[coreboot] Endian issue for libpayload options
Sean McNeil
seanmcneil3 at gmail.com
Thu May 29 11:37:35 CEST 2014
I think the following patch should be OK for either endian:
diff --git a/payloads/libpayload/drivers/options.c
b/payloads/libpayload/drivers
index 70c2b17..ae5e421 100644
--- a/payloads/libpayload/drivers/options.c
+++ b/payloads/libpayload/drivers/options.c
@@ -63,15 +63,20 @@ int options_checksum_valid(const struct
nvram_accessor *nvra
int range_start = lib_sysinfo.cmos_range_start / 8;
int range_end = lib_sysinfo.cmos_range_end / 8;
int checksum_location = lib_sysinfo.cmos_checksum_location / 8;
- u16 checksum = 0, checksum_old;
+ u16 checksum = 0;
+ union {
+ u16 w;
+ u8 b[2];
+ } checksum_old;
for(i = range_start; i <= range_end; i++) {
checksum += nvram->read(i);
}
- checksum_old = ((nvram->read(checksum_location)<<8) |
nvram->read(checks
+ checksum_old.b[0] = nvram->read(checksum_location);
+ checksum_old.b[1] = nvram->read(checksum_location+1);
- return (checksum_old == checksum);
+ return (checksum_old.w == checksum);
}
void fix_options_checksum_with(const struct nvram_accessor *nvram)
On 05/29/2014 03:57 PM, Sean McNeil wrote:
> options are broken for x86 because it is assuming big endian. A quick
> patch to make it work:
>
> diff --git a/payloads/libpayload/drivers/options.c
> b/payloads/libpayload/drivers
> index 70c2b17..a7a5d82 100644
> --- a/payloads/libpayload/drivers/options.c
> +++ b/payloads/libpayload/drivers/options.c
> @@ -69,7 +69,7 @@ int options_checksum_valid(const struct
> nvram_accessor *nvram)
> checksum += nvram->read(i);
> }
>
> - checksum_old = ((nvram->read(checksum_location)<<8) |
> nvram->read(checks
> + checksum_old = ((nvram->read(checksum_location+1)<<8) |
> nvram->read(chec
>
> return (checksum_old == checksum);
> }
>
> Maybe a union and assigning each byte is the correct approach?
>
> Cheers,
> Sean
>
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