pixman: add patch to fix SEGFAULT when parsing auxv

* without this patch emacs won't build
* temacs is executed in qemu and fails like this:
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
Segmentation fault
which is actually:
Program received signal SIGSEGV, Segmentation fault.
__GI_strncmp (s1=s1@entry=0x0, s2=s2@entry=0x40d68638 "v7l", n=n@entry=3) at strncmp.c:64
64      strncmp.c: No such file or directory.
(gdb) bt
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

2 files changed, 125 insertions, 2 deletions

diff --git a/meta-oe/recipes-graphics/xorg-lib/pixman-0.26.2/0001-ARM-qemu-related-workarounds-in-cpu-features-detecti.patch b/meta-oe/recipes-graphics/xorg-lib/pixman-0.26.2/0001-ARM-qemu-related-workarounds-in-cpu-features-detecti.patch
new file mode 100644
index 0000000000..b56e690e90
--- /dev/null
+++ b/meta-oe/recipes-graphics/xorg-lib/pixman-0.26.2/0001-ARM-qemu-related-workarounds-in-cpu-features-detecti.patch
@@ -0,0 +1,121 @@
+From dad8537110c27b45795f8879a3e0a54aa77546b9 Mon Sep 17 00:00:00 2001
+From: Siarhei Siamashka <siarhei.siamashka@nokia.com>
+Date: Tue, 11 Jan 2011 18:10:39 +0200
+Subject: [PATCH] ARM: qemu related workarounds in cpu features detection code
+
+Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
+---
+ pixman/pixman-cpu.c |   67 +++++++++++++++++++++++++++++++++++++++++---------
+ 1 files changed, 55 insertions(+), 12 deletions(-)
+
+diff --git a/pixman/pixman-cpu.c b/pixman/pixman-cpu.c
+index aa9036f..a8f2494 100644
+--- a/pixman/pixman-cpu.c
++++ b/pixman/pixman-cpu.c
+@@ -333,15 +333,30 @@ pixman_arm_read_auxv_or_cpu_features ()
+ #include <sys/types.h>
+ #include <sys/stat.h>
+ #include <sys/mman.h>
++#include <sys/utsname.h>
+ #include <fcntl.h>
+ #include <string.h>
+ #include <elf.h>
+ 
++/*
++ * The whole CPU capabilities detection is a bit ugly: when running in
++ * userspace qemu, we see /proc/self/auxv from the host system. To make
++ * everything even worse, the size of each value is 64-bit when running
++ * on a 64-bit host system. So the data is totally bogus because we expect
++ * 32-bit values. As AT_PLATFORM value is used as a pointer, it may cause
++ * segfault (null pointer dereference on x86-64 host). So in order to be
++ * on a safe side, we require that AT_PLATFORM value is found only once,
++ * and it has non-zero value (this is still not totally reliable for a big
++ * endian 64-bit host system running qemu and may theoretically fail).
++ */
+ static void
+ pixman_arm_read_auxv_or_cpu_features ()
+ {
+     int fd;
+     Elf32_auxv_t aux;
++    uint32_t hwcap = 0;
++    const char *plat = NULL;
++    int plat_cnt = 0;
+ 
+     fd = open ("/proc/self/auxv", O_RDONLY);
+     if (fd >= 0)
+@@ -350,32 +365,60 @@ pixman_arm_read_auxv_or_cpu_features ()
+ 	{
+ 	    if (aux.a_type == AT_HWCAP)
+ 	    {
+-		uint32_t hwcap = aux.a_un.a_val;
+-		/* hardcode these values to avoid depending on specific
+-		 * versions of the hwcap header, e.g. HWCAP_NEON
+-		 */
+-		arm_has_vfp = (hwcap & 64) != 0;
+-		arm_has_iwmmxt = (hwcap & 512) != 0;
+-		/* this flag is only present on kernel 2.6.29 */
+-		arm_has_neon = (hwcap & 4096) != 0;
++		hwcap = aux.a_un.a_val;
+ 	    }
+ 	    else if (aux.a_type == AT_PLATFORM)
+ 	    {
+-		const char *plat = (const char*) aux.a_un.a_val;
+-		if (strncmp (plat, "v7l", 3) == 0)
++		plat = (const char*) aux.a_un.a_val;
++		plat_cnt++;
++	    }
++	}
++	close (fd);
++
++	if (plat == NULL || plat_cnt != 1 || *plat != 'v')
++	{
++	    /*
++	     * Something seems to be really wrong, most likely we are
++	     * running under qemu. Let's use machine type from "uname" for
++	     * CPU capabilities detection:
++	     * http://www.mail-archive.com/qemu-devel at nongnu.org/msg22212.html
++	     */
++	    struct utsname u;
++	    hwcap = 0; /* clear hwcap, because it is bogus */
++	    if (uname (&u) == 0)
++	    {
++		if (strcmp (u.machine, "armv7l") == 0)
+ 		{
+ 		    arm_has_v7 = TRUE;
+ 		    arm_has_v6 = TRUE;
++		    hwcap |= 64; /* qemu is supposed to emulate vfp */
++		    hwcap |= 4096; /* qemu is supposed to emulate neon */
+ 		}
+-		else if (strncmp (plat, "v6l", 3) == 0)
++		else if (strcmp (u.machine, "armv6l") == 0)
+ 		{
+ 		    arm_has_v6 = TRUE;
++		    hwcap |= 64; /* qemu is supposed to emulate vfp */
+ 		}
+ 	    }
+ 	}
+-	close (fd);
++	else if (strncmp (plat, "v7l", 3) == 0)
++	{
++	    arm_has_v7 = TRUE;
++	    arm_has_v6 = TRUE;
++	}
++	else if (strncmp (plat, "v6l", 3) == 0)
++	{
++	    arm_has_v6 = TRUE;
++	}
+     }
+ 
++    /* hardcode these values to avoid depending on specific
++     * versions of the hwcap header, e.g. HWCAP_NEON
++     */
++    arm_has_vfp = (hwcap & 64) != 0;
++    arm_has_iwmmxt = (hwcap & 512) != 0;
++    arm_has_neon = (hwcap & 4096) != 0;
++
+     arm_tests_initialized = TRUE;
+ }
+ 
+-- 
+1.7.8.6
+
diff --git a/meta-oe/recipes-graphics/xorg-lib/pixman_0.26.2.bbappend b/meta-oe/recipes-graphics/xorg-lib/pixman_0.26.2.bbappend
index 579d5081e3..b5be2b50ca 100644
--- a/meta-oe/recipes-graphics/xorg-lib/pixman_0.26.2.bbappend
+++ b/meta-oe/recipes-graphics/xorg-lib/pixman_0.26.2.bbappend
@@ -1,8 +1,10 @@
 FILESEXTRAPATHS_prepend := "${THISDIR}/${P}:"
 
-PRINC := "${@int(PRINC) + 9}"
+PRINC := "${@int(PRINC) + 10}"
 
-SRC_URI += " file://0008-Generic-C-implementation-of-pixman_blt-with-overlapp.patch"
+SRC_URI += " file://0008-Generic-C-implementation-of-pixman_blt-with-overlapp.patch \
+  file://0001-ARM-qemu-related-workarounds-in-cpu-features-detecti.patch \
+"
 
 NEON = " --disable-arm-neon "
 NEON_armv7a = " "