linux-kernel - Re: [PATCH 06/16] Enforce minimum alignment of 1 page on allocations. The efi_high_alloc() and efi_low_alloc() functions use the EFI_ALLOCATE_ADDRESS option to the EFI function allocate_pages(), which requires a minimum of page alignment, and rejects all other requests.

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Message-Id: <20130830130811.7D7453E102A@localhost>
Date:	Fri, 30 Aug 2013 14:08:11 +0100
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Roy Franz <roy.franz@...aro.org>, linux-kernel@...r.kernel.org,
	linux-efi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	matt.fleming@...el.com, linux@....linux.org.uk
Cc:	Roy Franz <roy.franz@...aro.org>, dave.martin@....com,
	leif.lindholm@...aro.org, msalter@...hat.com
Subject: Re: [PATCH 06/16] Enforce minimum alignment of 1 page on allocations. The efi_high_alloc() and efi_low_alloc() functions use the EFI_ALLOCATE_ADDRESS option to the EFI function allocate_pages(), which requires a minimum of page alignment, and rejects all other requests.

On Fri,  9 Aug 2013 16:26:07 -0700, Roy Franz <roy.franz@...aro.org> wrote:
> The existing code could fail to allocate depending
> on allocation size, as although repeated allocation
> attempts were made, none were guaranteed to be page
> aligned.

Commit message. Otherwise looks reasonable.

Reviewed-by: Grant Likely <grant.likely@...aro.org>

> Signed-off-by: Roy Franz <roy.franz@...aro.org>
> ---
>  drivers/firmware/efi/efi-stub-helper.c |   14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
> index 1d0a079..647b3ba 100644
> --- a/drivers/firmware/efi/efi-stub-helper.c
> +++ b/drivers/firmware/efi/efi-stub-helper.c
> @@ -105,6 +105,13 @@ static efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
>  	if (status != EFI_SUCCESS)
>  		goto fail;
>  
> +	/* Enforce minimum alignment that EFI requires when requesting
> +	 * a specific address.  We are doing page-based allocations,
> +	 * so we must be aligned to a page.
> +	 */
> +	if (align < EFI_PAGE_SIZE)
> +		align = EFI_PAGE_SIZE;
> +
>  	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
>  again:
>  	for (i = 0; i < map_size / desc_size; i++) {
> @@ -184,6 +191,13 @@ static efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
>  	if (status != EFI_SUCCESS)
>  		goto fail;
>  
> +	/* Enforce minimum alignment that EFI requires when requesting
> +	 * a specific address.  We are doing page-based allocations,
> +	 * so we must be aligned to a page.
> +	 */
> +	if (align < EFI_PAGE_SIZE)
> +		align = EFI_PAGE_SIZE;
> +
>  	nr_pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
>  	for (i = 0; i < map_size / desc_size; i++) {
>  		efi_memory_desc_t *desc;
> -- 
> 1.7.10.4
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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