[Buildroot] strace on xtensa/uclibc

Thomas Petazzoni thomas.petazzoni at bootlin.com
Fri Dec 7 08:13:56 UTC 2018


Hello,

+Baruch, Max Filipov for Xtensa and Waldemar for uClibc-ng.

On Fri,  7 Dec 2018 08:00:29 +0100 (CET), Thomas Petazzoni wrote:

>       xtensa |                    strace-4.25 | NOK | http://autobuild.buildroot.net/results/5a0112b7a2c81fa5253c9adc93efe415256cd811 |     

I had a look at those failures of strace on xtensa:

  http://autobuild.buildroot.net/?reason=strace-4.25

I.e, strace 4.25 only fails to build on Xtensa. The reason is that
uClibc-ng doesn't have the correct values for some POLL* macros: they
don't match the kernel values.

Let's take POLLWRBAND as an example. The kernel defines it like this:

arch/xtensa/include/uapi/asm/poll.h:#define POLLWRBAND  0x0100

So strace 4.25 checks that it has the correct value:

#if defined(__m68k__) || defined(__mips__) || defined(__sparc__) || defined(__xtensa__)
#if defined(POLLWRBAND) || (defined(HAVE_DECL_POLLWRBAND) && HAVE_DECL_POLLWRBAND)
DIAG_PUSH_IGNORE_TAUTOLOGICAL_COMPARE
static_assert((POLLWRBAND) == (0x0100), "POLLWRBAND != 0x0100");

But uClibc-ng doesn't have an arch-specific header to define POLLWRBAND
on xtensa, so it falls back to the generic definition, which isn't
correct for xtensa:

libc/sysdeps/linux/common/bits/poll.h:# define POLLWRBAND       0x200           /* Priority data may be written.  */

The same issue happens with POLLREMOVE.

I think xtensa needs to have its own
libc/sysdeps/linux/xtensa/bits/poll.h in uClibc-ng.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com


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