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authorIlya Leoshkevich <iii@linux.ibm.com>2019-11-15 13:37:22 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2019-11-15 22:25:00 +0100
commitb7b3fc8dd95bc02bd30680da258e09dda55270db (patch)
treef495c80bad776b25b2734b3257f6906de6b9365d /include/linux/filter.h
parente47a179997ceee6864fbae620eee09ea9c345a4d (diff)
bpf: Support doubleword alignment in bpf_jit_binary_alloc
Currently passing alignment greater than 4 to bpf_jit_binary_alloc does not work: in such cases it silently aligns only to 4 bytes. On s390, in order to load a constant from memory in a large (>512k) BPF program, one must use lgrl instruction, whose memory operand must be aligned on an 8-byte boundary. This patch makes it possible to request 8-byte alignment from bpf_jit_binary_alloc, and also makes it issue a warning when an unsupported alignment is requested. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191115123722.58462-1-iii@linux.ibm.com
Diffstat (limited to 'include/linux/filter.h')
-rw-r--r--include/linux/filter.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 7a6f8f6f1da4..ad80e9c6111c 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -515,10 +515,12 @@ struct sock_fprog_kern {
struct sock_filter *filter;
};
+/* Some arches need doubleword alignment for their instructions and/or data */
+#define BPF_IMAGE_ALIGNMENT 8
+
struct bpf_binary_header {
u32 pages;
- /* Some arches need word alignment for their instructions */
- u8 image[] __aligned(4);
+ u8 image[] __aligned(BPF_IMAGE_ALIGNMENT);
};
struct bpf_prog {