linux-kernel - Re: [PATCH v2 2/3] ACPI: add BAD_MADT_GICC

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Date:	Fri, 19 Jun 2015 18:49:57 +0800
From:	Hanjun Guo <hanjun.guo@...aro.org>
To:	Al Stone <al.stone@...aro.org>, linux-acpi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
CC:	rjw@...ysocki.net, lenb@...nel.org, catalin.marinas@....com,
	will.deacon@....com, tglx@...utronix.de, jason@...edaemon.net,
	linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org,
	linaro-kernel@...ts.linaro.org, patches@...aro.org
Subject: Re: [PATCH v2 2/3] ACPI: add BAD_MADT_GICC_ENTRY() macro

On 06/19/2015 06:36 AM, Al Stone wrote:
> The BAD_MADT_ENTRY() macro is designed to work for all of the subtables
> of the MADT.  In the ACPI 5.1 version of the spec, the struct for the
> GICC subtable (struct acpi_madt_generic_interrupt) is 76 bytes long; in
> ACPI 6.0, the struct is 80 bytes long.  But, there is only one definition
> in ACPICA for this struct -- and that is the 6.0 version.  Hence, when
> BAD_MADT_ENTRY() compares the struct size to the length in the GICC
> subtable, it fails if 5.1 structs are in use, and there are systems in
> the wild that have them.
>
> This patch adds the BAD_MADT_GICC_ENTRY() that checks the GICC subtable
> only, accounting for the difference in specification versions that are
> possible.  The BAD_MADT_ENTRY() will continue to work as is for all other
> MADT subtables.
>
> Signed-off-by: Al Stone <al.stone@...aro.org>
> ---
>   include/linux/acpi.h | 10 ++++++++++
>   1 file changed, 10 insertions(+)
>
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 33ed313..d3a1758 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -127,6 +127,16 @@ static inline void acpi_initrd_override(void *data, size_t size)
>   		(!entry) || (unsigned long)entry + sizeof(*entry) > end ||  \
>   		((struct acpi_subtable_header *)entry)->length < sizeof(*entry))
>
> +#define ACPI_MADT_GICC_51_LENGTH	76
> +#define ACPI_MADT_GICC_60_LENGTH	80
> +
> +#define BAD_MADT_GICC_ENTRY(entry, end) (				    \
> +		(!entry) || (unsigned long)entry + sizeof(*entry) > end ||  \
> +		((ACPI_FADT_SPEC_VERSION == ACPI_SPEC_VERSION(5, 1)) &&	    \
> +		 (entry->header.length != ACPI_MADT_GICC_51_LENGTH))	||  \
> +		((ACPI_FADT_SPEC_VERSION == ACPI_SPEC_VERSION(6, 0)) &&	    \
> +		 (entry->header.length != ACPI_MADT_GICC_60_LENGTH)))
> +
>   char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
>   void __acpi_unmap_table(char *map, unsigned long size);
>   int early_acpi_boot_init(void);

Reviewed-by: Hanjun Guo <hanjun.guo@...aro.org>

Thanks
Hanjun
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