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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2015-06-01 22:48:34 -0700
committerDavid S. Miller <davem@davemloft.net>2015-06-03 19:31:39 -0700
commitbbac1c94880cb8c7e093718897f4822f3933dd3c (patch)
tree865f56d1af0735c404bccd455322a6db29dc213e /arch/s390/net
parentc46a024ea5eb0165114dbbc8c82c29b7bcf66e71 (diff)
downloadlinux-bbac1c94880cb8c7e093718897f4822f3933dd3c.tar.gz
s390/bpf: fix stack allocation
On s390x we have to provide 160 bytes stack space before we can call the next function. From the 160 bytes that we got from the previous function we only use 11 * 8 bytes and have 160 - 11 * 8 bytes left. Currently for BPF we allocate additional 160 - 11 * 8 bytes for the next function. This is wrong because then the next function only gets: (160 - 11 * 8) + (160 - 11 * 8) = 2 * 72 = 144 bytes Fix this and allocate enough memory for the next function. 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.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/net/bpf_jit.h b/arch/s390/net/bpf_jit.h
index ba8593a515ba..de156ba3bd71 100644
--- a/arch/s390/net/bpf_jit.h
+++ b/arch/s390/net/bpf_jit.h
@@ -48,7 +48,9 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
* We get 160 bytes stack space from calling function, but only use
* 11 * 8 byte (old backchain + r15 - r6) for storing registers.
*/
-#define STK_OFF (MAX_BPF_STACK + 8 + 4 + 4 + (160 - 11 * 8))
+#define STK_SPACE (MAX_BPF_STACK + 8 + 4 + 4 + 160)
+#define STK_160_UNUSED (160 - 11 * 8)
+#define STK_OFF (STK_SPACE - STK_160_UNUSED)
#define STK_OFF_TMP 160 /* Offset of tmp buffer on stack */
#define STK_OFF_HLEN 168 /* Offset of SKB header length on stack */