From d9ff286a0f59fa7843549e49bd240393dd7d8b87 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 23 Jan 2019 09:22:27 -0800 Subject: bpf: allow BPF programs access skb_shared_info->gso_segs field This adds the ability to read gso_segs from a BPF program. v3: Use BPF_REG_AX instead of BPF_REG_TMP for the temporary register, as suggested by Martin. v2: refined Eddie Hao patch to address Alexei feedback. Signed-off-by: Eric Dumazet Cc: Eddie Hao Cc: Martin KaFai Lau Acked-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann --- tools/include/uapi/linux/bpf.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/include') diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 91c43884f295..2940a9854f6d 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2540,6 +2540,7 @@ struct __sk_buff { __bpf_md_ptr(struct bpf_flow_keys *, flow_keys); __u64 tstamp; __u32 wire_len; + __u32 gso_segs; }; struct bpf_tunnel_key { -- cgit v1.2.3 From d405c7407a5468d4fc11724d76063e0647d80106 Mon Sep 17 00:00:00 2001 From: Jiong Wang Date: Sat, 26 Jan 2019 12:25:59 -0500 Subject: 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: Jakub Kicinski Signed-off-by: Jiong Wang Signed-off-by: Alexei Starovoitov --- Documentation/networking/filter.txt | 15 ++++++++------- include/uapi/linux/bpf.h | 1 + tools/include/uapi/linux/bpf.h | 1 + 3 files changed, 10 insertions(+), 7 deletions(-) (limited to 'tools/include') diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt index 2196b824e96c..01603bc2eff1 100644 --- a/Documentation/networking/filter.txt +++ b/Documentation/networking/filter.txt @@ -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: diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 2940a9854f6d..60b99b730a41 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -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 */ diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 2940a9854f6d..60b99b730a41 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -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 */ -- cgit v1.2.3 From a7b76c8857692b0fce063b94ed83da11c396d341 Mon Sep 17 00:00:00 2001 From: Jiong Wang Date: Sat, 26 Jan 2019 12:26:05 -0500 Subject: bpf: JIT blinds support JMP32 This patch adds JIT blinds support for JMP32. Like BPF_JMP_REG/IMM, JMP32 version are needed for building raw bpf insn. They are added to both include/linux/filter.h and tools/include/linux/filter.h. Reviewed-by: Jakub Kicinski Signed-off-by: Jiong Wang Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 20 ++++++++++++++++++++ kernel/bpf/core.c | 21 +++++++++++++++++++++ tools/include/linux/filter.h | 20 ++++++++++++++++++++ 3 files changed, 61 insertions(+) (limited to 'tools/include') diff --git a/include/linux/filter.h b/include/linux/filter.h index be9af6b4a9e4..e4b473f85b46 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -277,6 +277,26 @@ struct sock_reuseport; .off = OFF, \ .imm = IMM }) +/* Like BPF_JMP_REG, but with 32-bit wide operands for comparison. */ + +#define BPF_JMP32_REG(OP, DST, SRC, OFF) \ + ((struct bpf_insn) { \ + .code = BPF_JMP32 | BPF_OP(OP) | BPF_X, \ + .dst_reg = DST, \ + .src_reg = SRC, \ + .off = OFF, \ + .imm = 0 }) + +/* Like BPF_JMP_IMM, but with 32-bit wide operands for comparison. */ + +#define BPF_JMP32_IMM(OP, DST, IMM, OFF) \ + ((struct bpf_insn) { \ + .code = BPF_JMP32 | BPF_OP(OP) | BPF_K, \ + .dst_reg = DST, \ + .src_reg = 0, \ + .off = OFF, \ + .imm = IMM }) + /* Unconditional jumps, goto pc + off16 */ #define BPF_JMP_A(OFF) \ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index bba11c2565ee..a7bcb23bee84 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -949,6 +949,27 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); break; + case BPF_JMP32 | BPF_JEQ | BPF_K: + case BPF_JMP32 | BPF_JNE | BPF_K: + case BPF_JMP32 | BPF_JGT | BPF_K: + case BPF_JMP32 | BPF_JLT | BPF_K: + case BPF_JMP32 | BPF_JGE | BPF_K: + case BPF_JMP32 | BPF_JLE | BPF_K: + case BPF_JMP32 | BPF_JSGT | BPF_K: + case BPF_JMP32 | BPF_JSLT | BPF_K: + case BPF_JMP32 | BPF_JSGE | BPF_K: + case BPF_JMP32 | BPF_JSLE | BPF_K: + case BPF_JMP32 | BPF_JSET | BPF_K: + /* Accommodate for extra offset in case of a backjump. */ + off = from->off; + if (off < 0) + off -= 2; + *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); + *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, + off); + break; + case BPF_LD | BPF_IMM | BPF_DW: *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); diff --git a/tools/include/linux/filter.h b/tools/include/linux/filter.h index af55acf73e75..cce0b02c0e28 100644 --- a/tools/include/linux/filter.h +++ b/tools/include/linux/filter.h @@ -199,6 +199,16 @@ .off = OFF, \ .imm = 0 }) +/* Like BPF_JMP_REG, but with 32-bit wide operands for comparison. */ + +#define BPF_JMP32_REG(OP, DST, SRC, OFF) \ + ((struct bpf_insn) { \ + .code = BPF_JMP32 | BPF_OP(OP) | BPF_X, \ + .dst_reg = DST, \ + .src_reg = SRC, \ + .off = OFF, \ + .imm = 0 }) + /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */ #define BPF_JMP_IMM(OP, DST, IMM, OFF) \ @@ -209,6 +219,16 @@ .off = OFF, \ .imm = IMM }) +/* Like BPF_JMP_IMM, but with 32-bit wide operands for comparison. */ + +#define BPF_JMP32_IMM(OP, DST, IMM, OFF) \ + ((struct bpf_insn) { \ + .code = BPF_JMP32 | BPF_OP(OP) | BPF_K, \ + .dst_reg = DST, \ + .src_reg = 0, \ + .off = OFF, \ + .imm = IMM }) + /* Unconditional jumps, goto pc + off16 */ #define BPF_JMP_A(OFF) \ -- cgit v1.2.3