Commit 4a89d2c9 authored by Zi Shen Lim's avatar Zi Shen Lim Committed by Will Deacon
Browse files

arm64: introduce aarch64_insn_gen_bitfield() 



Introduce function to generate bitfield instructions.

Signed-off-by: default avatarZi Shen Lim <zlim.lnx@gmail.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 9951a157

arch/arm64/include/asm/insn.h

+16 −0
Original line number Diff line number Diff line
@@ -67,6 +67,8 @@ enum aarch64_insn_imm_type { 
	AARCH64_INSN_IMM_12,

	AARCH64_INSN_IMM_9,

	AARCH64_INSN_IMM_7,

	AARCH64_INSN_IMM_S,

	AARCH64_INSN_IMM_R,

	AARCH64_INSN_IMM_MAX

};
@@ -170,6 +172,12 @@ enum aarch64_insn_adsb_type { 
	AARCH64_INSN_ADSB_SUB_SETFLAGS

};



enum aarch64_insn_bitfield_type {

	AARCH64_INSN_BITFIELD_MOVE,

	AARCH64_INSN_BITFIELD_MOVE_UNSIGNED,

	AARCH64_INSN_BITFIELD_MOVE_SIGNED

};



#define	__AARCH64_INSN_FUNCS(abbr, mask, val)	\

static __always_inline bool aarch64_insn_is_##abbr(u32 code) \

{ return (code & (mask)) == (val); } \
@@ -186,6 +194,9 @@ __AARCH64_INSN_FUNCS(add_imm, 0x7F000000, 0x11000000) 
__AARCH64_INSN_FUNCS(adds_imm,	0x7F000000, 0x31000000)

__AARCH64_INSN_FUNCS(sub_imm,	0x7F000000, 0x51000000)

__AARCH64_INSN_FUNCS(subs_imm,	0x7F000000, 0x71000000)

__AARCH64_INSN_FUNCS(sbfm,	0x7F800000, 0x13000000)

__AARCH64_INSN_FUNCS(bfm,	0x7F800000, 0x33000000)

__AARCH64_INSN_FUNCS(ubfm,	0x7F800000, 0x53000000)

__AARCH64_INSN_FUNCS(b,		0xFC000000, 0x14000000)

__AARCH64_INSN_FUNCS(bl,	0xFC000000, 0x94000000)

__AARCH64_INSN_FUNCS(cbz,	0xFE000000, 0x34000000)
@@ -236,6 +247,11 @@ u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst, 
				 enum aarch64_insn_register src,

				 int imm, enum aarch64_insn_variant variant,

				 enum aarch64_insn_adsb_type type);

u32 aarch64_insn_gen_bitfield(enum aarch64_insn_register dst,

			      enum aarch64_insn_register src,

			      int immr, int imms,

			      enum aarch64_insn_variant variant,

			      enum aarch64_insn_bitfield_type type);



bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn);

arch/arm64/kernel/insn.c

+56 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <asm/insn.h>



#define AARCH64_INSN_SF_BIT	BIT(31)

#define AARCH64_INSN_N_BIT	BIT(22)



static int aarch64_insn_encoding_class[] = {

	AARCH64_INSN_CLS_UNKNOWN,
@@ -259,6 +260,14 @@ u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, 
		mask = BIT(7) - 1;

		shift = 15;

		break;

	case AARCH64_INSN_IMM_S:

		mask = BIT(6) - 1;

		shift = 10;

		break;

	case AARCH64_INSN_IMM_R:

		mask = BIT(6) - 1;

		shift = 16;

		break;

	default:

		pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",

			type);
@@ -599,3 +608,50 @@ u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst, 


	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm);

}



u32 aarch64_insn_gen_bitfield(enum aarch64_insn_register dst,

			      enum aarch64_insn_register src,

			      int immr, int imms,

			      enum aarch64_insn_variant variant,

			      enum aarch64_insn_bitfield_type type)

{

	u32 insn;

	u32 mask;



	switch (type) {

	case AARCH64_INSN_BITFIELD_MOVE:

		insn = aarch64_insn_get_bfm_value();

		break;

	case AARCH64_INSN_BITFIELD_MOVE_UNSIGNED:

		insn = aarch64_insn_get_ubfm_value();

		break;

	case AARCH64_INSN_BITFIELD_MOVE_SIGNED:

		insn = aarch64_insn_get_sbfm_value();

		break;

	default:

		BUG_ON(1);

	}



	switch (variant) {

	case AARCH64_INSN_VARIANT_32BIT:

		mask = GENMASK(4, 0);

		break;

	case AARCH64_INSN_VARIANT_64BIT:

		insn |= AARCH64_INSN_SF_BIT | AARCH64_INSN_N_BIT;

		mask = GENMASK(5, 0);

		break;

	default:

		BUG_ON(1);

	}



	BUG_ON(immr & ~mask);

	BUG_ON(imms & ~mask);



	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst);



	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src);



	insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_R, insn, immr);



	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, imms);

}