr)
+{
+	movbnd_from_mem_shadow((unsigned long *)buf, 0);
+}
+
+static __always_inline void mpx_test_helper4(uint8_t *buf, uint8_t *ptr)
+{
+	mpx_store_dsc_helper((unsigned long)buf, (unsigned long)ptr);
+	mpx_make_bound_helper((unsigned long)(ptr+0x12), 0x1800);
+}
+
+static __always_inline void mpx_test_helper4_shadow(uint8_t *buf, uint8_t *ptr)
+{
+	stdsc_shadow(0, buf, ptr);
+	mkbnd_shadow(ptr+0x12, 0, 0x1800);
+}
+
+static __always_inline void mpx_test_helper5(uint8_t *buf, uint8_t *ptr)
+{
+	mpx_load_dsc_helper((unsigned long)buf, (unsigned long)ptr);
+}
+
+static __always_inline void mpx_test_helper5_shadow(uint8_t *buf, uint8_t *ptr)
+{
+	lddsc_shadow(0, buf, ptr);
+}
+
+#define NR_MPX_TEST_FUNCTIONS 6
+
+/*
+ * For compatibility reasons, MPX will clear the bounds registers
+ * when you make function calls (among other things).  We have to
+ * preserve the registers in between calls to the "helpers" since
+ * they build on each other.
+ *
+ * Be very careful not to make any function calls inside the
+ * helpers, or anywhere else beween the xrstor and xsave.
+ */
+#define run_helper(helper_nr, buf, buf_shadow, ptr)	do {	\
+	xrstor_state(xsave_test_buf, flags);			\
+	mpx_test_helper##helper_nr(buf, ptr);			\
+	xsave_state(xsave_test_buf, flags);			\
+	mpx_test_helper##helper_nr##_shadow(buf_shadow, ptr);	\
+} while (0)
+
+static void run_helpers(int nr, uint8_t *buf, uint8_t *buf_shadow, uint8_t *ptr)
+{
+	uint64_t flags = 0x18;
+
+	dprint_context(xsave_test_buf);
+	switch (nr) {
+	case 0:
+		run_helper(0, buf, buf_shadow, ptr);
+		break;
+	case 1:
+		run_helper(1, buf, buf_shadow, ptr);
+		break;
+	case 2:
+		run_helper(2, buf, buf_shadow, ptr);
+		break;
+	case 3:
+		run_helper(3, buf, buf_shadow, ptr);
+		break;
+	case 4:
+		run_helper(4, buf, buf_shadow, ptr);
+		break;
+	case 5:
+		run_helper(5, buf, buf_shadow, ptr);
+		break;
+	default:
+		test_failed();
+		break;
+	}
+	dprint_context(xsave_test_buf);
+}
+
+unsigned long buf_shadow[1024]; /* used to check load / store descriptors */
+extern long inspect_me(struct mpx_bounds_dir *bounds_dir);
+
+long cover_buf_with_bt_entries(void *buf, long buf_len)
+{
+	int i;
+	long nr_to_fill;
+	int ratio = 1000;
+	unsigned long buf_len_in_ptrs;
+
+	/* Fill about 1/100 of the space with bt entries */
+	nr_to_fill = buf_len / (sizeof(unsigned long) * ratio);
+
+	if (!nr_to_fill)
+		dprintf3("%s() nr_to_fill: %ld\n", __func__, nr_to_fill);
+
+	/* Align the buffer to pointer size */
+	while (((unsigned long)buf) % sizeof(void *)) {
+		buf++;
+		buf_len--;
+	}
+	/* We are storing pointers, so make */
+	buf_len_in_ptrs = buf_len / sizeof(void *);
+
+	for (i = 0; i < nr_to_fill; i++) {
+		long index = (mpx_random() % buf_len_in_ptrs);
+		void *ptr = buf + index * sizeof(unsigned long);
+		unsigned long ptr_addr = (unsigned long)ptr;
+
+		/* ptr and size can be anything */
+		mpx_make_bound_helper((unsigned long)ptr, 8);
+
+		/*
+		 * take bnd0 and put it in to bounds tables "buf + index" is an
+		 * address inside the buffer where we are pretending that we
+		 * are going to put a pointer We do not, though because we will
+		 * never load entries from the table, so it doesn't matter.
+		 */
+		mpx_store_dsc_helper(ptr_addr, (unsigned long)ptr);
+		dprintf4("storing bound table entry for %lx (buf start @ %p)\n",
+				ptr_addr, buf);
+	}
+	return nr_to_fill;
+}
+
+unsigned long align_down(unsigned long alignme, unsigned long align_to)
+{
+	return alignme & ~(align_to-1);
+}
+
+unsigned long align_up(unsigned long alignme, unsigned long align_to)
+{
+	return (alignme + align_to - 1) & ~(align_to-1);
+}
+
+/*
+ * Using 1MB alignment guarantees that each no allocation
+ * will overlap with another's bounds tables.
+ *
+ * We have to cook our own allocator here.  malloc() can
+ * mix other allocation with ours which means that even
+ * if we free all of our allocations, there might still
+ * be bounds tables for the *areas* since there is other
+ * valid memory there.
+ *
+ * We also can't use malloc() because a free() of an area
+ * might not free it back to the kernel.  We want it
+ * completely unmapped an malloc() does not guarantee
+ * that.
+ */
+#ifdef __i386__
+long alignment = 4096;
+long sz_alignment = 4096;
+#else
+long alignment = 1 * MB;
+long sz_alignment = 1 * MB;
+#endif
+void *mpx_mini_alloc(unsigned long sz)
+{
+	unsigned long long tries = 0;
+	static void *last;
+	void *ptr;
+	void *try_at;
+
+	sz = align_up(sz, sz_alignment);
+
+	try_at = last + alignment;
+	while (1) {
+		ptr = mmap(try_at, sz, PROT_READ|PROT_WRITE,
+				MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+		if (ptr == (void *)-1)
+			return NULL;
+		if (ptr == try_at)
+			break;
+
+		munmap(ptr, sz);
+		try_at += alignment;
+#ifdef __i386__
+		/*
+		 * This isn't quite correct for 32-bit binaries
+		 * on 64-bit kernels since they can use the
+		 * entire 32-bit address space, but it's close
+		 * enough.
+		 */
+		if (try_at > (void *)0xC0000000)
+#else
+		if (try_at > (void *)0x0000800000000000)
+#endif
+			try_at = (void *)0x0;
+		if (!(++tries % 10000))
+			dprintf1("stuck in %s(), tries: %lld\n", __func__, tries);
+		continue;
+	}
+	last = ptr;
+	dprintf3("mpx_mini_alloc(0x%lx) returning: %p\n", sz, ptr);
+	return ptr;
+}
+void mpx_mini_free(void *ptr, long sz)
+{
+	dprintf2("%s() ptr: %p\n", __func__, ptr);
+	if ((unsigned long)ptr > 0x100000000000) {
+		dprintf1("uh oh !!!!!!!!!!!!!!! pointer too high: %p\n", ptr);
+		test_failed();
+	}
+	sz = align_up(sz, sz_alignment);
+	dprintf3("%s() ptr: %p before munmap\n", __func__, ptr);
+	munmap(ptr, sz);
+	dprintf3("%s() ptr: %p DONE\n", __func__, ptr);
+}
+
+#define NR_MALLOCS 100
+struct one_malloc {
+	char *ptr;
+	int nr_filled_btes;
+	unsigned long size;
+};
+struct one_malloc mallocs[NR_MALLOCS];
+
+void free_one_malloc(int index)
+{
+	unsigned long free_ptr;
+	unsigned long mask;
+
+	if (!mallocs[index].ptr)
+		return;
+
+	mpx_mini_free(mallocs[index].ptr, mallocs[index].size);
+	dprintf4("freed[%d]:  %p\n", index, mallocs[index].ptr);
+
+	free_ptr = (unsigned long)mallocs[index].ptr;
+	mask = alignment-1;
+	dprintf4("lowerbits: %lx / %lx mask: %lx\n", free_ptr,
+			(free_ptr & mask), mask);
+	assert((free_ptr & mask) == 0);
+
+	mallocs[index].ptr = NULL;
+}
+
+#ifdef __i386__
+#define MPX_BOUNDS_TABLE_COVERS 4096
+#else
+#define MPX_BOUNDS_TABLE_COVERS (1 * MB)
+#endif
+void zap_everything(void)
+{
+	long after_zap;
+	long before_zap;
+	int i;
+
+	before_zap = inspect_me(bounds_dir_ptr);
+	dprintf1("zapping everything start: %ld\n", before_zap);
+	for (i = 0; i < NR_MALLOCS; i++)
+		free_one_malloc(i);
+
+	after_zap = inspect_me(bounds_dir_ptr);
+	dprintf1("zapping everything done: %ld\n", after_zap);
+	/*
+	 * We only guarantee to empty the thing out if our allocations are
+	 * exactly aligned on the boundaries of a boudns table.
+	 */
+	if ((alignment >= MPX_BOUNDS_TABLE_COVERS) &&
+	    (sz_alignment >= MPX_BOUNDS_TABLE_COVERS)) {
+		if (after_zap != 0)
+			test_failed();
+
+		assert(after_zap == 0);
+	}
+}
+
+void do_one_malloc(void)
+{
+	static int malloc_counter;
+	long sz;
+	int rand_index = (mpx_random() % NR_MALLOCS);
+	void *ptr = mallocs[rand_index].ptr;
+
+	dprintf3("%s() enter\n", __func__);
+
+	if (ptr) {
+		dprintf3("freeing one malloc at index: %d\n", rand_index);
+		free_one_malloc(rand_index);
+		if (mpx_random() % (NR_MALLOCS*3) == 3) {
+			int i;
+			dprintf3("zapping some more\n");
+			for (i = rand_index; i < NR_MALLOCS; i++)
+				free_one_malloc(i);
+		}
+		if ((mpx_random() % zap_all_every_this_many_mallocs) == 4)
+			zap_everything();
+	}
+
+	/* 1->~1M */
+	sz = (1 + mpx_random() % 1000) * 1000;
+	ptr = mpx_mini_alloc(sz);
+	if (!ptr) {
+		/*
+		 * If we are failing allocations, just assume we
+		 * are out of memory and zap everything.
+		 */
+		dprintf3("zapping everything because out of memory\n");
+		zap_everything();
+		goto out;
+	}
+
+	dprintf3("malloc: %p size: 0x%lx\n", ptr, sz);
+	mallocs[rand_index].nr_filled_btes = cover_buf_with_bt_entries(ptr, sz);
+	mallocs[rand_index].ptr = ptr;
+	mallocs[rand_index].size = sz;
+out:
+	if ((++malloc_counter) % inspect_every_this_many_mallocs == 0)
+		inspect_me(bounds_dir_ptr);
+}
+
+void run_timed_test(void (*test_func)(void))
+{
+	int done = 0;
+	long iteration = 0;
+	static time_t last_print;
+	time_t now;
+	time_t start;
+
+	time(&start);
+	while (!done) {
+		time(&now);
+		if ((now - start) > TEST_DURATION_SECS)
+			done = 1;
+
+		test_func();
+		iteration++;
+
+		if ((now - last_print > 1) || done) {
+			printf("iteration %ld complete, OK so far\n", iteration);
+			last_print = now;
+		}
+	}
+}
+
+void check_bounds_table_frees(void)
+{
+	printf("executing unmaptest\n");
+	inspect_me(bounds_dir_ptr);
+	run_timed_test(&do_one_malloc);
+	printf("done with malloc() fun\n");
+}
+
+void insn_test_failed(int test_nr, int test_round, void *buf,
+		void *buf_shadow, void *ptr)
+{
+	print_context(xsave_test_buf);
+	eprintf("ERROR: test %d round %d failed\n", test_nr, test_round);
+	while (test_nr == 5) {
+		struct mpx_bt_entry *bte;
+		struct mpx_bounds_dir *bd = (void *)bounds_dir_ptr;
+		struct mpx_bd_entry *bde = mpx_vaddr_to_bd_entry(buf, bd);
+
+		printf("  bd: %p\n", bd);
+		printf("&bde: %p\n", bde);
+		printf("*bde: %lx\n", *(unsigned long *)bde);
+		if (!bd_entry_valid(bde))
+			break;
+
+		bte = mpx_vaddr_to_bt_entry(buf, bd);
+		printf(" te: %p\n", bte);
+		printf("bte[0]: %lx\n", bte->contents[0]);
+		printf("bte[1]: %lx\n", bte->contents[1]);
+		printf("bte[2]: %lx\n", bte->contents[2]);
+		printf("bte[3]: %lx\n", bte->contents[3]);
+		break;
+	}
+	test_failed();
+}
+
+void check_mpx_insns_and_tables(void)
+{
+	int successes = 0;
+	int failures  = 0;
+	int buf_size = (1024*1024);
+	unsigned long *buf = malloc(buf_size);
+	const int total_nr_tests = NR_MPX_TEST_FUNCTIONS * TEST_ROUNDS;
+	int i, j;
+
+	memset(buf, 0, buf_size);
+	memset(buf_shadow, 0, sizeof(buf_shadow));
+
+	for (i = 0; i < TEST_ROUNDS; i++) {
+		uint8_t *ptr = get_random_addr() + 8;
+
+		for (j = 0; j < NR_MPX_TEST_FUNCTIONS; j++) {
+			if (0 && j != 5) {
+				successes++;
+				continue;
+			}
+			dprintf2("starting test %d round %d\n", j, i);
+			dprint_context(xsave_test_buf);
+			/*
+			 * test5 loads an address from the bounds tables.
+			 * The load will only complete if 'ptr' matches
+			 * the load and the store, so with random addrs,
+			 * the odds of this are very small.  Make it
+			 * higher by only moving 'ptr' 1/10 times.
+			 */
+			if (random() % 10 <= 0)
+				ptr = get_random_addr() + 8;
+			dprintf3("random ptr{%p}\n", ptr);
+			dprint_context(xsave_test_buf);
+			run_helpers(j, (void *)buf, (void *)buf_shadow, ptr);
+			dprint_context(xsave_test_buf);
+			if (!compare_context(xsave_test_buf)) {
+				insn_test_failed(j, i, buf, buf_shadow, ptr);
+				failures++;
+				goto exit;
+			}
+			successes++;
+			dprint_context(xsave_test_buf);
+			dprintf2("finished test %d round %d\n", j, i);
+			dprintf3("\n");
+			dprint_context(xsave_test_buf);
+		}
+	}
+
+exit:
+	dprintf2("\nabout to free:\n");
+	free(buf);
+	dprintf1("successes: %d\n", successes);
+	dprintf1(" failures: %d\n", failures);
+	dprintf1("    tests: %d\n", total_nr_tests);
+	dprintf1(" expected: %jd #BRs\n", num_upper_brs + num_lower_brs);
+	dprintf1("      saw: %d #BRs\n", br_count);
+	if (failures) {
+		eprintf("ERROR: non-zero number of failures\n");
+		exit(20);
+	}
+	if (successes != total_nr_tests) {
+		eprintf("ERROR: succeded fewer than number of tries (%d != %d)\n",
+				successes, total_nr_tests);
+		exit(21);
+	}
+	if (num_upper_brs + num_lower_brs != br_count) {
+		eprintf("ERROR: unexpected number of #BRs: %jd %jd %d\n",
+				num_upper_brs, num_lower_brs, br_count);
+		eprintf("successes: %d\n", successes);
+		eprintf(" failures: %d\n", failures);
+		eprintf("    tests: %d\n", total_nr_tests);
+		eprintf(" expected: %jd #BRs\n", num_upper_brs + num_lower_brs);
+		eprintf("      saw: %d #BRs\n", br_count);
+		exit(22);
+	}
+}
+
+/*
+ * This is supposed to SIGSEGV nicely once the kernel
+ * can no longer allocate vaddr space.
+ */
+void exhaust_vaddr_space(void)
+{
+	unsigned long ptr;
+	/* Try to make sure there is no room for a bounds table anywhere */
+	unsigned long skip = MPX_BOUNDS_TABLE_SIZE_BYTES - PAGE_SIZE;
+#ifdef __i386__
+	unsigned long max_vaddr = 0xf7788000UL;
+#else
+	unsigned long max_vaddr = 0x800000000000UL;
+#endif
+
+	dprintf1("%s() start\n", __func__);
+	/* do not start at 0, we aren't allowed to map there */
+	for (ptr = PAGE_SIZE; ptr < max_vaddr; ptr += skip) {
+		void *ptr_ret;
+		int ret = madvise((void *)ptr, PAGE_SIZE, MADV_NORMAL);
+
+		if (!ret) {
+			dprintf1("madvise() %lx ret: %d\n", ptr, ret);
+			continue;
+		}
+		ptr_ret = mmap((void *)ptr, PAGE_SIZE, PROT_READ|PROT_WRITE,
+				MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+		if (ptr_ret != (void *)ptr) {
+			perror("mmap");
+			dprintf1("mmap(%lx) ret: %p\n", ptr, ptr_ret);
+			break;
+		}
+		if (!(ptr & 0xffffff))
+			dprintf1("mmap(%lx) ret: %p\n", ptr, ptr_ret);
+	}
+	for (ptr = PAGE_SIZE; ptr < max_vaddr; ptr += skip) {
+		dprintf2("covering 0x%lx with bounds table entries\n", ptr);
+		cover_buf_with_bt_entries((void *)ptr, PAGE_SIZE);
+	}
+	dprintf1("%s() end\n", __func__);
+	printf("done with vaddr space fun\n");
+}
+
+void mpx_table_test(void)
+{
+	printf("starting mpx bounds table test\n");
+	run_timed_test(check_mpx_insns_and_tables);
+	printf("done with mpx bounds table test\n");
+}
+
+int main(int argc, char **argv)
+{
+	int unmaptest = 0;
+	int vaddrexhaust = 0;
+	int tabletest = 0;
+	int i;
+
+	check_mpx_support();
+	mpx_prepare();
+	srandom(11179);
+
+	bd_incore();
+	init();
+	bd_incore();
+
+	trace_me();
+
+	xsave_state((void *)xsave_test_buf, 0x1f);
+	if (!compare_context(xsave_test_buf))
+		printf("Init failed\n");
+
+	for (i = 1; i < argc; i++) {
+		if (!strcmp(argv[i], "unmaptest"))
+			unmaptest = 1;
+		if (!strcmp(argv[i], "vaddrexhaust"))
+			vaddrexhaust = 1;
+		if (!strcmp(argv[i], "tabletest"))
+			tabletest = 1;
+	}
+	if (!(unmaptest || vaddrexhaust || tabletest)) {
+		unmaptest = 1;
+		/* vaddrexhaust = 1; */
+		tabletest = 1;
+	}
+	if (unmaptest)
+		check_bounds_table_frees();
+	if (tabletest)
+		mpx_table_test();
+	if (vaddrexhaust)
+		exhaust_vaddr_space();
+	printf("%s completed successfully\n", argv[0]);
+	exit(0);
+}
+
+#include "mpx-dig.c"