[PATCH] arm64: Add purgatory printing

[Matthias Brugger]

Hi Geoff,

On 18/09/2020 04:04, Geoff Levand wrote:
> Hi Matthias,
> 
> On 9/17/20 12:38 PM, matthias.bgg at kernel.org wrote:
> Add option to allow purgatory printing on arm64 hardware
>> by passing the console name which should be used.
> 
>> +static uint64_t find_purgatory_sink(const char *console)
>> +{
>> +	int fd, ret;
>> +	char folder[255], device[255], mem[255];
>> +	struct stat sb;
>> +	char buffer[18];
>> +	uint64_t iomem = 0x0;
>> +
>> +	if (!console)
>> +		return 0;
>> +
>> +	sprintf(device, "/sys/class/tty/%s", console);
>> +	if (!stat(folder, &sb) == 0 && S_ISDIR(sb.st_mode)) {
>> +		fprintf(stderr, "kexec: %s: No valid console found for %s\n",
>> +			__func__, device);
>> +		return 0;
>> +	}
>> +
>> +	sprintf(mem, "%s%s", device, "/iomem_base");
>> +	printf("console memory read from %s\n", mem);
>> +
>> +	fd = open(mem, O_RDONLY);
>> +	if (fd < 0) {
>> +		fprintf(stderr, "kexec: %s: No able to open %s\n",
>> +			__func__, mem);
>> +		return 0;
>> +	}
>> +
>> +	memset(buffer, '\0', sizeof(char) * 18);
> 
> I think I'd like to just see 'memset(buffer, 0, sizeof(buffer));'.
> 
>> +	ret = read(fd, buffer, 18);
> 
> And 'ret = read(fd, buffer, sizeof(buffer));'.
> 

You are correct, I'll add it to v2.

Thanks for the quick review!

Matthias

>> +	if (ret < 0) {
>> +		fprintf(stderr, "kexec: %s: not able to read fd\n", __func__);
>> +		close(fd);
>> +		return 0;
>> +	}
>> +
>> +	sscanf(buffer, "%lx", &iomem);
>> +	printf("console memory is at %#lx\n", iomem);
>> +
>> +	close(fd);
>> +	return iomem;
>> +}
>> +
> 
> Otherwise, looks OK.
> 
> -Geoff
>