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target/arm: fix missing exception class

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The DAIF and PAC checks used raise_exception_ra to raise an exception
and unwind CPU state but raise_exception_ra is currently designed for
handling data aborts as the syndrome is partially precomputed and
encoded in the TB and then merged in merge_syn_data_abort when handling
the data abort.  Using raise_exception_ra for DAIF and PAC checks
results in an empty syndrome being retrieved from data[2] in
restore_state_to_opc and setting ESR to 0.  This manifested as:

  kvm [571]: Unknown exception class: esr: 0x000000 –
  Unknown/Uncategorized

when launching a KVM guest when the host qemu used a CPU supporting
EL2+pointer authentication and enabling pointer authentication in the
guest.

Rework raise_exception_ra such that the state is restored before raising
the exception so that the exception is not clobbered by
restore_state_to_opc.

Fixes: 0d43e1a2d2 ("target/arm: Add PAuth helpers")
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jamie Iles <jamie@nuviainc.com>
[PMM: added comment]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Jamie Iles 2021-05-26 13:18:44 +01:00 committed by Peter Maydell
parent 0711a63435
commit 6e0c60a2be
1 changed files with 9 additions and 2 deletions
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11
target/arm/op_helper.c
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@ -63,8 +63,15 @@ void raise_exception(CPUARMState *env, uint32_t excp,
void raise_exception_ra(CPUARMState *env, uint32_t excp, uint32_t syndrome,
uint32_t target_el, uintptr_t ra)
{
CPUState *cs = do_raise_exception(env, excp, syndrome, target_el);
cpu_loop_exit_restore(cs, ra);
CPUState *cs = env_cpu(env);
/*
* restore_state_to_opc() will set env->exception.syndrome, so
* we must restore CPU state here before setting the syndrome
* the caller passed us, and cannot use cpu_loop_exit_restore().
*/
cpu_restore_state(cs, ra, true);
raise_exception(env, excp, syndrome, target_el);
}
uint64_t HELPER(neon_tbl)(CPUARMState *env, uint32_t desc,