From 0d2d0cedc0814edaa2b6cb290c78ec333b3eed71 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 4 May 2018 01:08:19 +0200 Subject: bpf, arm32: remove ld_abs/ld_ind Since LD_ABS/LD_IND instructions are now removed from the core and reimplemented through a combination of inlined BPF instructions and a slow-path helper, we can get rid of the complexity from arm32 JIT. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov --- arch/arm/net/bpf_jit_32.c | 77 ----------------------------------------------- 1 file changed, 77 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index b5030e1a41d8..82689b999257 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -1452,83 +1452,6 @@ exit: emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx); emit_ldx_r(dst, rn, dstk, off, ctx, BPF_SIZE(code)); break; - /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */ - case BPF_LD | BPF_ABS | BPF_W: - case BPF_LD | BPF_ABS | BPF_H: - case BPF_LD | BPF_ABS | BPF_B: - /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */ - case BPF_LD | BPF_IND | BPF_W: - case BPF_LD | BPF_IND | BPF_H: - case BPF_LD | BPF_IND | BPF_B: - { - const u8 r4 = bpf2a32[BPF_REG_6][1]; /* r4 = ptr to sk_buff */ - const u8 r0 = bpf2a32[BPF_REG_0][1]; /*r0: struct sk_buff *skb*/ - /* rtn value */ - const u8 r1 = bpf2a32[BPF_REG_0][0]; /* r1: int k */ - const u8 r2 = bpf2a32[BPF_REG_1][1]; /* r2: unsigned int size */ - const u8 r3 = bpf2a32[BPF_REG_1][0]; /* r3: void *buffer */ - const u8 r6 = bpf2a32[TMP_REG_1][1]; /* r6: void *(*func)(..) */ - int size; - - /* Setting up first argument */ - emit(ARM_MOV_R(r0, r4), ctx); - - /* Setting up second argument */ - emit_a32_mov_i(r1, imm, false, ctx); - if (BPF_MODE(code) == BPF_IND) - emit_a32_alu_r(r1, src_lo, false, sstk, ctx, - false, false, BPF_ADD); - - /* Setting up third argument */ - switch (BPF_SIZE(code)) { - case BPF_W: - size = 4; - break; - case BPF_H: - size = 2; - break; - case BPF_B: - size = 1; - break; - default: - return -EINVAL; - } - emit_a32_mov_i(r2, size, false, ctx); - - /* Setting up fourth argument */ - emit(ARM_ADD_I(r3, ARM_SP, imm8m(SKB_BUFFER)), ctx); - - /* Setting up function pointer to call */ - emit_a32_mov_i(r6, (unsigned int)bpf_load_pointer, false, ctx); - emit_blx_r(r6, ctx); - - emit(ARM_EOR_R(r1, r1, r1), ctx); - /* Check if return address is NULL or not. - * if NULL then jump to epilogue - * else continue to load the value from retn address - */ - emit(ARM_CMP_I(r0, 0), ctx); - jmp_offset = epilogue_offset(ctx); - check_imm24(jmp_offset); - _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx); - - /* Load value from the address */ - switch (BPF_SIZE(code)) { - case BPF_W: - emit(ARM_LDR_I(r0, r0, 0), ctx); - emit_rev32(r0, r0, ctx); - break; - case BPF_H: - emit(ARM_LDRH_I(r0, r0, 0), ctx); - emit_rev16(r0, r0, ctx); - break; - case BPF_B: - emit(ARM_LDRB_I(r0, r0, 0), ctx); - /* No need to reverse */ - break; - } - break; - } /* ST: *(size *)(dst + off) = imm */ case BPF_ST | BPF_MEM | BPF_W: case BPF_ST | BPF_MEM | BPF_H: -- cgit v1.2.3 From 38ca930601631585fbd7826f8f6908055a8dbc9e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 14 May 2018 23:22:30 +0200 Subject: bpf, arm32: save 4 bytes of unneeded stack space The extra skb_copy_bits() buffer is not used anymore, therefore remove the extra 4 byte stack space requirement. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov --- arch/arm/net/bpf_jit_32.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index 82689b999257..d3ea6454e775 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -234,18 +234,11 @@ static void jit_fill_hole(void *area, unsigned int size) #define SCRATCH_SIZE 80 /* total stack size used in JITed code */ -#define _STACK_SIZE \ - (ctx->prog->aux->stack_depth + \ - + SCRATCH_SIZE + \ - + 4 /* extra for skb_copy_bits buffer */) - -#define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT) +#define _STACK_SIZE (ctx->prog->aux->stack_depth + SCRATCH_SIZE) +#define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT) /* Get the offset of eBPF REGISTERs stored on scratch space. */ -#define STACK_VAR(off) (STACK_SIZE-off-4) - -/* Offset of skb_copy_bits buffer */ -#define SKB_BUFFER STACK_VAR(SCRATCH_SIZE) +#define STACK_VAR(off) (STACK_SIZE - off) #if __LINUX_ARM_ARCH__ < 7 -- cgit v1.2.3 From 2b589a7e2bd3eb610a4b7f5e61393481755a4de9 Mon Sep 17 00:00:00 2001 From: Wang YanQing Date: Fri, 11 May 2018 11:06:34 +0800 Subject: bpf, arm32: correct check_imm24 imm24 is signed, so the right range is: [-(1<<(24 - 1)), (1<<(24 - 1)) - 1] Note: this patch also fix a typo. Fixes: 39c13c204bb1 ("arm: eBPF JIT compiler") Signed-off-by: Wang YanQing Cc: Shubham Bansal Cc: linux-arm-kernel@lists.infradead.org Cc: linux@armlinux.org.uk Signed-off-by: Daniel Borkmann --- arch/arm/net/bpf_jit_32.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index d3ea6454e775..0d542007b49d 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -84,7 +84,7 @@ * * 1. First argument is passed using the arm 32bit registers and rest of the * arguments are passed on stack scratch space. - * 2. First callee-saved arugument is mapped to arm 32 bit registers and rest + * 2. First callee-saved argument is mapped to arm 32 bit registers and rest * arguments are mapped to scratch space on stack. * 3. We need two 64 bit temp registers to do complex operations on eBPF * registers. @@ -1192,8 +1192,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) s32 jmp_offset; #define check_imm(bits, imm) do { \ - if ((((imm) > 0) && ((imm) >> (bits))) || \ - (((imm) < 0) && (~(imm) >> (bits)))) { \ + if ((imm) >= (1 << ((bits) - 1)) || \ + (imm) < -(1 << ((bits) - 1))) { \ pr_info("[%2d] imm=%d(0x%x) out of range\n", \ i, imm, imm); \ return -EINVAL; \ -- cgit v1.2.3 From 68565a1af9f7012e6f2fe2bdd612f67d2d830c28 Mon Sep 17 00:00:00 2001 From: Wang YanQing Date: Fri, 11 May 2018 10:52:17 +0800 Subject: bpf, arm32: fix inconsistent naming about emit_a32_lsr_{r64,i64} The names for BPF_ALU64 | BPF_ARSH are emit_a32_arsh_*, the names for BPF_ALU64 | BPF_LSH are emit_a32_lsh_*, but the names for BPF_ALU64 | BPF_RSH are emit_a32_lsr_*. For consistence reason, let's rename emit_a32_lsr_* to emit_a32_rsh_*. This patch also corrects a wrong comment. Fixes: 39c13c204bb1 ("arm: eBPF JIT compiler") Signed-off-by: Wang YanQing Cc: Shubham Bansal Cc: linux-arm-kernel@lists.infradead.org Cc: linux@armlinux.org.uk Signed-off-by: Daniel Borkmann --- arch/arm/net/bpf_jit_32.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index 0d542007b49d..6e8b71613039 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -701,7 +701,7 @@ static inline void emit_a32_arsh_r64(const u8 dst[], const u8 src[], bool dstk, } /* dst = dst >> src */ -static inline void emit_a32_lsr_r64(const u8 dst[], const u8 src[], bool dstk, +static inline void emit_a32_rsh_r64(const u8 dst[], const u8 src[], bool dstk, bool sstk, struct jit_ctx *ctx) { const u8 *tmp = bpf2a32[TMP_REG_1]; const u8 *tmp2 = bpf2a32[TMP_REG_2]; @@ -717,7 +717,7 @@ static inline void emit_a32_lsr_r64(const u8 dst[], const u8 src[], bool dstk, emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); } - /* Do LSH operation */ + /* Do RSH operation */ emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_LSR, rt), ctx); @@ -767,7 +767,7 @@ static inline void emit_a32_lsh_i64(const u8 dst[], bool dstk, } /* dst = dst >> val */ -static inline void emit_a32_lsr_i64(const u8 dst[], bool dstk, +static inline void emit_a32_rsh_i64(const u8 dst[], bool dstk, const u32 val, struct jit_ctx *ctx) { const u8 *tmp = bpf2a32[TMP_REG_1]; const u8 *tmp2 = bpf2a32[TMP_REG_2]; @@ -1323,7 +1323,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) case BPF_ALU64 | BPF_RSH | BPF_K: if (unlikely(imm > 63)) return -EINVAL; - emit_a32_lsr_i64(dst, dstk, imm, ctx); + emit_a32_rsh_i64(dst, dstk, imm, ctx); break; /* dst = dst << src */ case BPF_ALU64 | BPF_LSH | BPF_X: @@ -1331,7 +1331,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) break; /* dst = dst >> src */ case BPF_ALU64 | BPF_RSH | BPF_X: - emit_a32_lsr_r64(dst, src, dstk, sstk, ctx); + emit_a32_rsh_r64(dst, src, dstk, sstk, ctx); break; /* dst = dst >> src (signed) */ case BPF_ALU64 | BPF_ARSH | BPF_X: -- cgit v1.2.3