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Commit 8c9602d3 authored by Russell King's avatar Russell King Committed by Daniel Borkmann
Browse files

ARM: net: bpf: use double-word load/stores where available 



Use double-word load and stores where support for this instruction is
supported by the CPU architecture.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent bef8968d

arch/arm/net/bpf_jit_32.c

+43 −12
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <asm/cacheflush.h>

#include <asm/hwcap.h>

#include <asm/opcodes.h>

#include <asm/system_info.h>



#include "bpf_jit_32.h"
@@ -192,6 +193,7 @@ struct jit_ctx { 
	unsigned int idx;

	unsigned int prologue_bytes;

	unsigned int epilogue_offset;

	unsigned int cpu_architecture;

	u32 flags;

	u32 *offsets;

	u32 *target;
@@ -319,10 +321,12 @@ static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8) 


#define ARM_LDR_I(rt, rn, off)	arm_bpf_ldst_imm12(ARM_INST_LDR_I, rt, rn, off)

#define ARM_LDRB_I(rt, rn, off)	arm_bpf_ldst_imm12(ARM_INST_LDRB_I, rt, rn, off)

#define ARM_LDRD_I(rt, rn, off)	arm_bpf_ldst_imm8(ARM_INST_LDRD_I, rt, rn, off)

#define ARM_LDRH_I(rt, rn, off)	arm_bpf_ldst_imm8(ARM_INST_LDRH_I, rt, rn, off)



#define ARM_STR_I(rt, rn, off)	arm_bpf_ldst_imm12(ARM_INST_STR_I, rt, rn, off)

#define ARM_STRB_I(rt, rn, off)	arm_bpf_ldst_imm12(ARM_INST_STRB_I, rt, rn, off)

#define ARM_STRD_I(rt, rn, off)	arm_bpf_ldst_imm8(ARM_INST_STRD_I, rt, rn, off)

#define ARM_STRH_I(rt, rn, off)	arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off)



/*
@@ -533,10 +537,16 @@ static const s8 *arm_bpf_get_reg64(const s8 *reg, const s8 *tmp, 
				   struct jit_ctx *ctx)

{

	if (is_stacked(reg[1])) {

		emit(ARM_LDR_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[1])),

		     ctx);

		emit(ARM_LDR_I(tmp[0], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[0])),

		     ctx);

		if (__LINUX_ARM_ARCH__ >= 6 ||

		    ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) {

			emit(ARM_LDRD_I(tmp[1], ARM_FP,

					EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);

		} else {

			emit(ARM_LDR_I(tmp[1], ARM_FP,

				       EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);

			emit(ARM_LDR_I(tmp[0], ARM_FP,

				       EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx);

		}

		reg = tmp;

	}

	return reg;
@@ -558,10 +568,16 @@ static void arm_bpf_put_reg64(const s8 *reg, const s8 *src, 
			      struct jit_ctx *ctx)

{

	if (is_stacked(reg[1])) {

		emit(ARM_STR_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[1])),

		     ctx);

		emit(ARM_STR_I(src[0], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[0])),

		     ctx);

		if (__LINUX_ARM_ARCH__ >= 6 ||

		    ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) {

			emit(ARM_STRD_I(src[1], ARM_FP,

				       EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);

		} else {

			emit(ARM_STR_I(src[1], ARM_FP,

				       EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);

			emit(ARM_STR_I(src[0], ARM_FP,

				       EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx);

		}

	} else {

		if (reg[1] != src[1])

			emit(ARM_MOV_R(reg[1], src[1]), ctx);
@@ -711,13 +727,27 @@ static inline void emit_a32_mov_r(const s8 dst, const s8 src, 
static inline void emit_a32_mov_r64(const bool is64, const s8 dst[],

				  const s8 src[],

				  struct jit_ctx *ctx) {

	if (!is64) {

		emit_a32_mov_r(dst_lo, src_lo, ctx);

	if (is64) {

		/* Zero out high 4 bytes */

		emit_a32_mov_i(dst_hi, 0, ctx);

	} else if (__LINUX_ARM_ARCH__ < 6 &&

		   ctx->cpu_architecture < CPU_ARCH_ARMv5TE) {

		/* complete 8 byte move */

		emit_a32_mov_r(dst_lo, src_lo, ctx);

		emit_a32_mov_r(dst_hi, src_hi, ctx);

	} else if (is_stacked(src_lo) && is_stacked(dst_lo)) {

		const u8 *tmp = bpf2a32[TMP_REG_1];



		emit(ARM_LDRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx);

		emit(ARM_STRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx);

	} else if (is_stacked(src_lo)) {

		emit(ARM_LDRD_I(dst[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx);

	} else if (is_stacked(dst_lo)) {

		emit(ARM_STRD_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx);

	} else {

		/* Zero out high 4 bytes */

		emit_a32_mov_i(dst_hi, 0, ctx);

		emit(ARM_MOV_R(dst[0], src[0]), ctx);

		emit(ARM_MOV_R(dst[1], src[1]), ctx);

	}

}
@@ -1778,6 +1808,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) 


	memset(&ctx, 0, sizeof(ctx));

	ctx.prog = prog;

	ctx.cpu_architecture = cpu_architecture();



	/* Not able to allocate memory for offsets[] , then

	 * we must fall back to the interpreter

arch/arm/net/bpf_jit_32.h

+2 −0
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ 
#define ARM_INST_LDST__IMM12	0x00000fff

#define ARM_INST_LDRB_I		0x05500000

#define ARM_INST_LDRB_R		0x07d00000

#define ARM_INST_LDRD_I		0x014000d0

#define ARM_INST_LDRH_I		0x015000b0

#define ARM_INST_LDRH_R		0x019000b0

#define ARM_INST_LDR_I		0x05100000
@@ -128,6 +129,7 @@ 


#define ARM_INST_STR_I		0x05000000

#define ARM_INST_STRB_I		0x05400000

#define ARM_INST_STRD_I		0x014000f0

#define ARM_INST_STRH_I		0x014000b0



#define ARM_INST_TST_R		0x01100000