Re: [kvm-unit-tests PATCH v9 08/12] s390x: retrieve decimal and hexadecimal kernel parameters

[Janosch Frank <frankja@linux.ibm.com>]

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On 6/15/20 11:31 AM, Pierre Morel wrote:
> We often need to retrieve hexadecimal kernel parameters.
> Let's implement a shared utility to do it.

Often?

My main problem with this patch is that it doesn't belong into the s390
library. atol() is already in string.c so htol() can be next to it.

util.c already has parse_keyval() so you should be able to extend it a
bit for hex values and add a function below that goes through argv[].

CCing Andrew as he wrote most of the common library

> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  lib/s390x/kernel-args.c | 60 +++++++++++++++++++++++++++++++++++++++++
>  lib/s390x/kernel-args.h | 18 +++++++++++++
>  s390x/Makefile          |  1 +
>  3 files changed, 79 insertions(+)
>  create mode 100644 lib/s390x/kernel-args.c
>  create mode 100644 lib/s390x/kernel-args.h
> 
> diff --git a/lib/s390x/kernel-args.c b/lib/s390x/kernel-args.c
> new file mode 100644
> index 0000000..2d3b2c2
> --- /dev/null
> +++ b/lib/s390x/kernel-args.c
> @@ -0,0 +1,60 @@
> +/*
> + * Retrieving kernel arguments
> + *
> + * Copyright (c) 2020 IBM Corp
> + *
> + * Authors:
> + *  Pierre Morel <pmorel@linux.ibm.com>
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2.
> + */
> +
> +#include <libcflat.h>
> +#include <string.h>
> +#include <asm/arch_def.h>
> +#include <kernel-args.h>
> +
> +static const char *hex_digit = "0123456789abcdef";
> +
> +static unsigned long htol(char *s)
> +{
> +	unsigned long v = 0, shift = 0, value = 0;
> +	int i, digit, len = strlen(s);
> +
> +	for (shift = 0, i = len - 1; i >= 0; i--, shift += 4) {
> +		digit = s[i] | 0x20;	/* Set lowercase */
> +		if (!strchr(hex_digit, digit))
> +			return 0;	/* this is not a digit ! */
> +
> +		if (digit <= '9')
> +			v = digit - '0';
> +		else
> +			v = digit - 'a' + 10;
> +		value += (v << shift);
> +	}
> +
> +	return value;
> +}
> +
> +int kernel_arg(int argc, char *argv[], const char *str, unsigned long *val)
> +{
> +	int i, ret;
> +	char *p, *q;
> +
> +	for (i = 0; i < argc; i++) {
> +		ret = strncmp(argv[i], str, strlen(str));
> +		if (ret)
> +			continue;
> +		p = strchr(argv[i], '=');
> +		if (!p)
> +			return -1;
> +		q = strchr(p, 'x');
> +		if (!q)
> +			*val = atol(p + 1);
> +		else
> +			*val = htol(q + 1);
> +		return 0;
> +	}
> +	return -2;
> +}
> diff --git a/lib/s390x/kernel-args.h b/lib/s390x/kernel-args.h
> new file mode 100644
> index 0000000..a88e34e
> --- /dev/null
> +++ b/lib/s390x/kernel-args.h
> @@ -0,0 +1,18 @@
> +/*
> + * Kernel argument
> + *
> + * Copyright (c) 2020 IBM Corp
> + *
> + * Authors:
> + *  Pierre Morel <pmorel@linux.ibm.com>
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2.
> + */
> +
> +#ifndef KERNEL_ARGS_H
> +#define KERNEL_ARGS_H
> +
> +int kernel_arg(int argc, char *argv[], const char *str, unsigned long *val);
> +
> +#endif
> diff --git a/s390x/Makefile b/s390x/Makefile
> index ddb4b48..47a94cc 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -51,6 +51,7 @@ cflatobjs += lib/s390x/sclp-console.o
>  cflatobjs += lib/s390x/interrupt.o
>  cflatobjs += lib/s390x/mmu.o
>  cflatobjs += lib/s390x/smp.o
> +cflatobjs += lib/s390x/kernel-args.o
>  
>  OBJDIRS += lib/s390x
>  
> 



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