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2017-01-27riscv: Fix crash when syscall argument reg index is too highAlec Roelke
By default, doSyscall gets the values of six registers to be used for system call arguments. RISC-V, by convention, only has four. Because RISC-V's implementation of these indices is as arrays of integers rather than as base indices plus offsets, trying to get the fifth argument register's value will cause a crash. This patch fixes that by returning 0 for any index higher than 3. Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
2016-11-09style: [patch 3/22] reduce include dependencies in some headersBrandon Potter
Used cppclean to help identify useless includes and removed them. This involved erroneously included headers, but also cases where forward declarations could have been used rather than a full include.
2016-11-09syscall_emul: [patch 2/22] move SyscallDesc into its own .hh and .ccBrandon Potter
The class was crammed into syscall_emul.hh which has tons of forward declarations and template definitions. To clean it up a bit, moved the class into separate files and commented the class with doxygen style comments. Also, provided some encapsulation by adding some accessors and a mutator. The syscallreturn.hh file was renamed syscall_return.hh to make it consistent with other similarly named files in the src/sim directory. The DPRINTF_SYSCALL macro was moved into its own header file with the include the Base and Verbose flags as well. --HG-- rename : src/sim/syscallreturn.hh => src/sim/syscall_return.hh
2016-11-30riscv: [Patch 7/5] Corrected LRSC semanticsAlec Roelke
RISC-V makes use of load-reserved and store-conditional instructions to enable creation of lock-free concurrent data manipulation as well as ACQUIRE and RELEASE semantics for memory ordering of LR, SC, and AMO instructions (the latter of which do not follow LR/SC semantics). This patch is a correction to patch 4, which added these instructions to the implementation of RISC-V. It modifies locked_mem.hh and the implementations of lr.w, sc.w, lr.d, and sc.d to apply the proper gem5 flags and return the proper values. An important difference between gem5's LLSC semantics and RISC-V's LR/SC ones, beyond the name, is that gem5 uses 0 to indicate failure and 1 to indicate success, while RISC-V is the opposite. Strictly speaking, RISC-V uses 0 to indicate success and nonzero to indicate failure where the value would indicate the error, but currently only 1 is reserved as a failure code by the ISA reference. This is the seventh patch in the series which originally consisted of five patches that added the RISC-V ISA to gem5. The original five patches added all of the instructions and added support for more detailed CPU models and the sixth patch corrected the implementations of Linux constants and structs. There will be an eighth patch that adds some regression tests for the instructions. [Removed some commented-out code from locked_mem.hh.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30riscv: [Patch 6/5] Improve Linux emulation for RISC-VAlec Roelke
This is an add-on patch for the original series that implemented RISC-V that improves the implementation of Linux emulation for SE mode. Basically it cleans up linux/linux.hh by removing constants that haven't been defined for the RISC-V Linux proxy kernel and rearranging the stat struct so it aligns with RISC-V's implementation of it. It also adds placeholders for system calls that have been given numbers in RISC-V but haven't been given implementations yet. These system calls are as follows: - readlinkat - sigprocmask - ioctl - clock_gettime - getrusage - getrlimit - setrlimit The first five patches implemented RISC-V with the base ISA and multiply, floating point, and atomic extensions and added support for detailed CPU models with memory timing. [Fixed incompatibility with changes made from patch 1.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30riscv: [Patch 5/5] Added missing support for timing CPU modelsAlec Roelke
Last of five patches adding RISC-V to GEM5. This patch adds support for timing, minor, and detailed CPU models that was missing in the last four, which basically consists of handling timing-mode memory accesses and telling the minor and detailed models what a no-op instruction should be (addi zero, zero, 0). Patches 1-4 introduced RISC-V and implemented the base instruction set, RV64I, and added the multiply, floating point, and atomic memory extensions, RV64MAFD. [Fixed compatibility with edit from patch 1.] [Fixed compatibility with hg copy edit from patch 1.] [Fixed some style errors in locked_mem.hh.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30riscv: [Patch 4/5] Added RISC-V atomic memory extension RV64AAlec Roelke
Fourth of five patches adding RISC-V to GEM5. This patch adds the RV64A extension, which includes atomic memory instructions. These instructions atomically read a value from memory, modify it with a value contained in a source register, and store the original memory value in the destination register and modified value back into memory. Because this requires two memory accesses and GEM5 does not support two timing memory accesses in a single instruction, each of these instructions is split into two micro- ops: A "load" micro-op, which reads the memory, and a "store" micro-op, which modifies and writes it back. Each atomic memory instruction also has two bits that acquire and release a lock on its memory location. Additionally, there are atomic load and store instructions that only either load or store, but not both, and can acquire or release memory locks. Note that because the current implementation of RISC-V only supports one core and one thread, it doesn't make sense to make use of AMO instructions. However, they do form a standard extension of the RISC-V ISA, so they are included mostly as a placeholder for when multithreaded execution is implemented. As a result, any tests for their correctness in a future patch may be abbreviated. Patch 1 introduced RISC-V and implemented the base instruction set, RV64I; patch 2 implemented the integer multiply extension, RV64M; and patch 3 implemented the single- and double-precision floating point extensions, RV64FD. Patch 5 will add support for timing, minor, and detailed CPU models that isn't present in patches 1-4. [Added missing file amo.isa] [Replaced information removed from initial patch that was missed during division into multiple patches.] [Fixed some minor formatting issues.] [Fixed oversight where LR and SC didn't have both AQ and RL flags.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30riscv: [Patch 3/5] Added RISCV floating point extensions RV64FDAlec Roelke
Third of five patches adding RISC-V to GEM5. This patch adds the RV64FD extensions, which include single- and double-precision floating point instructions. Patch 1 introduced RISC-V and implemented the base instruction set, RV64I and patch 2 implemented the integer multiply extension, RV64M. Patch 4 will implement the atomic memory instructions, RV64A, and patch 5 will add support for timing, minor, and detailed CPU models that is missing from the first four patches. [Fixed exception handling in floating-point instructions to conform better to IEEE-754 2008 standard and behavior of the Chisel-generated RISC-V simulator.] [Fixed style errors in decoder.isa.] [Fixed some fuzz caused by modifying a previous patch.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30riscv: [Patch 2/5] Added RISC-V multiply extension RV64MAlec Roelke
Second of five patches adding RISC-V to GEM5. This patch adds the RV64M extension, which includes integer multiply and divide instructions. Patch 1 introduced RISC-V and implemented the base instruction set, RV64I. Patch 3 will implement the floating point extensions, RV64FD; patch 4 will implement the atomic memory instructions, RV64A; and patch 5 will add support for timing, minor, and detailed CPU models that is missing from the first four patches. [Added mulw instruction that was missed when dividing changes among patches.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30arch: [Patch 1/5] Added RISC-V base instruction set RV64IAlec Roelke
First of five patches adding RISC-V to GEM5. This patch introduces the base 64-bit ISA (RV64I) in src/arch/riscv for use with syscall emulation. The multiply, floating point, and atomic memory instructions will be added in additional patches, as well as support for more detailed CPU models. The loader is also modified to be able to parse RISC-V ELF files, and a "Hello world\!" example for RISC-V is added to test-progs. Patch 2 will implement the multiply extension, RV64M; patch 3 will implement the floating point (single- and double-precision) extensions, RV64FD; patch 4 will implement the atomic memory instructions, RV64A, and patch 5 will add support for timing, minor, and detailed CPU models that is missing from the first four patches (such as handling locked memory). [Removed several unused parameters and imports from RiscvInterrupts.py, RiscvISA.py, and RiscvSystem.py.] [Fixed copyright information in RISC-V files copied from elsewhere that had ARM licenses attached.] [Reorganized instruction definitions in decoder.isa so that they are sorted by opcode in preparation for the addition of ISA extensions M, A, F, D.] [Fixed formatting of several files, removed some variables and instructions that were missed when moving them to other patches, fixed RISC-V Foundation copyright attribution, and fixed history of files copied from other architectures using hg copy.] [Fixed indentation of switch cases in isa.cc.] [Reorganized syscall descriptions in linux/process.cc to remove large number of repeated unimplemented system calls and added implmementations to functions that have received them since it process.cc was first created.] [Fixed spacing for some copyright attributions.] [Replaced the rest of the file copies using hg copy.] [Fixed style check errors and corrected unaligned memory accesses.] [Fix some minor formatting mistakes.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power <jason@lowepower.com>