Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d405c740 authored by Jiong Wang's avatar Jiong Wang Committed by Alexei Starovoitov
Browse files

bpf: allocate 0x06 to new eBPF instruction class JMP32 



The new eBPF instruction class JMP32 uses the reserved class number 0x6.
Kernel BPF ISA documentation updated accordingly.

Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarJiong Wang <jiong.wang@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent dbbd79ae

Documentation/networking/filter.txt

+8 −7
Original line number Diff line number Diff line
@@ -865,7 +865,7 @@ Three LSB bits store instruction class which is one of: 
  BPF_STX   0x03          BPF_STX   0x03

  BPF_ALU   0x04          BPF_ALU   0x04

  BPF_JMP   0x05          BPF_JMP   0x05

  BPF_RET   0x06          [ class 6 unused, for future if needed ]

  BPF_RET   0x06          BPF_JMP32 0x06

  BPF_MISC  0x07          BPF_ALU64 0x07



When BPF_CLASS(code) == BPF_ALU or BPF_JMP, 4th bit encodes source operand ...
@@ -902,9 +902,9 @@ If BPF_CLASS(code) == BPF_ALU or BPF_ALU64 [ in eBPF ], BPF_OP(code) is one of: 
  BPF_ARSH  0xc0  /* eBPF only: sign extending shift right */

  BPF_END   0xd0  /* eBPF only: endianness conversion */



If BPF_CLASS(code) == BPF_JMP, BPF_OP(code) is one of:

If BPF_CLASS(code) == BPF_JMP or BPF_JMP32 [ in eBPF ], BPF_OP(code) is one of:



  BPF_JA    0x00

  BPF_JA    0x00  /* BPF_JMP only */

  BPF_JEQ   0x10

  BPF_JGT   0x20

  BPF_JGE   0x30
@@ -912,8 +912,8 @@ If BPF_CLASS(code) == BPF_JMP, BPF_OP(code) is one of: 
  BPF_JNE   0x50  /* eBPF only: jump != */

  BPF_JSGT  0x60  /* eBPF only: signed '>' */

  BPF_JSGE  0x70  /* eBPF only: signed '>=' */

  BPF_CALL  0x80  /* eBPF only: function call */

  BPF_EXIT  0x90  /* eBPF only: function return */

  BPF_CALL  0x80  /* eBPF BPF_JMP only: function call */

  BPF_EXIT  0x90  /* eBPF BPF_JMP only: function return */

  BPF_JLT   0xa0  /* eBPF only: unsigned '<' */

  BPF_JLE   0xb0  /* eBPF only: unsigned '<=' */

  BPF_JSLT  0xc0  /* eBPF only: signed '<' */
@@ -936,8 +936,9 @@ Classic BPF wastes the whole BPF_RET class to represent a single 'ret' 
operation. Classic BPF_RET | BPF_K means copy imm32 into return register

and perform function exit. eBPF is modeled to match CPU, so BPF_JMP | BPF_EXIT

in eBPF means function exit only. The eBPF program needs to store return

value into register R0 before doing a BPF_EXIT. Class 6 in eBPF is currently

unused and reserved for future use.

value into register R0 before doing a BPF_EXIT. Class 6 in eBPF is used as

BPF_JMP32 to mean exactly the same operations as BPF_JMP, but with 32-bit wide

operands for the comparisons instead.



For load and store instructions the 8-bit 'code' field is divided as:

include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
/* Extended instruction set based on top of classic BPF */



/* instruction classes */

#define BPF_JMP32	0x06	/* jmp mode in word width */

#define BPF_ALU64	0x07	/* alu mode in double word width */



/* ld/ldx fields */

tools/include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
/* Extended instruction set based on top of classic BPF */



/* instruction classes */

#define BPF_JMP32	0x06	/* jmp mode in word width */

#define BPF_ALU64	0x07	/* alu mode in double word width */



/* ld/ldx fields */