Re: [PATCH v7] x86/setup: get ramdisk parameters only once

[Borislav Petkov]

On Fri, Feb 26, 2016 at 01:31:45PM +0600, Alexander Kuleshov wrote:
>  arch/x86/kernel/setup.c | 109 ++++++++++++++++++++++++++----------------------
>  1 file changed, 60 insertions(+), 49 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index d3d80e6..449b4da 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -169,6 +169,15 @@ static struct resource bss_resource = {
>  	.flags	= IORESOURCE_BUSY | IORESOURCE_MEM
>  };
>  
> +/*
> + * ramdisk setup
> + */

No need for that comment - the struct naming and members should be
sufficient.

> +struct ramdisk {
> +	u64 start_addr;		/* ramdisk load address */
> +	u64 end_addr;		/* ramdisk end address */
> +	u64 size;		/* ramdisk size */
> +	bool reserve_ramdisk;	/* do initrd provided by bootloader */
> +};
>  
>  #ifdef CONFIG_X86_32
>  /* cpu data as detected by the assembly code in head.S */
> @@ -318,90 +327,84 @@ static u64 __init get_ramdisk_size(void)
>  	return ramdisk_size;
>  }
>  
> -static void __init relocate_initrd(void)
> +static void __init relocate_initrd(struct ramdisk *ramdisk)
>  {
> -	/* Assume only end is not page aligned */
> -	u64 ramdisk_image = get_ramdisk_image();
> -	u64 ramdisk_size  = get_ramdisk_size();
> -	u64 area_size     = PAGE_ALIGN(ramdisk_size);
> -
>  	/* We need to move the initrd down into directly mapped mem */
>  	relocated_ramdisk = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
> -						   area_size, PAGE_SIZE);
> +						   ramdisk->size, PAGE_SIZE);
>  
>  	if (!relocated_ramdisk)
>  		panic("Cannot find place for new RAMDISK of size %lld\n",
> -		      ramdisk_size);
> +		      ramdisk->size);
>  
>  	/* Note: this includes all the mem currently occupied by
>  	   the initrd, we rely on that fact to keep the data intact. */
> -	memblock_reserve(relocated_ramdisk, area_size);
> +	memblock_reserve(relocated_ramdisk, ramdisk->size);
>  	initrd_start = relocated_ramdisk + PAGE_OFFSET;
> -	initrd_end   = initrd_start + ramdisk_size;
> +	initrd_end   = initrd_start + ramdisk->size;
>  	printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",

I think all those printks talking about ramdisk should be

	printk(KERN_INFO "RAMDISK: ..."

for easier grepping of dmesg about ramdisk-specific messages. This
should be another patch though.

> -	       relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
> +	       relocated_ramdisk, relocated_ramdisk + ramdisk->size - 1);
>  
> -	copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);
> +	copy_from_early_mem((void *)initrd_start, ramdisk->start_addr, ramdisk->size);
>  
>  	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
>  		" [mem %#010llx-%#010llx]\n",
> -		ramdisk_image, ramdisk_image + ramdisk_size - 1,
> -		relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
> +		ramdisk->start_addr, ramdisk->start_addr + ramdisk->size - 1,
> +		relocated_ramdisk, relocated_ramdisk + ramdisk->size - 1);
>  }
> -

That \n should not have been deleted here.

> -static void __init early_reserve_initrd(void)
> +static void __init early_reserve_initrd(struct ramdisk *ramdisk)
>  {
> -	/* Assume only end is not page aligned */
> -	u64 ramdisk_image = get_ramdisk_image();
> -	u64 ramdisk_size  = get_ramdisk_size();
> -	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
> -
> -	if (!boot_params.hdr.type_of_loader ||
> -	    !ramdisk_image || !ramdisk_size)
> -		return;		/* No initrd provided by bootloader */
> -
> -	memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
> +	if (!boot_params.hdr.type_of_loader || !ramdisk->start_addr || !ramdisk->size)
> +		ramdisk->reserve_ramdisk = false;	/* No initrd provided by bootloader */
> +	else
> +		memblock_reserve(ramdisk->start_addr, ramdisk->size);
>  }

Make this one even more readable:

static void __init early_reserve_initrd(struct ramdisk *ramdisk)
{
        /* No initrd provided by bootloader */
        if (!boot_params.hdr.type_of_loader ||
            !ramdisk->start_addr ||
            !ramdisk->size)
                ramdisk->reserve_ramdisk = false;
        else
                memblock_reserve(ramdisk->start_addr, ramdisk->size);
}

It also has some whitespace damage.

> -static void __init reserve_initrd(void)
> +
> +static void __init reserve_initrd(struct ramdisk *ramdisk)
>  {
> -	/* Assume only end is not page aligned */
> -	u64 ramdisk_image = get_ramdisk_image();
> -	u64 ramdisk_size  = get_ramdisk_size();
> -	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
>  	u64 mapped_size;
>  
> -	if (!boot_params.hdr.type_of_loader ||
> -	    !ramdisk_image || !ramdisk_size)
> -		return;		/* No initrd provided by bootloader */
> +	if (!ramdisk->reserve_ramdisk)
> +		return;
>  
>  	initrd_start = 0;
>  
>  	mapped_size = memblock_mem_size(max_pfn_mapped);
> -	if (ramdisk_size >= (mapped_size>>1))
> +	if (ramdisk->size >= (mapped_size>>1))

Space that shift out:

			 ...  mapped_size >> 1))

>  		panic("initrd too large to handle, "
>  		       "disabling initrd (%lld needed, %lld available)\n",

The string in this panic() call should be a single line only for easier
grepping. With another patch though.

> -		       ramdisk_size, mapped_size>>1);
> +		       ramdisk->size, mapped_size>>1);

Space that shift out too.

>  
> -	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
> -			ramdisk_end - 1);
> +	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n",
> +		ramdisk->start_addr, ramdisk->end_addr - 1);
>  
> -	if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
> -				PFN_DOWN(ramdisk_end))) {
> +	if (pfn_range_is_mapped(PFN_DOWN(ramdisk->start_addr),
> +				PFN_DOWN(ramdisk->end_addr))) {
>  		/* All are mapped, easy case */
> -		initrd_start = ramdisk_image + PAGE_OFFSET;
> -		initrd_end = initrd_start + ramdisk_size;
> +		initrd_start = ramdisk->start_addr + PAGE_OFFSET;
> +		initrd_end = initrd_start + ramdisk->size;
>  		return;
>  	}
>  
> -	relocate_initrd();
> +	relocate_initrd(ramdisk);
>  
> -	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
> +	memblock_free(ramdisk->start_addr,
> +		ramdisk->end_addr - ramdisk->start_addr);

Arg alignment should start at the function's opening brace.

>  }
>  #else
> -static void __init early_reserve_initrd(void)
> +static u64 __init get_ramdisk_image(void)
>  {
> +	return 0;
>  }
> -static void __init reserve_initrd(void)
> +static u64 __init get_ramdisk_size(void)
> +{
> +	return 0;
> +}
> +static void __init early_reserve_initrd(struct ramdisk *ramdisk)
> +{
> +
> +}
> +static void __init reserve_initrd(struct ramdisk *ramdisk)
>  {
>  }
>  #endif /* CONFIG_BLK_DEV_INITRD */
> @@ -844,13 +847,21 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
>   *
>   * Note: On x86_64, fixmaps are ready for use even before this is called.
>   */
> -
>  void __init setup_arch(char **cmdline_p)
>  {
> +	struct ramdisk ramdisk = {
> +		.start_addr = get_ramdisk_image(),
> +		.size  = PAGE_ALIGN(get_ramdisk_size()),
> +		.reserve_ramdisk = true
> +	};

More readable:

        struct ramdisk ramdisk = {
                .start_addr	 = get_ramdisk_image(),
                .size		 = PAGE_ALIGN(get_ramdisk_size()),
                .reserve_ramdisk = true,
        };

> +
> +	/* Assume end is not page aligned */
> +	ramdisk.end_addr = PAGE_ALIGN(ramdisk.start_addr + ramdisk.size);
> +
>  	memblock_reserve(__pa_symbol(_text),
>  			 (unsigned long)__bss_stop - (unsigned long)_text);
>  
> -	early_reserve_initrd();
> +	early_reserve_initrd(&ramdisk);
>  
>  	/*
>  	 * At this point everything still needed from the boot loader
> @@ -1135,7 +1146,7 @@ void __init setup_arch(char **cmdline_p)
>  	/* Allocate bigger log buffer */
>  	setup_log_buf(1);
>  
> -	reserve_initrd();
> +	reserve_initrd(&ramdisk);
>  
>  #if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD)
>  	acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start);
> -- 
> 2.7.2.335.g3476f70
> 

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
--