bpf: add comments to BPF ld/ldx sizes

Doc BPF ld/ldx size defines as comments in code, as it makes in faster to lookup in a programming/review setting, than looking up the sizes in Documentation/networking/filter.txt. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
mariux64 · Jan 18, 2018 · cb5f733 · cb5f733
1 parent eefa864
commit cb5f733
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
@@ -17,7 +17,7 @@
 #define BPF_ALU64	0x07	/* alu mode in double word width */
 
 /* ld/ldx fields */
-#define BPF_DW		0x18	/* double word */
+#define BPF_DW		0x18	/* double word (64-bit) */
 #define BPF_XADD	0xc0	/* exclusive add */
 
 /* alu/jmp fields */

diff --git a/include/uapi/linux/bpf_common.h b/include/uapi/linux/bpf_common.h
@@ -15,9 +15,10 @@
 
 /* ld/ldx fields */
 #define BPF_SIZE(code)  ((code) & 0x18)
-#define		BPF_W		0x00
-#define		BPF_H		0x08
-#define		BPF_B		0x10
+#define		BPF_W		0x00 /* 32-bit */
+#define		BPF_H		0x08 /* 16-bit */
+#define		BPF_B		0x10 /*  8-bit */
+/* eBPF		BPF_DW		0x18    64-bit */
 #define BPF_MODE(code)  ((code) & 0xe0)
 #define		BPF_IMM		0x00
 #define		BPF_ABS		0x20