linux-kernel - Re: [PATCH v2 3/7] intel-speed-select: Add check for CascadeLake-N models

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Date:   Fri, 04 Oct 2019 10:15:21 -0700
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     Prarit Bhargava <prarit@...hat.com>,
        platform-driver-x86@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...el.com>
Subject: Re: [PATCH v2 3/7] intel-speed-select: Add check for CascadeLake-N
 models

On Thu, 2019-10-03 at 08:11 -0400, Prarit Bhargava wrote:
> Three CascadeLake-N models (6252N, 6230N, and 5218N) have SST-PBF
> support.
> 
> Return an error if the CascadeLake processor is not one of these
> specific
> models.
> 
This patch sigfaults immediately on CLX.

> v2: Add is_clx_n_platform()
> 
> Signed-off-by: Prarit Bhargava <prarit@...hat.com>
> ---
>  .../x86/intel-speed-select/isst-config.c      | 44
> ++++++++++++++++++-
>  1 file changed, 42 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/power/x86/intel-speed-select/isst-config.c
> b/tools/power/x86/intel-speed-select/isst-config.c
> index f4a23678416e..734a7960458c 100644
> --- a/tools/power/x86/intel-speed-select/isst-config.c
> +++ b/tools/power/x86/intel-speed-select/isst-config.c
> @@ -23,6 +23,7 @@ static int debug_flag;
>  static FILE *outf;
>  
>  static int cpu_model;
> +static int cpu_stepping;
>  
>  #define MAX_CPUS_IN_ONE_REQ 64
>  static short max_target_cpus;
> @@ -72,7 +73,16 @@ void debug_printf(const char *format, ...)
>  	va_end(args);
>  }
>  
> -static void update_cpu_model(void)
> +
> +int is_clx_n_platform(void)
> +{
> +	if (cpu_model == 0x55)
> +		if (cpu_stepping == 0x6 || cpu_stepping == 0x7)
> +			return 1;
> +	return 0;
> +}
> +
> +static int update_cpu_model(void)
>  {
>  	unsigned int ebx, ecx, edx;
>  	unsigned int fms, family;
> @@ -82,6 +92,34 @@ static void update_cpu_model(void)
>  	cpu_model = (fms >> 4) & 0xf;
>  	if (family == 6 || family == 0xf)
>  		cpu_model += ((fms >> 16) & 0xf) << 4;
> +
> +	cpu_stepping = fms & 0xf;
> +
> +	/* only three CascadeLake-N models are supported */
> +	if (is_clx_n_platform()) {
> +		FILE *fp;
> +		size_t n;
> +		char *line;
Need n = 0 and *line = NULL here as getline() will require if it has to
allocate.

Anyway I will update the patchset and post after test.

Thanks,
Srinivas
> +		int ret = 1;
> +
> +		fp = fopen("/proc/cpuinfo", "r");
> +		if (!fp)
> +			err(-1, "cannot open /proc/cpuinfo\n");
> +
> +		while (getline(&line, &n, fp) > 0) {
> +			if (strstr(line, "model name")) {
> +				if (strstr(line, "6252N") ||
> +				    strstr(line, "6230N") ||
> +				    strstr(line, "5218N"))
> +					ret = 0;
> +				break;
> +			}
> +		}
> +		free(line);
> +		fclose(fp);
> +		return ret;
> +	}
> +	return 0;
>  }
>  
>  /* Open a file, and exit on failure */
> @@ -1889,7 +1927,9 @@ static void cmdline(int argc, char **argv)
>  		fprintf(stderr, "Feature name and|or command not
> specified\n");
>  		exit(0);
>  	}
> -	update_cpu_model();
> +	ret = update_cpu_model();
> +	if (ret)
> +		err(-1, "Invalid CPU model (%d)\n", cpu_model);
>  	printf("Intel(R) Speed Select Technology\n");
>  	printf("Executing on CPU model:%d[0x%x]\n", cpu_model,
> cpu_model);
>  	set_max_cpu_num();