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linux-user/nios2: Hoist pc advance to the top of EXCP_TRAP

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Note that this advance *should* be done by the translator, as
that's the pc value that's supposed to be generated by hardware.
However, that's a much larger change across sysemu as well.

In the meantime, produce the correct PC for any signals raised
by the trap instruction.  Note the special case of TRAP_BRKPT,
which itself is special cased within the kernel.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-2-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-04-21 08:16:32 -07:00
parent a1755db71e
commit 892d0f4afb
1 changed files with 8 additions and 2 deletions
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10
linux-user/nios2/cpu_loop.c
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@ -40,6 +40,12 @@ void cpu_loop(CPUNios2State *env)
break;
case EXCP_TRAP:
/*
* TODO: This advance should be done in the translator, as
* hardware produces an advanced pc as part of all exceptions.
*/
env->regs[R_PC] += 4;
switch (env->error_code) {
case 0:
qemu_log_mask(CPU_LOG_INT, "\nSyscall\n");
@ -56,7 +62,6 @@ void cpu_loop(CPUNios2State *env)
env->regs[2] = abs(ret);
/* Return value is 0..4096 */
env->regs[7] = ret > 0xfffff000u;
env->regs[R_PC] += 4;
break;
case 1:
@ -69,6 +74,8 @@ void cpu_loop(CPUNios2State *env)
break;
case 31:
qemu_log_mask(CPU_LOG_INT, "\nTrap 31\n");
/* Match kernel's breakpoint_c(). */
env->regs[R_PC] -= 4;
force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->regs[R_PC]);
break;
default:
@ -99,7 +106,6 @@ void cpu_loop(CPUNios2State *env)
o = env->regs[5];
n = env->regs[6];
env->regs[2] = qatomic_cmpxchg(h, o, n) - o;
env->regs[R_PC] += 4;
}
break;
}