linux-kernel - Re: [PATCH v2 1/1] efi/libstub: describe memory functions

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Date:   Mon, 17 Feb 2020 15:50:57 -0800
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Heinrich Schuchardt <xypron.glpk@....de>,
        Ard Biesheuvel <ardb@...nel.org>
Cc:     linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/1] efi/libstub: describe memory functions

On 2/17/20 1:54 PM, Heinrich Schuchardt wrote:
> Provide descriptions of:
> 
> * efi_get_memory_map()
> * efi_low_alloc_above()
> * efi_free()
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>
> ---
> v2:
> 	point out how efi_free() is rounding up the memory size
> ---
>  drivers/firmware/efi/libstub/mem.c | 36 ++++++++++++++++++++++++++++--
>  1 file changed, 34 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
> index c25fd9174b74..49116b9b0801 100644
> --- a/drivers/firmware/efi/libstub/mem.c
> +++ b/drivers/firmware/efi/libstub/mem.c
> @@ -16,6 +16,15 @@ static inline bool mmap_has_headroom(unsigned long buff_size,
>  	return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
>  }
> 

Hi,
Please use proper kernel-doc notation. See below...

> +/**
> + * efi_get_memory_map() - get memory map
> + * @map		on return pointer to memory map

    * @map:

> + *
> + * Retrieve the UEFI memory map. The allocated memory leaves room for
> + * up to EFI_MMAP_NR_SLACK_SLOTS additional memory map entries.
> + *
> + * Return:	status code
> + */
>  efi_status_t efi_get_memory_map(struct efi_boot_memmap *map)
>  {
>  	efi_memory_desc_t *m = NULL;
> @@ -109,8 +118,20 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
>  	}
>  	return EFI_SUCCESS;
>  }
> -/*
> - * Allocate at the lowest possible address that is not below 'min'.
> +/**
> + * efi_low_alloc_above() - allocate pages at or above given address
> + * @size:	size of the memory area to allocate
> + * @align:	minimum alignment of the allocated memory area. It should
> + *		a power of two.
> + * @addr:	on exit the address of the allocated memory
> + * @min:	minimum address to used for the memory allocation
> + *
> + * Allocate at the lowest possible address that is not below 'min' as
> + * EFI_LOADER_DATA. The allocated pages are aligned according to 'align' but at
> + * least EFI_ALLOC_ALIGN. The first allocated page will not below the address
> + * given by 'min'.
> + *
> + * Return:	status code
>   */
>  efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
>  				 unsigned long *addr, unsigned long min)
> @@ -187,6 +208,17 @@ efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
>  	return status;
>  }
> 
> +/**
> + * efi_free() - free memory pages
> + * @size	size of the memory area to free in bytes

    * @size:
    * @addr:

> + * @addr	start of the memory area to free (must be EFI_PAGE_SIZE
> + *		aligned)
> + *
> + * 'size' is rounded up to a multiple of EFI_ALLOC_ALIGN which is an
> + * architecture specific multiple of EFI_PAGE_SIZE. So this function should
> + * only be used to return pages allocated with efi_allocate_pages() or
> + * efi_low_alloc_above().
> + */
>  void efi_free(unsigned long size, unsigned long addr)
>  {
>  	unsigned long nr_pages;
> --
> 2.25.0
> 

Thanks.
-- 
~Randy