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authorTuan Ta <qtt2@cornell.edu>2017-09-17 12:57:21 -0400
committerTuan Ta <qtt2@cornell.edu>2018-01-10 01:02:53 +0000
commit3fb4d59a9d66d729b292bf804a8b5fdbe6e40d89 (patch)
treebba3357dcfe7cd0020b720b48c82743f3aa8de13
parente8236503ce70ea83f4f61716f54421b32ce009ce (diff)
downloadgem5-3fb4d59a9d66d729b292bf804a8b5fdbe6e40d89.tar.xz
arch-riscv,sim: Support clone syscall in RISC-V
(1) This patch sets a correct order of clone syscall's arguments for RISC-V. Linux kernel 4.15 uses CLONE_BACKWARDS flag by default for RISC-V. The flag in the Linux kernel defines the list of clone syscall's arguments in the following order: clone_flags (flags) newsp (newStack) parent_tidptr (ptidPtr) tls (tlsPtr) child_tidptr (ctidPtr) Code reference: https://github.com/riscv/riscv-linux/blob/master/kernel/fork.c https://github.com/riscv/riscv-linux/blob/master/arch/riscv/Kconfig (2) This patch copies a parent thread's register values to its child thread in clone syscall. Change-Id: I2eb1c8e80990861080ce7153503ed784fb2c7bdf Reviewed-on: https://gem5-review.googlesource.com/6904 Maintainer: Brandon Potter <Brandon.Potter@amd.com> Reviewed-by: Alec Roelke <ar4jc@virginia.edu>
-rw-r--r--src/sim/syscall_emul.hh14
1 files changed, 13 insertions, 1 deletions
diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index 2ffd6d6ae..ef61299a0 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -1241,11 +1241,23 @@ SyscallReturn
cloneFunc(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc)
{
int index = 0;
+
TheISA::IntReg flags = p->getSyscallArg(tc, index);
TheISA::IntReg newStack = p->getSyscallArg(tc, index);
Addr ptidPtr = p->getSyscallArg(tc, index);
+
+#if THE_ISA == RISCV_ISA
+ /**
+ * Linux kernel 4.15 sets CLONE_BACKWARDS flag for RISC-V.
+ * The flag defines the list of clone() arguments in the following
+ * order: flags -> newStack -> ptidPtr -> tlsPtr -> ctidPtr
+ */
+ Addr tlsPtr M5_VAR_USED = p->getSyscallArg(tc, index);
+ Addr ctidPtr = p->getSyscallArg(tc, index);
+#else
Addr ctidPtr = p->getSyscallArg(tc, index);
Addr tlsPtr M5_VAR_USED = p->getSyscallArg(tc, index);
+#endif
if (((flags & OS::TGT_CLONE_SIGHAND)&& !(flags & OS::TGT_CLONE_VM)) ||
((flags & OS::TGT_CLONE_THREAD) && !(flags & OS::TGT_CLONE_SIGHAND)) ||
@@ -1340,7 +1352,7 @@ cloneFunc(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc)
ctc->setMiscReg(TheISA::MISCREG_ASI, TheISA::ASI_PRIMARY);
for (int y = 8; y < 32; y++)
ctc->setIntReg(y, tc->readIntReg(y));
-#elif THE_ISA == ARM_ISA or THE_ISA == X86_ISA
+#elif THE_ISA == ARM_ISA or THE_ISA == X86_ISA or THE_ISA == RISCV_ISA
TheISA::copyRegs(tc, ctc);
#endif