netdev - [PATCH bpf-next 06/12] bpf, arm64: remove ld_abs/ld

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu,  3 May 2018 03:05:30 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     ast@...nel.org
Cc:     netdev@...r.kernel.org, Daniel Borkmann <daniel@...earbox.net>
Subject: [PATCH bpf-next 06/12] bpf, arm64: 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 arm64 JIT.

Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Acked-by: Alexei Starovoitov <ast@...nel.org>
---
 arch/arm64/net/bpf_jit_comp.c | 65 -------------------------------------------
 1 file changed, 65 deletions(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index a933504..0b40c8f 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -723,71 +723,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
 		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 r0 = bpf2a64[BPF_REG_0]; /* r0 = return value */
-		const u8 r6 = bpf2a64[BPF_REG_6]; /* r6 = pointer to sk_buff */
-		const u8 fp = bpf2a64[BPF_REG_FP];
-		const u8 r1 = bpf2a64[BPF_REG_1]; /* r1: struct sk_buff *skb */
-		const u8 r2 = bpf2a64[BPF_REG_2]; /* r2: int k */
-		const u8 r3 = bpf2a64[BPF_REG_3]; /* r3: unsigned int size */
-		const u8 r4 = bpf2a64[BPF_REG_4]; /* r4: void *buffer */
-		const u8 r5 = bpf2a64[BPF_REG_5]; /* r5: void *(*func)(...) */
-		int size;
-
-		emit(A64_MOV(1, r1, r6), ctx);
-		emit_a64_mov_i(0, r2, imm, ctx);
-		if (BPF_MODE(code) == BPF_IND)
-			emit(A64_ADD(0, r2, r2, src), ctx);
-		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_a64_mov_i64(r3, size, ctx);
-		emit(A64_SUB_I(1, r4, fp, ctx->stack_size), ctx);
-		emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
-		emit(A64_BLR(r5), ctx);
-		emit(A64_MOV(1, r0, A64_R(0)), ctx);
-
-		jmp_offset = epilogue_offset(ctx);
-		check_imm19(jmp_offset);
-		emit(A64_CBZ(1, r0, jmp_offset), ctx);
-		emit(A64_MOV(1, r5, r0), ctx);
-		switch (BPF_SIZE(code)) {
-		case BPF_W:
-			emit(A64_LDR32(r0, r5, A64_ZR), ctx);
-#ifndef CONFIG_CPU_BIG_ENDIAN
-			emit(A64_REV32(0, r0, r0), ctx);
-#endif
-			break;
-		case BPF_H:
-			emit(A64_LDRH(r0, r5, A64_ZR), ctx);
-#ifndef CONFIG_CPU_BIG_ENDIAN
-			emit(A64_REV16(0, r0, r0), ctx);
-#endif
-			break;
-		case BPF_B:
-			emit(A64_LDRB(r0, r5, A64_ZR), ctx);
-			break;
-		}
-		break;
-	}
 	default:
 		pr_err_once("unknown opcode %02x\n", code);
 		return -EINVAL;
-- 
2.9.5