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Unbreak -icount mode for RISC-V. #243

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Unbreak -icount mode for RISC-V. #243

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6 changes: 5 additions & 1 deletion target/riscv/op_helper_cheri.c
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Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,11 @@ void HELPER(cspecialrw)(CPUArchState *env, uint32_t cd, uint32_t cs,
{
uintptr_t _host_return_address = GETPC();
// Ensure that env->PCC.cursor is correct:
cpu_restore_state(env_cpu(env), _host_return_address, false);
/*
* This breaks -icount because it triggers early deallocation of the TB.
* It seems that it is only required for logging anyway.
*/
/* cpu_restore_state(env_cpu(env), _host_return_address, false); */
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I believe this is needed to read PCC correctly - we need a cursor that is up to date. But maybe the PC is already saved, might be possible to just assert that pc is current instead of calling this function?

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I re-enabled this and I can't seem to be able to reproduce the -icount bug. I suspect one of the latest merges with upstream qemu changed the code that invalidates the TB. I am hitting a loop condition that seems to trigger an interrupt loop in CheriBSD with -icount auto though. This is an unrelated problem, but I'm not sure how we can fix it.


assert(index <= 31 && "Bug in translator?");
enum SCRAccessMode mode = scr_info[index].access;
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