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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2018-08-06 14:26:39 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-08-07 13:38:16 +0200
commit26f843848bae973817b3587780ce6b7b0200d3e4 (patch)
tree99617d15709b26b2906ab6f661b7bdd20bd8c597 /arch/s390
parent5eda25b10297684c1f46a14199ec00210f3c346e (diff)
downloadlinux-26f843848bae973817b3587780ce6b7b0200d3e4.tar.gz
s390: fix br_r1_trampoline for machines without exrl
For machines without the exrl instruction the BFP jit generates
code that uses an "br %r1" instruction located in the lowcore page.
Unfortunately there is a cut & paste error that puts an additional
"larl %r1,.+14" instruction in the code that clobbers the branch
target address in %r1. Remove the larl instruction.

Cc: <stable@vger.kernel.org> # v4.17+
Fixes: de5cb6eb51 ("s390: use expoline thunks in the BPF JIT")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/net/bpf_jit_comp.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index d2db8acb1a55..9d4399a87fa2 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -485,8 +485,6 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
 			/* br %r1 */
 			_EMIT2(0x07f1);
 		} else {
-			/* larl %r1,.+14 */
-			EMIT6_PCREL_RILB(0xc0000000, REG_1, jit->prg + 14);
 			/* ex 0,S390_lowcore.br_r1_tampoline */
 			EMIT4_DISP(0x44000000, REG_0, REG_0,
 				   offsetof(struct lowcore, br_r1_trampoline));