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_BASE_CONFIG_H_ 18 #define BERBERIS_BASE_CONFIG_H_ 19 20 #include <cstddef> 21 #include <cstdint> 22 23 namespace berberis::config { 24 25 // Size of the stack frame allocated in translated code prologue. 26 // As translated code ('slow') prologue executes much less frequently than 27 // region ('fast') prologue, it makes sense to allocate a frame there that 28 // suits most regions. Outstanding regions will expand it in their prologue. 29 // Assume the stack is properly aligned when entering translated code. 30 // TODO(b/232598137): If we discover that most regions don't need stack frame 31 // at all, then we might want to avoid extra altering of stack pointer in 32 // translated code prologue and keep stack misaligned. Then we'll need a 33 // kStackMisalignAtTranslatedCode config variable. 34 // TODO(b/232598137): 12 is what we get on x86-32 after stack alignment, update 35 // with, say, 90-percentile of (dynamic) frame size. 36 inline constexpr uint32_t kFrameSizeAtTranslatedCode = sizeof(size_t) == 4 ? 12u : 8u; 37 // Attention: This flag traces every entry to RunGeneratedCode which 38 // may be *very* slow especially if kAllJumpsExitGeneratedCode flag is 39 // enabled. 40 inline constexpr bool kTraceGeneratedCode = false; 41 // Setting this to true enables instrumentation of every executed region in the 42 // main execution loop (ExecuteGuest). 43 inline constexpr bool kAllJumpsExitGeneratedCode = false; 44 // Eliminate overhead of exiting/reentering generated code by searching in 45 // the translation cache directly from the generated code. 46 inline constexpr bool kLinkJumpsBetweenRegions = !kAllJumpsExitGeneratedCode; 47 // Generate local jumps if jump's target address falls within the 48 // current region. If false dispatch to another region instead. 49 inline constexpr bool kLinkJumpsWithinRegion = !kAllJumpsExitGeneratedCode; 50 // Guest page size. Always 4K for now. 51 inline constexpr size_t kGuestPageSize = 4096; 52 // Number of hard registers assumed by the register allocator. 53 inline constexpr uint32_t kMaxHardRegs = 64u; 54 // Threshold for switching between gears 55 inline constexpr uint32_t kGearSwitchThreshold = 1000; 56 // Scratch area size for use in intrinsics with instructions which may only work with memory. 57 inline constexpr uint32_t kScratchAreaSize = 32; 58 // Scratch area alignment (important if we would use Movaps/Movapd). 59 inline constexpr uint32_t kScratchAreaAlign = 16; 60 // Scratch area slot size if more than one scratch is needed. 61 inline constexpr uint32_t kScratchAreaSlotSize = 8; 62 63 } // namespace berberis::config 64 65 #endif // BERBERIS_BASE_CONFIG_H_ 66