[LEDE-DEV] [PATCH] uqmi: Fix for big endian arch

[Oskari Lemmelä]

Hi,

This libubox patch seems to fix issue.

root at test:/tmp# ./uqmi -d /dev/cdc-wdm0 --wda-get-data-format
qmi_parse_wda_get_data_format_response: Invalid TLV length in message, 
tlv=0x11, len=4
"unknown"
root at test:/tmp# ./uqmi-libubox-patch  -d /dev/cdc-wdm0 --wda-get-data-format
"raw-ip"

Oskari

On 04/07/2018 11:43 AM, Felix Fietkau wrote:
> On 2018-04-01 16:22, Oskari Lemmela wrote:
>> leXX_to_cpu function messes up get_next value in big endian arch.
>>
>> Signed-off-by: Oskari Lemmelä <oskari at lemmela.net>
> Please try this libubox patch instead. It should ensure that
> the argument is evaluated only once.
> 
> --- a/utils.h
> +++ b/utils.h
> @@ -117,21 +117,29 @@ int clock_gettime(int type, struct timespec *tv);
>   	(((uint64_t)(x) & (uint64_t)0x00ff000000000000ULL) >> 40) |	\
>   	(((uint64_t)(x) & (uint64_t)0xff00000000000000ULL) >> 56)))
>   
> +/*
> + * This returns a constant expression while determining if an argument is
> + * a constant expression, most importantly without evaluating the argument.
> + */
> +#define __is_constant(x)						\
> +	(sizeof(int) == sizeof(*(1 ? ((void*)((long)(x) * 0l)) : (int*)1)))
>   
> -static inline uint16_t __u_bswap16(uint16_t val)
> -{
> -	return ((val >> 8) & 0xffu) | ((val & 0xffu) << 8);
> -}
> +#define __eval_once(func, x)						\
> +	({ typeof(x) __x = x; func(__x); })
> +
> +#define __eval_safe(func, x)						\
> +	__builtin_choose_expr(__is_constant(x),				\
> +			      func(x), __eval_once(func, x))
>   
>   #if __BYTE_ORDER == __LITTLE_ENDIAN
>   
> -#define cpu_to_be64(x) __constant_swap64(x)
> -#define cpu_to_be32(x) __constant_swap32(x)
> -#define cpu_to_be16(x) __constant_swap16(x)
> +#define cpu_to_be64(x) __eval_safe(__constant_swap64, x)
> +#define cpu_to_be32(x) __eval_safe(__constant_swap32, x)
> +#define cpu_to_be16(x) __eval_safe(__constant_swap16, x)
>   
> -#define be64_to_cpu(x) __constant_swap64(x)
> -#define be32_to_cpu(x) __constant_swap32(x)
> -#define be16_to_cpu(x) __constant_swap16(x)
> +#define be64_to_cpu(x) __eval_safe(__constant_swap64, x)
> +#define be32_to_cpu(x) __eval_safe(__constant_swap32, x)
> +#define be16_to_cpu(x) __eval_safe(__constant_swap16, x)
>   
>   #define cpu_to_le64(x) (x)
>   #define cpu_to_le32(x) (x)
> @@ -143,13 +151,13 @@ static inline uint16_t __u_bswap16(uint16_t val)
>   
>   #else /* __BYTE_ORDER == __LITTLE_ENDIAN */
>   
> -#define cpu_to_le64(x) __constant_swap64(x)
> -#define cpu_to_le32(x) __constant_swap32(x)
> -#define cpu_to_le16(x) __constant_swap16(x)
> +#define cpu_to_le64(x) __eval_safe(__constant_swap64, x)
> +#define cpu_to_le32(x) __eval_safe(__constant_swap32, x)
> +#define cpu_to_le16(x) __eval_safe(__constant_swap16, x)
>   
> -#define le64_to_cpu(x) __constant_swap64(x)
> -#define le32_to_cpu(x) __constant_swap32(x)
> -#define le16_to_cpu(x) __constant_swap16(x)
> +#define le64_to_cpu(x) __eval_safe(__constant_swap64, x)
> +#define le32_to_cpu(x) __eval_safe(__constant_swap32, x)
> +#define le16_to_cpu(x) __eval_safe(__constant_swap16, x)
>   
>   #define cpu_to_be64(x) (x)
>   #define cpu_to_be32(x) (x)
> 
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