Commit a8ef95a0 authored by Russell King's avatar Russell King Committed by Daniel Borkmann
Browse files

ARM: net: bpf: provide load/store ops with negative immediates 



Provide a set of load/store opcode generators that work with negative
immediates as well as positive ones.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent d449ceb1

arch/arm/net/bpf_jit_32.c

+28 −0
Original line number Diff line number Diff line
@@ -239,6 +239,34 @@ static int16_t imm8m(u32 x) 
	return -1;

}



static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12)

{

	op |= rt << 12 | rn << 16;

	if (imm12 >= 0)

		op |= ARM_INST_LDST__U;

	else

		imm12 = -imm12;

	return op | (imm12 & 0xfff);

}



static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8)

{

	op |= rt << 12 | rn << 16;

	if (imm8 >= 0)

		op |= ARM_INST_LDST__U;

	else

		imm8 = -imm8;

	return op | (imm8 & 0xf0) << 4 | (imm8 & 0x0f);

}



#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_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_STRH_I(rt, rn, off)	arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off)



/*

 * Initializes the JIT space with undefined instructions.

 */

arch/arm/net/bpf_jit_32.h

+13 −22
Original line number Diff line number Diff line
@@ -77,11 +77,12 @@ 
#define ARM_INST_EOR_R		0x00200000

#define ARM_INST_EOR_I		0x02200000



#define ARM_INST_LDRB_I		0x05d00000

#define ARM_INST_LDST__U	0x00800000

#define ARM_INST_LDRB_I		0x05500000

#define ARM_INST_LDRB_R		0x07d00000

#define ARM_INST_LDRH_I		0x01d000b0

#define ARM_INST_LDRH_I		0x015000b0

#define ARM_INST_LDRH_R		0x019000b0

#define ARM_INST_LDR_I		0x05900000

#define ARM_INST_LDR_I		0x05100000

#define ARM_INST_LDR_R		0x07900000



#define ARM_INST_LDM		0x08900000
@@ -124,9 +125,9 @@ 
#define ARM_INST_SBC_R		0x00c00000

#define ARM_INST_SBCS_R		0x00d00000



#define ARM_INST_STR_I		0x05800000

#define ARM_INST_STRB_I		0x05c00000

#define ARM_INST_STRH_I		0x01c000b0

#define ARM_INST_STR_I		0x05000000

#define ARM_INST_STRB_I		0x05400000

#define ARM_INST_STRH_I		0x014000b0



#define ARM_INST_TST_R		0x01100000

#define ARM_INST_TST_I		0x03100000
@@ -183,17 +184,14 @@ 
#define ARM_EOR_R(rd, rn, rm)	_AL3_R(ARM_INST_EOR, rd, rn, rm)

#define ARM_EOR_I(rd, rn, imm)	_AL3_I(ARM_INST_EOR, rd, rn, imm)



#define ARM_LDR_I(rt, rn, off)	(ARM_INST_LDR_I | (rt) << 12 | (rn) << 16 \

				 | ((off) & 0xfff))

#define ARM_LDR_R(rt, rn, rm)	(ARM_INST_LDR_R | (rt) << 12 | (rn) << 16 \

#define ARM_LDR_R(rt, rn, rm)	(ARM_INST_LDR_R | ARM_INST_LDST__U \

				 | (rt) << 12 | (rn) << 16 \

				 | (rm))

#define ARM_LDRB_I(rt, rn, off)	(ARM_INST_LDRB_I | (rt) << 12 | (rn) << 16 \

				 | (off))

#define ARM_LDRB_R(rt, rn, rm)	(ARM_INST_LDRB_R | (rt) << 12 | (rn) << 16 \

#define ARM_LDRB_R(rt, rn, rm)	(ARM_INST_LDRB_R | ARM_INST_LDST__U \

				 | (rt) << 12 | (rn) << 16 \

				 | (rm))

#define ARM_LDRH_I(rt, rn, off)	(ARM_INST_LDRH_I | (rt) << 12 | (rn) << 16 \

				 | (((off) & 0xf0) << 4) | ((off) & 0xf))

#define ARM_LDRH_R(rt, rn, rm)	(ARM_INST_LDRH_R | (rt) << 12 | (rn) << 16 \

#define ARM_LDRH_R(rt, rn, rm)	(ARM_INST_LDRH_R | ARM_INST_LDST__U \

				 | (rt) << 12 | (rn) << 16 \

				 | (rm))



#define ARM_LDM(rn, regs)	(ARM_INST_LDM | (rn) << 16 | (regs))
@@ -254,13 +252,6 @@ 
#define ARM_SUBS_I(rd, rn, imm)	_AL3_I(ARM_INST_SUBS, rd, rn, imm)

#define ARM_SBC_I(rd, rn, imm)	_AL3_I(ARM_INST_SBC, rd, rn, imm)



#define ARM_STR_I(rt, rn, off)	(ARM_INST_STR_I | (rt) << 12 | (rn) << 16 \

				 | ((off) & 0xfff))

#define ARM_STRH_I(rt, rn, off)	(ARM_INST_STRH_I | (rt) << 12 | (rn) << 16 \

				 | (((off) & 0xf0) << 4) | ((off) & 0xf))

#define ARM_STRB_I(rt, rn, off)	(ARM_INST_STRB_I | (rt) << 12 | (rn) << 16 \

				 | (((off) & 0xf0) << 4) | ((off) & 0xf))



#define ARM_TST_R(rn, rm)	_AL3_R(ARM_INST_TST, 0, rn, rm)

#define ARM_TST_I(rn, imm)	_AL3_I(ARM_INST_TST, 0, rn, imm)

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