bpfc: add gnu as style %-register prefix

Let a and x register also be addressed as %x and %a.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

3 files changed, 71 insertions, 3 deletions

diff --git a/bpf_lexer.l b/bpf_lexer.l
index 185faae..26accbc 100644
--- a/bpf_lexer.l
+++ b/bpf_lexer.l
@@ -91,6 +91,7 @@ label		[a-zA-Z_][a-zA-Z0-9_]+
 ":"		{ return ':'; }
 ","		{ return ','; }
 "#"		{ return '#'; }
+"%"		{ return '%'; }
 "["		{ return '['; }
 "]"		{ return ']'; }
 "("		{ return '('; }
diff --git a/bpf_parser.y b/bpf_parser.y
index 48a6e4c..c8d2a8f 100644
--- a/bpf_parser.y
+++ b/bpf_parser.y
@@ -135,7 +135,7 @@ static int find_intr_offset_or_panic(char *label_to_search)
 %token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE
 %token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF
 
-%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#'
+%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%'
 
 %token number label
 
@@ -198,6 +198,8 @@ labelled
 ldb
 	: OP_LDB '[' 'x' '+' number ']' {
 		set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
+	| OP_LDB '[' '%' 'x' '+' number ']' {
+		set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $6); }
 	| OP_LDB '[' number ']' {
 		set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
 	| OP_LDB K_PROTO {
@@ -244,6 +246,8 @@ ldb
 ldh
 	: OP_LDH '[' 'x' '+' number ']' {
 		set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
+	| OP_LDH '[' '%' 'x' '+' number ']' {
+		set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $6); }
 	| OP_LDH '[' number ']' {
 		set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
 	| OP_LDH K_PROTO {
@@ -342,6 +346,8 @@ ld
 		set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
 	| OP_LD '[' 'x' '+' number ']' {
 		set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); }
+	| OP_LD '[' '%' 'x' '+' number ']' {
+		set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $6); }
 	| OP_LD '[' number ']' {
 		set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); }
 	;
@@ -397,12 +403,19 @@ jeq
 		set_jmp_label($4, JTL);
 		set_jmp_label($6, JFL);
 		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JEQ '%' 'x' ',' label ',' label {
+		set_jmp_label($5, JTL);
+		set_jmp_label($7, JFL);
+		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
 	| OP_JEQ '#' number ',' label {
 		set_jmp_label($5, JTL);
 		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
 	| OP_JEQ 'x' ',' label {
 		set_jmp_label($4, JTL);
 		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JEQ '%' 'x' ',' label {
+		set_jmp_label($5, JTL);
+		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
 	;
 
 jneq
@@ -412,6 +425,9 @@ jneq
 	| OP_JNEQ 'x' ',' label {
 		set_jmp_label($4, JFL);
 		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
+	| OP_JNEQ '%' 'x' ',' label {
+		set_jmp_label($5, JFL);
+		set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
 	;
 
 jlt
@@ -421,6 +437,9 @@ jlt
 	| OP_JLT 'x' ',' label {
 		set_jmp_label($4, JFL);
 		set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JLT '%' 'x' ',' label {
+		set_jmp_label($5, JFL);
+		set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
 	;
 
 jle
@@ -430,6 +449,9 @@ jle
 	| OP_JLE 'x' ',' label {
 		set_jmp_label($4, JFL);
 		set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JLE '%' 'x' ',' label {
+		set_jmp_label($5, JFL);
+		set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
 	;
 
 jgt
@@ -441,12 +463,19 @@ jgt
 		set_jmp_label($4, JTL);
 		set_jmp_label($6, JFL);
 		set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JGT '%' 'x' ',' label ',' label {
+		set_jmp_label($5, JTL);
+		set_jmp_label($7, JFL);
+		set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
 	| OP_JGT '#' number ',' label {
 		set_jmp_label($5, JTL);
 		set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }  
 	| OP_JGT 'x' ',' label {
 		set_jmp_label($4, JTL);
 		set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
+	| OP_JGT '%' 'x' ',' label {
+		set_jmp_label($5, JTL);
+		set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
 	;
 
 jge
@@ -458,12 +487,19 @@ jge
 		set_jmp_label($4, JTL);
 		set_jmp_label($6, JFL);
 		set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JGE '%' 'x' ',' label ',' label {
+		set_jmp_label($5, JTL);
+		set_jmp_label($7, JFL);
+		set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
 	| OP_JGE '#' number ',' label {
 		set_jmp_label($5, JTL);
 		set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
 	| OP_JGE 'x' ',' label {
 		set_jmp_label($4, JTL);
 		set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
+	| OP_JGE '%' 'x' ',' label {
+		set_jmp_label($5, JTL);
+		set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
 	;
 
 jset
@@ -475,12 +511,19 @@ jset
 		set_jmp_label($4, JTL);
 		set_jmp_label($6, JFL);
 		set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
+	| OP_JSET '%' 'x' ',' label ',' label {
+		set_jmp_label($5, JTL);
+		set_jmp_label($7, JFL);
+		set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
 	| OP_JSET '#' number ',' label {
 		set_jmp_label($5, JTL);
 		set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
 	| OP_JSET 'x' ',' label {
 		set_jmp_label($4, JTL);
 		set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
+	| OP_JSET '%' 'x' ',' label {
+		set_jmp_label($5, JTL);
+		set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
 	;
 
 add
@@ -488,6 +531,8 @@ add
 		set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
 	| OP_ADD 'x' {
 		set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
+	| OP_ADD '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
 	;
 
 sub
@@ -495,6 +540,8 @@ sub
 		set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
 	| OP_SUB 'x' {
 		set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
+	| OP_SUB '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
 	;
 
 mul
@@ -502,6 +549,8 @@ mul
 		set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
 	| OP_MUL 'x' {
 		set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
+	| OP_MUL '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
 	;
 
 div
@@ -509,6 +558,8 @@ div
 		set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
 	| OP_DIV 'x' {
 		set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
+	| OP_DIV '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
 	;
 
 mod
@@ -516,6 +567,8 @@ mod
 		set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
 	| OP_MOD 'x' {
 		set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
+	| OP_MOD '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
 	;
 
 neg
@@ -528,6 +581,8 @@ and
 		set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
 	| OP_AND 'x' {
 		set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
+	| OP_AND '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
 	;
 
 or
@@ -535,6 +590,8 @@ or
 		set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
 	| OP_OR 'x' {
 		set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
+	| OP_OR '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
 	;
 
 xor
@@ -542,6 +599,8 @@ xor
 		set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
 	| OP_XOR 'x' {
 		set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
+	| OP_XOR '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
 	;
 
 lsh
@@ -549,6 +608,8 @@ lsh
 		set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
 	| OP_LSH 'x' {
 		set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
+	| OP_LSH '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
 	;
 
 rsh
@@ -556,13 +617,19 @@ rsh
 		set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
 	| OP_RSH 'x' {
 		set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
+	| OP_RSH '%' 'x' {
+		set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
 	;
 
 ret
 	: OP_RET 'a' {
 		set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
+	| OP_RET '%' 'a' {
+		set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
 	| OP_RET 'x' {
 		set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
+	| OP_RET '%' 'x' {
+		set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
 	| OP_RET '#' number {
 		set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
 	;
diff --git a/bpfc.8 b/bpfc.8
index 5ef7a04..c65fbec 100644
--- a/bpfc.8
+++ b/bpfc.8
@@ -158,7 +158,7 @@ unsigned data structures:
 .PP
    Addressing mode  Syntax               Description
 .PP
-    0               x                    Register X
+    0               x/%x                 Register X
     1               [k]                  BHW at byte offset k in the packet
     2               [x + k]              BHW at the offset X + k in the packet
     3               M[k]                 Word at offset k in M[]
@@ -167,7 +167,7 @@ unsigned data structures:
     6               L                    Jump label L
     7               #k,Lt,Lf             Jump to Lt if true, otherwise jump to Lf
     8               #k,Lt                Jump to Lt if predicate is true
-    9               a                    Accumulator A
+    9               a/%a                 Accumulator A
    10               extension            BPF extension (see next table)
 .PP
    Extension (and alias)                 Description