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authorAlec Roelke <ar4jc@virginia.edu>2017-01-27 15:05:01 -0600
committerAlec Roelke <ar4jc@virginia.edu>2017-01-27 15:05:01 -0600
commite4c57275d38c864798cb04a4644bac90a83572fd (patch)
tree3f26d0e4e89347a9bbead74471e4a16a00695659 /src/arch/riscv
parentc5df9308c99bd4af41b24119e2d86bde9eafdfa4 (diff)
downloadgem5-e4c57275d38c864798cb04a4644bac90a83572fd.tar.xz
riscv: Fix crash when syscall argument reg index is too high
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>
Diffstat (limited to 'src/arch/riscv')
-rw-r--r--src/arch/riscv/process.cc8
1 files changed, 7 insertions, 1 deletions
diff --git a/src/arch/riscv/process.cc b/src/arch/riscv/process.cc
index c1a67ec15..4eb3159af 100644
--- a/src/arch/riscv/process.cc
+++ b/src/arch/riscv/process.cc
@@ -217,7 +217,13 @@ RiscvLiveProcess::argsInit(int pageSize)
RiscvISA::IntReg
RiscvLiveProcess::getSyscallArg(ThreadContext *tc, int &i)
{
- return tc->readIntReg(SyscallArgumentRegs[i++]);
+ // RISC-V only has four system call argument registers by convention, so
+ // if a larger index is requested return 0
+ RiscvISA::IntReg retval = 0;
+ if (i < 4)
+ retval = tc->readIntReg(SyscallArgumentRegs[i]);
+ i++;
+ return retval;
}
void