Commit ec860426 authored by Alex Richardson's avatar Alex Richardson Committed by Aleksandar Markovic
Browse files

target/mips: Fix handling of LL/SC instructions after 7dd547e5 



After 7dd547e5 the env->llval value
is loaded as an unsigned value (instead of sign-extended as before).
Therefore, the CMPXCHG in gen_st_cond() in translate.c fails if the
sign bit is set in the loaded value.

Fix this by sign-extending the llval value for the 32-bit case.

I discovered this issue because FreeBSD MIPS64 was looping forever
in an atomic helper function when trying to start /sbin/init.

Signed-off-by: default avatarAlex Richardson <Alexander.Richardson@cl.cam.ac.uk>
Fixes: 7dd547e5 ("target/mips: Use cpu_*_mmuidx_ra instead of MMU_MODE*_SUFFIX")
Buglink: https://bugs.launchpad.net/qemu/+bug/1861605


Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Aleksandar Markovic <amarkovic@wavecomp.com>
Cc: Aleksandar Rikalo <aleksandar.rikalo@rt-rk.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: default avatarJames Clarke <jrtc27@jrtc27.com>
Signed-off-by: default avatarAleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Tested-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200202153409.28534-1-jrtc27@jrtc27.com>
parent f31160c7

target/mips/op_helper.c

+4 −4
Original line number Diff line number Diff line
@@ -305,7 +305,7 @@ static inline hwaddr do_translate_address(CPUMIPSState *env, 
    }

}



#define HELPER_LD_ATOMIC(name, insn, almask)                                  \

#define HELPER_LD_ATOMIC(name, insn, almask, do_cast)                         \

target_ulong helper_##name(CPUMIPSState *env, target_ulong arg, int mem_idx)  \

{                                                                             \

    if (arg & almask) {                                                       \
@@ -316,12 +316,12 @@ target_ulong helper_##name(CPUMIPSState *env, target_ulong arg, int mem_idx) \ 
    }                                                                         \

    env->CP0_LLAddr = do_translate_address(env, arg, 0, GETPC());             \

    env->lladdr = arg;                                                        \

    env->llval = cpu_##insn##_mmuidx_ra(env, arg, mem_idx, GETPC());          \

    env->llval = do_cast cpu_##insn##_mmuidx_ra(env, arg, mem_idx, GETPC());  \

    return env->llval;                                                        \

}

HELPER_LD_ATOMIC(ll, ldl, 0x3)

HELPER_LD_ATOMIC(ll, ldl, 0x3, (target_long)(int32_t))

#ifdef TARGET_MIPS64

HELPER_LD_ATOMIC(lld, ldq, 0x7)

HELPER_LD_ATOMIC(lld, ldq, 0x7, (target_ulong))

#endif

#undef HELPER_LD_ATOMIC

#endif