meta-microblaze: Fix glibc issues related to select/pselect

*) Select syscall is not implemented on microblaze, newselect should be
   used instead, but commit 4c3df0eba5e8fe98f0de917ade9b2ebba6951c5f
   from glibc removed this behavior.  Presumably by accident.

*) When the code path that doesn't use select, but instead uses
   pselect32 is used, microblaze provides it's own implementation
   but this implementation is only available when ASSUME_PSELECT
   is disabled.  We need to fallback to the default Linux implementation.

Signed-off-by: Mark Hatle <mark.hatle@xilinx.com>

4 files changed, 122 insertions, 0 deletions

diff --git a/meta-microblaze/recipes-core/glibc/files/0001-microblaze-Add-missing-implementation-when-__ASSUME_.patch b/meta-microblaze/recipes-core/glibc/files/0001-microblaze-Add-missing-implementation-when-__ASSUME_.patch
new file mode 100644
index 00000000..5c0dc42a
--- /dev/null
+++ b/meta-microblaze/recipes-core/glibc/files/0001-microblaze-Add-missing-implementation-when-__ASSUME_.patch
@@ -0,0 +1,61 @@
+From c75aa9246a8cfc814d99cf5f58229177bd69fc4f Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+Date: Tue, 28 Dec 2021 09:09:49 -0300
+Subject: [PATCH] microblaze: Add missing implementation when
+ !__ASSUME_TIME64_SYSCALLS
+
+In commit a92f4e6299fe0e3cb6f77e79de00817aece501ce ("linux: Add time64
+pselect support"), a Microblaze specific implementation of
+__pselect32() was added to cover the case of kernels < 3.15 which lack
+the pselect6 system call.
+
+This new file sysdeps/unix/sysv/linux/microblaze/pselect32.c takes
+precedence over the default implementation
+sysdeps/unix/sysv/linux/pselect32.c.
+
+However sysdeps/unix/sysv/linux/pselect32.c provides an implementation
+of __pselect32() which is needed when __ASSUME_TIME64_SYSCALLS is not
+defined. On Microblaze, which is a 32-bit architecture,
+__ASSUME_TIME64_SYSCALLS is only true for kernels >= 5.1.
+
+Due to sysdeps/unix/sysv/linux/microblaze/pselect32.c taking
+precedence over sysdeps/unix/sysv/linux/pselect32.c, it means that
+when we are with a kernel >= 3.15 but < 5.1, we need a __pselect32()
+implementation, but sysdeps/unix/sysv/linux/microblaze/pselect32.c
+doesn't provide it, and sysdeps/unix/sysv/linux/pselect32.c which
+would provide it is not compiled in.
+
+This causes the following build failure on Microblaze with for example
+Linux kernel headers 4.9:
+
+[...]/build/libc_pic.os: in function `__pselect64':
+(.text+0x120b44): undefined reference to `__pselect32'
+collect2: error: ld returned 1 exit status
+
+Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commit;h=c75aa9246a8cfc814d99cf5f58229177bd69fc4f]
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+Signed-off-by: Mark Hatle <mark.hatle@xilinx.com>
+---
+ sysdeps/unix/sysv/linux/microblaze/pselect32.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/sysdeps/unix/sysv/linux/microblaze/pselect32.c b/sysdeps/unix/sysv/linux/microblaze/pselect32.c
+index 70b7b52a48..dd9d56ba29 100644
+--- a/sysdeps/unix/sysv/linux/microblaze/pselect32.c
++++ b/sysdeps/unix/sysv/linux/microblaze/pselect32.c
+@@ -22,7 +22,9 @@
+ #include <sys/poll.h>
+ #include <sysdep-cancel.h>
+ 
+-#ifndef __ASSUME_PSELECT
++#ifndef __ASSUME_TIME64_SYSCALL
++#include <sysdeps/unix/sysv/linux/pselect32.c>
++#elif !defined __ASSUME_PSELECT
+ int
+ __pselect32 (int nfds, fd_set *readfds, fd_set *writefds,
+             fd_set *exceptfds, const struct __timespec64 *timeout,
+-- 
+2.17.1
+
diff --git a/meta-microblaze/recipes-core/glibc/files/select-use-newselect-syscall.patch b/meta-microblaze/recipes-core/glibc/files/select-use-newselect-syscall.patch
new file mode 100644
index 00000000..04231f0a
--- /dev/null
+++ b/meta-microblaze/recipes-core/glibc/files/select-use-newselect-syscall.patch
@@ -0,0 +1,50 @@
+Restore newselect syscall override of select syscall
+
+Commit 4c3df0eba5e8fe98f0de917ade9b2ebba6951c5f removed the check and override
+of select syscall with newselect if newselect was defined.
+
+This code path, using select instead of pselect is only executed when
+ASSUME_PSELECT is not enabled.  This happens on microblaze when the
+kernel version is set below 3.15.
+
+On Microblaze select is not implemented, only newselect is.  So this automatic
+conversion from select to newselect syscall is expected.  The original
+implementation of the select to newselect syscall was part of:
+
+  commit 26f28fd73d20df8847d93f88b6e2a7bd3bd9bf51
+  Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
+  Date:   Fri Nov 18 14:27:03 2016 -0200
+
+    Consolidate Linux select implementation
+    
+    This patch consolidates the select Linux syscall implementation on
+    sysdeps/unix/sysv/linux/select.c.  The changes are:
+    
+      1. Remove select from auto-generation syscalls.list on the architecture
+         that uses __NR_select.
+      2. Remove generic implementation add a default one that handle all
+         current cases (with the expection of alpha)
+         The new default implementation will either use __NR_select if
+         available of fallback to __NR_pselect6 otherwise.
+      3. Add a alpha outlier implementation which requires old compatibility
+         symbols.
+
+Upstream-Status: Submitted [https://sourceware.org/bugzilla/show_bug.cgi?id=28883]
+
+Signed-off-by: Mark Hatle <mark.hatle@xilinx.com>
+
+diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
+index da25b4b4cfe..0f4c67aa29e 100644
+--- a/sysdeps/unix/sysv/linux/select.c
++++ b/sysdeps/unix/sysv/linux/select.c
+@@ -101,6 +116,10 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+     TIMESPEC_TO_TIMEVAL (timeout, pts32);
+   return r;
+ # else
++#  ifdef __NR__newselect
++#   undef __NR_select
++#   define __NR_select __NR__newselect
++#  endif
+   struct timeval tv32, *ptv32 = NULL;
+   if (pts64 != NULL)
+     {
diff --git a/meta-microblaze/recipes-core/glibc/glibc_2.34.bbappend b/meta-microblaze/recipes-core/glibc/glibc_2.34.bbappend
new file mode 100644
index 00000000..ab93a9b5
--- /dev/null
+++ b/meta-microblaze/recipes-core/glibc/glibc_2.34.bbappend
@@ -0,0 +1,4 @@
+MB_INC_FILE = ""
+MB_INC_FILE:microblaze = "microblaze-glibc.inc"
+
+require ${MB_INC_FILE}
diff --git a/meta-microblaze/recipes-core/glibc/microblaze-glibc.inc b/meta-microblaze/recipes-core/glibc/microblaze-glibc.inc
new file mode 100644
index 00000000..f7820f24
--- /dev/null
+++ b/meta-microblaze/recipes-core/glibc/microblaze-glibc.inc
@@ -0,0 +1,7 @@
+# Workaround for microblaze being unable to boot
+FILESEXTRAPATHS:append:microblaze := ":${THISDIR}/files"
+
+SRC_URI:append:microblaze = " \
+        file://select-use-newselect-syscall.patch \
+        file://0001-microblaze-Add-missing-implementation-when-__ASSUME_.patch \
+"