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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2015-06-01 22:48:35 -0700
committerDavid S. Miller <davem@davemloft.net>2015-06-03 19:31:39 -0700
commit88aeca15d637c279171ba441730ef41e4c4ce0ed (patch)
tree3d052ee68f61b0ecc24acc130a674594b5175609 /arch/s390/net
parentbbac1c94880cb8c7e093718897f4822f3933dd3c (diff)
downloadlinux-88aeca15d637c279171ba441730ef41e4c4ce0ed.tar.gz
s390/bpf: fix bpf frame pointer setup
Currently the bpf frame pointer is set to the old r15. This is wrong because of packed stack. Fix this and adjust the frame pointer to respect packed stack. This now generates a prolog like the following: 3ff8001c3fa: eb67f0480024 stmg %r6,%r7,72(%r15) 3ff8001c400: ebcff0780024 stmg %r12,%r15,120(%r15) 3ff8001c406: b904001f lgr %r1,%r15 <- load backchain 3ff8001c40a: 41d0f048 la %r13,72(%r15) <- load adjusted bfp 3ff8001c40e: a7fbfd98 aghi %r15,-616 3ff8001c412: e310f0980024 stg %r1,152(%r15) <- save backchain Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/s390/net')
-rw-r--r--arch/s390/net/bpf_jit_comp.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 20c146d1251a..55423d8be580 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -384,13 +384,16 @@ static void bpf_jit_prologue(struct bpf_jit *jit)
}
/* Setup stack and backchain */
if (jit->seen & SEEN_STACK) {
- /* lgr %bfp,%r15 (BPF frame pointer) */
- EMIT4(0xb9040000, BPF_REG_FP, REG_15);
+ if (jit->seen & SEEN_FUNC)
+ /* lgr %w1,%r15 (backchain) */
+ EMIT4(0xb9040000, REG_W1, REG_15);
+ /* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */
+ EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED);
/* aghi %r15,-STK_OFF */
EMIT4_IMM(0xa70b0000, REG_15, -STK_OFF);
if (jit->seen & SEEN_FUNC)
- /* stg %bfp,152(%r15) (backchain) */
- EMIT6_DISP_LH(0xe3000000, 0x0024, BPF_REG_FP, REG_0,
+ /* stg %w1,152(%r15) (backchain) */
+ EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
REG_15, 152);
}
/*