1 /* 2 * Copyright (C) 2023 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef BERBERIS_GUEST_OS_PRIMITIVES_GUEST_CONTEXT_ARCH_H_ 18 #define BERBERIS_GUEST_OS_PRIMITIVES_GUEST_CONTEXT_ARCH_H_ 19 20 #include <cstdint> 21 #include <cstring> // memcpy 22 23 #include "berberis/base/checks.h" 24 #include "berberis/base/struct_check.h" 25 #include "berberis/guest_state/guest_state.h" 26 27 namespace berberis { 28 29 class GuestContext { 30 public: 31 GuestContext() = default; 32 GuestContext(const GuestContext&) = delete; 33 GuestContext& operator=(const GuestContext&) = delete; 34 Save(const CPUState * cpu)35 void Save(const CPUState* cpu) { 36 // Save everything. 37 cpu_ = *cpu; 38 39 // Save context. 40 memset(&ctx_, 0, sizeof(ctx_)); 41 static_assert(sizeof(cpu->x) == sizeof(ctx_.uc_mcontext.sc_regs)); 42 memcpy(&ctx_.uc_mcontext.sc_regs, cpu->x, sizeof(ctx_.uc_mcontext.sc_regs)); 43 // Use double FP state since GuestState supports both F and D extensions using 64-bit registers. 44 static_assert(sizeof(cpu->f) == sizeof(ctx_.uc_mcontext.sc_fpregs.d.f)); 45 memcpy(ctx_.uc_mcontext.sc_fpregs.d.f, cpu->f, sizeof(ctx_.uc_mcontext.sc_fpregs.d.f)); 46 ctx_.uc_mcontext.sc_regs.pc = cpu->insn_addr; 47 } 48 Restore(CPUState * cpu)49 void Restore(CPUState* cpu) const { 50 // Restore everything. 51 *cpu = cpu_; 52 53 // Overwrite from context. 54 memcpy(cpu->x, &ctx_.uc_mcontext.sc_regs, sizeof(ctx_.uc_mcontext.sc_regs)); 55 memcpy(cpu->f, ctx_.uc_mcontext.sc_fpregs.d.f, sizeof(ctx_.uc_mcontext.sc_fpregs.d.f)); 56 cpu->insn_addr = ctx_.uc_mcontext.sc_regs.pc; 57 } 58 ptr()59 void* ptr() { return &ctx_; } 60 61 private: 62 // See bionic/libc/kernel/uapi/asm-riscv/asm/ptrace.h 63 struct Guest_user_regs_struct { 64 uint64_t pc; 65 uint64_t ra; 66 uint64_t sp; 67 uint64_t gp; 68 uint64_t tp; 69 uint64_t t0; 70 uint64_t t1; 71 uint64_t t2; 72 uint64_t s0; 73 uint64_t s1; 74 uint64_t a0; 75 uint64_t a1; 76 uint64_t a2; 77 uint64_t a3; 78 uint64_t a4; 79 uint64_t a5; 80 uint64_t a6; 81 uint64_t a7; 82 uint64_t s2; 83 uint64_t s3; 84 uint64_t s4; 85 uint64_t s5; 86 uint64_t s6; 87 uint64_t s7; 88 uint64_t s8; 89 uint64_t s9; 90 uint64_t s10; 91 uint64_t s11; 92 uint64_t t3; 93 uint64_t t4; 94 uint64_t t5; 95 uint64_t t6; 96 }; 97 struct Guest__riscv_f_ext_state { 98 uint32_t f[32]; 99 uint32_t fcsr; 100 }; 101 struct Guest__riscv_d_ext_state { 102 uint64_t f[32]; 103 uint32_t fcsr; 104 }; 105 struct Guest__riscv_q_ext_state { 106 uint64_t f[64] __attribute__((aligned(16))); 107 uint32_t fcsr; 108 uint32_t reserved[3]; 109 }; 110 union Guest__riscv_fp_state { 111 struct Guest__riscv_f_ext_state f; 112 struct Guest__riscv_d_ext_state d; 113 struct Guest__riscv_q_ext_state q; 114 }; 115 116 // See bionic/libc/kernel/uapi/asm-riscv/asm/sigcontext.h 117 struct Guest_sigcontext { 118 struct Guest_user_regs_struct sc_regs; 119 union Guest__riscv_fp_state sc_fpregs; 120 }; 121 122 // See bionic/libc/kernel/uapi/asm-riscv/asm/ucontext.h 123 struct Guest_ucontext { 124 uint64_t uc_flags; 125 Guest_ucontext* uc_link; 126 // We assume guest stack_t is compatible with host (see RunGuestSyscall___NR_sigaltstack). 127 stack_t uc_stack; 128 Guest_sigset_t uc_sigmask; 129 uint8_t __linux_unused[1024 / 8 - sizeof(Guest_sigset_t)]; 130 Guest_sigcontext uc_mcontext; 131 }; 132 133 CHECK_STRUCT_LAYOUT(Guest_ucontext, 7680, 128); 134 CHECK_FIELD_LAYOUT(Guest_ucontext, uc_flags, 0, 64); 135 CHECK_FIELD_LAYOUT(Guest_ucontext, uc_link, 64, 64); 136 CHECK_FIELD_LAYOUT(Guest_ucontext, uc_stack, 128, 192); 137 // Bionic RISC-V sigset_t is 64 bits (generic implementation). 138 CHECK_FIELD_LAYOUT(Guest_ucontext, uc_sigmask, 320, 64); 139 CHECK_FIELD_LAYOUT(Guest_ucontext, uc_mcontext, 1408, 6272); 140 141 Guest_ucontext ctx_; 142 CPUState cpu_; 143 }; 144 145 } // namespace berberis 146 147 #endif // BERBERIS_GUEST_OS_PRIMITIVES_GUEST_CONTEXT_ARCH_H_