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arch-riscv,sim: Support clone syscall in RISC-V

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(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>
This commit is contained in:
Tuan Ta
2017-09-17 12:57:21 -04:00
parent e8236503ce
commit 3fb4d59a9d
1 changed files with 13 additions and 1 deletions
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14
src/sim/syscall_emul.hh
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@@ -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