[PATCH] perf: synchronize unistd.h between libc-headers and perf source

[bruce.ashfield@gmail.com]

From: Bruce Ashfield <bruce.ashfield@gmail.com>

During the build for some architectures, perf generates a program
which executes on the host to dump the syscall table.

The generation of that program uses the cross compiler + sysroot
to expand unistd.h. As such, we are getting the contents of that
file from linux-libc-headers.

The compilation of that generated program uses the host compiler
and a restricted include path to the perf source code. In the
perf source there is a captured unistd.h, as such it will be used
when compiling the host executable. The perf source code is copied
from the kernel version that is being built .. so we have a
mismatch between the generation and the compilation of the host
program.

Normally this mismatch is fine, but if the libc-headers are
newer than the kernel, we'll have syscalls (and their syscall
numbers) that are not defined in the perf source code. This
leads to a compiler error and a cascading failure of the perf
build due to a missing generated file.

To fix this, we can copy unistd.h from the recipe-sysroot
into the perf source code and they will always be in sync.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
---

Richard,

This should fix the perf build failure with 4.19 and the 5.0
libc-headers.

It also builds fine in the other combinations I was able to
test. No sense sitting on this, it can use some AB combinations
for more testing.

Bruce

 meta/recipes-kernel/perf/perf.bb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/meta/recipes-kernel/perf/perf.bb b/meta/recipes-kernel/perf/perf.bb
index 9120766858..2f85006ee1 100644
--- a/meta/recipes-kernel/perf/perf.bb
+++ b/meta/recipes-kernel/perf/perf.bb
@@ -235,6 +235,9 @@ do_configure_prepend () {
     for s in `find ${S}/tools/perf/scripts/python/ -name '*.py'`; do
         sed -i 's,/usr/bin/python2,/usr/bin/env python,' "${s}"
     done
+
+    # cp from the sysroot unistd.h to the perf unistd.h
+    cp ${RECIPE_SYSROOT}/usr/include/asm-generic/unistd.h ${S}/tools/include/uapi/asm-generic/unistd.h
 }
 
 python do_package_prepend() {
-- 
2.19.1