Commit 30c90f67 authored by Xu Kuohai's avatar Xu Kuohai Committed by Daniel Borkmann
Browse files

arm64, insn: Add ldr/str with immediate offset 



This patch introduces ldr/str with immediate offset support to simplify
the JIT implementation of BPF LDX/STX instructions on arm64. Although
arm64 ldr/str immediate is available in pre-index, post-index and
unsigned offset forms, the unsigned offset form is sufficient for BPF,
so this patch only adds this type.

Signed-off-by: default avatarXu Kuohai <xukuohai@huawei.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220321152852.2334294-2-xukuohai@huawei.com
parent 2975dbdc

arch/arm64/include/asm/insn.h

+9 −0
Original line number Diff line number Diff line
@@ -201,6 +201,8 @@ enum aarch64_insn_size_type { 
enum aarch64_insn_ldst_type {

	AARCH64_INSN_LDST_LOAD_REG_OFFSET,

	AARCH64_INSN_LDST_STORE_REG_OFFSET,

	AARCH64_INSN_LDST_LOAD_IMM_OFFSET,

	AARCH64_INSN_LDST_STORE_IMM_OFFSET,

	AARCH64_INSN_LDST_LOAD_PAIR_PRE_INDEX,

	AARCH64_INSN_LDST_STORE_PAIR_PRE_INDEX,

	AARCH64_INSN_LDST_LOAD_PAIR_POST_INDEX,
@@ -335,6 +337,7 @@ __AARCH64_INSN_FUNCS(load_pre, 0x3FE00C00, 0x38400C00) 
__AARCH64_INSN_FUNCS(store_post,	0x3FE00C00, 0x38000400)

__AARCH64_INSN_FUNCS(load_post,	0x3FE00C00, 0x38400400)

__AARCH64_INSN_FUNCS(str_reg,	0x3FE0EC00, 0x38206800)

__AARCH64_INSN_FUNCS(str_imm,	0x3FC00000, 0x39000000)

__AARCH64_INSN_FUNCS(ldadd,	0x3F20FC00, 0x38200000)

__AARCH64_INSN_FUNCS(ldclr,	0x3F20FC00, 0x38201000)

__AARCH64_INSN_FUNCS(ldeor,	0x3F20FC00, 0x38202000)
@@ -342,6 +345,7 @@ __AARCH64_INSN_FUNCS(ldset, 0x3F20FC00, 0x38203000) 
__AARCH64_INSN_FUNCS(swp,	0x3F20FC00, 0x38208000)

__AARCH64_INSN_FUNCS(cas,	0x3FA07C00, 0x08A07C00)

__AARCH64_INSN_FUNCS(ldr_reg,	0x3FE0EC00, 0x38606800)

__AARCH64_INSN_FUNCS(ldr_imm,	0x3FC00000, 0x39400000)

__AARCH64_INSN_FUNCS(ldr_lit,	0xBF000000, 0x18000000)

__AARCH64_INSN_FUNCS(ldrsw_lit,	0xFF000000, 0x98000000)

__AARCH64_INSN_FUNCS(exclusive,	0x3F800000, 0x08000000)
@@ -501,6 +505,11 @@ u32 aarch64_insn_gen_load_store_reg(enum aarch64_insn_register reg, 
				    enum aarch64_insn_register offset,

				    enum aarch64_insn_size_type size,

				    enum aarch64_insn_ldst_type type);

u32 aarch64_insn_gen_load_store_imm(enum aarch64_insn_register reg,

				    enum aarch64_insn_register base,

				    unsigned int imm,

				    enum aarch64_insn_size_type size,

				    enum aarch64_insn_ldst_type type);

u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,

				     enum aarch64_insn_register reg2,

				     enum aarch64_insn_register base,

arch/arm64/lib/insn.c

+53 −14
Original line number Diff line number Diff line
@@ -299,29 +299,24 @@ static u32 aarch64_insn_encode_register(enum aarch64_insn_register_type type, 
	return insn;

}



static const u32 aarch64_insn_ldst_size[] = {

	[AARCH64_INSN_SIZE_8] = 0,

	[AARCH64_INSN_SIZE_16] = 1,

	[AARCH64_INSN_SIZE_32] = 2,

	[AARCH64_INSN_SIZE_64] = 3,

};



static u32 aarch64_insn_encode_ldst_size(enum aarch64_insn_size_type type,

					 u32 insn)

{

	u32 size;



	switch (type) {

	case AARCH64_INSN_SIZE_8:

		size = 0;

		break;

	case AARCH64_INSN_SIZE_16:

		size = 1;

		break;

	case AARCH64_INSN_SIZE_32:

		size = 2;

		break;

	case AARCH64_INSN_SIZE_64:

		size = 3;

		break;

	default:

	if (type < AARCH64_INSN_SIZE_8 || type > AARCH64_INSN_SIZE_64) {

		pr_err("%s: unknown size encoding %d\n", __func__, type);

		return AARCH64_BREAK_FAULT;

	}



	size = aarch64_insn_ldst_size[type];

	insn &= ~GENMASK(31, 30);

	insn |= size << 30;
@@ -504,6 +499,50 @@ u32 aarch64_insn_gen_load_store_reg(enum aarch64_insn_register reg, 
					    offset);

}



u32 aarch64_insn_gen_load_store_imm(enum aarch64_insn_register reg,

				    enum aarch64_insn_register base,

				    unsigned int imm,

				    enum aarch64_insn_size_type size,

				    enum aarch64_insn_ldst_type type)

{

	u32 insn;

	u32 shift;



	if (size < AARCH64_INSN_SIZE_8 || size > AARCH64_INSN_SIZE_64) {

		pr_err("%s: unknown size encoding %d\n", __func__, type);

		return AARCH64_BREAK_FAULT;

	}



	shift = aarch64_insn_ldst_size[size];

	if (imm & ~(BIT(12 + shift) - BIT(shift))) {

		pr_err("%s: invalid imm: %d\n", __func__, imm);

		return AARCH64_BREAK_FAULT;

	}



	imm >>= shift;



	switch (type) {

	case AARCH64_INSN_LDST_LOAD_IMM_OFFSET:

		insn = aarch64_insn_get_ldr_imm_value();

		break;

	case AARCH64_INSN_LDST_STORE_IMM_OFFSET:

		insn = aarch64_insn_get_str_imm_value();

		break;

	default:

		pr_err("%s: unknown load/store encoding %d\n", __func__, type);

		return AARCH64_BREAK_FAULT;

	}



	insn = aarch64_insn_encode_ldst_size(size, insn);



	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);



	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,

					    base);



	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm);

}



u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,

				     enum aarch64_insn_register reg2,

				     enum aarch64_insn_register base,