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arm64: introduce aarch64_insn_gen_bitfield()

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Introduce function to generate bitfield instructions.

Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Zi Shen Lim 2014-08-27 05:15:23 +01:00 committed by Will Deacon
parent 9951a157fa
commit 4a89d2c98e
2 changed files with 72 additions and 0 deletions
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16
arch/arm64/include/asm/insn.h
View file

@ -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);

56
arch/arm64/kernel/insn.c
View file

@ -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);
}