Add arm64 string.h function implementations for use with hardware supporting MTE.
As it turns out, our "generic" arm64 implementations of certain string.h
functions are not actually generic, since they will eagerly read memory
possibly outside of the bounds of an MTE granule, which may lead to a segfault
on MTE-enabled hardware. Therefore, move the implementations into a "default"
directory and use ifuncs to select between them and a new set of "mte"
implementations, conditional on whether the hardware and kernel support MTE.
The MTE implementations are currently naive implementations written in C
but will later be replaced with a set of optimized assembly implementations.
Bug: 135772972
Change-Id: Ife37c4e0e6fd60ff20a34594cc09c541af4d1dd7
diff --git a/libc/Android.bp b/libc/Android.bp
index 45c4569..e30abb7 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -854,20 +854,28 @@
},
arm64: {
srcs: [
- "arch-arm64/generic/bionic/memchr.S",
"arch-arm64/generic/bionic/memcmp.S",
"arch-arm64/generic/bionic/memcpy.S",
"arch-arm64/generic/bionic/memmove.S",
"arch-arm64/generic/bionic/memset.S",
"arch-arm64/generic/bionic/stpcpy.S",
- "arch-arm64/generic/bionic/strchr.S",
- "arch-arm64/generic/bionic/strcmp.S",
"arch-arm64/generic/bionic/strcpy.S",
- "arch-arm64/generic/bionic/strlen.S",
- "arch-arm64/generic/bionic/strncmp.S",
- "arch-arm64/generic/bionic/strnlen.S",
"arch-arm64/generic/bionic/wmemmove.S",
+ "arch-arm64/default/bionic/memchr.S",
+ "arch-arm64/default/bionic/strchr.S",
+ "arch-arm64/default/bionic/strcmp.S",
+ "arch-arm64/default/bionic/strlen.S",
+ "arch-arm64/default/bionic/strncmp.S",
+ "arch-arm64/default/bionic/strnlen.S",
+
+ "arch-arm64/mte/bionic/memchr.c",
+ "arch-arm64/mte/bionic/strchr.cpp",
+ "arch-arm64/mte/bionic/strcmp.c",
+ "arch-arm64/mte/bionic/strlen.c",
+ "arch-arm64/mte/bionic/strncmp.c",
+ "arch-arm64/mte/bionic/strnlen.c",
+
"arch-arm64/bionic/__bionic_clone.S",
"arch-arm64/bionic/_exit_with_stack_teardown.S",
"arch-arm64/bionic/setjmp.S",
@@ -1494,6 +1502,9 @@
arm: {
srcs: ["arch-arm/static_function_dispatch.S"],
},
+ arm64: {
+ srcs: ["arch-arm64/static_function_dispatch.S"],
+ },
},
whole_static_libs: [
@@ -1519,6 +1530,9 @@
arm: {
srcs: ["arch-arm/dynamic_function_dispatch.cpp"],
},
+ arm64: {
+ srcs: ["arch-arm64/dynamic_function_dispatch.cpp"],
+ },
},
whole_static_libs: [
diff --git a/libc/arch-arm/dynamic_function_dispatch.cpp b/libc/arch-arm/dynamic_function_dispatch.cpp
index 75000a2..1d2f38f 100644
--- a/libc/arch-arm/dynamic_function_dispatch.cpp
+++ b/libc/arch-arm/dynamic_function_dispatch.cpp
@@ -149,7 +149,7 @@
typedef void* memcpy_func(void*, const void*, size_t);
DEFINE_IFUNC_FOR(memcpy) {
- return memmove_resolver();
+ return memmove_resolver(hwcap);
}
typedef void* __memcpy_func(void*, const void*, size_t);
diff --git a/libc/arch-arm64/generic/bionic/memchr.S b/libc/arch-arm64/default/bionic/memchr.S
similarity index 98%
rename from libc/arch-arm64/generic/bionic/memchr.S
rename to libc/arch-arm64/default/bionic/memchr.S
index 7b7e699..7fbcc8f 100644
--- a/libc/arch-arm64/generic/bionic/memchr.S
+++ b/libc/arch-arm64/default/bionic/memchr.S
@@ -69,7 +69,7 @@
* identify exactly which byte has matched.
*/
-ENTRY(memchr)
+ENTRY(memchr_default)
/*
* Magic constant 0x40100401 allows us to identify which lane matches
* the requested byte.
@@ -161,4 +161,4 @@
.Lzero_length:
mov result, xzr
ret
-END(memchr)
+END(memchr_default)
diff --git a/libc/arch-arm64/generic/bionic/strchr.S b/libc/arch-arm64/default/bionic/strchr.S
similarity index 98%
rename from libc/arch-arm64/generic/bionic/strchr.S
rename to libc/arch-arm64/default/bionic/strchr.S
index 2db0c76..f8cb724 100644
--- a/libc/arch-arm64/generic/bionic/strchr.S
+++ b/libc/arch-arm64/default/bionic/strchr.S
@@ -73,7 +73,7 @@
/* Locals and temporaries. */
-ENTRY(strchr)
+ENTRY(strchr_default)
/* Magic constant 0x40100401 to allow us to identify which lane
matches the requested byte. Magic constant 0x80200802 used
similarly for NUL termination. */
@@ -150,4 +150,4 @@
add result, src, tmp1, lsr #1
csel result, result, xzr, eq
ret
-END(strchr)
+END(strchr_default)
diff --git a/libc/arch-arm64/generic/bionic/strcmp.S b/libc/arch-arm64/default/bionic/strcmp.S
similarity index 99%
rename from libc/arch-arm64/generic/bionic/strcmp.S
rename to libc/arch-arm64/default/bionic/strcmp.S
index fbc215e..dfac7c4 100644
--- a/libc/arch-arm64/generic/bionic/strcmp.S
+++ b/libc/arch-arm64/default/bionic/strcmp.S
@@ -58,7 +58,7 @@
#define pos x11
/* Start of performance-critical section -- one 64B cache line. */
-ENTRY(strcmp)
+ENTRY(strcmp_default)
.p2align 6
eor tmp1, src1, src2
mov zeroones, #REP8_01
@@ -189,4 +189,4 @@
L(done):
sub result, data1, data2
ret
-END(strcmp)
+END(strcmp_default)
diff --git a/libc/arch-arm64/generic/bionic/strlen.S b/libc/arch-arm64/default/bionic/strlen.S
similarity index 99%
rename from libc/arch-arm64/generic/bionic/strlen.S
rename to libc/arch-arm64/default/bionic/strlen.S
index 6e540fc..07c5294 100644
--- a/libc/arch-arm64/generic/bionic/strlen.S
+++ b/libc/arch-arm64/default/bionic/strlen.S
@@ -94,7 +94,7 @@
whether the first fetch, which may be misaligned, crosses a page
boundary. */
-ENTRY(strlen)
+ENTRY(strlen_default)
and tmp1, srcin, MIN_PAGE_SIZE - 1
mov zeroones, REP8_01
cmp tmp1, MIN_PAGE_SIZE - 16
@@ -224,4 +224,4 @@
csel data2, data2, tmp2, eq
b L(page_cross_entry)
-END(strlen)
+END(strlen_default)
diff --git a/libc/arch-arm64/generic/bionic/strncmp.S b/libc/arch-arm64/default/bionic/strncmp.S
similarity index 99%
rename from libc/arch-arm64/generic/bionic/strncmp.S
rename to libc/arch-arm64/default/bionic/strncmp.S
index b81f43a..5432b73 100644
--- a/libc/arch-arm64/generic/bionic/strncmp.S
+++ b/libc/arch-arm64/default/bionic/strncmp.S
@@ -65,7 +65,7 @@
.rep 7
nop /* Pad so that the loop below fits a cache line. */
.endr
-ENTRY(strncmp)
+ENTRY(strncmp_default)
cbz limit, .Lret0
eor tmp1, src1, src2
mov zeroones, #REP8_01
@@ -277,4 +277,4 @@
.Lret0:
mov result, #0
ret
-END(strncmp)
+END(strncmp_default)
diff --git a/libc/arch-arm64/generic/bionic/strnlen.S b/libc/arch-arm64/default/bionic/strnlen.S
similarity index 98%
rename from libc/arch-arm64/generic/bionic/strnlen.S
rename to libc/arch-arm64/default/bionic/strnlen.S
index 0ad446e..1694532 100644
--- a/libc/arch-arm64/generic/bionic/strnlen.S
+++ b/libc/arch-arm64/default/bionic/strnlen.S
@@ -68,7 +68,7 @@
mov len, limit
ret
-ENTRY(strnlen)
+ENTRY(strnlen_default)
cbz limit, .Lhit_limit
mov zeroones, #REP8_01
bic src, srcin, #15
@@ -171,4 +171,4 @@
csinv data1, data1, xzr, le
csel data2, data2, data2a, le
b .Lrealigned
-END(strnlen)
+END(strnlen_default)
diff --git a/libc/arch-arm64/dynamic_function_dispatch.cpp b/libc/arch-arm64/dynamic_function_dispatch.cpp
new file mode 100644
index 0000000..37abea4
--- /dev/null
+++ b/libc/arch-arm64/dynamic_function_dispatch.cpp
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <platform/bionic/mte_kernel.h>
+#include <private/bionic_ifuncs.h>
+#include <stddef.h>
+#include <sys/auxv.h>
+
+extern "C" {
+
+static bool supports_mte(unsigned long hwcap2) {
+#ifdef ANDROID_EXPERIMENTAL_MTE
+ return hwcap2 & HWCAP2_MTE;
+#else
+ (void)hwcap2;
+ return false;
+#endif
+}
+
+typedef void* memchr_func(const void*, int, size_t);
+DEFINE_IFUNC_FOR(memchr) {
+ if (supports_mte(arg->_hwcap2)) {
+ RETURN_FUNC(memchr_func, memchr_mte);
+ } else {
+ RETURN_FUNC(memchr_func, memchr_default);
+ }
+}
+
+typedef char* strchr_func(const char*, int);
+DEFINE_IFUNC_FOR(strchr) {
+ if (supports_mte(arg->_hwcap2)) {
+ RETURN_FUNC(strchr_func, strchr_mte);
+ } else {
+ RETURN_FUNC(strchr_func, strchr_default);
+ }
+}
+
+typedef int strcmp_func(const char*, const char*);
+DEFINE_IFUNC_FOR(strcmp) {
+ if (supports_mte(arg->_hwcap2)) {
+ RETURN_FUNC(strcmp_func, strcmp_mte);
+ } else {
+ RETURN_FUNC(strcmp_func, strcmp_default);
+ }
+}
+
+typedef size_t strlen_func(const char*);
+DEFINE_IFUNC_FOR(strlen) {
+ if (supports_mte(arg->_hwcap2)) {
+ RETURN_FUNC(strlen_func, strlen_mte);
+ } else {
+ RETURN_FUNC(strlen_func, strlen_default);
+ }
+}
+
+typedef int strncmp_func(const char*, const char*, int);
+DEFINE_IFUNC_FOR(strncmp) {
+ if (supports_mte(arg->_hwcap2)) {
+ RETURN_FUNC(strncmp_func, strncmp_mte);
+ } else {
+ RETURN_FUNC(strncmp_func, strncmp_default);
+ }
+}
+
+typedef size_t strnlen_func(const char*, int);
+DEFINE_IFUNC_FOR(strnlen) {
+ if (supports_mte(arg->_hwcap2)) {
+ RETURN_FUNC(strnlen_func, strnlen_mte);
+ } else {
+ RETURN_FUNC(strnlen_func, strnlen_default);
+ }
+}
+
+} // extern "C"
diff --git a/libc/arch-arm64/mte/bionic/memchr.c b/libc/arch-arm64/mte/bionic/memchr.c
new file mode 100644
index 0000000..33b2fc2
--- /dev/null
+++ b/libc/arch-arm64/mte/bionic/memchr.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <upstream-openbsd/android/include/openbsd-compat.h>
+
+#define memchr memchr_mte
+#include <upstream-openbsd/lib/libc/string/memchr.c>
diff --git a/libc/arch-arm64/mte/bionic/strchr.cpp b/libc/arch-arm64/mte/bionic/strchr.cpp
new file mode 100644
index 0000000..7d394df
--- /dev/null
+++ b/libc/arch-arm64/mte/bionic/strchr.cpp
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#define strchr strchr_mte
+#include <bionic/strchr.cpp>
diff --git a/libc/arch-arm64/mte/bionic/strcmp.c b/libc/arch-arm64/mte/bionic/strcmp.c
new file mode 100644
index 0000000..0e134f0
--- /dev/null
+++ b/libc/arch-arm64/mte/bionic/strcmp.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <upstream-openbsd/android/include/openbsd-compat.h>
+
+#define strcmp strcmp_mte
+#include <upstream-openbsd/lib/libc/string/strcmp.c>
diff --git a/libc/arch-arm64/mte/bionic/strlen.c b/libc/arch-arm64/mte/bionic/strlen.c
new file mode 100644
index 0000000..de88320
--- /dev/null
+++ b/libc/arch-arm64/mte/bionic/strlen.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <upstream-openbsd/android/include/openbsd-compat.h>
+
+#define strlen strlen_mte
+#include <upstream-openbsd/lib/libc/string/strlen.c>
diff --git a/libc/arch-arm64/mte/bionic/strncmp.c b/libc/arch-arm64/mte/bionic/strncmp.c
new file mode 100644
index 0000000..54d08e9
--- /dev/null
+++ b/libc/arch-arm64/mte/bionic/strncmp.c
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <upstream-openbsd/android/include/openbsd-compat.h>
+
+#define strncmp strncmp_mte
+#include <upstream-openbsd/lib/libc/string/strncmp.c>
diff --git a/libc/arch-arm64/mte/bionic/strnlen.c b/libc/arch-arm64/mte/bionic/strnlen.c
new file mode 100644
index 0000000..3dc251d
--- /dev/null
+++ b/libc/arch-arm64/mte/bionic/strnlen.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#define strnlen strnlen_mte
+#include <bionic/strnlen.c>
diff --git a/libc/arch-arm64/static_function_dispatch.S b/libc/arch-arm64/static_function_dispatch.S
new file mode 100644
index 0000000..8e3a4c1
--- /dev/null
+++ b/libc/arch-arm64/static_function_dispatch.S
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <private/bionic_asm.h>
+
+#define FUNCTION_DELEGATE(name, impl) \
+ENTRY(name); \
+ b impl; \
+END(name)
+
+FUNCTION_DELEGATE(memchr, memchr_mte)
+FUNCTION_DELEGATE(strchr, strchr_mte)
+FUNCTION_DELEGATE(strcmp, strcmp_mte)
+FUNCTION_DELEGATE(strlen, strlen_mte)
+FUNCTION_DELEGATE(strncmp, strncmp_mte)
+FUNCTION_DELEGATE(strnlen, strnlen_mte)
diff --git a/libc/platform/bionic/mte_kernel.h b/libc/platform/bionic/mte_kernel.h
new file mode 100644
index 0000000..04f2bb6
--- /dev/null
+++ b/libc/platform/bionic/mte_kernel.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+// Defines constants used as part of the interface in an experimental MTE branch
+// of the Linux kernel, which may be found at:
+//
+// https://github.com/pcc/linux/tree/android-experimental-mte
+//
+// This interface should not be considered to be stable.
+
+#ifdef ANDROID_EXPERIMENTAL_MTE
+#define HWCAP2_MTE (1UL << 31)
+#define PROT_MTE 0x10
+#endif
diff --git a/libc/private/bionic_ifuncs.h b/libc/private/bionic_ifuncs.h
index 35961fb..f175bec 100644
--- a/libc/private/bionic_ifuncs.h
+++ b/libc/private/bionic_ifuncs.h
@@ -28,10 +28,22 @@
#pragma once
+#include <stdint.h>
+#include <sys/ifunc.h>
+
+#if defined(__aarch64__)
+#define IFUNC_ARGS (uint64_t hwcap __attribute__((unused)), \
+ __ifunc_arg_t* arg __attribute__((unused)))
+#elif defined(__arm__)
+#define IFUNC_ARGS (unsigned long hwcap __attribute__((unused)))
+#else
+#define IFUNC_ARGS ()
+#endif
+
#define DEFINE_IFUNC_FOR(name) \
name##_func name __attribute__((ifunc(#name "_resolver"))); \
__attribute__((visibility("hidden"))) \
- name##_func* name##_resolver()
+ name##_func* name##_resolver IFUNC_ARGS
#define DECLARE_FUNC(type, name) \
__attribute__((visibility("hidden"))) \
diff --git a/libc/upstream-openbsd/lib/libc/string/strlen.c b/libc/upstream-openbsd/lib/libc/string/strlen.c
new file mode 100644
index 0000000..a5721d3
--- /dev/null
+++ b/libc/upstream-openbsd/lib/libc/string/strlen.c
@@ -0,0 +1,44 @@
+/* $OpenBSD: strlen.c,v 1.9 2015/08/31 02:53:57 guenther Exp $ */
+
+/*-
+ * Copyright (c) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <string.h>
+
+size_t
+strlen(const char *str)
+{
+ const char *s;
+
+ for (s = str; *s; ++s)
+ ;
+ return (s - str);
+}
+
+DEF_STRONG(strlen);