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SubjectRe: [PATCH] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug
On Fri, Jul 21, 2017 at 12:41 PM, Song liwei <liwei.song@windriver.com> wrote:

> [Firmware Bug]: APEI: Invalid bit width + offset in GAR [0xb2/16/0/1/1]
>
> This is due to an 8-bit access width is specified for a 16-bit register,
> Do bit_width check just like what the original commit have done.

> else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 &&
> *access_bit_width < 64)
> *access_bit_width = 64;
> + else if (bit_width == 16 && bit_offset == 0 && (*paddr & 0x01) == 0 &&
> + *access_bit_width < 16)
> + *access_bit_width = 16;

Wouldn't be better to rearrange that it will go in a sequence
(16,32,64 or 64,32,16) ?

or move bit_offset == 0 into external condion

/* Fixup common BIOS bug */
if (bit_offset == 0) {
if (bit_width == 16 && (*paddr & 0x01) == 0 && *access_bit_width < 16)
*access_bit_width = 16;
else if (bit_width == 32 && (*paddr & 0x03) == 0 &&
*access_bit_width < 32)
*access_bit_width = 32;
else if (bit_width == 64 && (*paddr & 0x07) == 0 &&
*access_bit_width < 64)
*access_bit_width = 64;
}


It might be (I'm not sure it will make it better, just a side note)
considered to convert each internal conditional to

...if (bit_width == XX && (*paddr & YY) == 0)
*access_bit_width = max(*access_bit_width, bit_width);

--
With Best Regards,
Andy Shevchenko

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