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-rw-r--r--arch/riscv/kernel/traps_misaligned.c370
1 files changed, 370 insertions, 0 deletions
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
new file mode 100644
index 000000000000..46c4dafe3ba0
--- /dev/null
+++ b/arch/riscv/kernel/traps_misaligned.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/irq.h>
+
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/csr.h>
+
+#define INSN_MATCH_LB 0x3
+#define INSN_MASK_LB 0x707f
+#define INSN_MATCH_LH 0x1003
+#define INSN_MASK_LH 0x707f
+#define INSN_MATCH_LW 0x2003
+#define INSN_MASK_LW 0x707f
+#define INSN_MATCH_LD 0x3003
+#define INSN_MASK_LD 0x707f
+#define INSN_MATCH_LBU 0x4003
+#define INSN_MASK_LBU 0x707f
+#define INSN_MATCH_LHU 0x5003
+#define INSN_MASK_LHU 0x707f
+#define INSN_MATCH_LWU 0x6003
+#define INSN_MASK_LWU 0x707f
+#define INSN_MATCH_SB 0x23
+#define INSN_MASK_SB 0x707f
+#define INSN_MATCH_SH 0x1023
+#define INSN_MASK_SH 0x707f
+#define INSN_MATCH_SW 0x2023
+#define INSN_MASK_SW 0x707f
+#define INSN_MATCH_SD 0x3023
+#define INSN_MASK_SD 0x707f
+
+#define INSN_MATCH_FLW 0x2007
+#define INSN_MASK_FLW 0x707f
+#define INSN_MATCH_FLD 0x3007
+#define INSN_MASK_FLD 0x707f
+#define INSN_MATCH_FLQ 0x4007
+#define INSN_MASK_FLQ 0x707f
+#define INSN_MATCH_FSW 0x2027
+#define INSN_MASK_FSW 0x707f
+#define INSN_MATCH_FSD 0x3027
+#define INSN_MASK_FSD 0x707f
+#define INSN_MATCH_FSQ 0x4027
+#define INSN_MASK_FSQ 0x707f
+
+#define INSN_MATCH_C_LD 0x6000
+#define INSN_MASK_C_LD 0xe003
+#define INSN_MATCH_C_SD 0xe000
+#define INSN_MASK_C_SD 0xe003
+#define INSN_MATCH_C_LW 0x4000
+#define INSN_MASK_C_LW 0xe003
+#define INSN_MATCH_C_SW 0xc000
+#define INSN_MASK_C_SW 0xe003
+#define INSN_MATCH_C_LDSP 0x6002
+#define INSN_MASK_C_LDSP 0xe003
+#define INSN_MATCH_C_SDSP 0xe002
+#define INSN_MASK_C_SDSP 0xe003
+#define INSN_MATCH_C_LWSP 0x4002
+#define INSN_MASK_C_LWSP 0xe003
+#define INSN_MATCH_C_SWSP 0xc002
+#define INSN_MASK_C_SWSP 0xe003
+
+#define INSN_MATCH_C_FLD 0x2000
+#define INSN_MASK_C_FLD 0xe003
+#define INSN_MATCH_C_FLW 0x6000
+#define INSN_MASK_C_FLW 0xe003
+#define INSN_MATCH_C_FSD 0xa000
+#define INSN_MASK_C_FSD 0xe003
+#define INSN_MATCH_C_FSW 0xe000
+#define INSN_MASK_C_FSW 0xe003
+#define INSN_MATCH_C_FLDSP 0x2002
+#define INSN_MASK_C_FLDSP 0xe003
+#define INSN_MATCH_C_FSDSP 0xa002
+#define INSN_MASK_C_FSDSP 0xe003
+#define INSN_MATCH_C_FLWSP 0x6002
+#define INSN_MASK_C_FLWSP 0xe003
+#define INSN_MATCH_C_FSWSP 0xe002
+#define INSN_MASK_C_FSWSP 0xe003
+
+#define INSN_LEN(insn) ((((insn) & 0x3) < 0x3) ? 2 : 4)
+
+#if defined(CONFIG_64BIT)
+#define LOG_REGBYTES 3
+#define XLEN 64
+#else
+#define LOG_REGBYTES 2
+#define XLEN 32
+#endif
+#define REGBYTES (1 << LOG_REGBYTES)
+#define XLEN_MINUS_16 ((XLEN) - 16)
+
+#define SH_RD 7
+#define SH_RS1 15
+#define SH_RS2 20
+#define SH_RS2C 2
+
+#define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1))
+#define RVC_LW_IMM(x) ((RV_X(x, 6, 1) << 2) | \
+ (RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 5, 1) << 6))
+#define RVC_LD_IMM(x) ((RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 5, 2) << 6))
+#define RVC_LWSP_IMM(x) ((RV_X(x, 4, 3) << 2) | \
+ (RV_X(x, 12, 1) << 5) | \
+ (RV_X(x, 2, 2) << 6))
+#define RVC_LDSP_IMM(x) ((RV_X(x, 5, 2) << 3) | \
+ (RV_X(x, 12, 1) << 5) | \
+ (RV_X(x, 2, 3) << 6))
+#define RVC_SWSP_IMM(x) ((RV_X(x, 9, 4) << 2) | \
+ (RV_X(x, 7, 2) << 6))
+#define RVC_SDSP_IMM(x) ((RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 7, 3) << 6))
+#define RVC_RS1S(insn) (8 + RV_X(insn, SH_RD, 3))
+#define RVC_RS2S(insn) (8 + RV_X(insn, SH_RS2C, 3))
+#define RVC_RS2(insn) RV_X(insn, SH_RS2C, 5)
+
+#define SHIFT_RIGHT(x, y) \
+ ((y) < 0 ? ((x) << -(y)) : ((x) >> (y)))
+
+#define REG_MASK \
+ ((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES))
+
+#define REG_OFFSET(insn, pos) \
+ (SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK)
+
+#define REG_PTR(insn, pos, regs) \
+ (ulong *)((ulong)(regs) + REG_OFFSET(insn, pos))
+
+#define GET_RM(insn) (((insn) >> 12) & 7)
+
+#define GET_RS1(insn, regs) (*REG_PTR(insn, SH_RS1, regs))
+#define GET_RS2(insn, regs) (*REG_PTR(insn, SH_RS2, regs))
+#define GET_RS1S(insn, regs) (*REG_PTR(RVC_RS1S(insn), 0, regs))
+#define GET_RS2S(insn, regs) (*REG_PTR(RVC_RS2S(insn), 0, regs))
+#define GET_RS2C(insn, regs) (*REG_PTR(insn, SH_RS2C, regs))
+#define GET_SP(regs) (*REG_PTR(2, 0, regs))
+#define SET_RD(insn, regs, val) (*REG_PTR(insn, SH_RD, regs) = (val))
+#define IMM_I(insn) ((s32)(insn) >> 20)
+#define IMM_S(insn) (((s32)(insn) >> 25 << 5) | \
+ (s32)(((insn) >> 7) & 0x1f))
+#define MASK_FUNCT3 0x7000
+
+#define GET_PRECISION(insn) (((insn) >> 25) & 3)
+#define GET_RM(insn) (((insn) >> 12) & 7)
+#define PRECISION_S 0
+#define PRECISION_D 1
+
+#define STR(x) XSTR(x)
+#define XSTR(x) #x
+
+#define DECLARE_UNPRIVILEGED_LOAD_FUNCTION(type, insn) \
+static inline type load_##type(const type *addr) \
+{ \
+ type val; \
+ asm (#insn " %0, %1" \
+ : "=&r" (val) : "m" (*addr)); \
+ return val; \
+}
+
+#define DECLARE_UNPRIVILEGED_STORE_FUNCTION(type, insn) \
+static inline void store_##type(type *addr, type val) \
+{ \
+ asm volatile (#insn " %0, %1\n" \
+ : : "r" (val), "m" (*addr)); \
+}
+
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u8, lbu)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u16, lhu)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(s8, lb)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(s16, lh)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(s32, lw)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(u8, sb)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(u16, sh)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(u32, sw)
+#if defined(CONFIG_64BIT)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u32, lwu)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u64, ld)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(u64, sd)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(ulong, ld)
+#else
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u32, lw)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(ulong, lw)
+
+static inline u64 load_u64(const u64 *addr)
+{
+ return load_u32((u32 *)addr)
+ + ((u64)load_u32((u32 *)addr + 1) << 32);
+}
+
+static inline void store_u64(u64 *addr, u64 val)
+{
+ store_u32((u32 *)addr, val);
+ store_u32((u32 *)addr + 1, val >> 32);
+}
+#endif
+
+static inline ulong get_insn(ulong mepc)
+{
+ register ulong __mepc asm ("a2") = mepc;
+ ulong val, rvc_mask = 3, tmp;
+
+ asm ("and %[tmp], %[addr], 2\n"
+ "bnez %[tmp], 1f\n"
+#if defined(CONFIG_64BIT)
+ STR(LWU) " %[insn], (%[addr])\n"
+#else
+ STR(LW) " %[insn], (%[addr])\n"
+#endif
+ "and %[tmp], %[insn], %[rvc_mask]\n"
+ "beq %[tmp], %[rvc_mask], 2f\n"
+ "sll %[insn], %[insn], %[xlen_minus_16]\n"
+ "srl %[insn], %[insn], %[xlen_minus_16]\n"
+ "j 2f\n"
+ "1:\n"
+ "lhu %[insn], (%[addr])\n"
+ "and %[tmp], %[insn], %[rvc_mask]\n"
+ "bne %[tmp], %[rvc_mask], 2f\n"
+ "lhu %[tmp], 2(%[addr])\n"
+ "sll %[tmp], %[tmp], 16\n"
+ "add %[insn], %[insn], %[tmp]\n"
+ "2:"
+ : [insn] "=&r" (val), [tmp] "=&r" (tmp)
+ : [addr] "r" (__mepc), [rvc_mask] "r" (rvc_mask),
+ [xlen_minus_16] "i" (XLEN_MINUS_16));
+
+ return val;
+}
+
+union reg_data {
+ u8 data_bytes[8];
+ ulong data_ulong;
+ u64 data_u64;
+};
+
+int handle_misaligned_load(struct pt_regs *regs)
+{
+ union reg_data val;
+ unsigned long epc = regs->epc;
+ unsigned long insn = get_insn(epc);
+ unsigned long addr = csr_read(mtval);
+ int i, fp = 0, shift = 0, len = 0;
+
+ regs->epc = 0;
+
+ if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
+ len = 4;
+ shift = 8 * (sizeof(unsigned long) - len);
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) {
+ len = 8;
+ shift = 8 * (sizeof(unsigned long) - len);
+ } else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) {
+ len = 4;
+#endif
+ } else if ((insn & INSN_MASK_FLD) == INSN_MATCH_FLD) {
+ fp = 1;
+ len = 8;
+ } else if ((insn & INSN_MASK_FLW) == INSN_MATCH_FLW) {
+ fp = 1;
+ len = 4;
+ } else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) {
+ len = 2;
+ shift = 8 * (sizeof(unsigned long) - len);
+ } else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) {
+ len = 2;
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) {
+ len = 8;
+ shift = 8 * (sizeof(unsigned long) - len);
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 8;
+ shift = 8 * (sizeof(unsigned long) - len);
+#endif
+ } else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) {
+ len = 4;
+ shift = 8 * (sizeof(unsigned long) - len);
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 4;
+ shift = 8 * (sizeof(unsigned long) - len);
+ } else if ((insn & INSN_MASK_C_FLD) == INSN_MATCH_C_FLD) {
+ fp = 1;
+ len = 8;
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_FLDSP) == INSN_MATCH_C_FLDSP) {
+ fp = 1;
+ len = 8;
+#if defined(CONFIG_32BIT)
+ } else if ((insn & INSN_MASK_C_FLW) == INSN_MATCH_C_FLW) {
+ fp = 1;
+ len = 4;
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_FLWSP) == INSN_MATCH_C_FLWSP) {
+ fp = 1;
+ len = 4;
+#endif
+ } else {
+ regs->epc = epc;
+ return -1;
+ }
+
+ val.data_u64 = 0;
+ for (i = 0; i < len; i++)
+ val.data_bytes[i] = load_u8((void *)(addr + i));
+
+ if (fp)
+ return -1;
+ SET_RD(insn, regs, val.data_ulong << shift >> shift);
+
+ regs->epc = epc + INSN_LEN(insn);
+
+ return 0;
+}
+
+int handle_misaligned_store(struct pt_regs *regs)
+{
+ union reg_data val;
+ unsigned long epc = regs->epc;
+ unsigned long insn = get_insn(epc);
+ unsigned long addr = csr_read(mtval);
+ int i, len = 0;
+
+ regs->epc = 0;
+
+ val.data_ulong = GET_RS2(insn, regs);
+
+ if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) {
+ len = 4;
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) {
+ len = 8;
+#endif
+ } else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) {
+ len = 2;
+#if defined(CONFIG_64BIT)
+ } else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) {
+ len = 8;
+ val.data_ulong = GET_RS2S(insn, regs);
+ } else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 8;
+ val.data_ulong = GET_RS2C(insn, regs);
+#endif
+ } else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) {
+ len = 4;
+ val.data_ulong = GET_RS2S(insn, regs);
+ } else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 4;
+ val.data_ulong = GET_RS2C(insn, regs);
+ } else {
+ regs->epc = epc;
+ return -1;
+ }
+
+ for (i = 0; i < len; i++)
+ store_u8((void *)(addr + i), val.data_bytes[i]);
+
+ regs->epc = epc + INSN_LEN(insn);
+
+ return 0;
+}
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