Patch "s390/bpf: clear correct BPF accumulator register" has been added to the 4.1-stable tree

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

s390/bpf: clear correct BPF accumulator register

to the 4.1-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:
s390-bpf-clear-correct-bpf-accumulator-register.patch
and it can be found in the queue-4.1 subdirectory.

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

From: Michael Holzheu <[email protected]>
Date: Thu, 23 Jul 2015 19:26:15 +0200
Subject: s390/bpf: clear correct BPF accumulator register

From: Michael Holzheu <[email protected]>

commit 30342fe65e511007672437741158d493472f427f upstream.

Currently we assumed the following BPF to eBPF register mapping:

- BPF_REG_A -> BPF_REG_7
- BPF_REG_X -> BPF_REG_8

Unfortunately this mapping is wrong. The correct mapping is:

- BPF_REG_A -> BPF_REG_0
- BPF_REG_X -> BPF_REG_7

So clear the correct registers and use the BPF_REG_A and BPF_REG_X macros instead of BPF_REG_0/7.

---
 arch/s390/net/bpf_jit_comp.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

@@ -415,13 +415,13 @@ static void bpf_jit_prologue(struct bpf_
 		EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0,
 			      BPF_REG_1, offsetof(struct sk_buff, data));
 	}
-	/* BPF compatibility: clear A (%b7) and X (%b8) registers */
-	if (REG_SEEN(BPF_REG_7))
-		/* lghi %b7,0 */
-		EMIT4_IMM(0xa7090000, BPF_REG_7, 0);
-	if (REG_SEEN(BPF_REG_8))
-		/* lghi %b8,0 */
-		EMIT4_IMM(0xa7090000, BPF_REG_8, 0);
+	/* BPF compatibility: clear A (%b0) and X (%b7) registers */
+	if (REG_SEEN(BPF_REG_A))
+		/* lghi %ba,0 */
+		EMIT4_IMM(0xa7090000, BPF_REG_A, 0);
+	if (REG_SEEN(BPF_REG_X))
+		/* lghi %bx,0 */
+		EMIT4_IMM(0xa7090000, BPF_REG_X, 0);
 }
 
 /*

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

queue-4.1/s390-bpf-clear-correct-bpf-accumulator-register.patch