linux-kernel - Re: [PATCH v5 05/22] x86, ACPI: Increase override tables number limit

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Date:	Mon, 17 Jun 2013 17:35:29 -0600
From:	Toshi Kani <toshi.kani@...com>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Tejun Heo <tj@...nel.org>, Thomas Renninger <trenn@...e.de>,
	Tang Chen <tangchen@...fujitsu.com>,
	linux-kernel@...r.kernel.org, "Rafael J. Wysocki" <rjw@...k.pl>,
	linux-acpi@...r.kernel.org
Subject: Re: [PATCH v5 05/22] x86, ACPI: Increase override tables number
 limit

On Fri, 2013-06-14 at 17:56 -0700, Yinghai Lu wrote:
> Current acpi tables in initrd is limited to 10, that is too small.
> 64 should be good enough as we have 35 sigs and could have several
> SSDT.
> 
> Two problems in current code prevent us from increasing limit:
> 1. that cpio file info array is put in stack, as every element is 32
>    bytes, could run out of stack if we have that array size to 64.
>    We can move it out from stack, and make it as global and put it in
>    __initdata section.
> 2. early_ioremap only can remap 256k one time. Current code is mapping
>    10 tables one time. If we increase that limit, whole size could be
>    more than 256k, early_ioremap will fail with that.
>    We can map table one by one during copying, instead of mapping
>    all them one time.
> 
> -v2: According to tj, split it out to separated patch, also
>      rename array name to acpi_initrd_files.
> -v3: Add some comments about mapping table one by one during copying
>      per tj.
> 
> Signed-off-by: Yinghai <yinghai@...nel.org>
> Cc: Rafael J. Wysocki <rjw@...k.pl>
> Cc: linux-acpi@...r.kernel.org
> Acked-by: Tejun Heo <tj@...nel.org>
> Tested-by: Thomas Renninger <trenn@...e.de>
> Reviewed-by: Tang Chen <tangchen@...fujitsu.com>
> Tested-by: Tang Chen <tangchen@...fujitsu.com>

Acked-by: Toshi Kani <toshi.kani@...com>

Thanks,
-Toshi


> ---
>  drivers/acpi/osl.c | 26 +++++++++++++++-----------
>  1 file changed, 15 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 42c48fc..c4ea2b7 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -569,8 +569,8 @@ static const char * const table_sigs[] = {
>  
>  #define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
>  
> -/* Must not increase 10 or needs code modification below */
> -#define ACPI_OVERRIDE_TABLES 10
> +#define ACPI_OVERRIDE_TABLES 64
> +static struct cpio_data __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
>  
>  void __init acpi_initrd_override(void *data, size_t size)
>  {
> @@ -579,7 +579,6 @@ void __init acpi_initrd_override(void *data, size_t size)
>  	struct acpi_table_header *table;
>  	char cpio_path[32] = "kernel/firmware/acpi/";
>  	struct cpio_data file;
> -	struct cpio_data early_initrd_files[ACPI_OVERRIDE_TABLES];
>  	char *p;
>  
>  	if (data == NULL || size == 0)
> @@ -617,8 +616,8 @@ void __init acpi_initrd_override(void *data, size_t size)
>  			table->signature, cpio_path, file.name, table->length);
>  
>  		all_tables_size += table->length;
> -		early_initrd_files[table_nr].data = file.data;
> -		early_initrd_files[table_nr].size = file.size;
> +		acpi_initrd_files[table_nr].data = file.data;
> +		acpi_initrd_files[table_nr].size = file.size;
>  		table_nr++;
>  	}
>  	if (table_nr == 0)
> @@ -648,14 +647,19 @@ void __init acpi_initrd_override(void *data, size_t size)
>  	memblock_reserve(acpi_tables_addr, all_tables_size);
>  	arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
>  
> -	p = early_ioremap(acpi_tables_addr, all_tables_size);
> -
> +	/*
> +	 * early_ioremap only can remap 256k one time. If we map all
> +	 * tables one time, we will hit the limit. Need to map table
> +	 * one by one during copying.
> +	 */
>  	for (no = 0; no < table_nr; no++) {
> -		memcpy(p + total_offset, early_initrd_files[no].data,
> -		       early_initrd_files[no].size);
> -		total_offset += early_initrd_files[no].size;
> +		phys_addr_t size = acpi_initrd_files[no].size;
> +
> +		p = early_ioremap(acpi_tables_addr + total_offset, size);
> +		memcpy(p, acpi_initrd_files[no].data, size);
> +		early_iounmap(p, size);
> +		total_offset += size;
>  	}
> -	early_iounmap(p, all_tables_size);
>  }
>  #endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
>  


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