x86/net/bpf_jit_comp.c

123  * extra byte of encoding and is callee saved.
161  * which need extra byte of encoding.
178  * lower 8-bit registers dil,sil,bpl,spl,r8b..r15b, which need extra byte
195 static u8 add_1mod(u8 byte, u32 reg)
198 		byte |= 1;
199 	return byte;
202 static u8 add_2mod(u8 byte, u32 r1, u32 r2)
205 		byte |= 1;
207 		byte |= 4;
208 	return byte;
211 static u8 add_3mod(u8 byte, u32 r1, u32 r2, u32 index)
214 		byte |= 1;
216 		byte |= 2;
218 		byte |= 4;
219 	return byte;
222 /* Encode 'dst_reg' register into x86-64 opcode 'byte' */
223 static u8 add_1reg(u8 byte, u32 dst_reg)
225 	return byte + reg2hex[dst_reg];
228 /* Encode 'dst_reg' and 'src_reg' registers into x86-64 opcode 'byte' */
229 static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
231 	return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3);
234 /* Some 1-byte opcodes for binary ALU operations */
894 		/* 1-byte signed displacement.
896 		 * If off == 0 we could skip this and save one extra byte, but
902 		/* 4-byte signed displacement */
921  * Emit a REX byte if it will be necessary to address these registers
955 		/* Emit 'movzx rax, byte ptr [rax + off]' */
985 		/* Emit 'movsx rax, byte ptr [rax + off]' */
1007 		/* movzx rax, byte ptr [rax + r12 + off] */
1039 		/* Emit 'mov byte ptr [rax + off], al' */
1041 			/* Add extra byte for eregs or SIL,DIL,BPL in src_reg */
1073 		/* mov byte ptr [rax + r12 + off], al */
1105 		/* mov byte ptr [rax + r12 + off], imm8 */
1204 /* emit the 3-byte VEX prefix
1219 	const u8 b0 = 0xc4; /* first byte of 3-byte VEX prefix */
1228 	 * 2nd byte of 3-byte VEX prefix
1238 	 * 3rd byte of 3-byte VEX prefix
1503 				 * equivalent to 'xor rdx, rdx', but one byte less
2070 			/* test dst_reg, dst_reg to save one extra byte */
2196 					 *     to pad any extra byte (0 byte).
2221 					 * jmp, there is nothing to pad (0 byte).
2318 	 * on-stack with "push" instruction, which will take 8-byte
2323 	 * However, sometimes the compiler will only allocate 4-byte on
2326 	 * not more than 4 byte. In this case, there will be garbage
2327 	 * values on the upper 4-byte where we store the argument on
2332 	 * stack_arg_1(4-byte) xxx(4-byte)
2336 	 * stack_arg_1(8-byte): stack_arg_1(origin) xxx
2678  * eth_type_trans has 5 byte nop at the beginning. These 5 bytes will be
2803 		/* make sure the stack pointer is 16-byte aligned if we
2806 		 * should be 16-byte aligned. Following code depend on
2807 		 * that stack_size is already 8-byte aligned.
2928 		 * Coding Rule 11: All branch targets should be 16-byte
3117 	 * Coding Rule 11: All branch targets should be 16-byte