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/*
* Memory tagging testing code.
*
* Copyright (c) 2020, Arm Limited.
* SPDX-License-Identifier: MIT
*/
#ifndef __TEST_MTE_H
#define __TEST_MTE_H
#include <stdlib.h>
#if __ARM_FEATURE_MEMORY_TAGGING && WANT_MTE_TEST
#include <arm_acle.h>
#include <sys/mman.h>
#include <sys/prctl.h>
// These depend on a not yet merged kernel ABI.
#define PR_SET_TAGGED_ADDR_CTRL 55
#define PR_TAGGED_ADDR_ENABLE (1UL << 0)
#define PR_MTE_TCF_SHIFT 1
#define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT)
#define PR_MTE_TAG_SHIFT 3
#define PROT_MTE 0x20
#define MTE_GRANULE_SIZE 16
int
mte_enabled ()
{
static int enabled = -1;
if (enabled == -1)
{
int res = prctl (PR_SET_TAGGED_ADDR_CTRL,
PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC
| (0xfffe << PR_MTE_TAG_SHIFT),
0, 0, 0);
enabled = (res == 0);
}
return enabled;
}
static void *
mte_mmap (size_t size)
{
if (mte_enabled ())
{
return mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_MTE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
}
else
{
return malloc (size);
}
}
void *
alignup_mte (void *p)
{
return (void *) (((uintptr_t) p + MTE_GRANULE_SIZE - 1)
& ~(MTE_GRANULE_SIZE - 1));
}
void *
aligndown_mte (void *p)
{
return (void *) ((uintptr_t) p & ~(MTE_GRANULE_SIZE - 1));
}
void *
untag_pointer (void *p)
{
return (void *) ((unsigned long long) p & (~0ULL >> 8));
}
void
tag_buffer_helper (void *p, int len)
{
char *ptr = p;
char *end = alignup_mte (ptr + len);
ptr = aligndown_mte (p);
for (; ptr < end; ptr += MTE_GRANULE_SIZE)
{
__arm_mte_set_tag (ptr);
}
}
void *
tag_buffer (void *p, int len, int test_mte)
{
if (test_mte && mte_enabled ())
{
p = __arm_mte_increment_tag (p, 1);
tag_buffer_helper (p, len);
}
return p;
}
void *
untag_buffer (void *p, int len, int test_mte)
{
p = untag_pointer (p);
if (test_mte && mte_enabled ())
{
tag_buffer_helper (p, len);
}
return p;
}
#else // __ARM_FEATURE_MEMORY_TAGGING
int
mte_enabled ()
{
return 0;
}
static void *
mte_mmap (size_t size)
{
return malloc (size);
}
void *
tag_buffer (void *p, int len, int test_mte)
{
(void) len;
(void) test_mte;
return p;
}
void *
untag_buffer (void *p, int len, int test_mte)
{
(void) len;
(void) test_mte;
return p;
}
void *
untag_pointer (void *p)
{
return p;
}
#endif // __ARM_FEATURE_MEMORY_TAGGING
#endif
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