1 // Copyright 2019 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef V8_EXECUTION_ARM64_POINTER_AUTHENTICATION_ARM64_H_
6 #define V8_EXECUTION_ARM64_POINTER_AUTHENTICATION_ARM64_H_
7
8 #include "src/common/globals.h"
9 #include "src/deoptimizer/deoptimizer.h"
10 #include "src/execution/arm64/simulator-arm64.h"
11 #include "src/execution/pointer-authentication.h"
12
13 namespace v8 {
14 namespace internal {
15
16 // The following functions execute on the host and therefore need a different
17 // path based on whether we are simulating arm64 or not.
18
19 // clang-format fails to detect this file as C++, turn it off.
20 // clang-format off
21
22 // Authenticate the address stored in {pc_address}. {offset_from_sp} is the
23 // offset between {pc_address} and the pointer used as a context for signing.
AuthenticatePC(Address * pc_address,unsigned offset_from_sp)24 V8_INLINE Address PointerAuthentication::AuthenticatePC(
25 Address* pc_address, unsigned offset_from_sp) {
26 uint64_t sp = reinterpret_cast<uint64_t>(pc_address) + offset_from_sp;
27 uint64_t pc = static_cast<uint64_t>(*pc_address);
28 #ifdef USE_SIMULATOR
29 pc = Simulator::AuthPAC(pc, sp, Simulator::kPACKeyIB,
30 Simulator::kInstructionPointer);
31 #else
32 asm volatile(
33 " mov x17, %[pc]\n"
34 " mov x16, %[stack_ptr]\n"
35 " autib1716\n"
36 " ldr xzr, [x17]\n"
37 " mov %[pc], x17\n"
38 : [pc] "+r"(pc)
39 : [stack_ptr] "r"(sp)
40 : "x16", "x17");
41 #endif
42 return pc;
43 }
44
45 // Strip Pointer Authentication Code (PAC) from {pc} and return the raw value.
StripPAC(Address pc)46 V8_INLINE Address PointerAuthentication::StripPAC(Address pc) {
47 #ifdef USE_SIMULATOR
48 return Simulator::StripPAC(pc, Simulator::kInstructionPointer);
49 #else
50 asm volatile(
51 " mov x16, lr\n"
52 " mov lr, %[pc]\n"
53 " xpaclri\n"
54 " mov %[pc], lr\n"
55 " mov lr, x16\n"
56 : [pc] "+r"(pc)
57 :
58 : "x16", "lr");
59 return pc;
60 #endif
61 }
62
63 // Authenticate the address stored in {pc_address} and replace it with
64 // {new_pc}, after signing it. {offset_from_sp} is the offset between
65 // {pc_address} and the pointer used as a context for signing.
ReplacePC(Address * pc_address,Address new_pc,int offset_from_sp)66 V8_INLINE void PointerAuthentication::ReplacePC(Address* pc_address,
67 Address new_pc,
68 int offset_from_sp) {
69 uint64_t sp = reinterpret_cast<uint64_t>(pc_address) + offset_from_sp;
70 uint64_t old_pc = static_cast<uint64_t>(*pc_address);
71 #ifdef USE_SIMULATOR
72 uint64_t auth_old_pc = Simulator::AuthPAC(old_pc, sp, Simulator::kPACKeyIB,
73 Simulator::kInstructionPointer);
74 uint64_t raw_old_pc =
75 Simulator::StripPAC(old_pc, Simulator::kInstructionPointer);
76 // Verify that the old address is authenticated.
77 CHECK_EQ(auth_old_pc, raw_old_pc);
78 new_pc = Simulator::AddPAC(new_pc, sp, Simulator::kPACKeyIB,
79 Simulator::kInstructionPointer);
80 #else
81 // Only store newly signed address after we have verified that the old
82 // address is authenticated.
83 asm volatile(
84 " mov x17, %[new_pc]\n"
85 " mov x16, %[sp]\n"
86 " pacib1716\n"
87 " mov %[new_pc], x17\n"
88 " mov x17, %[old_pc]\n"
89 " autib1716\n"
90 " ldr xzr, [x17]\n"
91 : [new_pc] "+&r"(new_pc)
92 : [sp] "r"(sp), [old_pc] "r"(old_pc)
93 : "x16", "x17");
94 #endif
95 *pc_address = new_pc;
96 }
97
98
99 // Sign {pc} using {sp}.
SignAndCheckPC(Address pc,Address sp)100 V8_INLINE Address PointerAuthentication::SignAndCheckPC(Address pc,
101 Address sp) {
102 #ifdef USE_SIMULATOR
103 pc = Simulator::AddPAC(pc, sp, Simulator::kPACKeyIB,
104 Simulator::kInstructionPointer);
105 CHECK(Deoptimizer::IsValidReturnAddress(PointerAuthentication::StripPAC(pc)));
106 return pc;
107 #else
108 asm volatile(
109 " mov x17, %[pc]\n"
110 " mov x16, %[sp]\n"
111 " pacib1716\n"
112 " mov %[pc], x17\n"
113 : [pc] "+r"(pc)
114 : [sp] "r"(sp)
115 : "x16", "x17");
116 CHECK(Deoptimizer::IsValidReturnAddress(PointerAuthentication::StripPAC(pc)));
117 return pc;
118 #endif
119 }
120
121 // clang-format on
122
123 } // namespace internal
124 } // namespace v8
125 #endif // V8_EXECUTION_ARM64_POINTER_AUTHENTICATION_ARM64_H_
126