Re: [PATCH v2 2/3] linux-user: Emulate /proc/cpuinfo on aarch64 and arm

[Richard Henderson <richard.henderson@linaro.org>]

On 8/1/23 16:08, Helge Deller wrote:
> +#if defined(TARGET_AARCH64) || defined(TARGET_ARM)
> +static int open_cpuinfo(CPUArchState *cpu_env, int fd)
> +{
> +    const int is64 = TARGET_ABI_BITS == 64;
> +    ARMCPU *cpu = ARM_CPU(thread_cpu);
> +    uint64_t midr = cpu->midr;
> +    const int rev  = (midr & 0xf);
> +    const int arch = is64 ? 8 : 7;

The 32-bit arch is not automatically v7: -cpu max is v8 and -cpu ti925t is v4.

You need an if ladder for this:

     if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
         arch = 8;
     } else if (arm_feature(&cpu->env, ARM_FEATURE_V7)) {
         arch = 7;
     } else if (arm_feature(&cpu->env, ARM_FEATURE_V6)) {
         arch = 6;
     } else if (arm_feature(&cpu->env, ARM_FEATURE_V5)) {
         arch = 5;
     } else {
         arch = 4;
     }

Also,

     ref = FIELD_EX64(cpu->midr, MIDR_EL1, REVISION);

etc, instead of masking by hand.

> +        dprintf(fd, "model name\t: ARMv%d Processor rev %d (%s%c)\n",
> +            arch, rev, is64 ? "v8" : "armv7",

Will need adjustment.

> +#if TARGET_BIG_ENDIAN
> +            'b'
> +#else
> +            'l'
> +#endif

Don't need an ifdef: (TARGET_BIG_ENDIAN ? 'b' : 'l').

> +        dprintf(fd, "CPU implementer\t: %#02x\n", (int)(midr >> 24) & 0xff);
> +        dprintf(fd, "CPU architecture: %d\n",     arch);
> +        dprintf(fd, "CPU variant\t: %#x\n",       (int)(midr >> 20) & 0xf );
> +        dprintf(fd, "CPU part\t: %#03x\n",        (int)(midr >> 4) & 0xfff);
> +        dprintf(fd, "CPU revision\t: %d\n\n",     rev);
> +    }

FIELD_EX64(midr, MIDR_EL1, ...)

Though I have some memory of these fields changing across arch versions.
You might need to extract them earlier, within the if ladder.


r~