Re: [RFC PATCH v7 08/29] target/loongarch: Add LoongArch IOCSR instruction

[Richard Henderson]

On 3/28/22 06:57, Xiaojuan Yang wrote:
> +uint64_t helper_iocsr_read(CPULoongArchState *env, target_ulong r_addr,
> +                           uint32_t size)
> +{
> +    int cpuid = env_cpu(env)->cpu_index;
> +    CPUState  *cs = qemu_get_cpu(cpuid);
> +    env = cs->env_ptr;
> +    uint64_t ret;
> +
> +    /*
> +     * Adjust the per core address such as 0x10xx(IPI)/0x18xx(EXTIOI)
> +     */
> +    if (((r_addr & 0xff00) == 0x1000) || ((r_addr & 0xff00) == 0x1800)) {
> +        r_addr = r_addr + ((target_ulong)(cpuid & 0x3) << 8);
> +    }
> +
> +    switch (size) {
> +    case 1:
> +        ret = address_space_ldub(&env->address_space_iocsr, r_addr,
> +                                 MEMTXATTRS_UNSPECIFIED, NULL);
> +        break;
> +    case 2:
> +        ret = address_space_lduw(&env->address_space_iocsr, r_addr,
> +                                 MEMTXATTRS_UNSPECIFIED, NULL);
> +        break;
> +    case 4:
> +        ret = address_space_ldl(&env->address_space_iocsr, r_addr,
> +                                MEMTXATTRS_UNSPECIFIED, NULL);
> +        break;
> +    case 8:
> +        ret = address_space_ldq(&env->address_space_iocsr, r_addr,
> +                                MEMTXATTRS_UNSPECIFIED, NULL);
> +        break;
> +    default:
> +        break;
> +    }
> +
> +    return ret;
> +}

You should have seen an uninitialized use of 'ret' here.
The default case should be g_assert_not_reached().
And the same in helper_iocsr_write.


r~