| /* This test program is part of GDB, the GNU debugger. |
| |
| Copyright 2021 Free Software Foundation, Inc. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| /* Exercise AArch64's Memory Tagging Extension with tagged pointers. */ |
| |
| /* This test was based on the documentation for the AArch64 Memory Tagging |
| Extension from the Linux Kernel, found in the sources in |
| Documentation/arm64/memory-tagging-extension.rst. */ |
| |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <sys/auxv.h> |
| #include <sys/mman.h> |
| #include <sys/prctl.h> |
| |
| /* From arch/arm64/include/uapi/asm/hwcap.h */ |
| #define HWCAP2_MTE (1 << 18) |
| |
| /* From arch/arm64/include/uapi/asm/mman.h */ |
| #define PROT_MTE 0x20 |
| |
| /* From include/uapi/linux/prctl.h */ |
| #define PR_SET_TAGGED_ADDR_CTRL 55 |
| #define PR_GET_TAGGED_ADDR_CTRL 56 |
| #define PR_TAGGED_ADDR_ENABLE (1UL << 0) |
| #define PR_MTE_TCF_SHIFT 1 |
| #define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT) |
| #define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT) |
| #define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT) |
| #define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT) |
| #define PR_MTE_TAG_SHIFT 3 |
| #define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT) |
| |
| void |
| access_memory (unsigned char *tagged_ptr, unsigned char *untagged_ptr) |
| { |
| tagged_ptr[0] = 'a'; |
| } |
| |
| int |
| main (int argc, char **argv) |
| { |
| unsigned char *tagged_ptr; |
| unsigned char *untagged_ptr; |
| unsigned long page_sz = sysconf (_SC_PAGESIZE); |
| unsigned long hwcap2 = getauxval(AT_HWCAP2); |
| |
| /* Bail out if MTE is not supported. */ |
| if (!(hwcap2 & HWCAP2_MTE)) |
| return 1; |
| |
| /* Enable the tagged address ABI, synchronous MTE tag check faults and |
| allow all non-zero tags in the randomly generated set. */ |
| if (prctl (PR_SET_TAGGED_ADDR_CTRL, |
| PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC |
| | (0xfffe << PR_MTE_TAG_SHIFT), |
| 0, 0, 0)) |
| { |
| perror ("prctl () failed"); |
| return 1; |
| } |
| |
| /* Create a mapping that will have PROT_MTE set. */ |
| tagged_ptr = mmap (0, page_sz, PROT_READ | PROT_WRITE, |
| MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if (tagged_ptr == MAP_FAILED) |
| { |
| perror ("mmap () failed"); |
| return 1; |
| } |
| |
| /* Create another mapping that won't have PROT_MTE set. */ |
| untagged_ptr = mmap (0, page_sz, PROT_READ | PROT_WRITE, |
| MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
| if (untagged_ptr == MAP_FAILED) |
| { |
| perror ("mmap () failed"); |
| return 1; |
| } |
| |
| /* Enable MTE on the above anonymous mmap. */ |
| if (mprotect (tagged_ptr, page_sz, PROT_READ | PROT_WRITE | PROT_MTE)) |
| { |
| perror ("mprotect () failed"); |
| return 1; |
| } |
| |
| access_memory (tagged_ptr, untagged_ptr); |
| |
| return 0; |
| } |