[PATCH v3 4/8] riscv: Add asm/insn.h header

[Emil Renner Berthing <kernel@esmil.dk>]

Add new asm/insn.h header to consolidate RISC-V instruction constants
and inline helper functions.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
---
 arch/riscv/include/asm/insn.h | 151 ++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 arch/riscv/include/asm/insn.h

diff --git a/arch/riscv/include/asm/insn.h b/arch/riscv/include/asm/insn.h
new file mode 100644
index 000000000000..02f387a06ef3
--- /dev/null
+++ b/arch/riscv/include/asm/insn.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 Emil Renner Berthing
+ */
+#ifndef __ASM_RISCV_INSN_H
+#define __ASM_RISCV_INSN_H
+
+#include <linux/const.h>
+
+#define RISCV_INSN_LW		_AC(0x00002003, U)
+#define RISCV_INSN_LD		_AC(0x00003003, U)
+#define RISCV_INSN_ADDI		_AC(0x00000013, U)
+#define RISCV_INSN_NOP		RISCV_INSN_ADDI
+#define RISCV_INSN_SW		_AC(0x00002023, U)
+#define RISCV_INSN_SD		_AC(0x00003023, U)
+#define RISCV_INSN_AUIPC	_AC(0x00000017, U)
+#define RISCV_INSN_LUI		_AC(0x00000037, U)
+#define RISCV_INSN_JALR		_AC(0x00000067, U)
+#define RISCV_INSN_JAL		_AC(0x0000006f, U)
+
+#if __riscv_xlen == 64
+#define RISCV_INSN_REG_L	RISCV_INSN_LD
+#define RISCV_INSN_REG_S	RISCV_INSN_SD
+#define RISCV_INSN_SZREG	8
+#elif __riscv_xlen == 32
+#define RISCV_INSN_REG_L	RISCV_INSN_LW
+#define RISCV_INSN_REG_S	RISCV_INSN_SW
+#define RISCV_INSN_SZREG	4
+#else
+#error "Unexpected __riscv_xlen"
+#endif
+
+#define RISCV_INSN_RA		_AC(0x1, U)
+#define RISCV_INSN_SP		_AC(0x2, U)
+#define RISCV_INSN_T0		_AC(0x5, U)
+#define RISCV_INSN_T1		_AC(0x6, U)
+
+#define RISCV_INSN_RD_POS	7
+#define RISCV_INSN_RD_RA	(RISCV_INSN_RA << RISCV_INSN_RD_POS)
+#define RISCV_INSN_RD_SP	(RISCV_INSN_SP << RISCV_INSN_RD_POS)
+#define RISCV_INSN_RD_T0	(RISCV_INSN_T0 << RISCV_INSN_RD_POS)
+#define RISCV_INSN_RD_T1	(RISCV_INSN_T1 << RISCV_INSN_RD_POS)
+
+#define RISCV_INSN_RS1_POS	15
+#define RISCV_INSN_RS1_RA	(RISCV_INSN_RA << RISCV_INSN_RS1_POS)
+#define RISCV_INSN_RS1_SP	(RISCV_INSN_SP << RISCV_INSN_RS1_POS)
+#define RISCV_INSN_RS1_T0	(RISCV_INSN_T0 << RISCV_INSN_RS1_POS)
+#define RISCV_INSN_RS1_T1	(RISCV_INSN_T1 << RISCV_INSN_RS1_POS)
+
+#define RISCV_INSN_RS2_POS	20
+#define RISCV_INSN_RS2_RA	(RISCV_INSN_RA << RISCV_INSN_RS2_POS)
+#define RISCV_INSN_RS2_SP	(RISCV_INSN_SP << RISCV_INSN_RS2_POS)
+#define RISCV_INSN_RS2_T0	(RISCV_INSN_T0 << RISCV_INSN_RS2_POS)
+#define RISCV_INSN_RS2_T1	(RISCV_INSN_T1 << RISCV_INSN_RS2_POS)
+
+#define RISCV_INSN_I_IMM_MASK	_AC(0xfff00000, U)
+#define RISCV_INSN_S_IMM_MASK	_AC(0xfe000f80, U)
+#define RISCV_INSN_B_IMM_MASK	_AC(0xfe000f80, U)
+#define RISCV_INSN_U_IMM_MASK	_AC(0xfffff000, U)
+#define RISCV_INSN_J_IMM_MASK	_AC(0xfffff000, U)
+
+#define RISCV_INSN_CI_IMM_MASK	_AC(0x107c, U)
+#define RISCV_INSN_CSS_IMM_MASK	_AC(0x1f80, U)
+#define RISCV_INSN_CIW_IMM_MASK	_AC(0x1fe0, U)
+#define RISCV_INSN_CL_IMM_MASK	_AC(0x1c60, U)
+#define RISCV_INSN_CS_IMM_MASK	_AC(0x1c60, U)
+#define RISCV_INSN_CB_IMM_MASK	_AC(0x1c7c, U)
+#define RISCV_INSN_CJ_IMM_MASK	_AC(0x1ffc, U)
+
+#ifndef __ASSEMBLY__
+#include <linux/bits.h>
+#include <asm/types.h>
+
+/*
+ * The J-format jump and link instruction, jal, has a 20bit immediate except
+ * bit 0 is always taken to be 0, so it must be even and is interpreted as a
+ * signed value.
+ */
+static inline bool riscv_insn_valid_20bit_offset(ptrdiff_t val)
+{
+	return !(val & 1) && -(1L << 19) <= val && val < (1L << 19);
+}
+
+/*
+ * The auipc+jalr instruction pair can reach any PC-relative offset
+ * in the range [-2^31 - 2^11, 2^31 - 2^11)
+ */
+static inline bool riscv_insn_valid_32bit_offset(ptrdiff_t val)
+{
+#if __riscv_xlen == 32
+	return true;
+#else
+	return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11));
+#endif
+}
+
+static inline u32 riscv_insn_i_imm(u32 imm)
+{
+	return (imm & GENMASK(11, 0)) << 20;
+}
+
+static inline u32 riscv_insn_s_imm(u32 imm)
+{
+	return (imm & GENMASK( 4, 0)) << ( 7 - 0) |
+	       (imm & GENMASK(11, 5)) << (25 - 5);
+}
+
+static inline u32 riscv_insn_b_imm(u32 imm)
+{
+	return (imm & GENMASK(11, 11)) >> (11 -  7) |
+	       (imm & GENMASK( 4,  1)) << ( 8 -  1) |
+	       (imm & GENMASK(10,  5)) << (25 -  5) |
+	       (imm & GENMASK(12, 12)) << (31 - 12);
+}
+
+static inline u32 riscv_insn_u_imm(u32 imm)
+{
+	return imm & GENMASK(31, 12);
+}
+
+static inline u32 riscv_insn_j_imm(u32 imm)
+{
+	return (imm & GENMASK(19, 12)) << (12 - 12) |
+	       (imm & GENMASK(11, 11)) << (20 - 11) |
+	       (imm & GENMASK(10,  1)) << (21 -  1) |
+	       (imm & GENMASK(20, 20)) << (31 - 20);
+}
+
+static inline u16 riscv_insn_rvc_branch_imm(u16 imm)
+{
+	return (imm & GENMASK(5, 5)) >> ( 5 - 2) |
+	       (imm & GENMASK(2, 1)) << ( 3 - 1) |
+	       (imm & GENMASK(7, 6)) >> ( 6 - 5) |
+	       (imm & GENMASK(4, 3)) << (10 - 3) |
+	       (imm & GENMASK(8, 8)) << (12 - 8);
+}
+
+static inline u16 riscv_insn_rvc_jump_imm(u16 imm)
+{
+	return (imm & GENMASK( 5,  5)) >> ( 5 -  2) |
+	       (imm & GENMASK( 3,  1)) << ( 3 -  1) |
+	       (imm & GENMASK( 7,  7)) >> ( 7 -  6) |
+	       (imm & GENMASK( 6,  6)) << ( 7 -  6) |
+	       (imm & GENMASK(10, 10)) >> (10 -  8) |
+	       (imm & GENMASK( 9,  8)) << ( 9 -  8) |
+	       (imm & GENMASK( 4,  4)) << (11 -  4) |
+	       (imm & GENMASK(11, 11)) << (12 - 11);
+}
+
+#endif
+#endif
-- 
2.35.1