[Bug 1757363] Re: infinite loop due to improper deal with "eret" on mips32

[Alexey]

This seems to affect me too; I have a loop on interrupt handler after
the first interrupt called.

The version of qemu is latest 3.1 from upstream, so this is not Ubuntu
issue.

However, have you done with it? Just commenting out

env->CP0_Status &= ~(1 << CP0St_EXL);

does not help.

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https://bugs.launchpad.net/bugs/1757363

Title:
  infinite loop due to improper deal with "eret" on mips32

Status in QEMU:
  Expired

Bug description:
  1.qemu 2.9.1 release on the official web build with tcg
  2.cmd: qemu-system-mips -kernel kernelfile
  3. host: ubuntu 16.04.1 with linux kernel 4.6.2 x86_64
     guest: mips bigendian 32bit (tplink firmware)

  
  detail:

  static inline void exception_return(CPUMIPSState *env)
  {
      debug_pre_eret(env);
      if (env->CP0_Status & (1 << CP0St_ERL)) {
          set_pc(env, env->CP0_ErrorEPC);
          env->CP0_Status &= ~(1 << CP0St_ERL);
      } else {
          set_pc(env, env->CP0_EPC);
          env->CP0_Status &= ~(1 << CP0St_EXL);====================> ISSUE????
      }
      compute_hflags(env);
      debug_post_eret(env);
  }

  void helper_eret(CPUMIPSState *env)
  {
      exception_return(env);
      env->lladdr = 1;
  }

  
  In the Issue Line, there is no check CP0_Status whether int is disabled 
(should not enter int routine),
  that result in the cpu can not jump out the int routine.

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