Patch "ARM: 8445/1: fix vdsomunge not to depend on glibc specific byteswap.h" has been added to the 4.2-stable tree

This is a note to let you know that I've just added the patch titled

ARM: 8445/1: fix vdsomunge not to depend on glibc specific byteswap.h

to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm-8445-1-fix-vdsomunge-not-to-depend-on-glibc-specific-byteswap.h.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "H. Nikolaus Schaller" <[email protected]>
Date: Fri, 16 Oct 2015 22:19:06 +0100
Subject: ARM: 8445/1: fix vdsomunge not to depend on glibc specific byteswap.h

From: "H. Nikolaus Schaller" <[email protected]>

commit 8a603f91cc4848ab1a0458bc065aa9f64322e123 upstream.

If the host toolchain is not glibc based then the arm kernel build fails with

HOSTCC arch/arm/vdso/vdsomunge
arch/arm/vdso/vdsomunge.c:48:22: fatal error: byteswap.h: No such file or directory

Observed: with omap2plus_defconfig and compile on Mac OS X with arm ELF cross-compiler.

Reason: byteswap.h is a glibc only header.

Solution: replace by private byte-swapping macros (taken from arch/mips/boot/elf2ecoff.c and kindly improved by Russell King)

Tested to compile on Mac OS X 10.9.5 host.

---
 arch/arm/vdso/vdsomunge.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

@@ -45,7 +45,6 @@
  * it does.
  */
 
-#include <byteswap.h>
 #include <elf.h>
 #include <errno.h>
 #include <fcntl.h>

@@ -59,6 +58,16 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#define swab16(x) \
+	((((x) & 0x00ff) << 8) | \
+	 (((x) & 0xff00) >> 8))
+
+#define swab32(x) \
+	((((x) & 0x000000ff) << 24) | \
+	 (((x) & 0x0000ff00) <<  8) | \
+	 (((x) & 0x00ff0000) >>  8) | \
+	 (((x) & 0xff000000) << 24))
+
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 #define HOST_ORDER ELFDATA2LSB
 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__

@@ -104,17 +113,17 @@ static void cleanup(void)
 
 static Elf32_Word read_elf_word(Elf32_Word word, bool swap)
 {
-	return swap ? bswap_32(word) : word;
+	return swap ? swab32(word) : word;
 }
 
 static Elf32_Half read_elf_half(Elf32_Half half, bool swap)
 {
-	return swap ? bswap_16(half) : half;
+	return swap ? swab16(half) : half;
 }
 
 static void write_elf_word(Elf32_Word val, Elf32_Word *dst, bool swap)
 {
-	*dst = swap ? bswap_32(val) : val;
+	*dst = swap ? swab32(val) : val;
 }
 
 int main(int argc, char **argv)

Patches currently in stable-queue which might be from [email protected] are

queue-4.2/arm-8445-1-fix-vdsomunge-not-to-depend-on-glibc-specific-byteswap.h.patch queue-4.2/arm-8449-1-fix-bug-in-vdsomunge-swab32-macro.patch