Patch "MIPS: End spinlocks with .insn" has been added to the 4.4-stable tree

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

MIPS: End spinlocks with .insn

to the 4.4-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:
mips-end-spinlocks-with-.insn.patch
and it can be found in the queue-4.4 subdirectory.

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

From: Paul Burton <[email protected]>
Date: Thu, 23 Feb 2017 14:50:24 +0000
Subject: MIPS: End spinlocks with .insn

From: Paul Burton <[email protected]>

commit 4b5347a24a0f2d3272032c120664b484478455de upstream.

When building for microMIPS we need to ensure that the assembler always knows that there is code at the target of a branch or jump. Recent toolchains will fail to link a microMIPS kernel when this isn't the case due to what it thinks is a branch to non-microMIPS code.

mips-mti-linux-gnu-ld kernel/built-in.o: .spinlock.text+0x2fc: Unsupported branch between ISA modes. mips-mti-linux-gnu-ld final link failed: Bad value

This is due to inline assembly labels in spinlock.h not being followed by an instruction mnemonic, either due to a .subsection pseudo-op or the end of the inline asm block.

Fix this with a .insn direction after such labels.

Patchwork: https://patchwork.linux-mips.org/patch/15325/

---
 arch/mips/include/asm/spinlock.h |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

@@ -112,7 +112,7 @@ static inline void arch_spin_lock(arch_s
 		"	andi	%[ticket], %[ticket], 0xffff		\n"
 		"	bne	%[ticket], %[my_ticket], 4f		\n"
 		"	 subu	%[ticket], %[my_ticket], %[ticket]	\n"
-		"2:							\n"
+		"2:	.insn						\n"
 		"	.subsection 2					\n"
 		"4:	andi	%[ticket], %[ticket], 0xffff		\n"
 		"	sll	%[ticket], 5				\n"

@@ -187,7 +187,7 @@ static inline unsigned int arch_spin_try
 		"	sc	%[ticket], %[ticket_ptr]		\n"
 		"	beqz	%[ticket], 1b				\n"
 		"	 li	%[ticket], 1				\n"
-		"2:							\n"
+		"2:	.insn						\n"
 		"	.subsection 2					\n"
 		"3:	b	2b					\n"
 		"	 li	%[ticket], 0				\n"

@@ -367,7 +367,7 @@ static inline int arch_read_trylock(arch
 		"	.set	reorder					\n"
 		__WEAK_LLSC_MB
 		"	li	%2, 1					\n"
-		"2:							\n"
+		"2:	.insn						\n"
 		: "=" GCC_OFF_SMALL_ASM() (rw->lock), "=&r" (tmp), "=&r" (ret)
 		: GCC_OFF_SMALL_ASM() (rw->lock)
 		: "memory");

@@ -407,7 +407,7 @@ static inline int arch_write_trylock(arc
 			"	lui	%1, 0x8000			\n"
 			"	sc	%1, %0				\n"
 			"	li	%2, 1				\n"
-			"2:						\n"
+			"2:	.insn					\n"
 			: "=" GCC_OFF_SMALL_ASM() (rw->lock), "=&r" (tmp),
 			  "=&r" (ret)
 			: GCC_OFF_SMALL_ASM() (rw->lock)

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

queue-4.4/mips-end-spinlocks-with-.insn.patch queue-4.4/mips-force-o32-fp64-support-on-32bit-mips64r6-kernels.patch