[U-Boot] [PATCH v2] display_buffer: fix misaligned buffer

[Wolfgang Denk]

Dear Reinhard Meyer,

In message <1283243000-25427-1-git-send-email-u-boot at emk-elektronik.de> you wrote:
> use a union to cause necessary alignment per architecture
> 
> Signed-off-by: Reinhard Meyer <u-boot at emk-elektronik.de>
> ---
>  lib/display_options.c |   24 +++++++++++++-----------
>  1 files changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/lib/display_options.c b/lib/display_options.c
> index 20319e6..4f2ad69 100644
> --- a/lib/display_options.c
> +++ b/lib/display_options.c
> @@ -101,10 +101,12 @@ void print_size(unsigned long long size, const char *s)
>  #define DEFAULT_LINE_LENGTH_BYTES (16)
>  int print_buffer (ulong addr, void* data, uint width, uint count, uint linelen)
>  {
> -	uint8_t linebuf[MAX_LINE_LENGTH_BYTES + 1];
> -	uint32_t *uip = (void*)linebuf;
> -	uint16_t *usp = (void*)linebuf;
> -	uint8_t *ucp = (void*)linebuf;
> +	/* linebuf as a union causes proper alignment */
> +	union linebuf {
> +		uint32_t ui[MAX_LINE_LENGTH_BYTES/4 + 1];
> +		uint16_t us[MAX_LINE_LENGTH_BYTES/2 + 1];
> +		uint8_t  uc[MAX_LINE_LENGTH_BYTES/1 + 1];

Please replace the magic numbers 4, 2 and 1 by respective sizeof().


>  	int i;
>  
>  	if (linelen*width > MAX_LINE_LENGTH_BYTES)
> @@ -123,21 +125,21 @@ int print_buffer (ulong addr, void* data, uint width, uint count, uint linelen)
>  		for (i = 0; i < linelen; i++) {
>  			uint32_t x;
>  			if (width == 4)
> -				x = uip[i] = *(volatile uint32_t *)data;
> +				x = lb.ui[i] = *(volatile uint32_t *)data;
>  			else if (width == 2)
> -				x = usp[i] = *(volatile uint16_t *)data;
> +				x = lb.us[i] = *(volatile uint16_t *)data;
>  			else
> -				x = ucp[i] = *(volatile uint8_t *)data;
> +				x = lb.uc[i] = *(volatile uint8_t *)data;
>  			printf(" %0*x", width * 2, x);
>  			data += width;
>  		}
>  
>  		/* Print data in ASCII characters */
>  		for (i = 0; i < linelen * width; i++)
> -			if (!isprint(ucp[i]) || ucp[i] >= 0x80)
> -				ucp[i] = '.';
> -		ucp[i] = '\0';
> -		printf("    %s\n", ucp);
> +			if (!isprint(lb.uc[i]) || lb.uc[i] >= 0x80)
> +				lb.uc[i] = '.';

Please fix this old bug: the multi-line statement needs braces.


Best regards,

Wolfgang Denk

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