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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [RFC 09/16] xen/arm: arm64: Add helpers to decode and encode branch instructions
We may need to update branch instruction when patching Xen. The code has been imported from the files arch/arm64/kernel/insn.c and arch/arm64/include/asm/insn.h in Linux v4.6-rc3. Note that only the necessary helpers have been imported. Signed-off-by: Julien Grall <julien.grall@xxxxxxx> --- xen/arch/arm/arm64/Makefile | 1 + xen/arch/arm/arm64/insn.c | 213 +++++++++++++++++++++++++++++++++++++++ xen/include/asm-arm/arm64/insn.h | 72 +++++++++++++ xen/include/asm-arm/insn.h | 22 ++++ 4 files changed, 308 insertions(+) create mode 100644 xen/arch/arm/arm64/insn.c create mode 100644 xen/include/asm-arm/arm64/insn.h create mode 100644 xen/include/asm-arm/insn.h diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile index 39c6ac6..c1fa43f 100644 --- a/xen/arch/arm/arm64/Makefile +++ b/xen/arch/arm/arm64/Makefile @@ -5,6 +5,7 @@ obj-$(EARLY_PRINTK) += debug.o obj-y += domctl.o obj-y += domain.o obj-y += entry.o +obj-y += insn.o obj-y += smpboot.o obj-y += traps.o obj-y += vfp.o diff --git a/xen/arch/arm/arm64/insn.c b/xen/arch/arm/arm64/insn.c new file mode 100644 index 0000000..54a6b62 --- /dev/null +++ b/xen/arch/arm/arm64/insn.c @@ -0,0 +1,213 @@ +/* + * Based on Linux arch/arm64/kernel/insn.c + * + * Copyright (C) 2013 Huawei Ltd. + * Author: Jiang Liu <liuj97@xxxxxxxxx> + * + * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@xxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <xen/config.h> +#include <xen/types.h> +#include <xen/lib.h> +#include <xen/errno.h> +#include <xen/sizes.h> +#include <xen/bitops.h> +#include <asm/insn.h> +#include <asm/arm64/insn.h> + +bool aarch64_insn_is_branch_imm(u32 insn) +{ + return (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) || + aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) || + aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) || + aarch64_insn_is_bcond(insn)); +} + +static int aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type, + u32 *maskp, int *shiftp) +{ + u32 mask; + int shift; + + switch (type) { + case AARCH64_INSN_IMM_26: + mask = BIT(26) - 1; + shift = 0; + break; + case AARCH64_INSN_IMM_19: + mask = BIT(19) - 1; + shift = 5; + break; + case AARCH64_INSN_IMM_16: + mask = BIT(16) - 1; + shift = 5; + break; + case AARCH64_INSN_IMM_14: + mask = BIT(14) - 1; + shift = 5; + break; + case AARCH64_INSN_IMM_12: + mask = BIT(12) - 1; + shift = 10; + break; + case AARCH64_INSN_IMM_9: + mask = BIT(9) - 1; + shift = 12; + break; + case AARCH64_INSN_IMM_7: + mask = BIT(7) - 1; + shift = 15; + break; + case AARCH64_INSN_IMM_6: + 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: + return -EINVAL; + } + + *maskp = mask; + *shiftp = shift; + + return 0; +} + +#define ADR_IMM_HILOSPLIT 2 +#define ADR_IMM_SIZE SZ_2M +#define ADR_IMM_LOMASK ((1 << ADR_IMM_HILOSPLIT) - 1) +#define ADR_IMM_HIMASK ((ADR_IMM_SIZE >> ADR_IMM_HILOSPLIT) - 1) +#define ADR_IMM_LOSHIFT 29 +#define ADR_IMM_HISHIFT 5 + +u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn) +{ + u32 immlo, immhi, mask; + int shift; + + switch (type) { + case AARCH64_INSN_IMM_ADR: + shift = 0; + immlo = (insn >> ADR_IMM_LOSHIFT) & ADR_IMM_LOMASK; + immhi = (insn >> ADR_IMM_HISHIFT) & ADR_IMM_HIMASK; + insn = (immhi << ADR_IMM_HILOSPLIT) | immlo; + mask = ADR_IMM_SIZE - 1; + break; + default: + if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) { + printk(XENLOG_ERR "aarch64_insn_decode_immediate: unknown immediate encoding %d\n", + type); + return 0; + } + } + + return (insn >> shift) & mask; +} + +u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, + u32 insn, u64 imm) +{ + u32 immlo, immhi, mask; + int shift; + + switch (type) { + case AARCH64_INSN_IMM_ADR: + shift = 0; + immlo = (imm & ADR_IMM_LOMASK) << ADR_IMM_LOSHIFT; + imm >>= ADR_IMM_HILOSPLIT; + immhi = (imm & ADR_IMM_HIMASK) << ADR_IMM_HISHIFT; + imm = immlo | immhi; + mask = ((ADR_IMM_LOMASK << ADR_IMM_LOSHIFT) | + (ADR_IMM_HIMASK << ADR_IMM_HISHIFT)); + break; + default: + if (aarch64_get_imm_shift_mask(type, &mask, &shift) < 0) { + printk(XENLOG_ERR "aarch64_insn_encode_immediate: unknown immediate encoding %d\n", + type); + return AARCH64_BREAK_FAULT; + } + } + + /* Update the immediate field. */ + insn &= ~(mask << shift); + insn |= (imm & mask) << shift; + + return insn; +} + +/* + * Decode the imm field of a branch, and return the byte offset as a + * signed value (so it can be used when computing a new branch + * target). + */ +s32 aarch64_get_branch_offset(u32 insn) +{ + s32 imm; + + if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) { + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_26, insn); + return (imm << 6) >> 4; + } + + if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) || + aarch64_insn_is_bcond(insn)) { + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_19, insn); + return (imm << 13) >> 11; + } + + if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) { + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_14, insn); + return (imm << 18) >> 16; + } + + /* Unhandled instruction */ + BUG(); +} + +/* + * Encode the displacement of a branch in the imm field and return the + * updated instruction. + */ +u32 aarch64_set_branch_offset(u32 insn, s32 offset) +{ + if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn, + offset >> 2); + + if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) || + aarch64_insn_is_bcond(insn)) + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn, + offset >> 2); + + if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_14, insn, + offset >> 2); + + /* Unhandled instruction */ + BUG(); +} + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 8 + * indent-tabs-mode: t + * End: + */ diff --git a/xen/include/asm-arm/arm64/insn.h b/xen/include/asm-arm/arm64/insn.h new file mode 100644 index 0000000..cfcdbe9 --- /dev/null +++ b/xen/include/asm-arm/arm64/insn.h @@ -0,0 +1,72 @@ +/* + * Copyright (C) 2013 Huawei Ltd. + * Author: Jiang Liu <liuj97@xxxxxxxxx> + * + * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@xxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef __ARCH_ARM_ARM64_INSN +#define __ARCH_ARM_ARM64_INSN + +#include <xen/config.h> +#include <xen/types.h> +#include <xen/stdbool.h> + +enum aarch64_insn_imm_type { + AARCH64_INSN_IMM_ADR, + AARCH64_INSN_IMM_26, + AARCH64_INSN_IMM_19, + AARCH64_INSN_IMM_16, + AARCH64_INSN_IMM_14, + AARCH64_INSN_IMM_12, + AARCH64_INSN_IMM_9, + AARCH64_INSN_IMM_7, + AARCH64_INSN_IMM_6, + AARCH64_INSN_IMM_S, + AARCH64_INSN_IMM_R, + AARCH64_INSN_IMM_MAX +}; + +#define __AARCH64_INSN_FUNCS(abbr, mask, val) \ +static always_inline bool_t aarch64_insn_is_##abbr(u32 code) \ +{ return (code & (mask)) == (val); } \ +static always_inline u32 aarch64_insn_get_##abbr##_value(void) \ +{ return (val); } + +__AARCH64_INSN_FUNCS(b, 0xFC000000, 0x14000000) +__AARCH64_INSN_FUNCS(bl, 0xFC000000, 0x94000000) +__AARCH64_INSN_FUNCS(cbz, 0x7F000000, 0x34000000) +__AARCH64_INSN_FUNCS(cbnz, 0x7F000000, 0x35000000) +__AARCH64_INSN_FUNCS(tbz, 0x7F000000, 0x36000000) +__AARCH64_INSN_FUNCS(tbnz, 0x7F000000, 0x37000000) +__AARCH64_INSN_FUNCS(bcond, 0xFF000010, 0x54000000) + +bool aarch64_insn_is_branch_imm(u32 insn); + +u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn); +u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, + u32 insn, u64 imm); + +s32 aarch64_get_branch_offset(u32 insn); +u32 aarch64_set_branch_offset(u32 insn, s32 offset); + +#endif /* !__ARCH_ARM_ARM64_INSN */ +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 8 + * indent-tabs-mode: t + * End: + */ diff --git a/xen/include/asm-arm/insn.h b/xen/include/asm-arm/insn.h new file mode 100644 index 0000000..fe9419c --- /dev/null +++ b/xen/include/asm-arm/insn.h @@ -0,0 +1,22 @@ +#ifndef __ARCH_ARM_INSN +#define __ARCH_ARM_INSN + +#include <xen/types.h> + +#if defined(CONFIG_ARM_32) +# include <asm/arm32/insn.h> +#elif defined(CONFIG_ARM_64) +# include <asm/arm64/insn.h> +#else +# error "unknown ARM variant" +#endif + +#endif /* !__ARCH_ARM_INSN */ +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 8 + * indent-tabs-mode: t + * End: + */ -- 1.9.1 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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