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Merge "Adopt GNU calling convention for ifunc resolvers."

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am: 609d6ec416

Change-Id: Ie5bbd72a166321bcd361229e9f3adf784ec322b9
This commit is contained in:
Peter Collingbourne 2019-10-29 10:37:06 -07:00 committed by android-build-merger
commit 92adfbb687
7 changed files with 215 additions and 10 deletions
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1
libc/Android.bp
View file

@ -1070,6 +1070,7 @@ cc_library_static {
"bionic/atof.cpp",
"bionic/bionic_allocator.cpp",
"bionic/bionic_arc4random.cpp",
"bionic/bionic_call_ifunc_resolver.cpp",
"bionic/bionic_futex.cpp",
"bionic/bionic_netlink.cpp",
"bionic/bionic_systrace.cpp",

46
libc/bionic/bionic_call_ifunc_resolver.cpp Normal file
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@ -0,0 +1,46 @@
/*
* 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_call_ifunc_resolver.h"
#include <sys/auxv.h>
#include <sys/ifunc.h>
ElfW(Addr) __bionic_call_ifunc_resolver(ElfW(Addr) resolver_addr) {
#if defined(__aarch64__)
typedef ElfW(Addr) (*ifunc_resolver_t)(uint64_t, __ifunc_arg_t*);
static __ifunc_arg_t arg = { sizeof(__ifunc_arg_t), getauxval(AT_HWCAP), getauxval(AT_HWCAP2) };
return reinterpret_cast<ifunc_resolver_t>(resolver_addr)(arg._hwcap | _IFUNC_ARG_HWCAP, &arg);
#elif defined(__arm__)
typedef ElfW(Addr) (*ifunc_resolver_t)(unsigned long);
static unsigned long hwcap = getauxval(AT_HWCAP);
return reinterpret_cast<ifunc_resolver_t>(resolver_addr)(hwcap);
#else
typedef ElfW(Addr) (*ifunc_resolver_t)(void);
return reinterpret_cast<ifunc_resolver_t>(resolver_addr)();
#endif
}

7
libc/bionic/libc_init_static.cpp
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@ -39,6 +39,7 @@
#include "libc_init_common.h"
#include "pthread_internal.h"
#include "private/bionic_call_ifunc_resolver.h"
#include "private/bionic_elf_tls.h"
#include "private/bionic_globals.h"
#include "private/bionic_macros.h"
@ -81,11 +82,10 @@ static void call_ifunc_resolvers() {
return;
}
typedef ElfW(Addr) (*ifunc_resolver_t)(void);
for (ElfW(Rela) *r = __rela_iplt_start; r != __rela_iplt_end; ++r) {
ElfW(Addr)* offset = reinterpret_cast<ElfW(Addr)*>(r->r_offset);
ElfW(Addr) resolver = r->r_addend;
*offset = reinterpret_cast<ifunc_resolver_t>(resolver)();
*offset = __bionic_call_ifunc_resolver(resolver);
}
}
#else
@ -103,11 +103,10 @@ static void call_ifunc_resolvers() {
return;
}
typedef ElfW(Addr) (*ifunc_resolver_t)(void);
for (ElfW(Rel) *r = __rel_iplt_start; r != __rel_iplt_end; ++r) {
ElfW(Addr)* offset = reinterpret_cast<ElfW(Addr)*>(r->r_offset);
ElfW(Addr) resolver = *offset;
*offset = reinterpret_cast<ifunc_resolver_t>(resolver)();
*offset = __bionic_call_ifunc_resolver(resolver);
}
}
#endif

71
libc/include/sys/ifunc.h Normal file
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@ -0,0 +1,71 @@
/*
* 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
#include <sys/cdefs.h>
/**
* @file sys/ifunc.h
* @brief Declarations used for ifunc resolvers. Currently only meaningful for arm64.
*/
__BEGIN_DECLS
#if defined(__aarch64__)
/**
* Provides information about hardware capabilities to ifunc resolvers.
*
* Starting with API level 30, ifunc resolvers on arm64 are passed two arguments. The first is a
* uint64_t whose value is equal to getauxval(AT_HWCAP) | _IFUNC_ARG_HWCAP. The second is a pointer
* to a data structure of this type. Prior to API level 30, no arguments are passed to ifunc
* resolvers. Code that wishes to be compatible with prior API levels should not accept any
* arguments in the resolver.
*/
typedef struct __ifunc_arg_t {
/** Set to sizeof(__ifunc_arg_t). */
unsigned long _size;
/** Set to getauxval(AT_HWCAP). */
unsigned long _hwcap;
/** Set to getauxval(AT_HWCAP2). */
unsigned long _hwcap2;
} __ifunc_arg_t;
/**
* If this bit is set in the first argument to an ifunc resolver, indicates that the second argument
* is a pointer to a data structure of type __ifunc_arg_t. This bit is always set on Android
* starting with API level 30.
*/
#define _IFUNC_ARG_HWCAP (1ULL << 62)
#endif
__END_DECLS

34
libc/private/bionic_call_ifunc_resolver.h Normal file
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@ -0,0 +1,34 @@
/*
* 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
#include <link.h>
#include <sys/cdefs.h>
__LIBC_HIDDEN__ ElfW(Addr) __bionic_call_ifunc_resolver(ElfW(Addr) resolver_addr);

7
linker/linker.cpp
View file

@ -68,6 +68,7 @@
#include "linker_tls.h"
#include "linker_utils.h"
#include "private/bionic_call_ifunc_resolver.h"
#include "private/bionic_globals.h"
#include "android-base/macros.h"
#include "android-base/strings.h"
@ -2689,11 +2690,9 @@ bool link_namespaces_all_libs(android_namespace_t* namespace_from,
ElfW(Addr) call_ifunc_resolver(ElfW(Addr) resolver_addr) {
if (g_is_ldd) return 0;
typedef ElfW(Addr) (*ifunc_resolver_t)(void);
ifunc_resolver_t ifunc_resolver = reinterpret_cast<ifunc_resolver_t>(resolver_addr);
ElfW(Addr) ifunc_addr = ifunc_resolver();
ElfW(Addr) ifunc_addr = __bionic_call_ifunc_resolver(resolver_addr);
TRACE_TYPE(RELO, "Called ifunc_resolver@%p. The result is %p",
ifunc_resolver, reinterpret_cast<void*>(ifunc_addr));
reinterpret_cast<void *>(resolver_addr), reinterpret_cast<void*>(ifunc_addr));
return ifunc_addr;
}

59
tests/ifunc_test.cpp
View file

@ -16,12 +16,19 @@
#include <gtest/gtest.h>
#include <sys/auxv.h>
#if defined(__BIONIC__)
#include <sys/ifunc.h>
#endif
typedef int (*fn_ptr_t)();
int ret42() {
return 42;
}
extern "C" void* resolver() {
return (void*)ret42;
extern "C" fn_ptr_t resolver() {
return ret42;
}
int ifunc() __attribute__((ifunc("resolver")));
@ -29,3 +36,51 @@ int ifunc() __attribute__((ifunc("resolver")));
TEST(ifunc, function) {
ASSERT_EQ(42, ifunc());
}
#if defined(__BIONIC__)
#if defined(__aarch64__)
static uint64_t g_hwcap;
static __ifunc_arg_t g_arg;
extern "C" fn_ptr_t hwcap_resolver(uint64_t hwcap, __ifunc_arg_t* arg) {
g_hwcap = hwcap;
g_arg = *arg;
return ret42;
}
#elif defined(__arm__)
static unsigned long g_hwcap;
extern "C" fn_ptr_t hwcap_resolver(unsigned long hwcap) {
g_hwcap = hwcap;
return ret42;
}
#else
extern "C" fn_ptr_t hwcap_resolver() {
return ret42;
}
#endif
int hwcap() __attribute__((ifunc("hwcap_resolver")));
TEST(ifunc, hwcap) {
ASSERT_EQ(42, hwcap());
#if defined(__aarch64__)
EXPECT_EQ(getauxval(AT_HWCAP) | _IFUNC_ARG_HWCAP, g_hwcap);
EXPECT_EQ(sizeof(__ifunc_arg_t), g_arg._size);
EXPECT_EQ(getauxval(AT_HWCAP), g_arg._hwcap);
EXPECT_EQ(getauxval(AT_HWCAP2), g_arg._hwcap2);
#elif defined(__arm__)
EXPECT_EQ(getauxval(AT_HWCAP), g_hwcap);
#endif
}
#endif // defined(__BIONIC__)