FAILED: patch "[PATCH] MIPS: memset: Fix CPU_DADDI_WORKAROUNDS `small_fixup'" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: "Maciej W. Rozycki" <[email protected]>
Date: Tue, 2 Oct 2018 12:50:11 +0100
Subject: [PATCH] MIPS: memset: Fix CPU_DADDI_WORKAROUNDS `small_fixup'
regression

Fix a commit 8a8158c85e1e ("MIPS: memset.S: EVA & fault support for small_memset") regression and remove assembly warnings:

arch/mips/lib/memset.S: Assembler messages:
arch/mips/lib/memset.S:243: Warning: Macro instruction expanded into multiple instructions in a branch delay slot

triggering with the CPU_DADDI_WORKAROUNDS option set and this code:

	PTR_SUBU	a2, t1, a0
	jr		ra
	 PTR_ADDIU	a2, 1

This is because with that option in place the DADDIU instruction, which the PTR_ADDIU CPP macro expands to, becomes a GAS macro, which in turn expands to an LI/DADDU (or actually ADDIU/DADDU) sequence:

13c: 01a4302f dsubu a2,t1,a0
140: 03e00008 jr ra
144: 24010001 li at,1
148: 00c1302d daddu a2,a2,at

	...

Correct this by switching off the `noreorder' assembly mode and letting GAS schedule this jump's delay slot, as there is nothing special about it that would require manual scheduling. With this change in place correct code is produced:

13c: 01a4302f dsubu a2,t1,a0
140: 24010001 li at,1
144: 03e00008 jr ra
148: 00c1302d daddu a2,a2,at

	...

Patchwork: https://patchwork.linux-mips.org/patch/20833/
Cc: Ralf Baechle <[email protected]>
Cc: [email protected] # 4.17+

index 3a6f34ef5ffc..069acec3df9f 100644
@@ -280,9 +280,11 @@
 	 * unset_bytes = end_addr - current_addr + 1
 	 *      a2     =    t1    -      a0      + 1
 	 */
+	.set		reorder
 	PTR_SUBU	a2, t1, a0
+	PTR_ADDIU	a2, 1
 	jr		ra
-	 PTR_ADDIU	a2, 1
+	.set		noreorder
 
 	.endm