Re: DTB build failure due to preproccessing

From: Stephen Warren
Date: Fri May 31 2013 - 12:45:26 EST


On 05/31/2013 04:29 AM, Ian Campbell wrote:
> This affects arch/powerpc/boot/dts/virtex440-ml510.dts but I think it is
> actually a more general issue:
>
> $ make ARCH=powerpc CROSS_COMPILE=powerpc-linux- virtex440-ml510.dtb
> CC scripts/mod/devicetable-offsets.s
> GEN scripts/mod/devicetable-offsets.h
> HOSTCC scripts/mod/file2alias.o
> HOSTLD scripts/mod/modpost
> DTC arch/powerpc/boot/virtex440-ml510.dtb
> Error: arch/powerpc/boot/dts/virtex440-ml510.dts:374.6-7 syntax error
> FATAL ERROR: Unable to parse input tree
> make[1]: *** [arch/powerpc/boot/virtex440-ml510.dtb] Error 1
> make: *** [virtex440-ml510.dtb] Error 2
...
> interrupt-map = <
> # 375 "arch/powerpc/boot/dts/virtex440-ml510.dts"
> 0x3000 0 0 1 &xps_intc_0 3 2
> 0x3000 0 0 2 &xps_intc_0 2 2
> 0x3000 0 0 3 &xps_intc_0 5 2
> 0x3000 0 0 4 &xps_intc_0 4 2

I /think/ what's happening here is that dtc's rule for #line parsing
allows the formats:

# LINE FILENAME
or:
#LINE FILENAME FLAGS

where FLAGS is an integer

The lexer rule that optionally consumes flags requires some WS
(white-space) between the filename and flags. It looks like this
whitespace can actually cross a line boundary, so it ends up consuming
the first "0" of the hex constant on the next line, which then leaves
"x3000" to be parsed as cell data, which is a syntax error.

You can hack around this for testing by doing one of a few things:

a) Add an extra integer on to the end of the problematic #line directives.

b) Remove the leading "0x" from the constants following the #line
directives. I think this will still mean dtc eats the 3000 as part of
the #line directive, but hides the syntax error.

The solution here is to make dtc's #line matching regex:

<*>^"#"(line)?{WS}+[0-9]+{WS}+{STRING}({WS}+[0-9]+)? {

... use someting other than {WS} in the final instance; some kind of
{WS} that won't match/cross line boundaries. I'll see if I can cook up a
patch for this.
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